Immune reconstitution in severe combined immunodeficiency disease after lectin-treated, T-cell-depleted haplocompatible bone marrow transplantation

We describe our 9-year experience with lectin-treated T-cell-depleted haplocompatible parental bone marrow transplantation (BMT) for 24 patients with severe combined immunodeficiency disease (SCID). Nineteen of 21 evaluable patients had T-cell engraftment; 2 of 11 patients tested had B-cell and monocyte engraftment. Fourteen of 24 (58%) patients are alive 7 months to 9.8 years post-BMT. Seventeen of 24 patients received pretransplant conditioning with chemotherapy and/or total body irradiation, and 8 of 24 received more than one transplant. Patients who received conditioning had a survival rate of 61% versus 57% for those who received no conditioning. None received graft-versus- host disease (GVHD) prophylaxis and no patient had acute or chronic GVHD greater than grade I. Kinetics and follow-up of immune recovery were analyzed in 14 patients who are greater than 1 year from transplant. Half of the patients showed evidence of T-cell function by 3 months and normal T-cell function by 4 to 7 months post-BMT. On average, T-cell numbers and subsets became normal 10 to 12 months posttransplant. Recovery of B-cell function was more delayed, although in most patients B-cell numbers and IgM levels were normal by 12 months post-BMT. B-cell function, as determined by isohemagglutinin titers or specific antibodies to pneumococcal polysaccharide, keyhole limpet hemocyanin, or tetanus toxoid, became normal in 10 of 14 patients 2 to 8 years post-BMT. Seven of the 14 are off gammaglobulin therapy. Production of isohemagglutinins tended to predict recovery of antibody response to pneumococcal polysaccharide (P < .064). Based on these results, we believe that haplocompatible BMT is an effective, curative treatment for patients with SCID who lack an HLA-matched related donor.     

Single centre experience of umbilical cord stem cell transplantation for primary immunodeficiency

Primary immunodeficiencies (PID) are an important cause of childhood mortality. Haematopoietic stem cell transplantation (HSCT) is the best treatment for many PID. Umbilical cord stem cells are an alternative source of HSC. There is little data regarding outcome of umbilical cord stem cell transplantation (UCSCT) for PID. Our single centre experience is reported. A retrospective study of 14 of 148 patients transplanted for PID, who have received 15 UCSCT was performed, with specific regard to graft-versus-host disease (GvHD) and immune reconstitution. Eight patients with severe combined immunodeficiency (SCID), and six with other combined immunodeficiencies were treated. Of the patients, 12 received unrelated cords, and two had sibling transplants. Median age at transplant was 3.5 months, median nucleated cell dose was 0.8 x 10(8)/kg. All engrafted. Median time to neutrophil engraftment was 22 days, median time to platelet engraftment was 51 days. One developed significant grade III GvHD post transplantation. In total, 11 patients had full donor T and six full donor B-cell chimerism, six of nine patients >1 year post-BMT had normal IgG levels and specific antibody responses to tetanus and Hib vaccines; two are being assessed. Two patients died of multi-organ failure related to pre-existing infection and inflammatory complications respectively. UCSCT should be considered for patients requiring stem cell therapy for PID.     

Monoclonal antibody-purged bone marrow transplantation therapy for multiple myeloma

