Similar pattern of thymic-dependent T-cell reconstitution in infants with severe combined immunodeficiency after human leukocyte antigen (HLA)-identical and HLA-nonidentical stem cell transplantation

Donor T cells after stem cell transplantation reconstitute by 2 different pathways: by expansion from grafted, mature T cells and by intrathymic maturation from progenitor cells. This study characterized thymic-dependent reconstitution of CD4(+) T cells following different transplant modalities in patients with severe combined immunodeficiency (SCID). Three groups of patients were studied: one group after transplantation from human leukocyte antigen (HLA)-identical siblings with unmanipulated grafts without conditioning, a second group after transplantation from HLA-nonidentical parents with T-cell-depleted grafts without preconditioning, and a third group with prior conditioning. Reconstitution of the T-cell compartment was monitored by determining the expression of CD45 isoforms by developing CD4(+) cells in the peripheral blood and in discriminating expanded (CD45RO(+)) and newly generated (CD45RA(+)) T cells. Concomitantly, changes in the size of the thymus were evaluated sequentially by ultrasonography. Reconstitution of CD4(+)CD45RA(+) cells was delayed in all patients for several months, including patients after HLA-identical transplantation, and was always paralleled by normalization of the size of the thymus. No engraftment of donor progenitor cells was observed, as studied in one patient transplanted without conditioning. CD4(+)CD45RO(+) cells were detected early after transplantation only in patients given unmanipulated grafts. The study showed that thymic-dependent T-cell maturation in these patients with SCID runs an autonomous course, independent of graft manipulation, of major HLA disparities, and of whether conditioning is used or not. In addition, thymic maturation may not require engraftment of donor-derived CD34(+) cells in the marrow. (Blood. 2000;96:4344-4349)     

Immune reconstitution after haematopoietic cell transplantation in children: immunophenotype analysis with regard to factors affecting the speed of recovery

Immune reconstitution was studied prospectively in 66 children who underwent 77 haematopoietic cell transplantations (HCT): 46 autologous HCTs in 39 patients and 31 allogeneic HCTs in 27 patients. We studied the dynamic analysis of immune recovery with regard to potential factors affecting its speed, including age, type of HCT, diagnosis, graft-versus-host disease (GvHD) and cytomegalovirus (CMV) infection reactivation. Absolute counts of different lymphocyte subsets and immunoglobulin serum levels were determined in peripheral blood of patients on d -7 and +16, and then at various intervals up to 24 months post transplant. Common patterns of immune recovery after both allogeneic and autologous HCT were identified: (i) CD4+CD45RO+ peripheral T-cell expansion on d +16; (ii) inverted CD4+:CD8+ ratio from d +30 onwards; (iii) rapid natural killer (NK) cell (CD16+/-CD56+) count normalization. We observed prolonged T-cell lymphopenia (CD3+, CD3+CD4+, CD4+CD45RA+) until 24 months after autologous HCT, whereas in the allogeneic setting CD3+CD4+ cells, including naive CD45RA+ cells, returned to normal values at 9 months post transplant. Age > 10 years and coexistence of GvHD and CMV reactivation were associated with a substantial delay in T- (CD4+, including CD45RA+) and B-cell recovery after allogeneic HCT. Multidrug GvHD prophylaxis resulted in impaired T- (CD4+, CD4+CD45RA+) and B-cell reconstitution only in the early phase after allogeneic HCT (up to 4 months). Our results demonstrated that T-cell recovery was severely impaired in children after autologous HCT. It should be emphasized that specific approaches to enhance immune reconstitution are necessary to control minimal residual disease and avoid the risk of infectious complications in the autologous setting. Thymic involution after allogeneic HCT seems to be associated with age and coexistence of GvHD and CMV reactivation.     

