Graft-versus-host reactions and the effectiveness of donor lymphocyte infusions.

We retrospectively analyzed 83 consecutive recipients of donor lymphocyte infusions (DLI) after allogeneic transplantation for factors associated with disease response and graft-versus-host disease (GVHD). DLI was highly effective in relapsed chronic phase chronic myeloid leukemia (CML), with 71% of patients achieving durable complete remissions (CR). In relapsed acute myeloid leukemia, DLI led to durable CRs in 31% of patients; the rate was <20% in all other diseases. Achieving full donor chimerism and GVHD were predictive of CR. Grade II or higher acute or chronic GVHD occurred in 36 (43%) patients and contributed to death in 13 (16%). Even more patients, 33 (40%), died of their underlying malignancy, including 10 who developed active GVHD. In relapsed CML, most durable CRs occurred without clinically apparent GVHD, yet all responders achieved full donor chimerism, including 6 with coincident normal host hematopoiesis at the time of DLI. Thus, in CML, potent lymphohematopoietic graft-versus-host reactions occurred even in the absence of clinically apparent GVHD; this confirms the ability to dissociate these processes and argues against a leukemia-specific immunologic effect. DLI clearly has efficacy in the treatment of relapsed disease after allogeneic transplantation. However, with the exception of CML, most patients die of their underlying disease because of insufficient antitumor activity even with active GVHD.     

Long-term follow-up of patients who achieved complete remission after donor leukocyte infusions.

Donor leukocyte infusions (DLI) can induce a direct graft-vs-leukemia (GVL) reaction and restore complete remission for patients who relapse after allogeneic bone marrow transplantation (BMT). A critical and unanswered concern is the long-term safety and durability of DLI. To determine remission duration, long-term toxicity, and survival after DLI-induced remissions, we identified 73 patients who achieved complete remission after DLI. Follow-up information was obtained for 66 of the 73 patients, including 39 patients with chronic myelogenous leukemia (CML) and 27 patients with other diseases. Median follow-up for all patients was 32 months; the probability of survival at 1, 2, and 3 years was 83% (95% confidence interval [CI] 74-92), 71% (60-83), and 61% (49-74), respectively. For CML, survival probability at 1, 2, and 3 years was 87% (76-98), 76% (62-90), and 73% (58-88). For other diseases, survival probability at 1 and 2 years is 77% (61-93) and 65% (46-84). Five of 39 patients with CML relapsed, and 11 of 27 patients with other diseases relapsed. Treatment-related toxicity accounted for 10 deaths. Extended follow-up shows that DLI-induced remissions are durable, especially for patients with CML. Late relapses still occur, however, and toxicity remains significant. Continued follow-up will best define the long-term GVL effects of DLI, especially for diseases other than CML.     

The role of disease stage in the response to donor lymphocyte infusions as treatment for leukemic relapse.

Between 1991 and 1999, 44 leukemic patients received donor lymphocyte infusions (DLIs) at our center (22 patients with chronic myelogenous leukemia [CML]; 10 with acute myelogenous leukemia; 11 with acute lymphatic leukemia; and 1 with myelodysplastic syndrome). Seventeen patients received graft-versus-host disease (GVHD) prophylaxis with methotrexate (MTX) at the time of DLI. In CML patients, 15 of 22 (68%) re-entered complete remission after DLI. At 3 years post-DLI, patients with cytogenetic (n = 10) or molecular (n = 3) relapse had a current leukemia-free survival (cLFS) rate of 85% compared with 0% for patients with hematologic relapse (P < .001). Among 15 CML patients who initially responded to DLI, 4 patients relapsed within the first 2 years. Four of 16 patients (25%) with acute leukemia had an initial response with complete remission after DLI. Two of them subsequently relapsed within 1 year. Patients with acute leukemia who relapsed within 1 year of hematopoietic stem cell transplantation (n = 9) had 0% cLFS at 18 months; patients with later relapse had 29% cLFS (P = .015). The overall probability of cLFS at 3 years for CML patients was 46%. For other diseases, cLFS was 13% at 18 months after DLI. Patients who developed chronic GVHD secondary to DLI showed a 3-year cLFS of 51% compared with 18% for patients without chronic GVHD (P = .022). This study emphasizes the importance of early disease stage and presence of chronic GVHD for effective DLI.     

Randomized trial of CD8+ T-cell depletion in the prevention of graft-versus-host disease associated with donor lymphocyte infusion.