Forty patients with plasma cell dyscrasias underwent high-dose chemoradiotherapy and either anti-B-cell monoclonal antibody (MoAb)- treated autologous, anti-T-cell MoAb-treated HLA-matched sibling allogeneic or syngeneic bone marrow transplantation (BMT). The majority of patients had advanced Durie-Salmon stage myeloma at diagnosis, all were pretreated with chemotherapy, and 17 had received prior radiotherapy. At the time of BMT, all patients demonstrated good performance status with Karnofsky score of 80% or greater and had less than 10% marrow tumor cells; 34 patients had residual monoclonal marrow plasma cells and 38 patients had paraprotein. Following high-dose chemoradiotherapy, there were 18 complete responses (CR), 18 partial responses, one non-responder, and three toxic deaths. Granulocytes greater than 500/microL and untransfused platelets greater than 20,000/microL were noted at a median of 23 (range, 12 to 46) and 25 (range, 10 to 175) days posttransplant (PT), respectively, in 24 of the 26 patients who underwent autografting. In the 14 patients who received allogeneic or syngeneic grafts, granulocytes greater than 500/microL and untransfused platelets greater than 20,000/microL were noted at a median of 19 (range, 12 to 24) and 16 (range, 5 to 32) days PT, respectively. With 24 months median follow-up for survival after autologous BMT, 16 of 26 patients are alive free from progression at 2+ to 55+ months PT; of these, 5 patients remain in CR at 6+ to 55+ months PT. With 24 months median follow-up for survival after allogeneic and syngeneic BMT, 8 of 14 patients are alive free from progression at 8+ to 34+ months PT; of these, 5 patients remain in CR at 8+ to 34+ months PT. This therapy has achieved high response rates and prolonged progression-free survival in some patients and proven to have acceptable toxicity. However, relapses post-BMT, coupled with slow engraftment post-BMT in heavily pretreated patients, suggest that such treatment strategies should be used earlier in the disease course. To define the role of BMT in the treatment of myeloma, its efficacy should be compared with that of conventional chemotherapy in a randomized trial.     

Kinetics of antibody concentration and avidity for the assessment of immune response to pneumococcal vaccine among children with bone marrow transplants

The kinetics of the immune response to the 23-valent pneumococcal polysaccharide vaccine (PPV) were studied in 38 children who received bone marrow transplants (BMTs). Anti-pneumococcal antibody concentrations increased 1 and 3 months after vaccination for all 5 serotypes tested, but, in 21 children, the vaccine was not adequately immunogenic. Children vaccinated <18 months after receiving a BMT had a 4.2-fold increased odds of poor response (P=. 06). Antibody concentrations returned close to baseline levels 9 months after vaccination. Avidity declined significantly as early as 1 month after vaccination and remained low thereafter. Antibody concentration responses to PPV were superior among 9 healthy control children (P=.001); 37 of 38 children with a BMT elicited adequate, persistent immune responses to Haemophilus influenzae conjugate vaccine. Immune responses to PPV in children with a BMT are suboptimal, short lived, and associated with declining avidity. The different kinetics of antibody concentration and avidity indicate that both markers should be used for evaluating pneumococcal vaccines in this high-risk population.     

Matched unrelated bone marrow transplantation for combined immunodeficiency

Bone marrow transplantation (BMT) from siblings is the treatment of choice for severe combined immunodeficiency (SCID). The objective of this study was to evaluate the efficiency of BMT from matched unrelated donors (MUD) in congenital immunodeficiencies when a sibling donor is unavailable. Sixteen consecutive patients with SCID (n = 9) and CID (n= 7), were referred for an unrelated donor search. Acceptable donors were found for all patients. Fifteen patients received busulfan and cyclophosphamide pretransplant conditioning. One patient had an early loss of graft and was reconditioned using cyclophosphamide and total body irradiation. The graft-versus-host disease (GVHD) prophylaxis used was methylprednisolone, cyclosporin A with or without methotrexate. Neutrophil engraftment was rapid and was achieved in all patients within a mean of 15.4 days. Only 13 episodes of fever were recorded shortly after BMT. GVHD of grade II or more was apparent in 2/9 (22%) of SCID patients and in 4/7 (57%) of CID patients. Overall survival was 75% with a mean follow-up of 47.4 months (range 18-101). Six out of nine SCID patients (67%) and 6/7 (86%) of CID patients are alive and well. Eleven patients had normal humoral immunity, and cell-mediated immunity as measured by flow cytometry and mitogenic responses, was intact in all patients. Intradermal candida skin test was positive in 9/10 patients tested. We conclude that BMT from MUD results in rapid engraftment and is therefore associated with a low rate of infection contributing to the improved survival rate. The protocol used is especially favorable for patients with combined immunodeficiency.     

