Differences In Immune Reconstitution Research Articles

Cryopreservation of mouse thymus depletes thymocytes but supports immune reconstitution on transplantation.

Cryopreservation of mouse thymus depletes donor thymocytes but preserves thymus function when transplanted after thawing into athymic mice. No differences in immune reconstitution were observed between fresh and frozen/thawed transplants suggesting that donor thymocyte depletion does not affect outcome. Thus, cryopreservation of thymus may improve outcomes in thymus transplant patients.

Differential analysis of immune reconstitution after allogeneic hematopoietic stem cell transplantation in children with Wiskott-Aldrich syndrome and chronic granulomatous disease.

To investigate similarities and differences in immune reconstitution after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in children with Wiskott-Aldrich syndrome (WAS) and chronic granulomatous disease (CGD). We retrospectively analyzed the lymphocyte subpopulations and the serum level of various immune-related protein or peptide on Days 15, 30, 100, 180 and 360 post-transplantation in 70 children with WAS and 48 children with CGD who underwent allo-HSCT at the Transplantation Center of the Department of Hematology-Oncology, Children's Hospital of Chongqing Medical University from January 2007 to December 2020, and we analyzed the differences in the immune reconstitution process between the two groups. ① The WAS group had higher lymphocyte subpopulation counts than the CGD group. ② Among children aged 1-3 years who underwent transplantation, the WAS group had higher lymphocyte subpopulation counts than the CGD group. ③ Further comparisons were performed between children with non-umbilical cord blood transplantation (non-UCBT) and children with umbilical cord blood transplantation (UCBT) in the WAS group. On Day 15 and 30 post-transplantation, the non-UCBT group had higher B-cell counts than the UCBT group. On the remaining time points post-transplantation, the UCBT group had higher lymphocyte subpopulation counts than the non-UCBT group. ④ Comparisons were performed between children with non-UCBT in the WAS group and in the CGD group, the lymphocyte subpopulation counts were higher in the WAS group compared to the CGD group. ⑤ On Day 100 post-transplantation, the CGD group had higher C3 levels than the WAS group. On Day 360 post-transplantation, the CGD group had higher IgA and C4 levels than the WAS group. ① The rate of immunity recovery was faster in children within the WAS group compared to those children within the CGD group, which may be attributed to the difference of percentage undergoing UCBT and primary diseases. ② In the WAS group, the non-UCBT group had higher B-cell counts than the UCBT group at Day 15 and 30 post-transplantation, however, the UCBT group had higher B-cell counts than the non-UCBT group at Day 100 and 180 post-transplantation, suggesting that cord blood has strong B-cell reconstitution potentiality after transplantation.

Immune Reconstitution following High-Dose Chemotherapy and Autologous Stem Cell Transplantation with or without Pembrolizumab Maintenance Therapy in Patients with Lymphoma

