Dendritic Cell Subset Ratio in Tolerant, Weaning and Non-Tolerant Liver Recipients Is Not Affected by Extent of Immunosuppression

Dendritic cell (DC) subsets regulate alloimmune responses and may play a role in transplant tolerance. We extend an analysis of circulating precursors (p) of CD11c(+) CD123(-/lo) (IL-3Ralpha(-/lo)) (pDC1) and CD11c(-) CD123(hi) (pDC2) DC subsets in primary cadaveric liver allograft recipients. Additionally, we examine DC subset levels in relation to the nature and extent of immunosuppressive therapy. The data consolidate the finding that the pDC2/pDC1 subset ratio is significantly higher in patients on minimal calcineurin inhibitor monotherapy undergoing successful weaning (n = 36) and in those off all anti-rejection therapy (n = 18) compared with patients on maintenance immunosuppression (n = 21). No relationship was found between the incidence of either pDC subset or the pDC subset ratio and time post-transplant or time off immunosuppression in any group. There was also no correlation between the pDC subset ratio and either prednisone or tacrolimus dose or tacrolimus trough blood level. No evidence was found that combination of these drugs influenced the incidence of pDC2 relative to pDC1. Thus, a greater prevalence of pDC2 in stable liver recipients on low dose anti-rejection therapy or in those off immunosuppression, compared with that in patients on maintenance immunosuppression, does not reflect a differential effect of anti-rejection drugs on pDC subsets.     

Peripheral blood dendritic cells in human end-stage heart failure and the early post-transplant period: evidence for systemic Th1 immune responses.

OBJECTIVES: Dendritic cells (DCs) are antigen presenting cells that play a central role in inflammation, allograft rejection and immune tolerance. Myeloid (mDC) and plasmacytoid (pDC) subsets regulate immune reactions by polarising naive T-helper cells into a Th1 or Th2 response, respectively. In this study we examined total peripheral blood DCs, mDC and pDC subsets in chronic heart failure (CHF) and clinical heart transplantation (HTx). METHODS: We compared 16 heart transplant patients before and after HTx to 14 healthy controls. Whole blood was collected pre-HTx and 1-week post-HTx from patients and at corresponding time-points from controls. All patients received induction and maintenance immunosuppression post-HTx. mDCs and pDCs were measured by flow cytometry and were further characterised for maturation and homing potential to the secondary lymphoid organs with CD83 and CCR7, respectively. Data were expressed as absolute numbers/microl whole blood, percentage (%) mDC or pDC of total blood DCs and % positive DCs for CD83 and CCR7. RESULTS: CHF patients had more peripheral blood DCs compared to controls (P<0.01) while only the mDC fraction was increased compared to controls (P=0.01). Percentage CD83(+) and CCR7(+) mDCs was also higher than control levels (P<0.05). One week post-HTx, total DCs, mDCs and pDCs decreased below controls (P<0.001). At the same time % mDCs in peripheral blood increased markedly compared to CHF and control levels (P<0.001). The %CD83(+) mDC, %CD83(+) pDC and %CCR7(+) mDC also returned to control levels and only %CCR7(+) pDC decreased below control levels (P=0.005). CONCLUSIONS: Total peripheral blood DCs are elevated during CHF due to an increase in the mature fraction of the mDC subset suggesting a possible Th1 response in end-stage heart failure. The decrease in total DCs and mature mDCs and pDCs seen post-HTx, probably reflects immunological quiescence through adequate immunosuppression. Peripheral blood DC monitoring may provide a new insight into mechanisms of heart failure and allograft rejection by safe weaning from immunosuppression after clinical HTx.     

Rare-event analysis of circulating human dendritic cell subsets and their presumptive mouse counterparts.