Engraftment of Severe Combined Immune Deficient Mice Receiving Allogeneic Bone Marrow Via In Utero or Postnatal Transfer

Although in utero transplantation (IUT) has been shown to beeffective in treating human severe combined immune deficiency (SCID), the relative merit of IUT as compared withpostnatal bone marrow transplantation (BMT) for SCID is unknown.Therefore, comparative studies were undertaken in mice to determine theengraftment outcome in these two settings. Because T-cell depletion(TCD) reduces graft-versus-host disease (GVHD) severity but compromisesalloengraftment, studies were performed with TCD or non-TCD BM and GVHDrisk was assessed using a tissue scoring system and by the adoptivetransfer of splenocytes from engrafted mice into secondary recipients. Non-SCID recipients received pre-BMT irradiation to simulate those circumstances in which conditioning is required for alloengraftment. IUT recipients of non-TCD and especially TCD BM cells in general hadhigher levels of donor T-cell and myeloid peripheral blood (PB)engraftment than nonconditioned SCID recipients. Increased TCD ornon-TCD BM cell numbers in adult SCID recipients resulted in similarlevels of PB engraftment as IUT recipients. However, under theseconditions, mean GVHD scores were higher than in IUT recipients. Themajority of adoptive transfer recipients of splenocytes from IUTrecipients were GVHD-free, consistent with the in vitro evidence oftolerance to host alloantigens. Total body irradiation (TBI)-treatedmice that had the highest engraftment had evidence of thymic damage asdenoted by a higher proportion of thymic and splenic T cells with amemory phenotype as compared with IUT recipients. IUT mice had vigorousthymic reconstitution by 3 weeks of age. Our data indicate that IUT hasa number of advantages as compared with postnatal BMT. Future studiesexamining the fine specificity of immunoreconstitution in IUT versuspostnatal BMT are indicated.     

Late onset post-transplantation lymphoproliferative disease of recipient origin following cytogenetic relapse and occult autologous haematopoietic regeneration after allogeneic bone marrow transplantation for acute myeloid leukaemia

A post-transplantation lymphoproliferative disease (PTLD) of recipient origin was identified in one of 376 consecutive cases of allogeneic bone marrow transplantation (BMT). This occurred in a 36-year-old woman who received an allogeneic BMT for acute myeloid leukaemia in relapse. At 15 months after BMT, recipient haematopietic and leukaemic cells were found in the bone marrow, which disappeared on withdrawal of immunosuppression. However, severe graft-versus-host disease (GVHD) necessitated the continuation of immunosuppression, leading to the occurrence of PTLD in the liver and lung 12 months afterwards. Fluorescence in situ hybridisation showed that the neoplastic cells were of recipient origin. Although the PTLD also responded completely to withdrawal of immunosuppression, the patient finally died from the complications of GVHD. This case of late onset PTLD post-BMT showed features similar to those in solid organ transplantation, in that the tumour was of recipient origin and responded well to the withdrawal of immunosuppression. Of further interest is that recipient lymphoid regeneration had accompanied autologous haematopoietic regeneration and become a target for subsequent neoplastic transformation.     

Poor prognosis acute myeloid leukaemia treated by matched unrelated donor marrow transplant without preceding total body irradiation.

Two patients with acute myeloid leukaemia, one in relapse after autologous bone marrow transplantation (BMT) (aged 52 years) and the other with primary resistant disease secondary to previously treated malignancy, have received marrow transplants from matched unrelated donors. Cytoreductive conditioning in both cases was with high-dose combination chemotherapy alone. Engraftment was aided by the administration of total lymphoid irradiation together with in vivo antilymphocyte antibody prior to marrow infusion. Both patients survive in complete remission, currently at 12 and 15 months post-BMT respectively. The avoidance of total body irradiation in BMT patients at high risk of early treatment-related mortality may be advantageous.     

