Lack of isohemagglutinin production following minor ABO incompatible unrelated HLA mismatched umbilical cord blood transplantation

While immune hemolysis due to donor isohemagglutinin (IH) production often complicates minor ABO incompatible peripheral blood hematopoietic stem cell transplantation (PBSCT), it is not known if this occurs with umbilical cord blood transplantation (UCBT). We compared IH production and hemolysis following minor ABO allogeneic PBSCT and UCBT. We reviewed 24 ABO minor incompatible allogeneic PBSCTs and 14 ABO minor incompatible UCBTs. Patients were evaluated for donor-derived IH by reverse ABO grouping. Evaluation of hemolysis was based on clinical and laboratory findings of anemia associated with increased RBC transfusion need, concomitant with the appearance of donor-derived IH. Of the 24 ABO minor incompatible allogeneic PBSCTs, 15 produced donor-derived IH from 6 to 88 days following transplantation, with seven of 15 patients exhibiting clinically evident hemolysis. There was no significant difference in days to leukocyte engraftment or infused CD34 cells in patients with or without donor-derived IH. None of the 14 patients receiving ABO incompatible UCBTs showed evidence of donor-derived IH following transplantation with a median follow-up of 60 days. We conclude that donor IHs are not produced in patients undergoing minor ABO incompatible UCBTs suggesting fundamental immunologic differences between allogeneic PBSCT and UCBT.     

Four Cases of Desquamative Esophagitis Occurring after Hematopoietic Stem Cell Transplantation

We herein report four patients with desquamative esophagitis that developed one to nine days after peripheral blood stem cell transplantation (PBSCT). Three patients underwent allogeneic PBSCT for leukemia, and the other underwent autologous PBSCT for pineoblastoma. Esophagogastroduodenoscopy revealed mucosal sloughing and fresh blood in the esophagus. Fasting and intravenous proton pump inhibitor therapy in addition to blood transfusion improved the esophageal lesions within five to seven days in three patients. These cases indicate that desquamative esophagitis can occur in patients who receive hematopoietic stem cell transplantation. Although blood transfusions may be required, it can be resolved within seven days.     

High-dose acyclovir and pre-emptive ganciclovir in prevention of cytomegalovirus disease in pediatric patients following peripheral blood stem cell transplantation

Cytomegalovirus (CMV) disease remains an important cause of morbidity and mortality in patients undergoing hematopoietic stem cell transplantation (HSCT). We evaluated high-dose acyclovir (HDACV) and pre-emptive ganciclovir to prevent CMV disease in 76 children who underwent peripheral blood stem cell transplantation (PBSCT) and were at risk for CMV reactivation and disease (both recipient and donor seropositive) from May 1998 to April 2003. All received HDACV from day -9 to 6 months post transplant in conjunction with weekly CMV pp65 antigenemia monitoring. The incidence of antigenemia in this cohort was 19.7%, at a median of 22 days post-PBSCT. The frequencies were 26.4 and 4.4% in allogeneic and autologous groups, respectively (P=0.03). Patients with nonmalignant disease had higher CMV antigenemia than those with malignant disease (30.8 vs 8.1%, P=0.02). Age at PBSCT, sex, graft-versus-host disease (GVHD) prophylaxis regimen and presence of acute GVHD did not affect the risk of CMV antigenemia. None of the patients who had positive pp65 antigenemia developed CMV disease during the study period. We conclude that pp65 antigenemia-guided HDACV and pre-emptive ganciclovir may prevent CMV disease in children undergoing PBSCT.     

Comparisons between allogeneic peripheral blood stem cell transplantation and allogeneic bone marrow transplantation in adult hematologic disease: a single center experience