BACKGROUND: Considerable interest has focused recently on murine CD8alpha- and CD8alpha+ dendritic cell (DC) subsets, because of their roles in initiating and regulating immune responses. Attention has also centered on their presumed human counterparts, DC1 and DC2, respectively, and their precursors. Identification and quantification of these subsets in the blood may be crucial to understanding and monitoring of their immunologic significance, particularly in humans, where blood may be the only tissue readily or routinely available. METHODS: Leukocytes were isolated from anticoagulated human or mouse (C57BL/10J) blood using conventional procedures. Four-color, rare-event, flow cytometric analysis was used to identify DC1 precursors (pDC1; lineage [lin]- CD4+ CD11c+ HLA-DR+) or DC2 precursors (pDC2; lin- CD4+ CD11c- CD123(hi) [IL-3Ralpha(hi)] HLA-DR+) in normal humans. In mice, CD8alpha+ (CD11b(lo), CD11c+) and CD8alpha- (CD11b(hi), CD11c+) DC subsets were identified both in normal animals and after administration of the potent DC growth factor, fms-like tyrosine kinase 3 ligand (Flt3L). RESULTS: All human subjects examined had discrete populations of pDC1 and pDC2 comprising approximately 0.6% and 0.1% of blood mononuclear cells. CD8alpha- and CD8alpha+ DC constituted approximately 0.75% and 0.2%, respectively, of blood mononuclear cells in normal mice, and 12% and 0.5%, respectively, in Flt3L-treated animals. Flt3L administration substantially increased the absolute numbers of circulating CD11c+ DC by approximately 200-fold. CONCLUSIONS: In addition to pDC1 and CD8alpha- DC, pDC2 and CD8alpha+ DC can be identified in normal human or mouse blood, respectively. Monitoring and isolation or characterization of these cells may provide novel insights into their functional significance in transplantation and other clinical conditions.     

The effects of renal transplantation on circulating precursor dendritic cells

BACKGROUND: Dendritic cells (DCs) are potent antigen-presenting cells that induce and regulate immune responses. Recent advances allow accurate quantification of peripheral blood (PB) myeloid and plasmacytoid DC populations (mDC and pDC, respectively), although the response to renal transplantation (RT) remains unknown. METHODS: Using flow cytometry, PBDC levels were quantified in patients with end-stage renal disease (ESRD) undergoing renal transplantation. RESULTS: PBDC levels were significantly reduced in ESRD patients pretransplantation compared to healthy controls, with further reduction noted immediately following a hemodialysis session. RT resulted in a dramatic decrease in both subsets, with a greater reduction of pDC levels. Both subset levels were significantly lower than in control patients undergoing abdominal surgery without RT. Subgroup analysis revealed significantly greater mDC reduction in RT recipients receiving antilymphocyte therapy, with preferential binding of antibody preparation to this subset. Samples from later time points revealed a gradual return of PBDC levels back to pretransplant values concurrent with overall reduction of immunosuppression. Finally, PBDC levels were significantly reduced in patients with BK virus nephropathy compared to recipients with stable graft function, despite lower overall immunosuppression. CONCLUSIONS: Our findings suggest that PBDC levels may reflect the degree of immunosuppression in renal allograft recipients. Furthermore, PBDC monitoring may represent a novel strategy to predict important outcomes such as acute rejection, long-term graft loss, and infectious complications.     

High PD-L1/CD86 ratio on plasmacytoid dendritic cells correlates with elevated T-regulatory cells in liver transplant tolerance

BACKGROUND: Both dendritic cells (DC) and T-regulatory cells (Treg) have been implicated in regulation of alloimmune responses and transplant tolerance. METHODS: We analyzed B7 coregulatory molecule expression on circulating DC subset precursors, together with CD4+CD25(hi) Foxp3+ Treg by rare event, flow cytometric analysis in operationally tolerant pediatric liver transplant recipients (TOL), those undergoing prospective immunosuppressive drug weaning (PW) or maintenance immunosuppression (MI), and normal healthy individuals (controls). RESULTS: Use of DC subset-specific monoclonal antibodies confirmed elevated precursor plasmacytoid DC/myeloid DC ratios in TOL and PW compared with MI. In addition, Treg frequencies were higher in TOL than in PW and MI, but not controls. While there was no difference in levels of costimulatory and coinhibitory molecules on precursor myeloid DC between the groups, the programmed death ligand-1 (PD-L1=B7-H1):CD86 (B7-2) ratio on precursor plasmacytoid DC was significantly higher in TOL than MI and correlated with the Treg frequency. There was no relation between prednisone or tacrolimus dose or tacrolimus trough level and either the PD-L1/CD86 ratio on plasmacytoid DC or the Treg frequency. Moreover, clinically relevant concentrations of dexamethasone or tacrolimus did not affect these values in short-term culture. CONCLUSION: These novel findings suggest a possible functional relationship between the enhanced incidence of precursor plasmacytoid DC, their comparatively high relative expression of the coinhibitory molecule PD-L1, and the elevated frequency of Treg in operational liver transplant tolerance.     