A Critical Role for CD48 Antigen in Regulating Alloengraftment and Lymphohematopoietic Recovery After Bone Marrow Transplantation

The binding of CD2, present on T cells, to its counterreceptor CD48facilitates adhesion, signaling, alloantigen-induced cytokine production, and cytotoxic T-lymphocyte responses. Becausethese T-cell functions have been implicated in graft-versus-hostdisease (GVHD) pathogenesis, we have analyzed the effects of theCD2:CD48 pathway on GVHD mediated by CD4⁺ andCD8⁺ T cells infused into sublethally irradiatedrecipients. CD4⁺ T-cell-mediated, and to a lesserextent, CD8⁺ T-cell-mediated GVHD was inhibited byCD2 + 48 monoclonal antibody (MoAb) infusion. To assessthe effects of combined MoAb infusion on alloengraftment, two differentalloengraftment bone marrow transplantation (BMT) models were used. Inboth, MoAb infusion markedly inhibited alloengraftment andhematopoietic recovery post-BMT. To determine if the adverse effects onlymphohematopoiesis in the allogeneic BMT recipients were caused by animmune or nonimmune mechanism, studies were performed in congenic BMTrecipients to preclude an immune mechanism as the cause for delayedrecovery post-BMT. MoAb infusion resulted in impairedlymphohematopoietic recovery in congenic BMT recipients and markedlyreduced day 12 colony-forming unit-spleen formation in syngeneic BMTrecipients, consistent with a nonimmune mediated mechanism. Because thespleen is a site of early hematopoietic recovery post-BMT, studies were performed using adult splenectomized syngeneic BMT recipients. MoAbinfusion delayed recovery in both nonsplenectomized and splenectomized recipients post-BMT, indicating that the delayed hematopoietic recoverywas not the consequence of an abnormal homing pattern of hematopoieticprogenitors to the spleen early post-BMT. CD48 MoAb was necessaryand sufficient for the inhibition of GVHD lethality and delayedlymphohematopoietic effects of the combined MoAb regimen. CD48 MoAbwas found to induce a profound modulation of CD48 antigen expression onBM cells, suggesting that the CD48 antigen may have an importantfunction in hematopoiesis in the BM compartment. Taken together, thesedata provide evidence that the CD48 antigen plays a critical role inregulating hematopoiesis in post-BMT.     

Minimal residual disease is more common in patients who have mixed T- cell chimerism after bone marrow transplantation for chronic myelogenous leukemia

Determining both lymphoid chimerism and the presence of minimal residual disease after allogeneic bone marrow transplantation (BMT) for chronic myelogenous leukemia (CML) could be helpful to the understanding of the biology of leukemic relapse in this disease. We prospectively investigated 32 patients with CML post-BMT by assessing T- cell chimerism and minimal residual disease using sensitive polymerase chain reaction (PCR) methodologies. Patients were studied between 1 and 24 months post-BMT. Thirty patients received a T-cell-depleted marrow grafts and 2 received unmanipulated marrow. All but 1 patient were conditioned with total body irradiation (TBI)+thiotepa+cyclophosphamide (Cy). The other patient received TBI+Cy as conditioning. The T cells were exclusively of donor origin in 12 of 16 patients who were tested at 1 month post-BMT, but were mixed chimeric in 11 of these patients by > or = 3 months. Once mixed T-cell chimerism was documented, no patient returned to having all donor T-cells. At a median follow-up of 12 months, minimal residual disease was present in 18 of 22 patients with mixed T-cell chimerism and in 3 of 10 patients with full donor chimerism. The actuarial molecular relapse rate at 24 months for the two groups is 91% and 33%, respectively (P < .02). The finding of BCR- ABL mRNA within the first 6 months of transplant or on two consecutive assays was highly predictive of subsequent cytogenetic or hematologic relapse (P = .032 and P < .02, respectively). Ten patients, 9 with mixed T-cell chimerism, have relapsed (4 clinical, 6 cytogenetic) at a median of 12 months post-BMT. These data suggest that mixed T-cell chimerism may be a marker for abrogation of graft-versus-leukemia activity that is thought to be pivotal in eradicating minimal residual disease after BMT for CML.     