This retrospective study compared the outcomes in 32 adult patients with hematologic diseases (acute myeloid leukemia, acute lymphoblastic leukemia, chronic myeloid leukemia, myelodysplastic syndrome, severe aplastic anemia) who received allogeneic bone marrow transplantation (BMT, n = 14; median age, 28 years) or allogeneic peripheral blood stem cell transplantation (PBSCT, n = 18; median age, 29 years) from human leukocyte antigen-identical sibling donors. Median follow-up was 58 months in BMT recipients and 18 months in PBSCT recipients. Neutrophil (median, Day 8 vs Day 13, p < 0.001) and platelet engraftment (median, Day 9 vs Day 17, p < 0.001) was faster in the PBSCT group than in the BMT group. Patients receiving PBSCT required less platelet transfusion than those receiving BMT (median, 54 units vs 144 units, p < 0.001), but there was no significant difference in red cell transfusion. At 100 days, there was no difference in the incidence of acute graft-versus-host disease (GVHD) (42.9% vs 33.3%, p = 0.72) or grade II-IV acute GVHD (14.3% vs 5.6%, p = 0.57), and there was no difference in the cumulative incidence of chronic GVHD (20% vs 33.3%, p = 0.67). No chronic GVHD was noted in any relapsed patients (BMT, 5; PBSCT, 3), and no patients with chronic GVHD during follow-up had a relapse. Relapse was the most frequent cause of death inboth groups (BMT, 5/9, 55.6%; PBSCT, 3/4, 75%; p = 0.25); all relapses occurred within 1 year after transplantation. Overall survival was significantly better in the PBSCT group (35.7% vs 77.8%, p = 0.029), but this difference was lost if only hematologic malignancies were analyzed (30.8% vs 63.6%, p = 0.20). Our results are similar to those reported previously, with faster neutrophil and platelet engraftment and less severe acute GVHD and extensive chronic GVHD with PBSCT. Allogeneic PBSCT is a feasible and beneficial alternative to allogeneic BMT in adult hematologic disease.     

Bleeding risk and platelet transfusion refractoriness in patients with acute myelogenous leukemia who undergo autologous stem cell transplantation

Therapy for acute myelogenous leukemia can be complicated by alloimmunization to histocompatibility antigens (HLA), with resultant refractoriness to platelet transfusions. Autologous peripheral blood or bone marrow stem cell transplantation (referred here collectively as 'autoBMT') is emerging as a standard consolidative strategy in acute myelogenous leukemia (AML). We had noted life-threatening bleeding associated with platelet transfusion refractoriness following autoBMT; we therefore retrospectively analyzed 39 AML patients for this complication following BMT. All patients received high-dose chemoradiotherapy, followed by infusion of allogeneic sibling donor (n = 12, alloBMT) or autologous (n = 27, autoBMT) stem cells. HLA alloimmunization was assessed if patients were suspected of immune refractoriness to random donor platelet transfusions. Within 100 days of stem cell infusion, one of three alloBMT and six of 12 autoBMT recipients tested were HLA alloimmunized (not statistically significant, NS). Five of six HLA alloimmunized autoBMT patients experienced delayed bleeding, which contributed to their demise while still in remission (P < 0.001). Increased platelet requirements in HLA alloimmunized autoBMT recipients were observed between days 61 and 100 post-BMT, at a median of 211 platelet transfusions vs 0 in non-alloimmunized autoBMT patients (P < 0.01) and 17 in alloBMT patients. Our data suggest that platelet transfusion refractoriness, when associated with HLA alloimmunization, is a risk factor for increased platelet transfusion requirements, delayed bleeding, and poor outcome following autoBMT for AML.     

Successful non-myeloablative allogeneic peripheral blood stem cell transplantation (PBSCT) for Waldenström's macroglobulinemia with severe pancytopenia

We report a 62-year-old male who underwent non-myeloablative allogeneic peripheral blood stem cell transplantation (PBSCT) because of his life-threatening severe pancytopenia due to refractory Waldenstr?m's macroglobulinemia. This therapy was performed safely and he made a marked recovery from his cytopenia that had not been improved with any other therapy. Bone marrow aspirates showed post-transplant mixed chimerism during engraftment, and became completely donor-derived after a series of GVHD symptoms, without subsequent donor lymphocyte infusion. Our results suggest that non-myeloablative allogeneic PBSCT could be a good alternative for patients suffering from multi-drug resistant Waldenstr?m's macroglobulinemia.     

Universal prestorage leukoreduction in Canada decreases platelet alloimmunization and refractoriness

Randomized controlled trials have shown a reduction in platelet alloimmunization and refractoriness in patients with acute leukemia (AL) with the use of poststorage leukoreduction of blood products. Universal prestorage leukoreduction (ULR) of red cell and platelet products has been performed in Canada since August 1999. We conducted a retrospective analysis of 13 902 platelet transfusions in 617 patients undergoing chemotherapy (CT) for AL or stem cell transplantation (SCT) before (n = 315) and after (n = 302) the introduction of ULR. Alloimmunization was significantly reduced (19% to 7%, P <.001) in the post-ULR group. Alloimmune platelet refractoriness was similarly reduced (14% to 4%, P <.001). Fewer patients in the post-ULR group received HLA-matched platelets (14% vs 5%, P <.001). Alloimmunization and alloimmune refractoriness in the 318 patients who were previously pregnant and/or transfused were also reduced after ULR (P =.023 and P =.005, respectively). In a Cox regression model, the 3 independent factors that predicted for alloimmune refractoriness were nonleukoreduced blood products (relative risk [RR], 2.2 [95% CI, 1.2-4.3]), a history of pregnancy and/or transfusion (RR, 2.3 [95% CI, 1.3-4.2]), and receipt of 13 or more platelet transfusions (RR, 6.0 [95% CI, 2.4-15.3]). In conclusion, ULR reduces alloimmunization, refractoriness, and requirements for HLA-matched platelets when applied as routine transfusion practice to patients receiving CT or SCT.     

