Effects of escalating doses of recombinant human interleukin-2 in correcting functional T-cell defects following autologous bone marrow transplantation for lymphomas and solid tumors.

High-dose chemotherapy followed by autologous bone marrow transplantation (ABMT) in the treatment of malignancies is often associated with immune deficiency following transplantation, possibly contributing to tumor relapse or fatal infection. Interleukin 2 (IL-2), which enhances major histocompatibility complex (MHC)-unrestricted cytotoxicity in vitro, can be applied in vivo as immunotherapy to reduce these potential complications. Recombinant human IL-2 (rIL-2) was administered by continuous i.v. infusion for four courses in 19 patients following ABMT for lymphomas and solid tumors. The patients were assigned to five groups of escalating doses of rIL-2 ranging from 3 to 30 x 10(6) IU/m2/day. The immunological effects and toxicity were monitored. After a transient reduction of lymphocytes in the peripheral blood, a significant lymphocytosis was observed during the rIL-2 infusion with an augmentation of CD2+, CD25+, and CD8(+)-Ia+ T cells and a dose-related increase of CD56+ lymphocytes. Natural killer (NK) activity appeared enhanced in patients treated with as little as 6 x 10(6) IU/m2/day. No statistically significant increase in lymphokine-activated killer (LAK) activity was seen after rIL-2, when compared to LAK activity following ABMT prior to rIL-2 administration. Administration of exogenous rIL-2 to patients who have undergone ablative chemotherapy and ABMT has a role in restoring defective T-cell function. Further trials defining those patients most likely to benefit from rIL-2 integrated with ablative chemotherapy and ABMT are now warranted.     

Induction of in vitro graft-versus-leukemia activity following bone marrow transplantation for chronic myeloid leukemia

We studied the in vitro effects of lymphokine-activated killer (LAK) cells from the peripheral blood of chronic myeloid leukemia (CML) patients after allogeneic and syngeneic bone marrow transplantation (BMT). LAK cells were generated by incubating peripheral blood mononuclear cells from patients post-BMT with recombinant interleukin-2 (IL-2) (500 U/mL) in 10% AB serum for 7 days. They were phenotyped and tested for activity in a standard 4-hour 51Cr release assay (n = 37) and in a CFU-GM assay (n = 24). We found that the LAK cells were mainly activated natural killer cells, but some were CD3+ T cells. In the 51Cr release assay LAK cells from 20 of 33 (61%) allogeneic and 2 of 4 syngeneic recipients killed recipient CML cells and in 22 of 37 (60%) cases also killed the HLA disparate CML cells. In the CFU-GM assay the LAK cells incubated together with the CML cells in liquid culture before plating inhibited (P less than .05) colony growth in 16 of 22 allogeneic and 2 of 2 syngeneic recipients. Cell-cell contact was necessary for optimal effect. There was little or no inhibition of proliferation of donor marrow CFU-GM. This in vitro graft-versus-leukemia (GVL) effect could also be demonstrated after LAK effectors were depleted of CD3+ T cells. It was inducible in recipients of both T cell-depleted and T cell-replete donor marrow and in recipients with or without graft-versus-host disease. These results suggest that a major histocompatibility complex-unrestricted GVL effect is inducible following allogeneic and syngeneic BMT. The use of IL-2/LAK cells after BMT could reduce the risk of relapse.     

Enhancement of MHC-unrestricted cytotoxic activity of human CD56+ CD3− natural killer (NK) cells and CD3+ T cells by rhamnogalacturonan: Target cell specificity and activity against NK-insensitive targets