Dendritic Cell Deficiency in the Blood of Kidney Transplant Patients on Long-Term Immunosuppression: Results of a Prospective Matched-Cohort Study

Evidence from in vitro studies suggests that immunosuppressive drugs interfere with key functions of dendritic cells (DCs), but the in vivo relevance of these findings is elusive. We prospectively analyzed the major DC precursor subsets in the blood of kidney transplant recipients on long-term immunosuppression (> or =1 year). A total of 87 patients were compared to 87 age- and sex-matched controls. Total DC numbers and the precursor subsets, myeloid type 1 DCs, myeloid type 2 DCs (mDC1, mDC2) and plasmacytoid DCs (pDCs) were identified by four color flow cytometry. Long-term immunosuppression was associated with significant reduction of all major DC subsets in comparison to healthy controls (mDC1 p < 0.001; mDC2 p < 0.0001; two-tailed Mann-Whitney U-test) with the strongest negative impact on pDCs (p < 0.00001). In contrast, total leukocyte numbers were not significantly affected. Analysis of the relative impact of different agents revealed a significant impact of prednisolone on pDCs (p = 0.009) and mDCs2 (p = 0.006). The functional relevance of pDC deficiency was confirmed independently by Interferon-alpha analysis after Toll-like receptor 7 (p < or = 0.001) and 9 (p < 0.05) stimulation. These results indicate for the first time a profound negative impact of long-term immunosuppression on major DC subsets in kidney transplant recipients. DC deficiency may have important implications with respect to viral infections and tumor development.     

肾移植受者术后早期外周血树突状细胞亚群的动态变化及意义

目的 分析肾移植受者手术前后外周血中树突状细胞(DC)及其亚群骨髓源性DC(mDC)和浆细胞源性DC(pDC)的动态变化,探讨其与排斥反应的关系.方法 检测28例肾移植受者术前,术后1、7和28 d外周血中白细胞总数和单个核细胞数(PBMNC);应用流式细胞术测定DC及其亚群的数量和pDC/mDC.应用酶联免疫吸附试验法测定手术前后血清白细胞介素(IL)-10和IL-12水平.15名健康志愿者作为正常对照.结果 移植组术前外周血DC总数、pDC和mDC数量均低于对照组(P＜0.05),但两组pDC/mDC的差异无统计学意义(P＞0.05).移植组受者术后第1天外周血DC数量骤然降低,然后缓慢上升,第28天恢复至手术前的73.7％;mDC和pDC术后也降低,但mDC恢复较快,pDC恢复缓慢,至术后28 d分别达到术前水平的80.1％和50.1％(P＜0.05).术后第7天,移植组发生排斥反应者mDC数量高于未发生排斥反应者(P＜0.01).受者手术前后IL-10和IL-12的水平变化不明显.结论 DC及其亚群的变化与肾移植受者免疫状态有关,其变化异常提示受者免疫状态不稳定,在受者发生急性排斥反应时,可以作为诊断的参考指标.     

Preferential Depletion of Blood Myeloid Dendritic Cells During Acute Cardiac Allograft Rejection Under Controlled Immunosuppression

Allo-Ag presentation to Ag-specific T-lymphocytes by donor or recipient dendritic cells (DCs) induces acute rejection (AR) after solid organ transplantation. It is postulated that myeloid (mDC) and plasmacytoid (pDC) subsets circulate differentially between bone marrow, heart and lymphoid tissues after cardiac transplantation (HTx). We investigated peripheral blood DC subset distribution, maturation and lymphoid homing properties in relation to endomyocardial biopsy (EMB) rejection grade after clinical HTx. Twenty-one HTx recipients under standard immunosuppression were studied in a 9-month follow-up. mDC and pDC numbers were analyzed by flow cytometry in fresh venous whole blood samples collected during the EMB procedures and before histological diagnosis of AR. Subsets were further characterized for maturation marker CD83 and lymphoid homing chemokine receptor CCR7. Although numbers of both DC subsets remained low for the whole post-HTx period, we observed a negative association of mDCs with rejection grade. Repeated measurements analysis revealed that only mDCs decreased during AR episodes. Rejectors had lower mDC numbers after a 3-month follow-up compared to nonrejectors. Furthermore, patients during AR exhibited low proportions of mDCs positive for CD83 or CCR7. These findings suggest peripheral blood mDC depletion in association with selective lymphoid homing of this subset during AR after clinical HTx.     