The application of DLI is limited by the potential development of GVHD. Results of single-arm trials suggest that CD8+ depletion of DLI may reduce the incidence of GVHD while still inducing pathologic and cytogenetic remissions. To test the impact of CD8 depletion on GVHD, we initiated a randomized trial comparing outcome among patients receiving unselected donor lymphocytes or CD8+-depleted cells. DLI was administered to patients with disease in remission to prevent relapse 6 months after T-cell-depleted allogeneic BMT. CD8 depletion was performed with monoclonal antibody and rabbit complement. Donor lymphocytes obtained from the original donor were infused fresh without cryopreservation. Infusions were adjusted so that all patients received 1.0 x 10(7) CD4+ cells/kg. Patients randomized to CD8 depletion received a median of 0.7 x 10(5) versus 32.0 x 10(5) CD8+ cells/kg in the unmanipulated cohort. Six (67%) of 9 patients receiving unselected DLI developed acute GVHD compared with 0 (0%) of 9 recipients of CD8-depleted DLI (P = .009). In the unselected group, 2 patients died while the disease was in remission, and 3 patients had relapses. In the CD8-depleted cohort, there were no toxic deaths and only 1 relapse. Measures of immunologic reconstitution by T-cell receptor excision circle analysis and T-cell receptor spectratyping demonstrated similar patterns of T-cell recovery in both the CD8-depleted and the unselected cohorts. Both groups converted from mixed to full donor hematopoietic chimerism after DLI. Our results indicate that CD8 depletion reduces the incidence of GVHD associated with DLI without adversely affecting conversion to donor hematopoiesis or immunologic recovery.     

Graft-versus-leukemia and graft-versus-host reactions after donor lymphocyte infusion are initiated by host-type antigen-presenting cells and regulated by regulatory T cells in early and long-term chimeras.

Regulatory T (T(reg)) cells and host antigen-presenting cells (APCs) have been implicated in graft-versus-host disease (GVHD) and the graft-versus-leukemia (GVL) effect after donor lymphocyte infusion (DLI), but their relative contributions remain unclear in early versus long-term complete donor or mixed murine allogeneic hematopoietic stem cell (HSC) chimeras. We have previously demonstrated that donor HSC-derived Thy1(+) T(reg) cells, consisting primarily of CD4(+)CD25(+) cells, play an important role in the suppression of graft-versus-host (GVH) reactivity when DLI is given to complete donor chimeras 28 days after HSC transplantation. Data presented here demonstrate that protection against GVHD exerted by Thy1(+) T(reg) cells is less evident with time and eventually is not required in long-term complete donor chimeras because of an absence of host-type APCs to activate alloreactive T cells. Lethal GVHD was observed when Thy1(+) T(reg) cells were depleted from complete donor chimeras given by DLI at day 28, 35, or 42; however, T(reg) cell depletion and DLI at day 70 no longer induced GVHD-associated mortality. Moreover, the failure of DLI to induce GVHD with T(reg) depletion correlated with a loss of the DLI-induced GVL effect in long-term (day 100) complete donor chimeras. In contrast to the results from complete donor chimeras, GVL reactivity in day 100 mixed chimeras was robust after DLI. Loss of a DLI-induced GVL effect in long-term complete donor chimeras was attributed to the absence of host APCs because the infusion of exogenous host-type dendritic cells partially restored both DLI-induced GVL and GVH reactions in day 100 complete donor chimeras. The GVL and GVH reactions restored by infusion of host dendritic cells in day 100 complete donor chimeras were at least partially regulated by T(reg) cells because transient depletion of CD25(+) cells increased both the GVL effect and the severity of GVHD after DLI. Taken together, these data suggest that T(reg) cells can regulate DLI-induced GVL and GVH reactions in both early and long-term complete donor chimeras, and a state of mixed chimerism is superior to complete donor chimerism because host-type APCs facilitate a DLI-induced GVL effect without severe GVHD.     

Pilot Study of Prophylactic Ex Vivo Costimulated Donor Leukocyte Infusion After Reduced-Intensity Conditioned Allogeneic Stem Cell Transplantation