Autologous stem cell transplantation (ASCT) is a standard of care for patients with chemosensitive, relapsed/refractory (R/R) classical Hodgkin lymphoma (cHL) and diffuse large B cell lymphoma (DLBCL). Whereas the clinical benefit of ASCT has traditionally been attributed solely to cytoreduction from intensive chemotherapy, ASCT has important immunogenic effects that may contribute to its antitumor efficacy and could provide a favorable immune environment for post-ASCT immune-based maintenance treatments. We previously reported clinical results of a phase II trial (ClinicalTrials.gov identifier NCT02362997) testing 8 doses of pembrolizumab maintenance therapy after ASCT for patients with R/R cHL or DLBCL. To clarify the impact of pembrolizumab on immune reconstitution, we compared the kinetics of peripheral blood immune cell recovery after ASCT for trial patients receiving pembrolizumab maintenance to those of a contemporaneous control cohort of similar patients undergoing ASCT without pembrolizumab maintenance. This study was conducted to characterize the impact of post-ASCT pembrolizumab maintenance therapy on immune reconstitution for patients with R/R DLBCL and cHL and to identify candidate biomarkers of efficacy and immune-related adverse events (irAEs). Peripheral blood (PB) mononuclear cell samples were prospectively collected at 1 to 18 months after ASCT and analyzed by flow cytometry using a panel of fluorophore-conjugated monoclonal antibodies to identify B cells, natural killer (NK) cells, and various dendritic cell (DC) and T cell subsets. A median of 5 (range, 1 to 8) post-ASCT PB samples were collected from 144 patients (59 in the pembrolizumab group and 85 in the control group). Clinical characteristics of the 2 cohorts were similar. Compared with cHL patients, DLBCL patients (all of whom received anti-CD20 monoclonal antibody therapy before ASCT) had delayed CD19+ cell reconstitution that persisted for at least 18 months after ASCT. No other differences in immune reconstitution based on lymphoma subtype were observed. Post-ASCT pembrolizumab maintenance therapy was associated with an elevation in circulating DCs (driven by higher levels of plasmacytoid and immature DCs) that persisted for the duration of pembrolizumab treatment, along with a significant reduction in PD-1+ T cells that persisted for 6 to 12 months after completion of pembrolizumab therapy. Despite the key role of T cells in mediating the effects of PD-1 blockade, pembrolizumab maintenance did not affect recovery of any T cell subsets. In an exploratory analysis, a higher baseline CD4+ terminal effector memory cell count (defined as CD3+CD4+CD45RA+CD62L-) was associated with inferior progression-free survival (PFS), but only among patients who received pembrolizumab maintenance (P=.003). As continuous variables, lower absolute levels of NK cells (P=.009), PD-1+ CD4+ T cells (P=.005), and PD-1+ CD8+ T cells (P=.005) before pembrolizumab initiation were each associated with a higher risk of grade 2+ irAEs. Our findings indicate that post-ACST pembrolizumab maintenance therapy is associated with a persistent elevation of circulating DCs, but its impact on the reconstitution of other immune cells in peripheral blood appears limited. Our study suggests that early features of post-ASCT immune reconstitution could be associated with PFS and the risk of irAE and warrant additional investigation. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

Do Combination Antiretroviral Therapy Regimens for HIV Infection Feature Diverse T-Cell Phenotypes and Inflammatory Profiles?

Immune abnormalities featuring HIV infection persist despite the use of effective combination antiretroviral therapy (cART) and may be linked to the development of noninfectious comorbidities. The aim of the present narrative, nonsystematic literature review is to understand whether cART regimens account for qualitative differences in immune reconstitution. Many studies have reported differences in T-cell homeostasis, inflammation, coagulation, and microbial translocation parameters across cART classes and in the course of triple vs dual regimens, yet such evidence is conflicting and not consistent. Possible reasons for discrepant results in the literature are the paucity of randomized controlled clinical trials, the relatively short follow-up of observational studies, the lack of clinical validation of the numerous inflammatory biomarkers utilized, and the absence of research on the effects of cART in tissues. We are currently thus unable to establish if cART classes and regimens are truly accountable for the differences observed in immune/inflammation parameters in different clinical settings. Questions still remain as to whether an early introduction of cART, specifically in the acute stage of disease, or newer drugs and novel dual drug regimens are able to significantly impact the quality of immune reconstitution and the risk of disease progression in HIV-infected subjects.

A Phase I Study of Haploidentical Bone Marrow Transplantation with Post-Transplant Cyclophosphamide and/or Bendamustine