Rhamnogalacturonan-mediated enhancement of MHC-unrestricted cytotoxicity was studied with freshly isolated CD56⁺CD3^– natural killer (NK) cells, interleukin-2 (IL-2)-activated CD56⁺ lymphokine-activated killer (LAK) cells und IL-2/anti-CD3-activated T cells as effector cells using NK-sensitive and NK-insensitive tumor cells as targets. The rhamnogalacturonan fractions IM, IP, and IQ were prepared from commercially available extracts ofViscum album. The dose/response relation of IM, IP, and IQ demonstrated the presence of various concentrations of cytotoxicity-enhancing compounds in all three fractions that were identified as rhamnogalacturonans by degradation studies with poly--d-galacturonidase (EC 3.2.1.15) and -1,6-rhamnosidase (EC 3.2.1.40). Specific cytotoxicity of all three effector cell populations as well as the respective rhamnogalacturonan-mediated cytotoxicity enhancement was readily inhibited in a dose-dependent manner by 60%-deacetylated mannose pentaacetate. Rhamnogalacturonan-mediated enhancement of cytotoxicity of fresh CD56⁺ NK cells was also observed with four of five NK-insensitive tumor cells as targets, indicating that the effector-cell/tumor-cell bridging activity of rhamnogalacturonans renders NK-insensitive targets susceptible to NK-mediated lysis. Moreover, the rhamnogalacturonan-mediated cytotoxicity enhancement became even more prominent when lymphokine-activated CD56⁺ LAK and CD3⁺ T cells were assayed with the NK-insensitive tumor cell targets.Abbreviations E/T effector cell/tumor cell ratio - IL interleukin - LAK lymphokinje-activated killer - LDH lactic acid dehydrogenase - MHC major histocompatibility complex - NK natural killer - PBMC peripheral blood mononuclear cells - PNAC peripheral non-adherent cells     

Evaluation of natural killer and lymphokine-activated killer (LAK) cell activity in vivo in patients treated with high-dose interleukin-2 and adoptive transfer of autologous LAK cells

Summary This study investigated the development of peripheral blood natural killer (NK) and lymphokineactivated killer (LAK) cell activity in vivo in cancer patients treated with high doses of recombinant interleukin-2 and autologous LAK cell infusion. It was found that interleukin-2 administration by bolus injection resulted in an early but transient rise of NK and LAK cell activity in vivo during the first 5–9 days of treatment (postpriming period), whereas continuous infusion of interleukin-2 caused an increase in both cytotoxic activities in the second phase of the treatment, concomitant with infusions of autologous LAK cells. Elevated NK but not LAK cell activity in vivo in the continuous-infusion patients persisted up to 180 days after completion of therapy. In both bolus and continuous interleukin-2 protocols, augmented NK cell activity in vivo appeared to be correlated with a beneficial response to therapy.Supported by the US-Poland Cancer Program (NCI) and by NCI Contract NO1-CM-73705     

Association of natural killer cell immune recovery with a graft-versus-leukemia effect independent of graft-versus-host disease following allogeneic bone marrow transplantation

 There is good evidence that T lymphocytes play an important role in the graft-versus-leukemia (GVL) effect following allogeneic bone marrow transplantation (BMT) for hematologic malignancies. However, the role of natural killer (NK) cells in GVL is less clear. To further investigate a possible association of NK cells with GVL we studied 15 patients undergoing BMT for chronic myeloid leukemia (CML), correlating T-cell (CD4+ and CD8+) and NK-cell (CD16+56+) recovery with relapse and graft-versus-host disease (GVHD). Patients were studied on three occasions up to 9 months after BMT, for lymphocyte surface phenotype and for spontaneous and IL-2-stimulated (LAK cell) cytotoxic function. Circulating CD8+ and NK but not CD4+ cell numbers were significantly lower in five patients who relapsed compared with those remaining in remission after BMT (mean 0.03 vs 0.32×10⁹/l, p=0.002 for CD8+ cells; mean 0.03 vs 0.11×10⁹/l, p=0.002 for NK cells). There was no correlation of CD4+, CD8+, or NK cell numbers and development of grade-II or more acute GVHD. Spontaneous NK cytotoxic function rose to within the normal range in the first month after BMT. LAK function remained low during the study period. These results link NK cell recovery more closely with a GVL than with a GVH effect. Received: 1 May 1996/Accepted: 19 September 1996     

Radiation sensitivity of resting and activated nonspecific cytotoxic cells of T lineage and NK lineage