Donor leukocyte infusion (DLI) can induce potent graft-versus-leukemia (GVL) activity in patients with relapsed hematologic malignancies after allogeneic hematopoietic stem cell transplantation (HSCT). Unfortunately, except in patients with chronic-phase chronic myelogenous leukemia, responses to DLI have been disappointing. GVL induction is likely to be most effective in the setting of minimal residual disease. Prevention of relapse through the provision of prophylactic DLI to high-risk patients may improve the outcome of allogeneic HSCT. We previously reported that ex vivo costimulated T cell infusion of activated DLI (aDLI) as treatment for relapse is safe and has potent GVL effects. We hypothesized that prophylactic aDLI can be given safely and prevent relapse in high-risk patients after allogeneic HSCT. Eighteen patients with acute myeolgenous leukemia (n = 14), acute lymphoblastic leukemia (n = 3), or myelodysplastic syndrome (n = 1) underwent allogeneic HSCT after a reduced-intensity conditioning (RIC) regimen with alemtuzumab, fludarabine, and busulfan. Graft-versus-host-disease (GVHD) prophylaxis consisted of tacrolimus and methotrexate with a planned early and rapid taper of tacrolimus. Patients without GVHD, off immune suppression, and in remission received aDLI at a dose of 1 × 10⁷ CD3⁺ cells/kg (aDLI 1) at day +120, followed by a second infusion of 1 × 10⁸ CD3 cells/kg (aDLI 2) at day +180. At a median follow-up of 58 months, 5 of the 18 patients (28%) were alive, and 4 patients were in remission. Eleven patients (65%) relapsed, at a median time of 191 days. Twelve of the 18 patients received at least one aDLI, and 6 of these 12 patients also received aDLI 2. Six patients did not receive any aDLI owing to early relapse (n = 2), protocol ineligibility (n = 1), or GVHD (n = 3). Only 2 of the 12 patients who received aDLI 1 developed GVHD. Two out of the 12 patients remain in remission at the time of this report. Disease recurrence was the cause of death in 10 of the 13 patients (77%) who died. Our data indicate that prophylactic ex vivo costimulated CD3/CD28 DLI is safe, feasible, and not associated with significant GVHD. Relapse remains the major cause of treatment failure after RIC HSCT even with rapid withdrawal of immune suppression and the use of prophylactic aDLI, and better strategies to prevent relapse are needed.     

Conversion to full donor chimerism following donor lymphocyte infusion is associated with disease response in patients with multiple myeloma.

Donor lymphocyte infusions (DLIs) have been demonstrated to induce clinical responses in patients with relapsed multiple myeloma after allogeneic bone marrow transplantation, but the immunologic mechanisms involved have not been well characterized. In patients with chronic myelocytic leukemia (CML), remissions following DLI are invariably associated with conversion to complete donor hematopoiesis, suggesting that the target antigens of this response are expressed on both normal and CML-derived hematopoietic stem cells. In the present study, we examined hematopoietic chimerism and the complexity of the T-cell receptor (TCR) repertoire in 4 patients with relapsed multiple myeloma who received infusions of donor CD4+ lymphocytes. Three of 4 patients had a clinical response that began 1 to 2 months after DLI. All 3 responding patients developed lymphocytosis at the initiation of response that was due to a 2- to 4.5-fold increase in the number of CD3+ T cells. In 1 patient, this was due primarily to increases in CD3+ and CD8+ cells; in 2 patients, to increased numbers of CD3+ and CD8+ and CD3+ and CD4+ T cells. In all responding patients, conversion to complete donor hematopoiesis occurred in the first 2 months after DLI. The single nonresponding patient remained it 100% recipient hematopoiesis. The TCR repertoire complexity was examined by polymerase chain reaction amplification of complementary-determining region 3 (CDR3) derived from 24 Vbeta gene subfamilies. In 2 patients, the initiation of myeloma response and conversion to complete donor hematopoiesis was associated with normalization of TCR complexity. Complete donor chimerism and normal TCR complexity remained stable in all patients and did not change with subsequent relapse or development of graft-versus-host disease (GVHD). Thus, conversion to full donor chimerism was temporally associated with the antimyeloma effect of DLI but not with the development of GVHD. Nevertheless, the maintenance of stable donor hematopoiesis did not prevent disease relapse and was not associated with prolonged remission. The selective relapse of myeloma cells without concomitant return of mixed hematopoietic chimerism suggests that myeloma tumor cells in some patients develop resistance to immune destruction.     

Graft-vs.-host and graft-vs.-leukemia reactions after delayed infusions of donor T-subsets.

Infusions of donor leukocytes have been given to allogeneic bone marrow recipients after transplant to treat leukemia relapse. Treatment with these delayed infusions of donor cells has been called delayed or donor leukocyte infusion (DLI). While graft-vs.-host disease (GVHD) has typically been less severe than expected after DLI, it still remains a significant risk factor. Recently, we used a full major histocompatibility complex (MHC)-mismatched model (C57BL/6 into AKR) to determine how increased immunogenetic disparity affects GVH and graft-vs.-leukemia (GVL) reactions after DLI. In contrast to an MHC-matched model (B10.BR into AKR), GVHD was still observed when MHC-mismatched donor T cells were infused 3 weeks posttransplant. Limiting dilution analysis was used to determine the frequency of alloreactive cytotoxic T lymphocytes (CTL) and interleukin (IL)-2-secreting T helper cells in the spleens of MHC-mismatched recipients 7 days after DLI treatment. GVHD correlated with elevated frequencies of alloreactive T-helper cells. One strategy for reducing the severity of GVHD after DLI is the selective administration of CD4 or CD8 T-subsets. Delayed infusion of purified T-subsets 3 weeks posttransplant resulted in significantly less GVHD than infusion of a mixture of the two subsets. No GVH-associated mortality was observed after DLI with purified donor CD4+ T cells. In GVL studies, MHC-mismatched CD8+ T cells were the most potent antitumor effectors against an acute T cell leukemia. The GVL effect of MHC-mismatched T-subsets was compared with that of MHC-matched subsets. When naive MHC-matched cells were given as DLI, depletion of either T-subset eliminated the GVL effect. CD8+ T cells from MHC-matched donors primed against host alloantigens, however, mediated a CD4 (T-helper)-independent GVL reaction. Together, these results suggest that administration of T-subsets can significantly reduce GVHD after DLI without loss of the beneficial GVL effect.     