Background The nearly universal donor accessibility afforded by haploidentical bone marrow transplantation (haplo-BMT) is salient for our program, as half of the patients undergoing hematopoietic cell transplantation (HCT) are ethnic or racial minorities. This highlights the need for effective haplo-BMT regimens and improvements in graft-versus-host disease (GvHD) prophylaxis. Balancing GvHD prevention with the maintenance of graft-versus-leukemia (GvL) is an ongoing challenge in the field of HCT. We have previously shown in mice that bendamustine (BEN) can safely replace cyclophosphamide (CY) as post-transplant (PT) GvHD prophylaxis following haplo-BMT, with comparable protection from GvHD and superior GvL effects. Based on our preclinical data, we have initiated a Phase I/II study to replace PT-CY (given on days +3 and +4) with PT-BEN following haplo-BMT. Methods Phase I is a standard 3 + 3 dose escalation design with six dose level cohorts. The first three cohorts (1-3) consist of a combination of sequentially reduced doses of CY and increased doses of BEN on day +4 post-BMT with the dose of CY on day +3 remaining unchanged. The next three cohorts (4-6) will involve progressive substitution of CY with BEN on day +3. We are enrolling patients ages 8-60 years with a diagnosis of acute leukemia, chronic myeloid leukemia, myelodysplastic syndrome, Hodgkin's or non-Hodgkin's lymphoma who do not have a readily available HLA-matched (10/10) donor. Myeloablative busulfan, fludarabine, and melphalan or TBI and fludarabine are used as conditioning regimens. Engraftment, immune reconstitution, T-cell receptor β (TRB) diversity, GvHD, infections, relapse, non-relapse mortality (NRM), event-free survival (EFS) and overall survival (OS) are monitored. Patients undergoing haplo-BMT (using the same conditioning regimens) who do not wish to receive PT-BEN are consented as PT-CY controls for the clinical endpoints and immune reconstitution studies. Results We have enrolled through Cohort 2 with no dose-limiting toxicities. Cohort 2 of PT-BEN had significantly earlier neutrophil engraftment than PT-CY controls (median day +13 compared to +17), with >5-fold higher neutrophil to lymphocyte ratios through day +100. PT-BEN patients displayed higher CD4 to CD8 ratio and demonstrated significantly greater TRB diversity than PT-CY only patients through 1 year following transplant. Patients receiving PT-BEN had a trend toward a lower incidence of CMV reactivation, 33% compared to 100% in PT-CY controls. No PT-BEN patient has developed grade III-IV acute GvHD or chronic GvHD. Conclusions PT-BEN has been well-tolerated, with patients demonstrating early engraftment. Preliminary data with PT-BEN indicate potential differences in immune reconstitution and TRB diversity. This may be advantageous in viral control, as well as in GvHD and GvL responses.

Identification of Lymphocyte Subsets Associated with Outcomes in Patients with Hematological Malignancy Following Allogeneic Stem Cell Transplantation: A Single Institute Study