Impact of early NK cell recovery on development of GvHD and CMV reactivation in dose-reduced regimen prior to allogeneic PBSCT

Dose-reduced allogeneic peripheral blood stem cell transplantation (PBSCT) is a therapeutic approach for patients with haematological malignancies who are not eligible for conventional allogeneic PBSCT. We analysed early development of lymphocyte subpopulations and the occurrence of cytomegalovirus (CMV) reactivation and acute graft-versus-host reaction (GvHD) in patients undergoing the protocol according to Slavin vs conventionally treated patients. Lymphocyte status prior to conditioning and at day +30 after allogeneic PBSCT was determined in 24 out of 51 patients who received conventional allogeneic PBSCT (eg cyclophosphamide plus total body irradiation) and compared with 27 patients being treated according to the Slavin protocol (fludarabine, busulphan and ATG). There is a significant delay in CD4 (T helper) cell development and consecutive lower CD4/CD8 ratios and a better reconstitution of CD8 (T cytotoxic) and NK (natural killer) cells after the Slavin protocol. Patients undergoing this protocol and no, or only grade I, acute GvHD show an even better NK cell reconstitution compared to patients with grade II-IV GvHD. A low CD4/CD8 ratio represents a CMV risk factor only in conventionally treated patients with grade 0-I GvHD, while after preparative regimen according to the Slavin protocol, the NK/CD8 ratio might be a marker for the prediction of CMV reactivation in addition to CMV risk status.     

Cytomegalovirus antigenemia and outcomes of patients undergoing allogeneic peripheral blood stem cell transplantation: effects of long-term high-dose acyclovir prophylaxis and preemptive ganciclovir treatment

Cytomegalovirus (CMV) disease is a frequent cause of morbidity and mortality following allogeneic hematopoietic stem cell transplantation. In order to investigate the relationships between antigenemia, high-dose acyclovir (HDACV) prophylaxis, preemptive ganciclovir (GCV) therapy, and outcomes, we analyzed the records of 105 patients, including both pediatric and adult populations, who underwent allogeneic peripheral blood stem cell transplantation (PBSCT) and who were at risk for CMV reactivation and disease (both recipient and donor seropositive). All received HDACV until neutrophil engraftment, but prophylaxis was continued till post-transplant day 180 only in pediatric patients in conjunction with weekly CMV pp65 antigenemia monitoring. Antigenemia-guided preemptive strategy with GCV was used for all patients. CMV antigenemia developed in 45 patients (42.9%) and CMV disease in 13 (12.4%). The frequencies for antigenemia were 31.3 and 63.2% in pediatric and adult groups (P = 0.002). All CMV diseases were in the adult group (P<0.001). Age at transplantation, underlying disease, long-term HDACV prophylaxis and acute graft versus host disease (aGVHD) were all found to be a significant risk factors for antigenemia. All of these factors other than aGVHD and conditioning regimen were also the significant risk factors for CMV disease. However, when we analyzed the pediatric and adult patients separately, dropping "long-term HDACV prophylaxis," none of these parameters were significant risk factors for CMV disease. In conclusion, we hypothesize that long-term HDACV prophylaxis in the GCV era results in a low incidence of CMV reactivation and disease in patients undergoing PBSCT.     