Numerical and functional assessment of blood dendritic cells in prostate cancer patients

BACKGROUND: Prostate cancer is one of the leading causes of cancer deaths in males and there are currently no effective treatments available for metastatic disease. Although recent clinical trials using dendritic cell (DC) based immunotherapy treatments have demonstrated safety, immunological responses, and some clinical efficacy, better vaccine delivery strategies need to be developed. We have undertaken the first detailed analysis of blood DC (BDC) subsets and their function in prostate cancer patients, with a view to utilizing immunoselected BDC for immunotherapy. METHODS: We enumerated the CD11c+CD1c+, CD11c+CD16+, and CD11c-CD123+ BDC subsets in whole blood of prostate cancer patients using a single platform TruCOUNT assay. These subsets were identified and purified using flow cytometry and immunomagnetic selection, and their functional capacity analyzed by costimulatory molecule expression, cytokine secretion, and antigen presenting ability. RESULTS: There were no significant differences in the number or composition of these subsets compared to healthy donors and these cells could be purified with equal efficiency from both groups. The prostate cancer patients BDC had similar levels of key costimulatory molecules and cytokine expression profiles, compared to healthy donors, and these were upregulated to the same extent, in response to exogenous stimuli. BDC from both groups were capable of eliciting allogeneic proliferative responses and inducing autologous CD4+ responses to na?ve and recall antigens, and antigen-specific CD8+ responses to influenza matrix protein and prostate specific antigen. CONCLUSIONS: These results indicate that an immunoselected CD1c+ BDC preparation could provide a suitable vaccine delivery vehicle for future prostate cancer immunotherapy trials.     

Observational support for an immunoregulatory role of CD3+CD4+CD25+IFN-gamma+ blood lymphocytes in kidney transplant recipients with good long-term graft outcome.

There is evidence that interferon-gamma (IFN-gamma)-dependent interactions of dendritic cell (DC), T regulatory (Treg), and T suppressor (Ts) subpopulations contribute to allograft acceptance. We measured DC subsets, CD3+CD4+CD25+ (Treg phenotype) and CD3+CD8+CD28(-) (Ts phenotype) peripheral blood lymphocytes (PBL) expressing Foxp3, Th1 or Th2 cytokines, peripheral T- and B-cell counts, and plasma cytokines in 33 kidney transplant recipients with a serum creatinine of < or =1.8 mg/dl and 32 recipients with a serum creatinine of > or =2.0 mg/dl more than 100 days post-transplant. Cell subsets were measured in whole blood using four-color flow cytometry. Patients with increased creatinine had less frequently detectable CD3+CD4+CD25+IFN-gamma+ PBL than patients with good graft function (P = 0.017). In patients with good graft function, CD3+CD4+CD25+IFN-gamma+ PBL were associated with high Foxp3+, IL-2+, IL-12+, IL-4+, and IL-10+ CD3+CD4+CD25+ T PBL (P < 0.001), low CD3+CD8+CD28(-)Foxp3+ (P = 0.002), CD3+CD4+DR+ (P = 0.002), CD3+CD8+DR+ T (P = 0.005) and CD19+ B PBL (P = 0.005), and low lineage(-)HLA-DR+CD11c+CD123(-) DC1 (P = 0.006). Patients with impaired graft function did not show these associations. Additional flow cytometric analysis confirmed strong co-expression of IFN-gamma and Foxp3 by CD4+CD25+ PBL particularly in patients with good graft function. Our data support an immunoregulatory role of CD3+CD4+CD25+Foxp3+IFN-gamma+ cells in a subgroup of transplant recipients with good graft acceptance.     