Background: Immune reconstitution after allogeneic stem cell transplantation (SCT) is a complicated process influenced by factors such as preconditioning regimens, graft-versus-host disease (GVHD) prophylaxis, and grafts. We studied the association between the kinetics of lymphocyte subsets and transplant outcome to clarify the differences in immune reconstitution after hematopoietic cell transplantation according to stem cell sources and its clinical significance.Patients and Methods: Clinical data were collected from patients' medical charts at Kanagawa Cancer Center, Yokohama, Japan. Patients with hematological malignancies aged ≥18 years old who underwent SCT between April 2009 and December 2017 were initially selected. Those who died or experienced disease relapse before day 100 post SCT were excluded. We measured absolute lymphocyte count (ALC) and lymphocyte subsets by flow cytometry with antibodies against CD2, CD3, CD4, CD8, CD11b, CD11c, CD16, CD25, CD29, CD56, CD57, CD45RA, and CD45RO on days 100, 180, 365, and 730 post SCT.Results: The final cohort included 314 patients (acute leukemia, n = 249; myelodysplastic syndrome, n = 44; chronic myelogenous leukemia, n = 9; malignant lymphoma, n = 6; and others, n = 6). The median age was 51 (range: 18- 69) years, with 184 males and 130 females. The disease risk at transplantation was standard in 209 and high in 105 patients. Myeloablative preconditioning was administered to 114 and reduced-intensity preconditioning to 200 patients. Bone marrow transplantation (BMT), peripheral blood SCT (PBSCT), and cord blood transplantation (CBT) were performed in 121, 57, and 136 patients, respectively. A calcineurin inhibitor with short-term methotrexate was mainly used for GVHD prevention. The median follow-up of surviving patients was 869 (range: 103-3074) days. The 2-year overall survival (OS), cumulative incidence of relapse (CIR), and non-relapse mortality (NRM) in BMT, PBSCT, and CBT were 62%, 68%, and 76% (P = 0.023); 33%, 38%, and 27% (P = 0.068); and 17%, 16%, and 13% (P = 0.82); respectively. The 2-year cumulative incidence of chronic GVHD was 43% in BMT, 45% in PBSCT, and 28% in CBT (P = 0.027).There were significant differences between lymphocyte subset recovery and stem cell sources (Table). ALC; CD20+ B cell; CD4+, CD4+CD29+, CD4+CD45RO+, CD4+CD45RO− , and CD4+CD45RA+ T cell subsets; and CD3−CD56+ and CD16+CD57− natural killer (NK) cell subsets were significantly elevated in CBT compared with BMT and PBSCT at day 100 post SCT. Conversely, CD8+CD11b+ and CD8+CD11b− T cell subsets and CD3+CD56+ NKT cells were significantly lower in CBT than in BMT and PBSCT on day 100. Univariate analysis revealed that lymphocyte subsets exhibiting higher levels of CD20+ B cell; CD16+CD57− and CD3−CD56+ NK cells; and CD4+CD25+, CD4+CD29+, CD4+CD45RA+, CD8+CD11b+, and CD8+CD11b− T cell subsets at day 100 were associated with a better 2-year OS. There were strong correlations with a lower CIR and higher CD16+CD57+ and CD16+CD57− NK cell levels . A higher incidence of chronic GVHD was associated with lower levels of CD16+CD57− NK cells and CD4+CD25+ T cells and with higher levels of CD8+CD11b+ T cells and CD8+CD11b− and CD3+CD56+ NKT cells. Further, a lower NRM correlated with higher levels of CD20+ B cells and CD8+CD11b− T cells.The lymphocyte subsets were used for multivariate analysis. Favorable factors for better OS were higher levels of CD16+CD57− NK cells [hazard ratio (HR), 0.62; 95% confidence index (CI), 0.38-0.81; P = 0.024] and CD20+ B cells (HR, 0.56; 95% CI, 0.31-0.0.98; P = 0.048). Prognostic factors for lower CIR were higher levels of CD16+CD57+ NK cells (HR, 0.51; 95% CI, 0.27-0.95; P = 0.034) and CD16+CD57− NK cells (HR, 0.52; 95% CI, 0.28-0.99; P = 0.048). A lower incidence of NRM was associated with higher levels of CD8+CD11b− T cells (HR, 0.18; 95% CI, 0.08-0.39; P < 0.001) and CD20+ B cells (HR, 0.24; 95% CI, 0.08-0.70; P = 0.0088). High levels of CD8+CD11b+ T cells were an independent predictor for a higher incidence of chronic GVHD (HR, 2.38; 95% CI, 1.22-4.95; P = 0.012).Conclusions: The distinct differences in immune reconstitution according to stem cell sources and lymphocyte subset analysis at day 100 post SCT are useful for predicting transplant outcome. Furthermore, the results suggest that characteristic immune recovery in CBT positively affects transplant outcome. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Immune Reconstitution and Infection Patterns after Early Alemtuzumab and Reduced Intensity Transplantation for Nonmalignant Disorders in Pediatric Patients