Can Only Partial T-Cell Depletion of the Graft before Hematopoietic Stem Cell Transplantation Mitigate Graft-versus-Host Disease While Preserving a Graft-versus-Leukemia Reaction? A Prospective Phase II Study

The study comprised 37 consecutive patients who underwent transplantation with a Campath-1H in vitro T cell-depleted granulocyte colony-stimulating factor-mobilized peripheral blood stem cell graft from an HLA-identical sibling, followed 24 hours later by an unmanipulated graft. Acute graft-versus-host disease (GVHD) was limited to grade I to II, whereas chronic graft-versus-host disease occurred in 9 patients, mostly (n = 7) with limited disease. Molecular relapses (8 chronic myeloid leukemia [CML] and 1 non-Hodgkin lymphoma) that occurred not earlier than the sixth month after transplantation were treated with donor lymphocyte infusion (DLI), which induced complete remission in all but 1 CML patient with persistent very low BCR-ABL molecular levels. With a median follow-up of 54 months (range, 29-84 months), the actuarial 5-year overall survival, disease-free survival, and transplant-related mortality are 78% (95% confidence interval [CI], 52%-88%), 78% (95% CI, 52%-86%), and 6% (95% CI, 1.5%-32%), respectively. All CML patients are alive and free of disease. The results of this prospective, nonrandomized study show that incomplete T-cell depletion in vitro with Campath-1H (in combination with DLI for molecular relapses in CML) may decrease the incidence of GVHD and transplant-related mortality with no adverse effect on disease-free survival. The described method decreases the number of T cells to an extent that severe GVHD is prevented while relapse is postponed to a time when the patient can be treated with DLI without severe side effects.     

Leucyl-leucine methyl ester-treated haploidentical donor lymphocyte infusions can mediate graft-versus-leukemia activity with minimal graft-versus-host disease risk.

L-leucyl-L-leucine methyl ester (LLME) prevents GVHD in several animal models by depleting dipeptidyl peptidase I (DPPI)-expressing cytotoxic cellular subsets. However, clinical application has been hampered by difficulties in stem cell engraftment following treatment of donor bone marrow inocula with LLME at the concentrations necessary to purge DPPI-expressing T-cells. Noting that T-cells can mediate graft-versus-leukemia (GVL) responses via both perforin (usually co-expressed in cytotoxic granules with DPPI) and Fas ligand pathways in a murine model, we hypothesized that LLME might be useful for treatment of delayed DLIs for potential GVL activity with a decreased risk of GVHD induction. In regard to the clinical setting, the ex vivo use of LLME for this purpose would circumvent any toxicity issues for donor stem cells, because by that time patients would have already achieved successful engraftment. For our preclinical studies, we used the haploidentical C57BL/6 (B6) (H2b) --> ((B6 x DBA/2)F1 (H(2b/d)) murine model with lethally irradiated hosts that had received transplants of T-cell-depleted bone marrow cells and were challenged with the MMD2-8 myeloid leukemia line (H2d) of DBA/2 origin. A DLI of LLME-treated donor splenocytes, from B6 mice presensitized to recipient alloantigens, was administered in varying doses 14 days post-marrow transplantation, and the potential for both GVHD and GVL activity was assessed. All mice that received any dose of LLME-treated DLI survived indefinitely, without evidence of cachexia nor B-cell hypoplasia, in contrast to the severe and lethal GVHD induced by mock-treated DLI. Histological analysis largely correlated with the symptomatic findings and revealed no GVHD-like lesions in the spleens of LLME-treated DLI recipients, although some mice displayed various degrees of hepatic mononuclear infiltration. Most notably, mice given LLME-treated DLI also experienced DLI dose-dependent increases in survival against the challenge with the MMD2-8 leukemia. LLME-treated splenocytes remained immunocompetent, as these cells could proliferate in response to mitogens and to restimulation with ovalbumin when used as a recall antigen. In conclusion, LLME-treated DLI possesses immune potential and, in particular, GVL activity without inducing clinically evident GVHD.     