Immune reconstitution after allogeneic marrow transplantation compared with blood stem cell transplantation

Allogeneic peripheral blood stem cell grafts contain about 10 times more T and B cells than marrow grafts. Because these cells may survive in transplant recipients for a long time, recipients of blood stem cells may be less immunocompromised than recipients of marrow. Immune reconstitution was studied in 115 patients randomly assigned to receive either allogeneic marrow or filgrastim-mobilized blood stem cell transplantation. Between day 30 and 365 after transplantation, counts of most lymphocyte subsets were higher in the blood stem cell recipients. The difference was most striking for CD4 T cells (about 4-fold higher counts for CD45RA(high) CD4 T cells and about 2-fold higher counts for CD45RA(low/-)CD4 T cells; P <.05). On assessment using phytohemagglutinin and herpesvirus antigen-stimulated proliferation, T cells in the 2 groups of patients appeared equally functional. Median serum IgG levels were similar in the 2 groups. The rate of definite infections after engraftment was 1.7-fold higher in marrow recipients (P =.001). The rate of severe (inpatient treatment required) definite infections after engraftment was 2.4-fold higher in marrow recipients (P =.002). The difference in the rates of definite infections was greatest for fungal infections, intermediate for bacterial infections, and lowest for viral infections. Death associated with a fungal or bacterial infection occurred between day 30 and day 365 after transplantation in 9 marrow recipients and no blood stem cell recipients (P =.008). In conclusion, blood stem cell recipients have higher lymphocyte-subset counts and this appears to result in fewer infections. (Blood. 2001;97:3380-3389)     

Phenotypic characteristics of B cells in Behçet's disease: increased activity in B cell subsets

OBJECTIVE: Increased numbers of spontaneous Ig secreting B cells and elevated immunoglobulin levels have been described in Beh?et's disease (BD), in addition to changes in numbers and activities of T cells, natural killer cells, and monocyte-macrophages. We investigated other characteristics of B cells in BD. METHODS: B lymphocyte subsets (CD19+CD5+, CD19+CD13+, CD19+CD28+, CD19+CD33+, CD19+CD80+, CD5+CD19+CD45RA+, CD5+CD19+CD45RO+) were phenotypically evaluated in 50 patients with BD, 80 healthy subjects, and 20 other patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and sepsis. RESULTS: Although the B cell number (CD19+) was normal, CD13 and CD33 positive B cells were more numerous in BD and sepsis compared to healthy controls and patients with RA and SLE. The percentage of CD45RO positive B cells was higher in both BD and sepsis, while the percentage of CD80 positive B cells was high only in BD. There was no increase in the CD5+CD19+ B cell subset, previously shown to be increased in several autoimmune diseases. Naive (CD45RA) and memory (CD45RO) status of CD5+CD19+ and CD5-CD19+ B cells showed that CD45RA expression was higher in CD5+CD19+ B cells, whereas expression of both CD45RA and CD45RO was higher in the CD5-CD19+ B cell group compared with healthy controls. CONCLUSION: Although the total B cell number was normal, increased levels of activated and memory B cell subsets suggest a modified B cell function in BD, which may be related to a weak stimulus by an unknown external antigen.     

Flow cytometry of blood and bone marrow cells from patients with hairy cell leukemia: phenotype of hairy cells and lymphocyte subsets after treatment with 2-chlorodeoxyadenosine

By flow cytometry and an extensive set of markers, we characterized leukemic cells from the blood and bone marrow of 68 symptomatic patients with hairy cell leukemia (HCL). Hairy cells identified in the large cell gate always expressed CD19, CD20, HLA-DR, CD45RA, and B-ly 7. Other markers were occasionally expressed, such as CD38, CD45RO, CD23, CD15, CD4, CD5, and CD10 (expressed on more than 20% of the hairy cells in 44%, 25%, 21%, 18%, 12%, 10%, and 5% of evaluated cases, respectively). During treatment with 2-chlorodeoxyadenosine (CdA), the median lymphocyte counts decreased from 2,000/microL to 300/microL. Flow cytometry was repeated at the nadir (n = 24) of lymphocyte counts, at 3 months (n = 46), at 6 months (n = 50), at 1 year (n = 39), and at 2 years (n = 12) after treatment. The initial decrease of CD8+ and CD20+ cells was greater than that of CD4+ and natural killer (NK) cells, leading to an increasing CD4/CD8 ratio. Median nadir values of CD4+, CD8+, CD20+, and NK cells were 128/microL, 78/microL, 10/microL, and 13/microL, respectively. The subsequent recovery was quicker for CD8+ and NK cells, leading to a normalization within 3 months, whereas CD20+ and CD4+ cells required 1 or 2 years to enter the normal range. The CD4/CD8 ratio thus decreased after the nadir and remained less than 1. CD45RA+ CD4 cells and CD45RA+/CD45RO+ double-positive cells were less affected by CdA. Activated T cells, ie, HLA-DR+ cells, rarely decreased below the normal range and often recovered with an overshoot. CD10+ cells increased in the bone marrow posttreatment as an indication of normal B-cell regeneration in 16 of 36 (44%) patients. The quick regeneration of certain lymphoid subsets might explain the lack of late infections in CdA-treated HCL patients.     