Hematopoietic stem cell transplantation (HSCT) is a therapeutic option for many nonmalignant disorders (NMD) and is curative or prevents disease progression. Reduced-intensity conditioning (RIC) in HSCT for NMD may reduce regimen-related acute toxicities and late complications. Myeloablation is often replaced by immune suppression in RIC regimens to support donor engraftment. The pace of immune reconstitution after immune suppression by RIC regimens is influenced by agents used, donor source, and graft-versus-host disease prophylaxis/treatment. In a multicenter trial (NCT 00920972) of HSCT for NMD, a RIC regimen consisting of alemtuzumab, fludarabine, and melphalan was substituted for myeloablation. Alemtuzumab was administered early (days -21 to -19) to mitigate major lymphodepletion of the incoming graft and the risk of graft rejection. Immune reconstitution and infectious complications were prospectively monitored for 1-year post-HSCT. Seventy-one patients met inclusion criteria for this report and received marrow or peripheral blood stem cell transplants. Immune reconstitution and infections are reported for related donor (RD) and unrelated donor (URD) transplants at 3 time-points (100days, 6 months, and 1 year post-HSCT). Natural killer cell recovery was rapid, and numbers normalized in both cohorts by day +100. Mean CD3, CD4, and CD8 T-lymphocyte numbers normalized by 6 months after RD HSCT and by 1 year in the URD group. CD4 and CD8 T-lymphocyte counts were significantly higher in patients who received RD HSCT at 6 months and at 1 year, respectively, post-HSCT compared with patients who received URD HSCT. The pace of CD19 B-cell recovery was markedly different between RD and URD cohorts. Mean B-cell numbers were normal by day 100 after RD HSCT but took 1 year post-HSCT to normalize in the URD cohort. Despite these differences in immune reconstitution, the timing and nature of infections did not differ between the groups, presumably because of comparable T-lymphocyte recovery. Immune reconstitution occurred at a faster pace than in prior reports using RIC with T-cell depletion. The incidence of infections was similar for both cohorts and occurred most frequently in the first 100days post-HSCT. Viral and fungal infections occurred at a lower incidence in this cohort, with "early" alemtuzumab compared with regimens administering serotherapy in the peritransplantation period. Patients were susceptible to bacterial infections primarily in the first 100days irrespective of donor source and had no increase in mortality from the same. The overall mortality rate from infections was 1.4% at 1 year. Close monitoring and prophylaxis against bacterial infections in the first 100days post-HSCT is necessary but is followed by robust immune reconstitution, especially in the T-cell compartment.

Differential expression and localization of tubular injury markers NGAL and KIM-1 in a rat model of renal ischemia/reperfusion injury

Autologous stem cell transplantation (ASCT) is a standard of care for patients with chemosensitive, relapsed/refractory (R/R) classical Hodgkin lymphoma (cHL) and diffuse large B cell lymphoma (DLBCL). Whereas the clinical benefit of ASCT has traditionally been attributed solely to cytoreduction from intensive chemotherapy, ASCT has important immunogenic effects that may contribute to its antitumor efficacy and could provide a favorable immune environment for post-ASCT immune-based maintenance treatments. We previously reported clinical results of a phase II trial (ClinicalTrials.gov identifier NCT02362997) testing 8 doses of pembrolizumab maintenance therapy after ASCT for patients with R/R cHL or DLBCL. To clarify the impact of pembrolizumab on immune reconstitution, we compared the kinetics of peripheral blood immune cell recovery after ASCT for trial patients receiving pembrolizumab maintenance to those of a contemporaneous control cohort of similar patients undergoing ASCT without pembrolizumab maintenance. This study was conducted to characterize the impact of post-ASCT pembrolizumab maintenance therapy on immune reconstitution for patients with R/R DLBCL and cHL and to identify candidate biomarkers of efficacy and immune-related adverse events (irAEs). Peripheral blood (PB) mononuclear cell samples were prospectively collected at 1 to 18 months after ASCT and analyzed by flow cytometry using a panel of fluorophore-conjugated monoclonal antibodies to identify B cells, natural killer (NK) cells, and various dendritic cell (DC) and T cell subsets. A median of 5 (range, 1 to 8) post-ASCT PB samples were collected from 144 patients (59 in the pembrolizumab group and 85 in the control group). Clinical characteristics of the 2 cohorts were similar. Compared with cHL patients, DLBCL patients (all of whom received anti-CD20 monoclonal antibody therapy before ASCT) had delayed CD19+ cell reconstitution that persisted for at least 18 months after ASCT. No other differences in immune reconstitution based on lymphoma subtype were observed. Post-ASCT pembrolizumab maintenance therapy was associated with an elevation in circulating DCs (driven by higher levels of plasmacytoid and immature DCs) that persisted for the duration of pembrolizumab treatment, along with a significant reduction in PD-1+ T cells that persisted for 6 to 12 months after completion of pembrolizumab therapy. Despite the key role of T cells in mediating the effects of PD-1 blockade, pembrolizumab maintenance did not affect recovery of any T cell subsets. In an exploratory analysis, a higher baseline CD4+ terminal effector memory cell count (defined as CD3+CD4+CD45RA+CD62L-) was associated with inferior progression-free survival (PFS), but only among patients who received pembrolizumab maintenance (P = .003). As continuous variables, lower absolute levels of NK cells (P = .009), PD-1+ CD4+ T cells (P = .005), and PD-1+ CD8+ T cells (P = .005) before pembrolizumab initiation were each associated with a higher risk of grade 2+ irAEs. Our findings indicate that post-ACST pembrolizumab maintenance therapy is associated with a persistent elevation of circulating DCs, but its impact on the reconstitution of other immune cells in peripheral blood appears limited. Our study suggests that early features of post-ASCT immune reconstitution could be associated with PFS and the risk of irAE and warrant additional investigation.© 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