Alpha-interferon with very-low-dose donor lymphocyte infusion for hematologic or cytogenetic relapse of chronic myeloid leukemia induces rapid and durable complete remissions and is associated with acceptable graft-versus-host disease.

Donor lymphocyte infusion (DLI) results in complete cytogenetic remission (CCR) of relapsed chronic-phase chronic myeloid leukemia (CML-CP) after allogeneic stem cell transplantation (SCT) in up to 80% of patients. The main complication of DLI is graft-versus-host disease (GVHD). Decreasing the dose of DLI is associated with less GVHD but also with a longer interval between treatment and CCR. We postulated that combining alpha-interferon (alpha-IFN) with DLI would enable us to decrease the dose of DLI, thereby limiting GVHD, and at the same time to decrease the interval between DLI and CCR for patients with either a hematologic or cytogenetic relapse. For molecular relapses, we hypothesized that because of a lower tumor load, very low doses of DLI without alpha-IFN could be an effective treatment. Two groups of CML-CP patients treated with DLI at a very low dose of 0.5 to 1.0 x 10(7) mononuclear cells per kilogram, containing 2 to 6 x 10(6) CD3+ T cells per kilogram, were analyzed: 13 patients with a cytogenetic or a hematologic relapse after allogeneic SCT (group A) were treated with additional alpha-IFN therapy at a dose of 3 x 10(6) U 5 d/wk, and 8 patients with a molecular relapse were treated without alpha-IFN (group B). Twelve patients from group A reached a CCR. The median interval between DLI and CCR was 7 weeks (range, 5-18 weeks) for group A. All patients with a CCR reached complete donor chimerism at a median of 10 weeks after DLI (range, 6-121 weeks). Eleven patients reached molecular remission at a median of 15 weeks after DLI (range, 8-34 weeks). In group B, all patients reached a molecular remission at a median of 14 weeks (range, 12-29 weeks). Five patients from group A developed acute GVHD grade II to IV and extensive chronic GVHD. In group B, 1 patient developed acute GVHD grade II to IV and subsequently developed extensive chronic GVHD. With a median follow-up of 62 months, 10 patients in group A are alive and in continuous CCR. One patient had a molecular relapse, for which she successfully received additional DLI; another patient reached molecular remission only after 5 doses of DLI. Two patients from group A died of a gram-negative sepsis, and 1 died of an acute myocardial infection. In group B, all patients are alive and in molecular remission with a median follow-up of 20 months. One patient's disease progressed but was successfully treated with DLI plus alpha-IFN. In conclusion, very-low-dose DLI in combination with alpha-IFN as treatment for cytogenetic or hematologic relapses of CML-CP after allogeneic SCT reduced the interval to obtain a CCR with acceptable GVHD when compared with the literature. Patients with a CCR also reached complete donor chimerism and complete molecular remissions. For patients with a molecular relapse, very-low-dose DLI alone is sufficient to induce molecular remissions in most patients and is associated with limited GVHD.     

High Alloreactivity of Low-Dose Prophylactic Donor Lymphocyte Infusion in Patients with Acute Leukemia Undergoing Allogeneic Hematopoietic Cell Transplantation with an Alemtuzumab-Containing Conditioning Regimen

The value of prophylactic donor lymphocyte infusion (pDLI) is unclear and differs among diseases and transplantation protocols. Experience with this approach in patients with acute leukemia undergoing hematopoietic cell transplantation (HCT) with an alemtuzumab-incorporating conditioning protocol is lacking. We conducted a single-center prospective study to investigate the applicability and efficacy of prophylactic donor lymphocyte infusion (pDLI) in patients with leukemia undergoing HCT with a low-dose alemtuzumab-containing conditioning regimen. Inclusion criteria were high-risk acute myelogenous leukemia, acute lymphoblastic leukemia, or increasing mixed chimerism. All patients included were tapered off of immunotherapy. Exclusion criteria were a history of ≥grade II or active graft-versus-host disease (GVHD). Of the 56 consecutive patients who underwent HCT with an alemtuzumab-containing regimen, 15 patients (8 with acute myelogenous leukemia and 7 with acute lymphoblastic leukemia) met the study inclusion criteria and received prophylactic DLI (total of 45 infusions) from 7 sibling donors and 8 unrelated donors. The first infusion was given at a median of 162 days posttransplantation. The median number of DLIs was 3, and the median cumulative CD3⁺ cell dose was 2 × 10⁶cells/kg. Six of the 8 patients (75%) who received pDLI while in mixed chimerism converted to stable, complete donor chimerism. Some 47% of DLI recipients developed GVHD (4 acute GVHD and 3 with chronic GVHD) after a median cumulative dose of 2 × 10⁶ CD3⁺ cells/kg. After a median follow-up of 575 days, 11 (73%) pDLI recipients were alive. All 4 deaths were due to GVHD-related causes. None of the patients who received pDLIs relapsed. Patients with leukemia who received low-dose pDLI after conditioning with alemtuzumab are at low risk for relapse; however, this approach is associated with a relatively high incidence of severe GVHD.     