梅毒与梅毒合并病毒性肝炎患者外周血T淋巴细胞亚群变化*

目的 调查梅毒及其合并病毒性肝炎患者外周血T淋巴细胞亚群的变化。方法 2016年1月～2020年6月我院收治的93例感染苍白螺旋体(TP)梅毒患者中,单纯梅毒感染61例,TP合并CHB患者21例和TP合并CHC患者11例,另选择健康体检者84例。使用流式细胞仪检测外周血T淋巴细胞亚群。结果 梅毒患者外周血CD3⁺、CD4⁺、CD4⁺CD45RO⁺和CD8⁺CD45RA⁺细胞百分比及CD4⁺/CD8⁺细胞比值分别为(52.2±8.5)%、(40.3±5.7)%、(18.1±3.9)%、(12.4±3.7)%和(1.2±0.3),均显著低于健康人[分别为(69.1±7.6)%、(50.7±6.9)%、(20.6±4.7)%、(16.2±4.3)%和(1.9±0.5),P＜0.05],而外周血CD8⁺、CD4⁺CD45RA⁺和CD8⁺CD45RO⁺细胞百分比显著高于健康人[分别为(32.4±7.3)%、(24.7±6.5)%和(8.7±1.5)%对(26.2±5.4)%、(21.8±6.2)%和(5.4±1.1)%,P＜0.05];三组外周血CD8⁺、CD4⁺CD45RA⁺、CD4⁺CD45RO⁺、CD8⁺CD45RA⁺和CD8⁺CD45RO⁺细胞百分比及CD4⁺/CD8⁺细胞比值比较,差异有统计学意义(P＜0.05),TP合并CHB组和TP合并CHC组患者外周血CD8⁺、CD4⁺CD45RA⁺和CD8⁺CD45RO⁺细胞百分比均显著高于TP组(P＜0.05),而TP合并CHB组和TP合并CHC组患者外周血CD4⁺/CD8⁺比值、CD4⁺CD45RO⁺和CD8⁺CD45RA⁺细胞百分比显著低于TP组(P＜0.05),TP合并CHB组与TP合并CHC组患者外周血CD8⁺、CD4⁺CD45RA⁺、CD4⁺CD45RO⁺、CD8⁺CD45RA⁺和CD8⁺CD45RO⁺细胞百分比及CD4⁺/CD8⁺细胞比值比较均无统计学差异(P＞0.05)。结论 梅毒患者存在显著的外周血淋巴细胞亚群变化,合并CHB或合并CHC患者细胞免疫功能变化更明显,其临床意义值得进一步探讨。     

Poor lymphocyte recovery following CD34-selected autologous peripheral blood stem cell transplantation for non-Hodgkin's lymphoma