Immune Reconstitution Kinetics as an Early Predictor for Mortality using Various Hematopoietic Stem Cell Sources in Children

The severity of complications of allogeneic hematopoietic stem cell transplantation (HSCT) is governed mainly by the status of immune reconstitution. In this study, we investigated differences in immune reconstitution with different cell sources and the association between the kinetics of immune reconstitution and mortality. Immunophenotyping was performed every 2 weeks in children who had undergone HSCT between 2004 and 2008 at University Medical Center Utrecht. Lymphocyte reconstitution in the first 90 days after HSCT was studied in relation to mortality in 3 HSCT groups: matched sibling bone marrow (BM) recipients (35 patients), unrelated BM recipients (32 patients), and unrelated cord blood recipients (36 patients). The median age of recipients was 5.9 years (range, 0.1-21 years). The nature and speed of T cell, B cell, and natural killer (NK) cell reconstitution were highly dependent on the cell source. In the first 90 days after HSCT, faster B cell and NK cell reconstitution and delayed T cell reconstitution were shown in unrelated cord blood recipients compared with matched sibling BM and unrelated BM recipients. Of the lymphocyte subsets investigated, a large number of NK cells and a more rapid CD4+ immune reconstitution over time, resulting in sustained higher CD4+ counts, were the only predictors of a lower mortality risk in all cell sources. The final model showed that during the first 90 days, patients with an area under the CD4+ cell receiver- operating curve of >4,300 cells/day and no peak in CD4+ cell counts had the highest likelihood of survival (hazard ratio for mortality, 0.2; 95% confidence interval, 0.06-0.5). Our data indicate that CD4+ kinetics may be used to identify patients at greatest risk for mortality early after HSCT.

Gender Differences in Immune Reconstitution: A Multicentric Cohort Analysis in Sub-Saharan Africa

BackgroundIn sub-Saharan Africa, men living with HIV often start ART at more advanced stages of disease and have higher early mortality than women. We investigated gender difference in long-term immune reconstitution.Methods/Principal FindingsAntiretroviral-naïve adults who received ART for at least 9 months in four HIV programs in sub-Saharan Africa were included. Multivariate mixed linear models were used to examine gender differences in immune reconstitution on first line ART.A total of 21,708 patients (68% women) contributed to 61,912 person-years of follow-up. At ART start,. Median CD4 at ART were 149 [IQR 85–206] for women and 125 cells/µL [IQR 63–187] for men. After the first year on ART, immune recovery was higher in women than in men, and gender-based differences increased by 20 CD4 cells/µL per year on average (95% CI 16–23; P<0.001). Up to 6 years after ART start, patients with low initial CD4 levels experienced similar gains compared to patients with high initial levels, including those with CD4>250cells/µL (difference between patients with <50 cells/µL and those with >250 was 284 cells/µL; 95% CI 272–296; LR test for interaction with time p = 0.63). Among patients with initial CD4 count of 150–200 cells/µL, women reached 500 CD4 cells after 2.4 years on ART (95% CI 2.4–2.5) and men after 4.5 years (95% CI 4.1–4.8) of ART use.ConclusionWomen achieved better long-term immune response to ART, reaching CD4 level associated with lower risks of AIDS related morbidity and mortality quicker than men.