Allogeneic peripheral blood stem cell transplantation for a hepatitis B virus carrier with Epstein-Barr virus associated with hemophagocytic syndrome

We report herein a 21-year-old hepatitis B virus (HBV) female carrier who developed persistent fever, lymphadenopathy and pancytopenia in September of 2000. Hemophagocytes were found in the bone marrow smears. Epstein-Barr virus (EBV) serology showed positive for VCA-IgG, IgM and EB-ER and negative for EBNA. The EBV genome was detected in the peripheral blood. The patient was diagnosed as having EBV-associated hemophagocytic syndrome (EBV-AHS) and received chemotherapy. Although she was treated with lamivudine three months after the initiation of chemotherapy, she developed severe hepatitis. She recovered from the hepatitis through a combination of plasma exchange, immunosuppressive and antiviral therapies. Because of the refractoriness of her EBV-AHS to chemotherapy, she received allogeneic peripheral blood stem cell transplantation (PBSCT) from her HLA-identical brother. Hepatitis B did not recur after the PBSCT under administration of lamivudine. The EBV genome in the peripheral blood disappeared soon after the PBSCT but it was revealed again after the initiation of prednisolone for the treatment of acute GVHD. A donor lymphocyte infusion (DLI) was given on day 169 and the EBV genome copy number in the peripheral blood gradually decreased and disappeared. Although the origin of the EBV-infected cells could not be determined as being from the host or donor, DLI was a useful treatment for the recurrence of EBV infection after allogeneic stem cell transplantation for EBV-AHS.     

An animal model of allogeneic donor platelet refractoriness: the effect of the time of leukodepletion.

Approximately 50% of multi-transfused individuals become refractory to random donor platelets. Recent clinical data suggest that those patients receiving leukocyte-depleted blood products are less likely to become refractory to random donor platelets than recipients of non-leukocyte-depleted products. Leukocyte depletion can be performed immediately after collection of a unit of whole blood before its storage (prestorage leukodepletion) or just before the transfusion of the blood product to a recipient, after its storage (poststorage leukodepletion). However, the most appropriate time for the leukodepletion of blood products has not been established. The present study was undertaken to establish an animal model of allogeneic platelet refractoriness, and to compare the effect of prestorage and poststorage leukodepletion on the frequency of refractoriness to allogeneic donor platelets. In this model, two strains of rabbits were used: California Black rabbits were used as blood donors, while New Zealand White rabbits were used as recipients. Eight weekly infusions of nonleukodepleted allogeneic fresh blood resulted in an allogeneic platelet refractory rate of 91.2% (31/34). The prestorage leukodepletion of the donor blood was associated with a significantly higher allogeneic platelet survival and lower refractory rate (33.3%) to allogeneic platelets than poststorage leukodepletion (66.7%). Furthermore, the data suggest that cell-free plasma products are capable of inducing refractoriness to allogeneic donor platelets; the stored plasma having a greater likelihood of inducing such refractoriness than fresh plasma. Thus, these data provide evidence that the prestorage leukodepletion of allogeneic donor blood is associated with a lower frequency of refractoriness and better allogeneic platelet survival than poststorage leukodepletion.     

First report of donor cell-derived acute leukemia as a complication of umbilical cord blood transplantation

Donor cell leukemia is a rare complication after allogeneic hematopoietic stem cell transplantation. A 12-month-old boy underwent unrelated donor umbilical cord blood transplant (UCBT) for refractory Langerhan's cell histiocytosis. Forty months after transplantation, he developed acute myeloid leukemia. Cytogenetic and molecular analysis confirmed donor cell origin. The Cord Blood Bank (CBB) contacted the donor's family and established that the child, now 7 years old, was healthy. This represents the first reported case of donor cell leukemia following UCBT. This case illustrates that donor cell leukemia is a rare but real event after UCBT as with other stem cell sources and highlights the need for CBBs to maintain linkage data between donors and recipients.     

Successful treatment with allogeneic peripheral blood stem cell transplantation and granulocyte transfusion for severe aplastic anemia with sinusitis

A 43-year-old woman with severe aplastic anemia (SAA) received anti-thymocyte globulin and cyclosporin A (CyA) and achieved hematological remission. Although she had maintained hematological remission, the disease relapsed 10 months after arbitrary discontinuance of maintenance therapy with CyA. Resumption of CyA therapy was not effective, and her condition became complicated with progressive sinusitis with bone destruction, which was refractory to antibiotics, antifungal agents, granulocyte colony-stimulating factor, and surgical drainage. Because of the necessity for early neutrophil recovery (to resolve the infection), we proceeded with a combination therapy using allogeneic peripheral blood stem cell transplantation (PBSCT) promptly followed by granulocyte transfusion (GTX) from the same human leukocyte antigen-identical donor rather than carrying out a second immunosuppressive therapy. The patient showed temporal resolution of infection on the second day after a single GTX. Although the patient had pneumonia on day 11, it was resolved promptly after engraftment on day 16. This report suggests the clinical utility of a salvage therapy with allogeneic PBSCT followed by GTX in a particular case of recurrent SAA with refractory infections.     