Positive selection of CD34+ cells in autologous grafts, designed to deplete tumour cells, also results in T-cell depletion. To assess the reconstitution of the different lymphocyte subsets and of the T-cell repertoire diversity following autologous transplantation of selected CD34+ peripheral blood stem cells (PBSC), we analysed sequential blood samples in eight patients autografted for advanced B-cell non-Hodgkin's lymphoma in a phase I-II pilot study. Although natural killer cell recovery was rapid, T- and B-cell recovery was delayed with a median of 110/microliters CD4+, 175/microliters CD8+ T cells and 45/microliters B cells at 12 months post-transplant. The naive CD45RA+ T-cell compartment was profoundly deficient up to 12 months for both CD4+ and CD8+ subsets. A transient expansion of memory CD8+CD45RO+ T cells consisting of an increased percentage of CD57+CD28- cells occurred within the first 3 months post-transplant, but the memory CD4+CD45RO+ T cells remained far below the normal value. The CD8+CD28+ T-cell subset did not recover. Using multiplex PCR analysis of the T-cell receptor gamma locus, we found that the repertoire diversity improved at 12 months after being poor and oligoclonal during the first 3 months post-transplant. As shown by monoplex PCRgamma analysis of every VJ combination, despite T-cell depletion of the graft, mature T cells were carried over with the selected CD34+ PBSC and contributed to the T-cell recovery after transplantation.     

The reappearance of 10 differentiation antigens on peripheral blood lymphocytes after allogeneic bone marrow transplantation.

Ten monoclonal antibodies and flow cytometry were applied to characterize the recovery of lymphocyte subsets in peripheral blood after allogeneic bone marrow transplantation (BMT). Ten patients were first followed for 150 days (short-term survey) and then analysed 2 years after BMT on average (long-term analysis). Eight of the 10 recipients showed increased relative and absolute numbers of CD8+ cells and reduced numbers of CD4+ cells resulting in an inverse helper/suppressor ratio. In these eight patients the CD8+ cell predominance was long-lasting and still detectable in the long-term analysis. Two patients had a normal helper/suppressor ratio throughout the study but otherwise a similar reconstitution. Despite the slow recovery of CD4+ cells, CD4+ Leu8- and CD4+ CD45RA- helper subsets were in a normal range already on day 30 and their proportions stayed higher than those of CD4+ Leu8+ and CD4+ CD45RA+ helper cells for the whole short-term survey. The number of activated suppressor cells (CD8+ HLA-DR+) increased markedly after BMT. Similarly, in eight patients high numbers of cytotoxic CD8+ CD57+ cells were found from day 50 onwards. An early and sharp rise of NK cells (CD16+, CD56+) was observed in all recipients, and seven recipients also showed an early increase in CD20+ B cells. Later on, normal or slightly elevated numbers of these cells occurred.     

Immune reconstitution and early infectious complications following nonmyeloablative hematopoietic stem cell transplantation

Non-myeloablative stem cell transplantation (NMT) has been increasingly used in compromised patients who would otherwise have been unable to undergo allotransplant. There is little understanding of the kinetics of immune reconstitution and its influence on infective complications following NMT. The aim of present study was to evaluate lymphocyte subset reconstitution over the first 12 months post-transplant in 15 adult patients receiving NMT with comparison to that of 30 patients grafted with a conventional hemopoietic stem cell transplantation (HSCT). NMT recipients were conditioned with fludarabine-based conditioning regimens. Peripheral blood stem cell (PBSC) was the source of stem cells in 13 NMT recipients and in 24 conventional HSCT recipients. Absolute numbers of helper (CD4+) T cells, naive (CD4+ CD45RA+) and memory (CD4+ CD45RO+) T cells as well as suppressor (CD8+) T cells, CD19+ B cells and NK cells were comparable in the two groups at all time points after transplantation. A median value of 200 CD4+ T cells/microl was achieved at 2 months post-transplant by the NMT and HSCT recipients. The CD4:CD8 ratio remained severely depressed throughout the study period. Almost all CD4+ lymphocytes expressed CD45RO antigen in the both groups of patients B lymphocytes showed low counts throughout the entire study period in both groups. Bacteremia and CMV antigenemia occurred respectively in 13 and 36% of the patients in the NMT group and in 15 and 39% of the patients in the HSCT group. Our preliminary data indicate that patients receiving a NMT have a lymphocyte reconstitution similar to that observed in patients who received a conventional HSCT. The incidence of bacteremia and CMV infection were not significantly different between the groups. Nevertheless, due to the small sample size, these results should be considered suggestive rather than definitive.     