Donor immunization with Haemophilus influenzae type b (HIB)-conjugate vaccine in allogeneic bone marrow transplantation

Bone marrow transplant patients are at increased risk for infections with polysaccharide encapsulated organisms and respond poorly to polysaccharide vaccines. We evaluated the effect of donor immunization with Haemophilus influenzae type b (HIB) polysaccharide-conjugate vaccine on recipient antibody responses following allogeneic bone marrow transplantation. Thirty-two allogeneic transplant patients and their donors were immunized before transplantation with HIB-conjugate, tetanus toxoid and 23-valent pneumococcal vaccines. Following transplantation, patients received HIB-conjugate and tetanus toxoid vaccines at 3, 6, 12, and 24 months and 23-valent pneumococcal vaccine at 12 and 24 months. Thirty-three patients with unimmunized donors were immunized following transplantation in an identical manner. Patients whose donors were immunized had significantly higher total anti-HIB antibody concentrations at 3 months (P = .0001), 6 months (P = .0001), 12 months (P = .0001), and 24 months (P = .002) after transplant compared with patients whose donors were unimmunized. Higher antitetanus toxoid antibody concentrations were also noted in patients with immunized donors, whereas donor immunization with pneumococcal vaccine had no effect on antibody concentrations following transplantation. Donor immunization with HIB-conjugate vaccine resulted in higher antibody concentrations in patients as early as 3 months after allogeneic transplantation and may be an effective strategy to prevent HIB infections.     

Defective interleukin 2 production in patients after bone marrow transplantation and in vitro restoration of defective T lymphocyte proliferation by highly purified interleukin 2

Using OKT3 monoclonal antibody as a mitogen, we have studied interleukin 2 (IL2) production and proliferation in peripheral blood mononuclear cells (PBMC) of 23 patients receiving bone marrow transplants. Twenty patients were recipients of allogeneic bone marrow for treatment of hematologic malignancies, aplastic anemias (AA), or severe combined immunodeficiencies (SCID). Three patients with Hodgkin's disease or neuroblastoma received autologous bone marrow. Endogenous IL2 production was not detectable (less than 0.2 U/mL) in PBMC of 18 patients and was very low in PBMC from five patients (0.5 to 1.5 U/mL), as compared to normal controls (median 3.5 U/mL) or pretransplant patients (median 1.5 U/mL). The low IL2 production was associated with defective OKT3-induced proliferation of PBMC in 19 of 23 patients studied. In the first 6 months after BMT, 14 of 15 patients (93%) showed defective proliferation of PBMC as compared to five of eight patients (63%) tested between 7 and 18 months after BMT (P less than .1). In all but three patients, addition of highly purified human lymphocyte IL2 (hpIL2) restored OKT3-induced proliferation of PBMC to within the normal range. This study demonstrates that PBMC in patients after BMT have a defect of IL2 production but are able to express IL2 receptors in response to OKT3 antibody and to proliferate normally upon addition of hpIL2. PBMC of all patients showed similar functional defects, whether or not they received additional therapy, including various conditioning regimens prior to BMT and immunosuppressive therapy after BMT. These observations suggest that T cell defects after BMT are most likely secondary to quantitative or qualitative defects of transplanted T lymphocytes or their precursors.     