Long-term follow-up of T cell-depleted allogeneic bone marrow transplantation in refractory multiple myeloma: importance of allogeneic T cells.

Multiple myeloma may be cured by myeloablative conditioning and allogeneic blood or marrow transplantation (alloBMT), but this occurs at the expense of high transplant-related mortality. In an endeavor to reduce procedure-related toxicity, this study retrospectively evaluated the safety, tolerability, and efficacy of T cell depletion by counterflow centrifugal elutriation before alloBMT. Fifty-one patients with stage II (6) or III (45) multiple myeloma received alloBMTs using T cell depletion by elutriation. Fifty-three percent (27 of 51) of patients had primary refractory disease at the time of transplantation, 10% (5 of 51) had relapsed disease, and 4% (2 of 51) had refractory relapsed disease. The median age was 49 (range, 32 to 62) years, and the median time from diagnosis to transplantation was 9 (range, 4 to 58) months. Patients had received a median of 1 (range, 1 to 3) regimen and 4 (range, 2 to 16) cycles of chemotherapy. In this population, transplant-related mortality rate was 24% (12 of 51) with 2 patients dying of graft-versus-host disease (GVHD). Thirty-one of 39 evaluable patients have experienced relapse, and the probability of progression-free survival 5 years after alloBMT alone is 16%. Sixteen patients were given donor lymphocyte infusions (DLI) at the time of relapse (n = 11) or for persistent disease 1 year after transplantation (n = 5). Acute or chronic GVHD was seen in 63% (10 of 16) of patients given DLI. Responses were seen in 8 of 16 patients (6 complete response [CR], 2 partial response [PR]) with 6 of 8 responding patients having GVHD. Five recipients of DLI remain in a continuous CR, ranging from 3 to 64 months in duration. Thus, like chronic myelogenous leukemia, allogeneic T cells appear to have potent antimyeloma activity that is critical for achieving a cure. DLI-induced remissions of multiple myeloma can be durable, even in patients with refractory multiple myeloma. Unlike chronic myelogenous leukemia, the antimyeloma effect of allogeneic T cells rarely occurs in the absence of clinically significant GVHD.     

Long-Term Results of Prophylactic Donor Lymphocyte Infusions for Patients with Multiple Myeloma after Allogeneic Stem Cell Transplantation

The major reason for treatment failure after allografting in multiple myeloma (MM) is relapse. Donor lymphocyte infusions (DLIs) are considered a valuable post-transplant strategy mainly for relapsed patients but using them to prevent relapse in MM has been reported rarely. In the present study, we examined the efficacy of prophylactic DLIs after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in myeloma patients with a long-term follow-up of more than 5 years. A total of 61 patients with MM who did not relapse or develop disease progression after allo-HSCT were treated with prophylactic DLI in an escalating fashion (overall 132 DLI procedures) to deepen remission status and prevent relapse. Overall response rate to DLI was 77%. Thirty-three patients (54%) upgraded their remission status, 41 patients (67%) achieved or maintained complete remission, and 26% achieved a molecular remission. Incidence of acute graft-versus-host disease (GVHD) grade II to IV was 33% and no DLI-related mortality was noted. After a median follow-up of 68.7 months from first DLI the estimated 8-year progression-free survival (PFS), and overall survival (OS) in a landmark analysis was 43% (95% confidence interval [CI], 28% to 57%) and 67% (95% CI, 53% to 82%), respectively, with best outcome for patients who acquired molecular remission (8-year PFS was 62% and 8-year OS was 83%). Prophylactic escalating DLI in a selected cohort of MM patients to prevent relapse after allograft resulted in a low incidence of severe GVHD and encouraging long-term results, especially if molecular remission is achieved.     