Natural killer (NK) cell-mediated killing of tumor cells is a radiation- sensitive function that in most subjects is completely abrogated by treatment of the effector cells with 3,000 cGy. The radiation sensitivity of LAK (lymphokine-activated killer) cells and their precursors, the bulk of which are NK cells, is undetermined. In this study, functional cytotoxicity assays and electron microscopy were used to determine the effect of radiation on the cytotoxic function of NK cells, LAK cells (generated by three-day culture of peripheral blood lymphocytes with IL-2), and LAK cell precursors (lymphocytes irradiated prior to culture with IL-2). For comparison, we analyzed the radiation sensitivity of lectin-dependent cell-mediated cytotoxicity (LDCC), which is primarily a function of CD3+ CD8+ granular lymphocytes. We also analyzed the radiation sensitivity of nonspecific cytotoxicity mediated by mitogen-activated T cells (AK activity). Following 3,000 cGy irradiation, NK cells retained their ability to bind to tumor cell targets but, as shown by both morphologic and functional analyses, they did not undergo activation after conjugate formation, and were unable to release the content of their granules. In order to evaluate LDCC, lymphocytes were depleted of CD16+ cells and tested in a cytotoxicity assay in the presence of Con A. The radiation sensitivity curve was comparable to that of NK cell-mediated cytotoxicity. IL-2-treated lymphocytes (LAK cells) were relatively radioresistant as compared with untreated NK cells, and their cytotoxic function was not abrogated until treatment with greater than 10,000 cGy. Cells receiving such radiation doses displayed cytoplasmic blebbing and damage of their cytoskeletal structures, with disruption of centrioles and microtubules, and disarray of the intermediate filaments. As was shown with NK cells, irradiated LAK cells formed conjugates with tumor targets but failed to degranulate. The radiation sensitivity of nonspecific cytotoxicity mediated by mitogen-activated T cells was identical to that of LAK effector cells. Doses up to 2,000 cGy did not prevent generation of LAK cells from blood lymphocytes, but 3,000 cGy did so. Blast transformation similar to that observed in IL-2- stimulated controls occurred when lymphocytes irradiated with 3,000 cGy were cultured with IL-2. These transformed cells were not cytotoxic and displayed a normal cytoskeletal apparatus but did not bear electron- dense granules.(ABSTRACT TRUNCATED AT 400 WORDS)     

Hematologic and immunologic effects of the systemic administration of recombinant interleukin-2 after autologous bone marrow transplantation

T cells from allogeneic bone marrow grafts are responsible for a graft versus leukemia effect. Use of recombinant Interleukin-2 (rIL-2) after autologous bone marrow transplantation (BMT) may enhance immune function and hopefully reproduce the allogeneic reaction. We report here the hematologic and immunologic changes observed in the first 10 patients of a phase 1 trial studying the infusion of IL-2 after autologous BMT. All patients had high-risk malignancies and received 6 days of a constant infusion of IL-2 (Eurocetus, Amsterdam, The Netherlands) at dose of 3 x 10(6) Cetus Units/m2/d, 79 +/- 12 days after autologous BMT. Clinical toxicities involving cutaneous, cholestatic, gastrointestinal, and hemodynamic effects occurred during IL-2 treatment but reversed in all cases. Completion of treatment was 91% of the scheduled dose of IL-2. Hematologic toxicity was moderate and transient with no graft failure. Increases in eosinophil and lymphocyte counts were significant (P less than .05). Stimulation of the immune system was intense and prolonged, manifested by increase numbers of CD3+, CD3+DR+, CD3+ CD25+ lymphocytes, and natural killer (NK) cells (all P less than .01), and increase of Lymphokine-activated killers (LAK) and NK activities (P less than .01 and P less than .05). This study establishes the feasibility of a 6-day administration of rIL-2 after autologous BMT leading to a major immune activation 2.5 months after BMT.     