Impact of ABO incompatibility on outcome after allogeneic peripheral blood stem cell transplantation

Few studies have addressed the incidence of graft-versus-host disease (GVHD) or survival after ABO-incompatible allogeneic peripheral blood stem cell transplantation (PBSCT). We analyzed the clinical outcome of ABO incompatibility after allogeneic PBSCT. A total of 89 consecutive adult patients with hematological diseases including 49 ABO-identical, 20 major, 15 minor, and five bidirectional ABO-incompatible transplants were enrolled from four medical centers in Korea. No significant difference in engraftment times, graft failure, or transfusion requirements between groups was noted. A clinical diagnosis of severe immune hemolysis or pure red cell aplasia was not made for any patient after transplantation. The incidence of acute or chronic GVHD did not statistically differ between groups. With a median follow-up duration of 13 months (range, 0.5-61 months), the 3-year overall survival estimates for the ABO-identical, major/bidirectional, and minor group were 44.6.0+/-9.0, 43.1+/-11.6, and 43.8+/-13.5%, respectively (P=0.8652), while the 3-year disease-free survival estimates were 33.8+/-7.6, 39.9+/-11.4, and 45.7+/-13.1%, respectively (P=0.8546). We observed that time to neutrophil, platelet, and red blood cell engraftment, transfusion requirements, incidence of acute or chronic GVHD, relapse, and survival were not influenced by ABO incompatibility after allogeneic PBSCT from HLA-matched sibling donors.     

Reticulated platelets as a marker of platelet recovery after allogeneic stem cell transplantation

Reticulated platelets (RP) are the youngest forms of platelets in blood and reflect the rate of bone marrow platelet production. In the present study, we used flow cytometric analysis to determine the percentage of RPs in patients undergoing allogeneic stem cell transplantation. We investigated 10 patients after transplantation from HLA identical siblings: five with acute myeloid leukemia (AML), four with chronic myeloid leukemia (CML), and one patient with myelodysplastic syndrome (MDS). Of the patients examined, four patients underwent allogeneic bone marrow transplantation and six patients underwent peripheral blood stem cell transplantation. It was observed that the initially reduced percentage of RPs (2.9 +/- 1.7%; mean +/- SD) was significantly higher (P = 0.0109) in all patients (13.6 +/- 6.4%) in the following 10-26 days. The RP percentage peak preceded the recovery of peripheral platelet count up to 45.6 x 10(9)/l on average by 3 days. We found no difference in RP% between the AML and CML patients but we did observe that in CML patients the RP percentage increased on average 7 days earlier than in AML patients. The elevated RP percentage reflects increased bone marrow regeneration and can be considered an additional marker of thrombopoietic recovery in the patients undergoing allogeneic stem cell transplantation.     

A randomized, double-blind trial of filgrastim (granulocyte colony-stimulating factor) versus placebo following allogeneic blood stem cell transplantation

Blood stem cell transplantation (BSCT) results in rapid hematopoietic recovery in both the allogeneic and autologous transplant settings. Because of the large numbers of progenitor cells in mobilized blood, the administration of growth factors after transplantation may not provide further acceleration of hematopoietic recovery. A randomized, double-blind, placebo-controlled study was performed to determine the effects of filgrastim (granulocyte colony-stimulating factor; G-CSF) administration on hematopoietic recovery after allogeneic BSCT. Fifty-four patients with hematologic malignancies undergoing a related, HLA-matched allogeneic BSCT were randomly assigned to receive daily filgrastim at 10 microg/kg or placebo starting on the day of transplantation. A minimum of 3 x 10(6) CD34(+) cells/kg in the allograft was required for transplantation. All patients received a standard preparative regimen and a standard regimen for the prevention of graft-versus-host disease (GVHD). The median time to achieve an absolute neutrophil count greater than 0.5 x 10(9)/L was 11 days (range, 9-20 days) for patients who received filgrastim compared with 15 days (range, 10-22 days) for patients who received placebo (P =.0082). The median time to achieve a platelet count greater than 20 x 10(9)/L was 13 days (range, 8-35 days) for patients who received filgrastim compared with 15.5 days (range, 8-42 days) for patients who received placebo (P =.79). There were no significant differences for red blood cell transfusion independence, the incidence of acute GVHD, or 100-day mortality between the groups. The administration of filgrastim appears to be a safe and effective supportive-care measure following allogeneic BSCT.     