Changes in CD4+ T Lymphocyte Subsets in Circulating Blood and Synovial Fluid Following Filtration Leukocytapheresis Therapy in Patients with Rheumatoid Arthritis

The purpose of this study is to determine the changes in CD4+ T lymphocyte subsets in the circulating blood and synovial fluid following filtration leukocytapheresis (LCP) therapy for patients with rheumatoid arthritis (RA). A Cellsorba column packed with polyester fibers was used for the removal of circulating leukocytes. For patients with RA, filtration LCP or sham procedures were performed 3 times with 1 week intervals between procedures. T lymphocyte surface markers in the peripheral blood and synovial fluid were measured by flow cytometry. The proportions of activated CD4+ T cells (CD4+DR+, CD4+CD25+, and CD4+CD71+) and CD4+CD29+ T cells increased significantly in the peripheral blood, but the counts of these cells were significantly reduced in the synovial fluid after 2 treatment sessions in the LCP group. No significant changes were observed in the proportion of these cells in the control group. Our findings suggest that filtration LCP may cause a redistribution of activated T cells from affected joints into the circulating blood.     

Analysis of peripheral blood T-cell subsets in active thyroid-associated ophthalmopathy: absence of effect of octreotide-LAR on T-cell subsets in patients with thyroid-associated ophthalmopathy.

Thyroid-associated ophthalmopathy (TAO) is thought to be a T-cell-mediated autoimmune disorder. We sought to characterize abnormalities in the peripheral blood T-cell subsets in patients with TAO, and examine whether the long-acting somatostatin analogue, octreotide-LAR, treatment affects these cells. We analyzed peripheral blood T-cell subsets by flow cytometry in 26 euthyroid patients with moderately severe active TAO and 24 controls. Twenty-five of the patients with TAO were enrolled in a randomized trial to receive either 30 mg of octreotide-LAR (n = 11) or placebo (n = 14) every 4 weeks for 16 weeks; all 25 patients subsequently received octreotide-LAR 30 mg every 4 weeks from week 16 to 32. T-cell subsets were analysed at baseline, week 16, and week 32. At baseline, the relative percentage of CD4+ helper T-cells (p = 0.0003) and the CD4+/CD8+ ratio (p = 0.008) were significantly higher in patients with TAO compared to controls. Patients with TAO had higher na?ve active T cells (CD45RA+, CD45RA+ CD4+) and lower memory T cells (CD45RO+, CD45RO+ CD4+) than controls. At weeks 16 and 32, there were no significant differences in any T-cell subsets between the octreotide-LAR-treated and placebo groups. These results support a role of T cell in the pathogenesis of TAO, and show that octreotide-LAR has no effect on T-cell subsets during 32-weeks of treatment.     

Lymphocyte reconstitution following allogeneic hematopoietic stem cell transplantation: a retrospective study including 148 patients

Here we investigated the influence of parameters known before hematopoietic stem cell transplantation (HSCT) as well as the relevance of graft-versus-host disease (GvHD) and cytomegalovirus (CMV) reactivation on post transplant lymphocyte reconstitution in 148 patients treated in our institution between 1996 and 2003. Median patient age was 42 (19-68) years, HSCT followed standard high dose (n=91) or reduced-intensity conditioning regimens (n=57) with bone marrow (BM, n=67) or peripheral blood stem cells (PBSC, n=81) from related (n=71) or unrelated (n=77) donors. In the first months, we observed a partially faster reconstitution of CD3+4+, CD3+8+ and CD4+45RA+ T cells in patients following peripheral blood stem cell transplantation when compared to bone marrow transplantation. Prolonged CD3+4+ and CD4+45RA+ lymphopenia was noted after unrelated donor HSCT and GvHD prophylaxis containing anti-T-lymphocyte globulin. Lymphocyte subset counts in patients older than the median age were comparable to those in patients transplanted at a younger age and not influenced by the conditioning regimen. CD3+8+ T cell reconstitution was strongly correlated with CMV reactivation, but not significantly affected by CMV serostatus before HSCT. Incidence or extent of GvHD did not significantly influence lymphocyte reconstitution. Therefore, the source of graft is the most predictive parameter in early lymphocyte reconstitution, but the differences in lymphocyte recovery completely resolved within the first year after HSCT.     