Interleukin 2-activated killer cells in patients following transplants of soybean lectin-separated and E rosette-depleted bone marrow

During the early period following bone marrow transplantation before the immune system has reached full functional maturity, unprimed, nonspecific lytic systems may play a critical role as antiviral or antitumor effectors. The reconstitution of cells with this potential is of particular importance in recipients of bone marrow that has been depleted of mature T lymphocytes to prevent graft v host disease (GVHD). We examined the recovery of natural killer (NK) cells and interleukin 2 (IL 2)-augmented lymphokine-activated killer cells (LAK) in 48 patients at various intervals following transplantation of bone marrow depleted of mature cellular elements by treatment with soybean agglutinin and sheep RBCs (SBA-E- BMT). We found normal levels of both NK and LAK activity as early as 3 weeks following SBA-E- BMT. When compared with cells from controls, NK and LAK precursors from transplant recipients appeared to be activated in vivo in that freshly isolated peripheral blood mononuclear cells (PBMCs) from patients had an elevated cytolytic activity toward NK-insensitive targets and a more rapid response to activation by IL 2. In patients as well as controls, both LAK precursors and LAK effectors lacked antigens present on mature T lymphocytes (CD3, CD4, or CD8) but expressed antigens present on NK cells (CD2, CD16, and NKH1A). The LAK cells did not lyse either donor or host peripheral blood T cell targets. The activity of NK effectors but not LAK precursors survived the in vivo total body irradiation used for pretransplant conditioning in three patients studied. LAK precursors could be demonstrated as early as 18 days following transplant at a time when the bone marrow contained primarily donor- derived cells. Little or no LAK activity could be generated from cells of the SBA-E- BM graft itself, suggesting that LAK precursors differentiate rapidly from more primitive progenitors in the marrow graft. Thus, our data indicate that the NK and LAK lytic systems are among the earliest activities to recover during immune reconstitution following T cell-depleted BMTs.     

Natural cytotoxicity to autologous antigen-pulsed dendritic cells in multiple myeloma

To analyse autologous lymphocyte cytolytic activities of potential importance for cell-based immunotherapy in multiple myeloma (MM), in vitro differentiated dendritic cells (DCs) loaded with patient-specific monoclonal immunoglobulin (mIg) were used as autologous target cellsin cytotoxicity assays. Effector populations consisted of purified natural killer (NK) cells (CD56+, CD3-) and T cells (CD3+). The MM patients' NK cells cultured in the presence of interleukin 2 (IL-2) showed pronounced cytotoxic activity towards autologous mature DCs. Autologous MM DC targets displayed similar susceptibility to NK cell lysis, compared with allogeneic control DC targets, despite high surface expression of self major histocompatibility complex (MHC) antigens. However, some degree of classic MHC class I-mediated negative regulation was implicated in the NK-DC interactions, as indicated by class I blocking experiments. NK-mediated lysis was also discerned towards primary autologous MM cells. The results indicated that the major effector mechanism was mediated through the perforin-granzyme exocytosis pathway. In conclusion, NK cells from MM patients displayed significant and consistent cytotoxicity towards autologous mature DCs, suggesting that innate immunity could be implicated in MM and may influence the outcome of the administration of tumour antigen-pulsed DCs in treatment trials.     

Synergism of interleukin-2 and cyclosporine A in induction of a graft-versus-tumor effect without graft-versus-host disease after syngeneic bone marrow transplantation.

Interleukin-2 (IL-2) therapy generates killer cells with major histocompatibility complex (MHC)-unrestricted cytotoxicity against most tumors but not normal tissues. Cyclosporine A (CsA) has been reported to break tolerance to self and to induce killer cells with specificity against class II MHC (Ia) antigens both on the host and the tumor cells, resulting in a mild graft-versus-host disease (GVHD) in an autologous bone marrow transplantation (BMT) setting in the rat. We used these two agents in a syngeneic BMT model in a strain of mice that does not develop GVHD with CsA. Therapy with either agent alone was ineffective, whereas a combination of CsA plus IL-2 after BMT induced a potent graft-versus-tumor (GVT) effect against a melanoma and an acute myeloid leukemia. The antitumor effect could be adoptively transferred by infusing spleen cells harvested from mice treated with CsA plus IL-2 into secondary recipients that received chemoradiotherapy. The cytotoxicity of these cells was not influenced by treatment of tumor cells with gamma-interferon or Ia antibody. The cytotoxic effect was mediated by Thy 1+ and asialo GM 1+ cells. There was no GVHD either in the primary recipients of CsA and IL-2 or in those receiving the adoptively transferred spleen cells. Our findings show that combination therapy with CsA and IL-2 after syngeneic BMT induces a potent GVT effect in a non-MHC-restricted manner, and point to the existence of differences between the mechanisms of GVT and GVHD.     