Nonmyeloablative allogeneic bone marrow transplantation for treatment of myelodysplastic syndrome complicated by recent intracerebral hemorrhage

A patient with intracerebral hemorrhage is considered ineligible for hematopoietic stem cell transplantation (HSCT). We report a 49-year-old woman with myelodysplastic syndrome (MDS) complicated by refractoriness to platelet transfusion and intracerebral hemorrhage, who underwent allogeneic bone marrow transplantation from an HLA-identical unrelated male donor. Nine days before the scheduled transplantation, she developed dysarthria and right hemiparesis; computed tomography (CT) of the brain disclosed an acute hematoma in the left parietal lobe exceeding 3 cm in diameter. She underwent conditioning with reduced-intensity, including fludarabine (30 mg/m2/day on days -8 to -3), busulfan (4 mg/kg/day on days -6 and -5), and total body irradiation (4 Gy on day -2). Two weeks after transplantation, dysarthria and right hemiparesis began to resolve, and CT showed spontaneous resolution of the hematoma. Simultaneously, engraftment was confirmed. Thus, recent stroke may be not an absolute contraindication for HSCT.     

前列腺素E脂质微球联合小剂量肝素及丹参预防60例异基因造血干细胞移植后肝静脉闭塞病

目的:探讨前列腺素E脂质微球联合小剂量肝素及复方丹参预防肝静脉闭塞病(VOD)的效果.方法:59例急、慢性白血病患者及1例T细胞淋巴瘤患者接受移植治疗.移植患者中3例曾有乙型肝炎病史,1例有轻度脂肪肝病史.移植前所有患者肝功能均正常.采用CyTBI加Ara-C/VP-16或改良BuCy2方案预处理.VOD预防方案:移植前8 d至移植后28 d,采用前列腺素E脂质微球(凯时)30～40vg/d联合小剂量肝素(100U/kg·d-1)及复方丹参30～40 ml/d,发生VOD后继续上述治疗,加用去纤苷10 mg/kg·d-1.结果:59例均获得植入,1例植入失败.2例出现重症VOD,其中1例为接受单倍型半相合外周血干细胞移植的复发ALL患者,1例患者有轻度脂肪肝,接受非血缘外周血干细胞移植.2例均采用较强的清髓性预处理方案,最终死于多脏器功能衰竭.结论:本研究采用的VOD预防方案,VOD发生率低于文献报道,提示前列腺素E脂质微球联合小剂量肝素及复方丹参方案对预防VOD的发生可能有一定效果.     

A possible association between the presence of interleukin-4-secreting cells and a reduction in the risk of acute graft-versus-host disease

OBJECTIVE: We monitored cytokine-secreting cells using an enzyme-linked immunospot (ELISPOT) assay in a prospective study to assess the cytokine network after transplantation. PATIENTS AND METHODS: Peripheral blood mononuclear cells were collected from 23 patients who received allogeneic stem cell transplantation, from before the preconditioning regimen to 56 days after transplantation. The number of interleukin-4 (IL-4), interferon-gamma (IFN-gamma), and tumor necrosis factor-alpha (TNF-alpha)-secreting cells were measured by ELISPOT assay. For IL-4 and IFN-gamma, in vitro stimulation with phorbol 12-myristate 13-acetate and phytohemagglutinin was performed. RESULTS: The frequency of IL-4-secreting cells was significantly higher in five patients receiving peripheral blood stem cell transplantation (PBSCT) than that in 18 patients who received bone marrow transplantation (BMT). Based on IFN-gamma and TNF-alpha release, there was a trend toward a decrease in the number of cytokine-secreting cells in PBSCT compared with BMT. Furthermore, patients who did not develop acute graft-vs-host disease (GVHD, n=5) showed a significantly higher number of IL-4-secreting cells compared with those who developed acute GVHD (n=18). Both IFN-gamma-secreting cells and TNF-alpha-secreting cells showed a trend to increase in number in patients with acute GVHD. In patients who received reduced-intensity stem cell transplantation (n=7) compared with conventional stem cell transplantation (n=16), there was a large number of cytokine-secreting cells detected by IL-4 and IFN-gamma release. CONCLUSIONS: These results are consistent with the hypothesis that IL-4-producing cells inhibit the development of acute GVHD. In addition, the increased percentage of IL-4-secreting cells may be responsible for the unexpected low incidence of acute GVHD in PBSCT, despite the presence of large numbers of mature T cells in the donor infusion.