Impaired circulating dendritic cell reconstitution identifies rejecting recipients after clinical heart transplantation independent of rejection therapy.

OBJECTIVE: Dendritic cell (DC) mediated allo-antigen presentation to host antigen specific T-lymphocytes initiates acute allograft rejection. We investigated peripheral blood DC (PBDC) incidence and DC subset reconstitution in relation to histological diagnosis of acute cellular rejection (AR) and administration of rejection therapy after clinical heart transplantation (post-HTx). METHODS: Venous blood from 20 HTx recipients under standard immunosuppression was collected during serial endomyocardial biopsy (EMB) prior to administration of rejection therapy in a 9-month follow-up post-HTx. Echocardiographic assessment of allograft function during EMB was performed to distinguish clinical necessity for rejection therapy within histologically rejecting patients (R). Myeloid (mDC) and plasmacytoid (pDC) subsets identified by flow-cytometry were analysed for different ISHLT rejection grades. Circulating PBDC incidence and mDC/pDC ratio were compared sequentially between non-rejecting (NR) recipients and R patients treated (3A(+)) or not-treated (3A(-)) with rejection therapy during follow-up. RESULTS: Eleven samples from biopsy-proven AR episodes (AR(+): ISHLT>or=3) were compared to 89 samples from non-rejection episodes (AR(-): ISHLT grade 0, n=52; grade 1, n=29; grade 2, n=8). We observed an inverse correlation of mDCs (P<0.05) but not pDCs with increasing rejection grade. PBDC incidence and mDC/pDC ratio were low in blood samples obtained during AR (P<0.05 and P<0.01, respectively). Both PBDCs and mDC/pDC ratio decreased during each AR episode (P<0.05). Comparison of 3A(+) and 3A(-) rejectors with NR patients after 12 weeks post-HTx revealed lower PBDC incidence (P<0.01) and mDC/pDC ratio (P<0.05) for R patients, independent of rejection therapy. CONCLUSIONS: Defective DC subset reconstitution by dendritic cell profiling identifies patients at risk for AR after 3 months post-HTx. This finding may contribute to further optimization of immunosuppressive treatment strategies after clinical heart transplantation.     

The effects of renal transplantation on peripheral blood dendritic cells

Recent advances allow accurate quantification of peripheral blood (PB) myeloid and plasmacytoid dendritic cell (DC) populations (mDC and pDC, respectively), although the response to renal transplantation (RT) remains unknown. Using flow cytometry, PBDC levels were quantified in patients with end stage renal disease (ESRD) undergoing RT. PBDC levels were significantly reduced in ESRD patients pre-RT compared to healthy controls, with further reduction noted immediately following a hemodialysis session. RT resulted in a dramatic decrease in both subsets, with a greater reduction of pDC levels. Both subset levels were significantly lower than in control patients undergoing abdominal surgery without RT. Subgroup analysis revealed significantly greater mDC reduction in RT recipients receiving anti-lymphocyte therapy, with preferential binding of antibody preparation to this subset. Samples from later time points revealed a gradual return of PBDC levels back to pre-transplant values concurrent with overall reduction of immunosuppression (IS). Finally, PBDC levels were significantly reduced in patients with BK virus nephropathy compared to recipients with stable graft function, despite lower overall IS. Our findings suggest that PBDC levels reflect the degree of IS in renal allograft recipients. Furthermore, PBDC monitoring may represent a novel strategy to predict important outcomes such as acute rejection, long-term graft loss and infectious complications.     

Selective effects of cyclosporine a on Th2-skewed dendritic cells matured with viral-like stimulus by means of toll-like receptors

Successful prevention of allograft rejection and graft-versus-host disease with immunosuppression depends on controlled balance of Th1 and Th2 immune responses to establish tolerance and fight infection. Here, we have analyzed the effects of cyclosporine A (CsA) on the differentiation and functions of dendritic cells (DC2) that induce Th2 T cells. DC2 were differentiated from monocytes in the presence of CsA and were matured with viral or bacterial agonists (poly[I:C] or lipopolysaccharide). DC2 differentiation was not affected by CsA. In contrast, cytokine responses were altered with inhibition of interleukin-10 production in poly(I:C)-matured DC2. Surprisingly, interleukin-10 secretion by immature DC2 was increased after CsA treatment. Internalization was impaired in treated DC2, and CsA decreased the T-cell proliferative capacity of DC2 matured with poly(I:C), but not with lipopolysaccharide. In conclusion, CsA altered T-cell activating functions of DC2 with, notably, a regulatory phenotype for immature DC2 and opposite effects on poly(I:C)-matured cells.     