Markedly increased serum erythropoietin levels following conditioning for allogeneic bone marrow transplantation

Serum erythropoietin (EPO) levels were measured by radioimmunoassay in 36 patients undergoing allogeneic bone marrow transplantation (BMT). Serum EPO levels before conditioning treatment for BMT were generally higher than the levels obtained from healthy controls (49 +/- 17 (SEM) and 17 +/- 0.6, respectively). One day prior to BMT, after conditioning by chemotherapy with or without total body irradiation, the mean EPO level was markedly elevated (218 +/- 23 U/l, p less than 0.001) and reached to its highest level at 1 week post-BMT (269 +/- 40 U/l). Although, the EPO levels were significantly lower at 1 month (98 +/- 24 U/l, p less than 0.001), they were still elevated up to 3 months post-BMT, after which they gradually normalized. Patients given methotrexate and cyclosporine for prophylaxis against graft-versus-host disease (GVHD) had significantly lower EPO levels during the first 3 months post-BMT than patients transplanted with T cell-depleted marrow (p less than 0.05). Patients with post-transplant nephrotoxicity had lower, though not statistically significant, EPO levels than patients with normal renal function (p = 0.07). Acute GVHD and number of blood transfusions had no influence on serum EPO levels after BMT.     

Histological changes during clearance of chronic hepatitis B virus infection by adoptive immunity transfer

BACKGROUND: Serological clearance of hepatitis B surface antigen (HBsAg) has been described after reception of hepatitis B surface antibody positive marrow, via allogeneic bone marrow transplantation (BMT). Histological changes during the clearance of HBsAg are unknown. METHODS AND RESULTS: We described two chronic hepatitis B carriers (both hepatitis B e antigen negative), who cleared HBsAg after allogeneic bone marrow transplantation. Both received hepatitis B surface and core antibody positive human leucocyte antigen identical donors' marrow and had serological clearance of HBsAg 15 and 7 weeks after allogeneic BMT, respectively. Both events were preceded by hepatic flare. Both patients were also treated with famciclovir for the prevention of hepatitis B reactivation after BMT. Histological examination during the flare showed only mild necroinflammatory activity with multiple foci of confluent necrosis, associated with moderate lymphocytic infiltration. The majority of these lymphocytes were cluster of differentiation (CD) 8 positive. Using immunohistochemistry, there was no detectable hepatic expression of hepatitis B core antigen. However, HBsAg was positive, mainly in the area of confluent necrosis. Using in situ hybridization, hepatitis B virus (HBV) DNA was detected in the nucleus of 5% of hepatocytes, but not in the cytoplasm. CONCLUSIONS: At their last follow up, 22 and 16 months after BMT, the serum of both patients remained HBsAg negative, hepatitis B surface antibody positive and HBV-DNA negative by branched DNA assay.     

The effect of tumor necrosis factor blockade on the response to pneumococcal vaccination in patients with rheumatoid arthritis and ankylosing spondylitis

OBJECTIVE: To assess the effect of anti-tumor necrosis factor (TNF) alpha therapies on the immunogenicity of pneumococcal vaccination in patients with rheumatoid arthritis (RA) and ankylosing spondylitis (AS). METHODS: A group of 16 consecutive patients (11 with RA and 5 with AS) treated either with infliximab or etanercept, and a control group of 17 age-matched RA patients treated with disease-modifying medications other than anti-TNF-alpha, received intradeltoid injection with 0.5 mL of pneumococcal vaccine. Pneumococcal polysaccharide (PPS)-specific IgG to 7 vaccine PPS (representing high- and low-prevalence serotypes) was measured by enzyme-linked immunosorbent assay in sera obtained before and 1 month after pneumococcal immunization. RESULTS: One month after vaccination, both groups had significant increases in the geometric mean concentration of capsule PPS-specific antibody and in the mean fold increase in antibody levels to all 7 serotypes, compared with prevaccination levels. However, compared with the control group, the TNF-alpha blockade-treated patients tended to have lower antibody increases for all the serotypes tested except serotype 14. In addition, lower proportions of TNF-alpha blockade-treated patients responded to pneumococcal vaccination compared with patients on other therapies. Similarly, more TNF-alpha blockade-treated patients were poor responders compared with patients not on anti-TNF-alpha treatment. CONCLUSION: Treatment of groups of patients with etanercept or infliximab does not impair their mean antibody responses to pneumococcal vaccination. However, a larger proportion of RA patients may not respond adequately to pneumococcal vaccination once on TNF-alpha blockade therapies. Consequently, pneumococcal vaccination before starting TNF-alpha blockade therapy is recommended.     