Reduction of CD45RA isoform expression and decrease in CD4 and CD8 receptor density in lymphocytes of patients with primary biliary cirrhosis

BACKGROUND: The immunological background of primary biliary cirrhosis (PBC) remains largely obscure. METHODS: Using double colour flow cytometry, we estimated the distribution of functionally different lymphocyte subpopulations in the peripheral blood of 25 PBC patients and 18 controls. We examined: 1) the expression of CD3, CD4, CD8, CD19 and CD56 surface receptors, 2) the distribution of lymphocyte subsets bearing 'naive' (CD45RA+) and 'memory' (CD45RO+) phenotypes in both CD4+ and CD8+ cell populations, 3) the expression of an early activation marker (CD69), 4) the distribution of C1.7 mAb binding cytotoxic effectors in CD3+, CD8+ and CD56+ cells. The surface marker expression was evaluated in terms of percentage of positive cells and receptor density. RESULTS: We found: 1) a decrease in the percentage of total CD3+ and CD4+ cells, an unchanged proportion of CD8+ cells but elevated proportion of CD19+ cells and NK lymphocytes; 2) a reduction in the percentage of 'naive' CD4+ but normal proportion of 'naive' CD8+ as well as CD4+ and CD8+ 'memory' cell subsets; 3) a decrease in the density of CD4 and CD8 receptors in the subsets of 'naive' and 'memory' T cells, 4) an increase in the percentage of CD69 receptor bearing T cells but unchanged proportion of C1.7 mAb. CONCLUSIONS: It is concluded that the reduction in number of 'suppressor-inducer-like 'naive' CD4+ T-cell subsets in association with the decrease in fluorescence intensity for CD4 and CD8 may significantly contribute to the mechanisms that could account for a development of PBC.     

Transfusion-Related Immunomodulation in Chinese Children with Thalassaemia

Background and objectives: Multiple transfusions can induce immunomodulation. This study was carried out to investigate the immunological status of 50 transfusion-dependent children with β-thalassaemia, taking into account that lymphocyte characteristics are affected by sex, age and race. We paid particular attention to the influence of transfusion and serum ferritin on the lymphocyte subsets which may be affected by the exposure to foreign antigens. Materials and methods: By multicolour immunofluorescent analysis using flow cytometry, we determined lymphocyte characteristics with regard to major subsets (T lymphocytes, B lymphocytes and NK cells), activation (membrane IL-2 receptor CD25, HLA-D) and memory/naive T cells (CD45RO/CD45RA). Data from 51 age- and sex-balanced children served as controls. Results: The normal Chinese children had higher NK levels than the β-thalassaemia children. The levels of CD25 and HLA-D indicated a broad-based increase in activation status. Memory T cells were also increased when compared with their normal counterparts. We found additional and more marked alterations in the lymphocyte subsets of those who had received over 100 transfusions. While levels of NK cells were inversely correlated with the number of transfusions, CD25+ cells increased with transfusions. Conclusion: Many multitransfused β-thalassaemia children have altered levels of lymphocyte subsets compared with normals. What remains to be investigated is the long-term consequence of possessing low NK and non-MHC-restricted T cells (CD3+CD56+CD16+) and a high activation status in terms of resistance of infections and development of malignancy.     

Allogeneic peripheral blood stem cell transplantation results in less alteration of early T cell compartment homeostasis than bone marrow transplantation