DLI治疗CML病人的克隆性增殖TCR Vβ细胞分析

目的：了解供者淋巴细胞输注（DLI）后,产生GVL效应的克隆性TCR Vβ亚家族T细胞的情况。方法：利用RT－PCR分别扩增2例CML经allo-BMT后复发病人DIL治疗前后不同时间外周血单个核细胞的TCR Vβ24个亚家族基因的CDR3,了解病人各Vβ亚家族的利用情况。阳性的PCR产物进一步经荧光素标记和基因扫描分析产物的CDR3长度,了解T细胞克隆性。结果：DLI治疗前病人外周血仅表达4－11个Vβ亚家族,而DL1治疗后缓解期则可检测到12－21个Vβ亚家族。基因扫描显示DLI后病人外周出血某些新的Vβ亚家族克隆性增殖T细胞。结论：病人的TCR Vβ亚家族T细胞存在倾斜性分布现象,该倾斜现象在完全缓解时逐步恢复正常。DLI治疗病人时,可能通过某些克隆性增殖TCR Vβ亚家族T细胞而发挥GVL作用。     

Ex vivo fludarabine exposure inhibits graft-versus-host activity of allogeneic T cells while preserving graft-versus-leukemia effects.

Allogeneic donor T cells in bone marrow transplantation (BMT) can contribute to beneficial graft-versus-leukemia (GVL) effects but can also cause detrimental graft-versus-host disease (GVHD). A successful method for the ex vivo treatment of donor T cells to limit their GVHD potential while retaining GVL activity would have broad clinical applications for patients undergoing allogeneic hematopoietic cell transplantation for malignant diseases. We hypothesized that donor lymphocyte infusions treated with fludarabine, an immunosuppressive nucleoside analog, would have reduced GVHD potential in a fully major histocompatibility complex-mismatched C57BL/6 --> B10.BR mouse BMT model. Recipients of fludarabine-treated donor lymphocyte infusions (F-DLI) had significantly reduced GVHD mortality, reduced histopathologic evidence of GVHD, and lower inflammatory serum cytokine levels than recipients of untreated DLI. Combined comparisons of GVHD incidence and donor-derived hematopoietic chimerism indicated that F-DLI had a therapeutic index superior to that of untreated DLI. Furthermore, adoptive immunotherapy of lymphoblastic lymphoma using F-DLI in the C57BL/6 --> B10.BR model demonstrated a broad therapeutic index with markedly reduced GVHD activity and preservation of GVL activity compared with untreated allogeneic T cells. Fludarabine exposure markedly reduced the CD4+CD44(low)-naive donor T-cell population within 48 hours of transplantation and altered the relative representation of cytokine-producing CD4+ T cells, consistent with T-helper type 2 polarization. However, proliferation of fludarabine-treated T cells in allogeneic recipient spleens was equivalent to that of untreated T cells. The results suggest that fludarabine reduces the GVHD potential of donor lymphocytes through effects on a CD4+CD44(low) T-cell population, with less effect on alloreactive T cells and CD4+CD44(high) memory T cells that are able to mediate GVL effects. Thus, F-DLI represents a novel method of immune modulation that may be useful to enhance immune reconstitution among allograft recipients with reduced risk of GVHD while retaining beneficial GVL effects.     

Donor chimerism does not predict response to donor lymphocyte infusion for relapsed chronic myelogenous leukemia after allogeneic hematopoietic cell transplantation.

We studied the effect of donor chimerism level on the outcome of donor lymphocyte infusion (DLI) therapy in 42 patients with persistent or relapsed hematologic malignancies after non-T cell-depleted allogeneic hematopoietic cell transplantation. Seventy-five percent of chronic myelogenous leukemia (CML) and 39% of non-CML patients entered remission after DLI therapy. Remission and survival rates were similar for CML patients irrespective of their pre-DLI donor chimerism levels; however, remission occurred sooner in patients with > or =10% pre-DLI donor chimerism. None of the non-CML patients with <10% pre-DLI donor chimerism and 47% of those with > or =10% pre-DLI donor chimerism attained remission. The 2-year survival rates after DLI were 75% for CML and 17% for non-CML patients. We conclude that a low level of donor marrow chimerism is not an adverse prognostic factor for response to DLI in CML patients, but for non-CML patients it may confer worse outcomes. Better methods to augment the response to DLI for patients with hematologic malignancies other than CML that recur after allogeneic hematopoietic cell transplantation are needed, whereas for relapsed CML patients, combination therapies including imatinib mesylate or other promising antileukemic agents may provide outcomes superior to those with DLI alone.     