Human herpesvirus-6 infection in bone marrow transplantation.

Twenty-five pediatric patients who received bone marrow transplantation (BMT) were studied prospectively to determine the relationship between BMT and human herpesvirus-6 (HHV-6) infection by the virus isolation from peripheral blood and/or bone marrow and by determining neutralizing antibodies to HHV-6 during the 2 months following BMT. All of the 25 donors and the recipients were immune to HHV-6 at the time of BMT and the virus was not isolated from them. HHV-6 was isolated from peripheral blood and/or bone marrow mononuclear cells in ten (40%) of the 25 recipients between day 14 and day 22 of BMT, but not from any other day. Two additional recipients showed a significant increase in the antibody titer. Thus, infection with HHV-6 was confirmed in 12 (48%) of the 25 recipients. Four of the 12 developed skin rashes; three of these four had a febrile episode when the virus was isolated, whereas none of the remaining 13 developed the skin rash. These results suggest a frequent infection with HHV-6 only a few weeks after BMT and a close association between the infection with the virus and the development of skin rashes.     

Cytotoxic T-lymphocyte response to cytomegalovirus after human allogeneic bone marrow transplantation: pattern of recovery and correlation with cytomegalovirus infection and disease.

The high rate of severe cytomegalovirus (CMV) disease after bone marrow transplantation (BMT) is related to the profound immunodeficiency posttransplant. Because cytotoxic T lymphocytes (CTL) have been implicated in resistance to viral infections, we examined the restoration of the CMV-specific CTL response in 20 patients who received bone marrow from HLA-matched, CMV-seropositive donors. Blood specimens were obtained from patients at 1, 2, and 3 months after BMT and from the donors on a single occasion. Peripheral blood mononuclear cells were cocultured with CMV-infected donor-derived fibroblasts for 2 weeks and then tested for cytotoxicity against CMV-infected and uninfected autologous or HLA-mismatched fibroblasts. Cytolytic activity was detected in all 20 donors, with specificity for autologous CMV-infected targets demonstrable in 17 (median CMV-specific lysis at an effector:target ratio of 15:1 was 32%, range 18% to 83%). Specific lysis was mediated by CD8+, class I-restricted T cells, as shown by inhibition with anti-class I monoclonal antibody and by selective depletion of effector cells. By contrast, CMV-specific CTL were detected in only 10 of 20 patients after BMT (median lysis 29% at 3 months post-BMT). None of these 10 patients developed CMV pneumonia, whereas 6 of the 10 patients with an undetectable CMV-specific CTL response after BMT died with CMV pneumonia. These results demonstrate that restoration of CMV-specific CTL responses may require an extended time period after BMT in some patients, and that such patients are at increased risk of developing severe CMV disease. Approaches to reconstitute CMV immunity in BMT patients by adoptive transfer of CMV-specific CD8+ CTL clones derived from the bone marrow donor are now being pursued.     

Busulphan/cyclophosphamide conditioning for bone marrow transplantation may lead to failure of hair regrowth

Following the introduction of bulsulphan and cyclophosphamide (BUCY) conditioning in our unit in 1987, a number of patients noted incomplete scalp hair regrowth following bone marrow transplantation (BMT). Between August 1987 and May 1989, 22 patients had undergone allogeneic or autologous BMT in our unit and we recalled for detailed assessment the 14 who were alive and well at least 6 months post grafting. Six patients had experienced incomplete hair regrowth of varying severity 7-27 months following BMT. All those affected had received BUCY conditioning and the four most severely affected were allogeneic BMT recipients. No patient had received any post-BMT chemotherapy or radiation. None of the patients had evidence of graft-versus-host disease. No laboratory test abnormalities distinguished the affected from the unaffected patients. Despite the relatively small number of patients, our results suggest that BUCY has caused permanent damage to the hair follicles of the affected patients. Prolonged alopecia may markedly impair the quality of life for long-term survivors of BMT and this unexpected complication also has significant medicolegal implications.     