Since low T cell counts evaluated 1 month after allogeneic bone marrow transplantation (BMT) are associated with an increased risk of leukemia relapse (Powles et al., Blood 1998; 91: 3481-3486), we compared, in a randomized multicentric clinical study, the peripheral blood cells obtained 30 days after allogeneic BMT vs allogeneic G-CSF-mobilized peripheral blood stem cell transplantation (BCT) in an HLA-identical setting. T cell counts were higher 30 days after BCT (718+/-142 cells/microl, n = 20) than after BMT (271+/-53 cells/microl, n = 26, P = 0.006). However, T cells were less activated after BCT than after BMT, as demonstrated by a lower expression level of CD25 and a lower percentage of HLA-DR+ and CD95+ T cells. Furthermore, CD4+, CD8+ and CD45RA+ post-BCT T cell counts correlated with the number of cells infused with the PBSC graft, while such a correlation was not observed between post-BMT counts and BM graft cell numbers, suggesting that the intensity of post-transplant peripheral lymphoid expansion and/or deletion differed between BCT and BMT. A comparison of the input of T cells expressing different CD45 isoforms with the post-transplant cell recovery further confirmed that, within the CD4+ T cell subset, post-transplant expansions occurred at a higher level after BMT than after BCT, affecting mainly the CD4+ CD45RO+ subset. Altogether, our data demonstrate for the first time in a randomized setting that homeostasis of the T cell pool is less altered early after BCT than after BMT. This may have a strong impact on the graft-versus-leukemia (GVL) effect and subsequent relapse rate.     

CD45RA+ and CD45RO+ lymphocyte subpopulations in patients with monoclonal gammopathies: correlations with diagnosis, clinical stage and treatment status

Alterations in blood lymphocyte subsets may be involved in the development of overt myeloma. Naive (CD4+CD45RA+) and memory (CD4+CD45RO+) helper T-cell subsets are important effectors of immune T-cell regulation. We analyzed the distribution of these blood lymphocyte subpopulations in patients with monoclonal gammopathies, considering the type of disorder, clinical stage, and treatment status.     

Immune reconstitution after blood cell transplantation

Immune clinical events and pattern of recovery of total lymphocytes, T cells and CD4+/CD8+ T cell subsets, B cells and NK cells, were analysed after allogeneic blood cell transplantation (BCT) for 12 months following transplant (n = 33). Results were compared with immune recovery after allogeneic bone marrow transplantation (BMT) (n = 15) and autologous blood cell transplantation (n = 19). Rates of acute GVHD were comparable in the two allotransplantation groups. Fourteen out of 17 evaluable alloBCT group patients have presented an extensive cGVHD. Total T cell, CD4+T cells and CD56+NK cell reconstitution were improved in alloBCT group vs alloBMT group. CD4+/CD8+ ratio evolution were improved in alloBCT group vs alloBMT and autoBCT groups. These results confirm that rapid immune recovery is associated with allogeneic blood stem cell transplantation.     

Analysis of bone marrow and peripheral blood immunoregulatory lymphocytes in patients with myelodysplastic syndrome

The cell surface phenotype of immunoregulatory lymphocytes in bone marrow (BM) and peripheral blood (PB) in myelodysplastic syndrome (MDS), a stem cell disorder, was analyzed. Mononuclear cells from 25 patients with refractory anemia (RA) and nine with RA with an excess of blasts (RAEB) were characterized by two-color flow cytometry using various monoclonal antibodies. No significant change of CD3+, CD4+, and CD8+ cells in PB, but a decrease of the percent of positive cells for CD8+ among the total lymphocyte (%CD8+ +) was noticed in RA patients. On the other hand, in BM of RA patients, a decrease in the number of CD4+cells, but not CD8+ +cells, was noted. In RAEB patients, the absolute numbers of CD3+, CD4+, CD8+, and CD8+ +cells in BM were decreased; however, the ratio of these lymphocytes was not changed. No change was observed among the CD4 + subsets in PB of RA or RAEB patients. In BM, a decrease in percentage of CD4+ CD45RA+ (% CD4+ CD45RA+; naive cell) and increases in CD4+ CD45RO+ (% CD4+ CD45RO+; memory cell) and CD4+ CD29+ (%CD4+ CD29+; helper/inducer) among CD4+ cells were found in both RA and RAEB patients. Analysis of the CD8+ + subset showed an increased number of CD8+ + CD11a+ cells (activated CTL) in both BM and PB of RA patients, but not of RAEB patients. Furthermore, increments in CD56+ and CD16+ cells among CD3- cells (natural killer; NK cells) were seen in RA patients but not in RAEB patients. It remains unclear whether lymphocytes in MDS patients were involved in the abnormal (MDS) clones, but our results regarding the increments of CD8+ + CD11a+ and NK cells in RA patients suggest that the mechanism of immune surveillance against the abnormal MDS clones was activated in these RA patients, but not in RAEB patients. Further investigation is required to clarify the functions of these immunoregulatory lymphocytes in MDS patients.     