Surface antigen expression of human neoplastic plasma cells includes molecules associated with lymphocyte recirculation and adhesion

Adherent lymphokine activated killer (ALAK) cells are a subpopulation of activated natural killer (NK) cells with MHC unrestricted antitumour activity distinguished by their propensity to adhere to plastic in the presence of interleukin-2 (IL-2). We generated ALAK cells from seven patients with chronic myeloid leukaemia (CML) following Campath-1-depleted bone marrow transplantation (BMT). Five had relapsed and were in chronic phase, one had cytogenetic evidence of relapse and one had prior evidence of cytogenetic relapse but was in complete remission at time of study. Phenotypically the ALAK cells included both CD56+/CD3- NK cells and CD56-/CD3+ T cells. The CD3- subpopulation were studied cytogenetically and their functional activity tested in a 4 h 51Cr release cytotoxicity assay using the pretransplant leukaemia cells as targets. Cytogenetic studies showed that the ALAK cells from six patients were Ph negative, and where donor and recipient were sex mismatched, ALAK cells were exclusively of donor origin. In one patient ALAK cells were Ph positive and of recipient origin in eight of nine metaphases. In the 51Cr release assay the ALAK cells showed significant lysis of the pretransplant leukaemia in five of the seven patients tested. These data indicate that in CML patients who relapse post-BMT the NK cells are usually of donor origin but may be recipient-derived. In most patients these ALAK cells have antileukaemic activity in vitro.     

Endogenously generated activated killer cells circulate after autologous and allogeneic marrow transplantation but not after chemotherapy

After marrow transplantation, major histocompatibility complex (MHC)-unrestricted natural killer (NK) lymphocytes are among the first cells to appear in the circulation. After T-cell-depleted bone marrow transplantation (TD-BMT), these cells have an activated pattern of target cell killing; they also secrete lymphokines including gamma-interferon (gamma-IFN), interleukin-2 (IL-2), and tumor necrosis factor (TNF) and may have a significant role as a primary defense against viral reactivation and in the elimination of residual host malignancy. We studied 43 patients with hematologic malignancy, treated by allogeneic TD-BMT, autologous nondepleted BMT, or chemotherapy alone to investigate (a) the mechanisms underlying the generation of these activated killer cells, (b) the range of conditions under which they are produced, and (c) their surface phenotype. We showed that gamma-IFN-secreting activated killer cells with the capacity to kill MHC-nonidentical NK-resistant targets are generated 4 to 6 weeks after either allogeneic TD-BMT or autologous BMT but do not appear after treatment with chemotherapy. Production therefore is not owing to T-cell depletion per se or to host donor alloreactivity, nor is it caused by stimulation by alloantigens contained in blood product support since no significant difference exists between allograft and chemotherapy patients in the number of units of blood platelet support given in the posttreatment period. Because most patients had no evidence of stimulation from virus reactivation/infection, the phenomenon of activation therefore appears to represent posttransplant immune disregulation following repopulation of the host immune system with lymphoid subsets derived exclusively from blood and marrow. Activated killing is predominantly mediated by the CD16+ CD3- subset, but substantial activity remains in the CD16- CD3+ cell fraction. Monoclonal antibodies (MoAbs) that block interaction with class-I MHC molecules at the level of target cell (W6/32 anti-HLA class I) or effector cell (CD8) do not inhibit killing by CD16- CD3+ cells. Activated killer cells may contribute to the lower risk of relapse after marrow transplantation as compared with intensive chemotherapy.     

CD16- CD56+ natural killer cells after bone marrow transplantation.