Immune Reconstitution after Double Umbilical Cord Blood Stem Cell Transplantation: Comparison with Unrelated Peripheral Blood Stem Cell Transplantation

Double umbilical cord blood (DUCB) transplantation is an accepted transplantation strategy for patients without suitable human leukocyte antigen (HLA) matched donors. However, DUCB transplantation is associated with increased morbidity and mortality because of slow recovery of immunity and a high risk of infection. To define the differences in immune reconstitution between DUCB transplantation and HLA matched unrelated donor (MUD) transplantation, we performed a detailed, prospective analysis of immune reconstitution in 42 DUCB recipients and 102 filgrastim-mobilized unrelated peripheral blood stem cell recipients. Reconstitution of CD3 T cells was significantly delayed in the DUCB cohort compared with the MUD cohort for 1 to 6 months posttransplantation (P < .001), including naive (CD45RO-) and memory (CD45RO+) CD4 T cells, regulatory (CD4CD25) T cells, and CD8 T cells. In contrast, CD19 B cells recovered more rapidly in the DUCB cohort and numbers remained significantly greater from 3 to 24 months after transplantation (P = .001). CD56CD16 natural killer (NK) cells also recovered more rapidly in DUCB recipients and remained significantly greater from 1 to 24 months after transplantation. B cell activating factor (BAFF) levels were higher in the DUCB cohort at 1 month (P < .001), were similar in both cohorts at 3 and 6 months, and were lower in the DUCB cohort at 12 months (P = .002). BAFF/CD19 B cell ratios were lower in the DUCB cohort at 3 (P = .045), 6 (P = .02), and 12 months (P = .002) after transplantation. DUCB recipients had more infections within the first 100 days after transplantation (P < .001), and there was less chronic graft-versus-host disease (P < .001), but there were no differences in cumulative incidence of relapse, nonrelapse death, progression-free survival, or overall survival between the 2 groups. These results suggest that increased risk of infections is specifically associated with delayed reconstitution of all major T cell subsets, but the increased risk is limited to the first 3 months after DUCB transplantation. There is no increased risk of relapse, suggesting that graft-versus-leukemia activity is maintained. Early reconstitution of B cells and NK cells may, in part, account for these findings.

A prospective and randomized study of two conditioning regimens in treatment of severe systemic autoimmune diseases with autologous peripheral blood stem cell transplantation