Recovery of immune reactivity after T-cell-depleted bone marrow transplantation depends on thymic activity

To evaluate the importance of the thymus for the reconstitution of immunity in recipients of a T-cell-depleted bone marrow, we measured the appearance of CD4(+)CD45RA(+)RO(-) naive T cells (thymic rebound), restoration of the diversity of the T-cell-receptor (TCR) repertoire and the response to vaccinations with tetanus toxoid (TT). Repopulation by CD4(+)CD45RA(+)RO(-) thymic emigrants varied among patients, starting at approximately 6 months after transplantation. Young patients reconstituted swiftly, whereas in older patients, the recovery of normal numbers of naive CD4(+) T cells could take several years. Restoration of TCR diversity was correlated with the number of naive CD4(+)CD45RA(+)RO(-) T cells. Moreover, the extent of the thymic rebound correlated with the patient's capacity to respond to vaccinations. Patients without a significant thymic rebound at the moment of vaccination (CD4(+)CD45RA(+)RO(-) T cells less than 30 microL) did not respond, or responded only marginally even after 3 boosts with TT. We conclude that during the first year after transplantation, the absence of an immune response is due mainly to the loss of an adequate T-cell repertoire. Restoration of the repertoire can come only from a thymic rebound that can be monitored by measuring the increase of CD4(+)CD45RA(+)RO(-) naive T cells. This will allow postponing revaccinations to a moment when the patient will be able to respond more effectively. This may be particularly useful in the elderly patient who, owing to low thymic activity, might not yet be able to respond 1 year after transplant when revaccinations are usually scheduled.     

Lymphocyte subset abnormalities,autoantibodies and their relationship with HLA DR types in children with Type 1 (insulin-dependent) diabetes and their first degree relatives

Summary Type 1 (insulin-dependent) diabetes mellitus is associated with abnormalities of circulating lymphocyte subsets and autoantibodies. To investigate the prevalence of these in non-diabetic siblings and non-diabetic parents of children with Type 1 diabetes, we analysed T-cell subsets of function and activation in 31 families with an index case of Type 1 diabetes and related these to autoantibodies and HLA DR type. Using two and three colour cytofluorimetry, we studied total and activated (HLA-DR+) CD3+, CD4+, CD8+ lymphocytes and on CD4+ lymphocytes the CD45RA/RO “naive” and “memory” cell phenotypes. Diabetic children (mean duration of disease 3.1 years) had a reduced total lymphocyte count (p <0.05), their non-diabetic siblings a reduced CD4+ T-helper cell count (p <0.05), and their parents a reduced percentage and number of CD3+ T cells (p <0.01 and p <0.05) compared with age-matched control subjects. Diabetic children, their siblings and parents all had significantly increased levels of activated CD4+ T-helper cells (p <0.01, p <0.05 and p <0.01). In diabetic children and their siblings there was a significant over-expression of the CD45RO “memory” cell marker and significant under-expression of the CD45RA “naive” cell marker, whilst these were normal in the parents. Islet cell antibody positive diabetic children had significantly higher levels of CD45RO-expressing CD4+ lymphocytes than those who were islet cell antibody negative (p <0.05). Amongst the siblings and parents, possession of HLA-DR4 was associated with lower percentages of CD4+ and higher percentages of CD8+ T cells. These findings extend current knowledge about the role of immunoregulatory CD45RA/ RO cells in Type 1 diabetes. In addition, they demonstrate lymphocyte subset abnormalities in unaffected family members, some of which may be influenced by HLA DR alleles. [Diabetologia (1994) 37: 155–165] Received: 1 March 1993 and in final revised form: 16 August 1993