Natural killer (NK) cells are phenotypically defined as lymphocytes expressing the antigens CD56 and mostly CD16 (Fc gamma RIII), but lacking CD3. A small CD3- CD16- CD56+ NK cell subset has been described in normal individuals representing less than 2% of peripheral blood lymphocytes. We analyzed here 70 patients for their reconstitution of the immune system during follow-up after autologous or allogeneic bone marrow transplantation. In 35% of these patients, two different NK cell subsets, namely CD56+dim and CD56+bright cells, were observed. The mean duration of these two subsets after transplant was 4 months. Sixty-five percent of the patients exhibited an increased number of NK cells, but only the typical CD16+ CD56+dim population. The CD56+bright subpopulation represented a particular CD3- CD16- NK subset, with posttransplant frequencies up to 70% of all NK cells and 40% of peripheral blood lymphocytes, respectively. In contrast to normal CD56+dim NK cells, CD56+bright cells coexpressed the activation antigens p75 beta-chain of interleukin-2 receptor (IL-2R), CD2R, and CD26, but were negative for CD16. NK and antibody-dependent cellular cytotoxicity activity of CD56+bright cells was low compared with CD56+dim NK cells. But using IL-2 and interferon gamma, their cytotoxicity could be enhanced even more than in CD56+dim lymphocytes. These different subsets may reflect distinct activation or differentiation steps of NK cells during reconstitution of the immune system. Their differential response to IL-2 may be of functional importance for posttransplant cytokine therapy.     

Lymphokine activated killer (LAK) cell activity in the peripheral blood lymphocytes of systemic sclerosis (SSc) patients

Lymphokine activated killer (LAK) cells, which arise from interleukin-2 (IL-2) activation of natural killer (NK) cells, are capable of lysing NK-resistant cell targets, including endothelial cells (EC). Since EC cytotoxicity is postulated to play a role in the pathogenesis of systemic sclerosis (SSc), experiments were performed to measure LAK activity in the peripheral blood lymphocytes (PBL) of 10 SSc patients and 10 normal controls. SSc patients had no significant spontaneous cytotoxicity against NK-resistant cell targets, including EC. After IL-2 stimulation in vitro, SSc patients and normal controls demonstrated cytotoxicity toward NK-resistant cell targets, including EC. This LAK-mediated EC cytotoxicity was actually lower for SSc patients than for normal controls. These studies do not preclude a role for LAK-mediated EC cytotoxicity in the pathogenesis of SSc, but demonstrate that LAK cells are not spontaneously present in circulating PBL.     

Cytotoxicity of interleukin 2-activated lymphocytes for leukemia and lymphoma cells

Studies were undertaken to determine whether leukemia and lymphoma cells would be lysed by autologous and allogeneic lymphokine-activated killer (LAK) cells. Peripheral blood mononuclear cells (PBMC) from patients and normal donors were cultured for five days, 2 weeks, and 4 weeks with medium containing 2,500 units of recombinant interleukin 2 (IL-2) per mL, and their cytotoxicity was assayed by a five-hour 51Cr-release test. Of primary tumors isolated from patients with acute nonlymphoblastic leukemia, acute lymphoblastic leukemia, and non-Hodgkin's lymphoma, tumors of 37 out of 40 patients tested were shown to be susceptible to normal donors' LAK, and tumors of 18 of 20 patients tested were shown to be susceptible to autologous LAK. LAK cultured for longer periods showed a tendency to have lower cytotoxicity. LAK had also low, but significant, levels of cytotoxicity for nonmalignant target cells. Because PBMC expanded in IL-2-containing medium consisted mainly of OKT3-positive pan T cells, OKT8-positive suppressor/cytotoxic cells, and Leu-11-positive natural killer (NK) cells, and treatment with OKT3 and Leu-11 monoclonal antibodies (mAb) reduced LAK activity for autologous and allogeneic tumor cells, both T and NK cells appeared to be effector cells for LAK activity. Mechanisms of target-cell recognition in the LAK system seem to be different from those in alloreactive cytotoxic T lymphocytes (CTL) based on the results that, while cytotoxicity of alloreactive CTL was inhibited by the treatment of effector cells with mAb, OKT3, and OKT8, and by the treatment of target cells with a mAb that reacts with HLA class I antigen, LAK activity was not inhibited by the above treatment. When chromosomes of IL-2-expanded PBMC in nine patients and two normal individuals were analyzed, PBMC from one patient showed chromosomes of clonal abnormalities, and PBMC from five donors showed those of nonclonal abnormalities.     