Preferential induction of Th1 responses by functionally mature hepatic (CD8alpha- and CD8alpha+) dendritic cells: association with conversion from liver transplant tolerance to acute rejection

BACKGROUND: Liver grafts are accepted across major histocompatibility barriers in mice without immunosuppressive therapy. Potentially tolerogenic immature donor dendritic cells (DC) may play a key role in this phenomenon, but recovery of purified DC from normal livers for functional analysis is inherently difficult. Administration of in vitro propagated immature donor DC to recipients of different types of allograft can prolong transplant survival. By contrast, marked increases in donor liver DC as the result of Flt3 ligand (FL) administration and the resulting augmentation of allostimulatory activity within host lymphoid tissue, is associated with acute graft rejection. Here, we compared the capacity of in vitro generated normal liver immature DC and FL-treated donor liver DC to induce alloimmune CD4+ T helper (Th) 1/Th2 and CD8+ T cytotoxic (Tc) 1/Tc2 responses, in vitro and in vivo. METHODS: B10 (H2b, IAb) immature liver DC were propagated from normal hepatic nonparenchymal cells in granulocyte macrophage-colony stimulating factor (GM-CSF) for 6-8 days. Freshly isolated DC from livers of FL-treated mice (FL-liver DC) were cultured overnight (o/n) in GM-CSF, and both myeloid (CD11c+ CD8alpha-) and lymphoid DC (CD11c+ CD8alpha+) flow-sorted for functional analysis. Proliferative activity and production of interferon (IFN)-gamma, interleukin (IL)-4, and IL-10 by naive C3H (H2k, IEk) T cells in response to DC stimulation was assessed by [3H]thymidine incorporation, and by multicolor flow cytometric analysis, respectively, after 3-day mixed leukocyte reactions. To investigate their in vivo trafficking, B10 DC were injected subcutaneously into normal C3H mice. Sections of lymphoid tissue were immunostained for donor MHC class II+ (IAb+) cells, and for IFN-gamma, IL-4, and IL-10 production. Donor cells and clusters of specific cytokine-secreting cells were enumerated. RESULTS: Both in vitro propagated normal liver-derived DC, and freshly isolated bulk FL-liver DC showed an immature phenotype (MHC class II(lo), CD40-, CD80-, and CD86-) and were weak stimulators of naive allogeneic T cells. After o/n incubation in GM-CSF, both CD8alpha- and CD8alpha+ FL-liver DC exhibited marked up-regulation of surface MHC class II and costimulatory molecules, and acquired potent stimulatory activity for Th1 (mainly) and Th2 cells. Both in vitro propagated immature DC and o/n-cultured mature FL-liver DC homed in vivo to host lymphoid tissues, but with different kinetics. Whereas the mature allogeneic FL-liver DC induced IFN-gamma+ clusters in splenic T-cell areas within 2 days, the IFN-gamma response to immature DC was much slower and weaker. CONCLUSIONS: FL-treated donor livers that are rejected acutely contain markedly enhanced numbers of myeloid (CD8alpha-) and lymphoid (CD8alpha+) DC, many of which are capable of maturing rapidly into strong inducers of Th1 and Tcl responses. Substantial differences in quantity, and both the phenotypic and functional characteristics of the DC constituency of donor livers, may contribute significantly toward the distinct outcomes of liver transplant tolerance and rejection.     