To investigate the differences in immune reconstitution, hematopoietic reconstitution, efficacy, and complication between the two conditioning regimens with or without total body irradiation (TBI) in patients with refractory and severe autoimmune diseases (AID) who receiving autologous peripheral blood stem cell transplantation (APBSCT). Thirty-two AID patients, 5 males and 27 females, aged 29 (15 - 49), underwent APBSCT. The CD34(+) cells were mobilized with cytoxan (CTX) + granulocyte-colony stimulating factor (G-CSF) and selected by clinical magnetic activated cell sorting (CliniMACS). The conditioning regimen included CTX + antithymocyte globulin (ATG) in 11 patients and CTX + TBI in 21 patients. All the patients were followed up for more than 12 months. The median time of granulocyte recovery were 11 and 9 days in the CTX + TBI and CTX + ATG groups respectively (P = 0.003), the median time of platelet recovery were 13 and 8 days respectively (P = 0.001). In both groups, the lymphocyte subsets were recovered with the inverted CD4/CD8 ratio 12 months after transplantation. Relapse was seen in 3 cases of the CTX + TBI group (14.3%), and 2 cases of the CTX + ATG group (18.2%), and the rest of patients remained free of AID. During transplantation incidence of bacteria infection occurred in 5 of the 21 cases in the CTX + TBI group (23.8%) and in 2 of the 11 cases of the CTX + ATG group (18.2%) respectively; viral infection occurred in 1 of the 21 cases of the CTX + TBI group (4.8%) and in 2 of the 11 cases of the CTX + ATG group (18.2%) respectively. The number of radiated parotitis was 4 among the 21 patients of the CTX + TBI group (19%) and was 3 among the 12 patients of the CTX + ATG group (25%). Serum sickness reaction occurred in 3 of the 12 patients of the CTX + ATG group (25%). Bacterial and viral infections were cured soon after antibacterial or antiviral therapy, no fatal bleeding occurred due to thrombocytopenia in both groups. The conditioning regimen of TBI + CTX delays the hematopoietic reconstitution compared with the ATG + CTX regimen in treating AID. The regimen of CTX + TBI can be better tolerated, but there are no significant differences in efficacy and immune reconstitution among these two regimens.

Differences in Immune Reconstitution and Cytokine Production in Children with Sibling Donor BMT Versus T-Cell Depleted PBSCT from Unrelated or Mismatched Family Donors.

Introduction: Transplantation of haematopoietic stem cell (HSCT) from human leucocyte antigen (HLA)-disparate parental donors presents an approach for the treatment of patients lacking an HLA-matched donor, but little is known about differences in immune reconstitution as compared to conventional BMT. We prospectively compared paediatric recipients of positively selected CD34+ peripheral blood stem cells from unrelated or HLA-mismatched donors vs. recipients of unmanipulated bone marrow from matched sibling donors.Patients: Immune reconstitution was studied in 20 children (20 transplants [5 sibling, vs. 8 UD, 7 haplo]; median age was 9,6 years; range 7m-26y; 7 female, 13 male). Blood samples were drawn before allo-HSCT, on days 14 (take), 30, 60, 100, 200 and 365 and >15months after SCT.Methods: We analyzed lymphocyte subpopulations using flow cytometry. Cytokines (IFNg, IL2, TNFa, IL4, IL5, IL10) were determined by FACS after in vitro stimulation with PMA, ionomycin and brefeldin for 24h. Additionally, we measured IL2, IL7, IL13, IL15, IFNg and TGFb in unstimulated sera by ELISA. Further more, we studied TREC values and did spectratype analysis by real time-PCR and gel electrophoresis.Results: After allo-HSCT, NK-cells were the cells, which regenerated first. In T-cells, decreased absolute counts could be detected as well as an inverted CD4-CD8-ratio during the first year after SCT. In CD4+ T-cells, the memory phenotype (CD45RO+) predominated. Sibling recipients show a faster T-cell regeneration than recipients of UD or mismatched family donors (MM).As to cytokine levels in unstimulated sera, IFNg levels remained stable, while we saw high level of IL4 shortly after allo-HSCT; IL4 levels decreased during the first year after SCT. TGFb showed increased levels post-transplantation for up to two years. In stimulated T-cells, we measured a rise in Th2-cytokines (IL4, IL5, IL10) until d60 and a decrease of IFNg/TNFa. Th2-cytokines returned to pre-transplantation levels until d200, whereas Th1-cytokines rise to higher level than before transplantation. We could find that IL2 was produced predominantly by CD4+ / IFNg+ cells and by CD8+cells. Patients who received T-cell depleted stem cell preparations show lower IFNg and TNFa values and higher Th2-cytokine levels than patients who received bone marrow.TREC counts appear earlier in sib HSCT (median d60) than in MM-transplant (median d200). As to spectratype values, we found a distribution of the 24Vb gene families of 4,18% per Vb-family with clonal expansion, especially in the first months after HSCT, of BV6b>BV23>BV1>BV16.