Proliferation and cytolytic function of anti-CD3 + interleukin-2 stimulated peripheral blood mononuclear cells following bone marrow transplantation.

We evaluated the proliferation, cytolytic function, and phenotypic characteristics of anti-CD3 plus interleukin-2 (IL-2) stimulated peripheral blood mononuclear cells (PBMCs) from 44 patients with leukemia or non-Hodgkin's lymphoma (NHL) treated with multiagent chemotherapy or following bone marrow transplantation (BMT). BMT patients had decreased cell growth with only a 1.35 +/- 0.25 (autologous BMT for acute lymphoblastic leukemia [ALL]), 1.24 +/- 0.25 (autologous BMT for NHL), and 0.8 +/- 0.1 (allogeneic BMT for leukemia) mean fold increase by day 5 of culture compared with controls (4.0 +/- 0.4), P less than .001. Anti-CD3 + IL-2 activated cells from patients with ALL and NHL who had received autologous BMT and cells from patients with leukemia who underwent allogeneic BMT were more effective in lysing the natural killer (NK) sensitive target, K562, and the NK-resistant target, Daudi, compared with controls. In contrast, cytolysis of K562 and Daudi by cultured PBMCs from patients with ALL and NHL receiving multi-agent chemotherapy was similar to that of controls. Cultures from BMT recipients had a significant increase in CD16+ (autologous ALL 5.7 +/- 1.5%, P less than .01; autologous NHL 12.4 +/- 3.5%, P less than .001; allogeneic 14.3 +/- 2.9%, P less than .001) and CD56+ cells (autologous ALL 27.6 +/- 12.0%, P less than .01; autologous NHL 39.3 +/- 9.5%, P less than .001; allogeneic 42.7 +/- 7.4%, P less than .001) compared with controls (CD16+ 2.5 +/- 0.4%; CD56+ 6.9 +/- 0.9%). Stimulation of PBMCs with anti-CD3 + IL-2 is effective in generating cells with high cytolytic function post-BMT.     

Administration of interleukin-7 after allogeneic bone marrow transplantation improves immune reconstitution without aggravating graft-versus-host disease

Prolonged immunodeficiency after allogeneic bone marrow transplantation (BMT) causes significant morbidity and mortality from infection. This study examined in murine models the effects of interleukin-7 (IL-7) given to young and middle-aged (9-month-old) recipients of major histocompatibility complex (MHC)-matched or -mismatched allogeneic BMT. Although administration of IL-7 from day 0 to 14 after syngeneic BMT promoted lymphoid reconstitution, this regimen was ineffective after allogeneic BMT. However, IL-7 administration from day 14 (or 21) to 27 after allogeneic BMT accelerated restoration of the major lymphoid cell populations even in middle-aged recipients. This regimen significantly expanded donor-derived thymocytes and peripheral T cells, B-lineage cells in bone marrow and spleen, splenic natural killer (NK) cells, NK T cells, and monocytes and macrophages. Interestingly, although recipients treated with IL-7 had significant increases in CD4(+) and CD8(+) memory T-cell populations, increases in naive T cells were less profound. Most notable, however, were the observations that IL-7 treatment did not exacerbate graft-versus-host disease (GVHD) in recipients of an MHC-matched BMT, and would ameliorate GVHD in recipients of a MHC-mismatched BMT. Nonetheless, graft-versus-leukemia (GVL) activity (measured against 32Dp210 leukemia) remained intact. Although activated and memory CD4(+) and CD8(+) T cells normally express high levels of IL-7 receptor (IL-7R, CD127), activated and memory alloreactive donor-derived T cells from recipients of allogeneic BMT expressed little IL-7R. This might explain the failure of IL-7 administration to exacerbate GVHD. In conclusion, posttransplant IL-7 administration to recipients of an allogeneic BMT enhances lymphoid reconstitution without aggravating GVHD while preserving GVL.     