Failed adoptive immunity transfer: reactivation or reinfection?

A 26-year-old female bone marrow transplant (BMT) recipient was hepatitis B surface antigen (HBsAg) and hepatitis B e antibody (HBeAb) positive. The donor, her human leucocyte antigen (HLA)-compatible sister, was HBsAg negative but hepatitis B surface antibody (HBsAb) and hepatitis B core antibody (HBcAb) positive. Twelve weeks post-BMT the patient became HBsAg negative, as determined using a monoclonal antibody-based assay. At 16 weeks post-BMT, HBsAg became undetectable by monoclonal and polyclonal immunoassay with seroconversion to HBsAb; however, at 24 weeks post-BMT the patient again became HBsAg positive. Both the recipient and the donor were retrospectively tested by hepatitis B virus (HBV) polymerase chain reaction (PCR) and found to be positive. The recipient displayed variants at amino acids 4 and 47 of the surface (S) gene prior to BMT. These mutations were not detected 32 weeks post-BMT when the S gene sequence was identical to that of an adr prototype. The donor was found to have four unique amino acid substitutions at positions 30, 98, 101 and 210 of the S gene. However, in vitro -expressed HBsAg from the donor was detected by commercial kits and an immunofluorescence assay, indicating that antigenic alteration did not explain HBsAg negativity. This donor highlights the value of PCR as the gold standard test for current HBV infection. It also demonstrates that discordance between two commercial HBsAg assays may not always be caused by antigenic variants. The second episode of hepatitis may theoretically have been caused by reactivation, selection of an escape mutant by HBsAb, reinfection or recombination. We suggest it was reactivation because none of the donor variants was seen in the recipient post-BMT.     

The development of cellular immunity to Epstein-Barr virus after allogeneic bone marrow transplantation

Epstein-Barr virus-induced lymphoproliferative disease (EBV-LPD) is a potentially lethal complication during the first 6 months after allogeneic bone marrow transplantation (BMT). To determine whether deficiencies of EBV-specific cellular immunity contribute to EBV-LPD susceptibility and distinguish patients at risk, we performed limiting dilution analysis to quantify anti-EBV cytotoxic T-lymphocyte precursor (CTLp) frequencies in 26 recipients of unmodified or T-cell-depleted (TCD) grafts from EBV-seropositive donors. At 3 months post-BMT (n = 26), only five patients had EBV CTLp frequencies in the range of seropositive normal controls, irrespective of the type of transplant administered. By 6 months post-BMT, 9 of 13 patients tested had EBV CTLp frequencies within the normal range. The time period in which these patients had deficient cellular immunity to EBV corresponds to the period in which we have observed EBV-LPD in most prior patients. One patient with a low EBV CTLp frequency at 4 months post-BMT developed an EBV-LPD. Within 2 weeks of receiving an infusion of donor peripheral blood mononuclear cells (PBMC) providing less than 1,200 EBV- specific cytotoxic T-cell precursors, populations of EBV-specific CTL in the circulation were restored to levels detected in normal seropositive adults. Concurrently, the patient achieved a regression of the EBV-LPD, which has been sustained without further therapy. These studies indicate that recipients of both unmodified and TCD marrow grafts have profound deficiencies of EBV-specific T cell-mediated immunity early posttransplant, and that the period of risk for EBV-LPD closely corresponds to this interval of severe deficiency. Treatment of one patient with EBV-LPD with marrow donor-derived PBMC induced a rapid expansion of EBV-specific cytotoxic T-cell populations that occurred contemporaneously with the clinical regression of disease.