Reversal of T Cell Exhaustion by the First Donor Lymphocyte Infusion Is Associated with the Persistently Effective Antileukemic Responses in Patients with Relapsed AML after Allo-HSCT

Donor lymphocyte infusion (DLI) is an effective approach to treat acute myelogenous leukemia (AML) relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT) that significantly improves the survival of relapsed patients. However, the mechanism of an effective antileukemic response following DLI in AML relapse remains elusive. Here, we investigated the role of T cell exhaustion in AML relapse after allo-HSCT in prospective cohorts of 41 patients with the first AML relapse and 41 nonrelapsed AML control subjects after allo-HSCT and determined whether DLI exerts effective antileukemic effects by reversing T cell exhaustion in the relapsed cohorts by detecting the phenotypes and functions of T cells using flow cytometry. We found that both CD4⁺?and CD8⁺?T cells experienced exhaustion with upregulated coexpression of PD-1 and Tim-3, and functional impairments in cytokine production, proliferation, and cytotoxic potentials. The reversal of T cell exhaustion by the first DLI is associated with persistent complete remission in relapsed AML patients. In addition, the reversal of T cell–exhausted status after successful DLI in bone marrow was concurrent with the mitigated inversion of CD4/CD8 T cell ratio. In conclusion, our study shows a clinical correlation between T cell exhaustion and AML relapse after allo-HSCT, and uncovers the role of reversing T cell exhaustion in the antileukemic response by DLI and identifies possible immunological markers to evaluate and predict the graft-versus-leukemia effects induced by DLI.     

Infusion of select leukemia-reactive TCR Vbeta+ T cells provides graft-versus-leukemia responses with minimization of graft-versus-host disease following murine hematopoietic stem cell transplantation.

T-cell receptor (TCR) Vbeta-expression analysis by complementarity-determining region 3 (CDR3)-size spectratyping can identify the reactive populations in an immunologic response. This analysis was used in this study to characterize the Vbeta responses of C57BL/6 (B6) CD4+ and CD8+ T cells directed to either alloantigen (against [B6xDBA/2]F1; anti-H2d) or the syngeneic myeloid leukemia MMB3.19. Vbeta families exhibiting reactivity to the leukemia cells were then enriched for and administered in both syngeneic and allogeneic hematopoietic stem cell transplantation (HSCT) models to assess in vivo graft-versus-leukemia (GVL) potential. In syngeneic transplants, enrichment for pools of selected Vbeta families (Vbeta7, -11, and -13) of T cells or for a single Vbeta family (Vbeta7) of CD4+ T cells conveyed a beneficial GVL response to the recipients. Furthermore, in the haploidentical allogeneic model, both Vbeta6,7-enriched donor B6 T cells and Vbeta7-enriched CD4+ T cells exhibited significant GVL responses with concomitant minimization of graft-versus-host disease (GVHD) development compared with equal numbers of unfractionated T cells. These results suggest that CDR3-size spectratype analysis of and subsequent selection from donor T-cell repertoires can be an effective approach to separate GVL and GVHD potential following allogeneic HSCT.     

Reduced-intensity transplantation with in vivo T-cell depletion and adjuvant dose-escalating donor lymphocyte infusions for chemotherapy-sensitive myeloma: limited efficacy of graft-versus-tumor activity.

Reduced-intensity conditioning regimens allow application of allogeneic stem cell transplantation to greater numbers of patients with myeloma by reducing transplantation-related mortality. We prospectively evaluated the role of an approach incorporating in vivo T-cell depletion and subsequent adjuvant donor lymphocyte infusions (DLIs) as part of front-line therapy for chemotherapy-sensitive multiple myeloma. Twenty patients with HLA-matched related (n = 12) or unrelated (n = 8) donors entered the study. None had previously undergone autologous transplantation. Acute graft-versus-host disease (GVHD) following transplantation was minimal (3 grade II and no grade III or IV). Nonrelapse mortality rate was relatively low (15%) compared with conventional myeloablative allogeneic transplantation series, although it remained significantly higher than in the autologous setting. Disease responses by 6 months posttransplantation were modest (2 in complete remission, 4 in partial remission, 2 were minimally responsive, 6 had no change, 3 had progressive disease, and 3 were not evaluable). Fourteen patients received escalating-dose DLI for residual/progressive disease. Three developed acute GVHD and 2 developed limited chronic GVHD. Seven demonstrated further disease responses, which appeared to be more common in those developing GVHD (5 of 5 versus 2 of 9; P =.02). All responses were associated with conversion from mixed to full donor T-cell chimerism. Response durations were disappointing (5 <12 months) and progression often occurred despite persisting full donor chimerism. Two-year estimated overall survival and current progression-free survival rates (intention to treat with DLI from 6 months) were 71% and 30%, respectively. The current approach incorporating T-cell depletion appears excessively immunosuppressive despite attempts to restore immune function with DLI. Dose escalation failed to allow convincing dissociation of graft-versus-myeloma from GVHD. Attempts to hasten immune reconstitution and to focus and amplify appropriate components of allogeneic T-cell responses will be required to increase complete remission rates and response durations.