Functional character and augmentation of lymphocytes in regional lymph nodes of patients with lung cancer

It appears that lymph node metastases are more frequent in lung cancer than in other cancers because of impaired defensive mechanisms in the regional lymph nodes. However, little is known about the immunologic function of regional lymph node lymphocytes (RLNL) in patients with lung cancer. We have studied the immunologic properties of RLNL in comparison with peripheral blood lymphocytes (PBL). We measured the natural killer (NK) cell activity of RLNL and PBL in patients with lung cancer and found that the NK activity was significantly more depressed in the RLNL than in the PBL. In contrast, interleukin-2 (IL-2) production was markedly higher in the RLNL than in the PBL. The cytotoxic effect of RLNL in nonmetastatic lymph nodes on target cells (such as K562 cells) or PC-3 and PC-10 cells (NK-resistant, human lung cancer of adenocarcinoma and epidermoid carcinoma, respectively) was significantly enhanced by in vitro incubation with recombinant IL-2 (rIL-2). Furthermore, we clarified that both rIL-2 and OK-432, which is a biologic response modifier and IL-2 inducer as well, augmented the cytotoxicity of RLNL and that these effector cells were lymphokine-activated killer (LAK) cells. The depletion of lymphocyte subsets by pretreatment with specific monoclonal antibody showed that the LAK activity in RLNL was mediated by CD3+ and CD8+ cells, whereas the lymphocyte subsets contributing the LAK activity in PBL were CD3+ and CD16+ cells. It was concluded that a majority of the effector cells in RLNL were LAK cells of the cytotoxic T cell population.     

Inhibition of human granulocyte-macrophage colony formation by interleukin 2-treated lymphocytes

The effects of interleukin 2 (IL-2)-treated lymphocytes on human myeloid progenitors (CFU-GM) were studied. When peripheral blood mononuclear cells (PBMC) were cultured for 3 days with recombinant IL-2, they developed lymphokine-activated killer (LAK) activity against normal bone marrow cells, and also suppressed colony formation by CFU-GM. Suppression of CFU-GM was found to be mediated mainly by natural killer (NK) cells, and to a lesser degree by T cells according to the results showing that isolated NK cells and T cells exhibited strong and moderate suppressor function, respectively. Since the levels of LAK activity and of CFU-GM inhibitory activity were not parallel in each individual, inhibition of CFU-GM does not seem to be due to a direct lytic action by LAK cells. This possibility was supported by our finding that the supernatant of IL-2-treated PBMC contained factor(s) that inhibited CFU-GM colony formation.     

Allogeneic cell-mediated immunotherapy for eradication of minimal residual disease: comparison of T-cell and IL-2 activated killer (LAK) cell-mediated adoptive immunotherapy in murine models

In the course of allogeneic bone marrow transplantation (BMT), avoiding graft-versus-host disease (GVHD) while retaining the antileukemic effects of the T cells remains a major challenge. T-cell depletion (TCD) reduces the incidence of GVHD but increases the relapse rate after allogeneic BMT. We attempted to develop a regimen that would retain or increase the graft-versus-leukemia effect induced by donor T cells while preventing GVHD. Immunosuppressed mice were given immunocompetent donor cells, i.e., fresh lymphocytes or lymphokine-activated killer (LAK) cells differing from the host in major (MHC) or minor (MiHC) histocompatibility antigens. Engraftment of donor cells was documented by polymerase chain reaction analysis. Administration of MHC- and MiHC-incompatible allogeneic LAK cells, especially in conjunction with recombinant interleukin-2 (rIL-2), increased disease manifestations and mortality associated with GVHD. On the other hand, irradiated LAK cells or TCD-LAK cells prevented GVHD in both mice models studied. Phenotypic analysis of LAK cells demonstrated that CD8(+)-equivalent (Lyt-2) T cells are of significance in aggravation of GVHD. The in vitro cytotoxic capacity of LAK cells against MHC-nonrestricted target cells was not reduced by either irradiation or TCD. These results provide the background for designing improved protocols for immunotherapy of residual disease after BMT. In addition, the data imply that antitumor effects may be retained by irradiated rIL-2-activated allogeneic cells without causing GVHD. Whereas unmodified allogeneic LAK cells can induce more effective graft-versus-leukemia effects at the cost of GVHD, irradiated allogeneic donor LAK cells might play some role in eradication of minimal residual disease following autologous or allogeneic BMT without causing GVHD.