Characterisation of dendritic cell subsets in chronically inflamed human epididymis

Infection and inflammation of the genital tract are thought to be a primary aetiological factor of male infertility. Chronic epididymitis appears to be more important than prostatitis or seminal vesiculitis due to the direct interaction between sperm cells and epididymal epithelium. Dendritic cells (DCs) are a heterogeneous population of antigen‐presenting cells that play a crucial role in the regulation of the immune response and immunological tolerance. The aim of this study was to investigate the expression and characteristic of different DC subsets in chronic inflammation of human epididymis and controls. Our study demonstrated that normal human epididymis contained only immature CD1a⁺ DCs, CD11c⁺ myeloid DCs (mDCs) and CD209⁺ DCs whereas CD123⁺ plasmacytoid DCs and CD83⁺ mature DCs were virtually absent. The number of both CD11c⁺IL‐23⁺ mDCs and CD123⁺ pDCs were significantly elevated in inflamed epididymis; meanwhile the mDC populations of CD1a⁺, CD209⁺ immature DCs and CD83⁺ mature DCs also increased in inflamed group. Moreover, Th17 (CD4⁺IL‐17⁺) cells were predominantly distributed under chronic inflammation of human epididymis. Taken together these results suggest that epididymal DCs might play a pivotal role in the development of chronic epididymitis and induce an increased recruitment of Th17 cells under inflammatory conditions.     

Alemtuzumab (Campath-1H) induction therapy and dendritic cells: Impact on peripheral dendritic cell repertoire in renal allograft recipients

Dendritic cells (DC) are the most potent antigen-presenting cells (APC) and are pivotal for initiating allograft immunity. Recently, particular DC subsets have been implicated also in allogeneic T cell hyporesponsiveness. Alemtuzumab (anti-CD52, Campath-1H) is a novel T cell depleting antibody that is currently under investigation for the use in allogeneic organ transplantation. While recent studies demonstrated a conspicuous effect of alemtuzumab on peripheral DC in clinical graft-versus-host disease, its efficiency in patients receiving allogeneic organ transplants is still undefined. In the present study we assessed the peripheral DC repertoire in kidney transplant recipients after either alemtuzumab induction therapy followed by FK506 monotherapy or after conventional immunosuppression (FK506, mycophenolate mofetil and steroids) without any induction agent. Induction with alemtuzumab caused a strong and sustained reduction of the total number of peripheral DC and a significant shift from myeloid to plasmacytoid DC subsets (mDC/pDC ratio) as early as 1 month post-transplantation. These data show that alemtuzumab induction targets the peripheral DC repertoire, which might add another mechanism allowing immunosuppressive drug minimization. Further studies are warranted to further elucidate the functional significance of these finding in the setting of allogeneic organ transplantation.     

Circulating dendritic cells following burn

Burns are associated with immune suppression and subsequent development of sepsis. Dendritic cells (DCs) are potent antigen-presenting cells that serve as a critical link between the innate and acquired immune systems, and are essential in coordinating the host response to pathogens. Using multicolour flow cytometry, the percentages of LIN^? DR⁺ CD11c⁺ myeloid (mDC) and LIN^? DR⁺ CD123⁺ plasmacytoid (pDC) subsets were determined in peripheral blood from 32 people (15 septic and 5 non-septic burn victims and 12 age- and gender-matched healthy controls, up to 20 days from injury). Analysis revealed significant reductions in circulating mDCs and pDCs in survivor as well as non-survivor septic cases compared with non-septic cases and controls (p < 0.001). These findings suggest that deficiencies in mDCs and pDC subsets are related to sepsis following severe burn, and may contribute to immunosuppression among burn victims.     

右美托咪定对胃癌根治术患者围术期白细胞介素-6、皮质醇及T淋巴细胞亚群的影响

目的观察右美托咪定对胃癌根治术患者围术期白细胞介素-6(IL-6)、皮质醇(Cor)及T淋巴细胞亚群的影响。方法 40例择期全麻下行胃癌根治术患者,随机均分为右美托咪定组(D组)和对照组(C组)。两组分别于麻醉诱导时在15min内静脉泵入1μg/kg右美托咪定和等容量的生理盐水,随后持续静脉输注右美托咪定0.2～0.7μg·kg-1·h-1和生理盐水0.125ml·kg-1·h-1。检测麻醉诱导前(T0)、切皮前(T1)、手术1h(T2)、术毕(T3)、术后1d(T4)和术后3d(T5)血清IL-6、血浆Cor浓度及外周血T淋巴细胞亚群(CD3+、CD4+、CD8+、CD4+/CD8+)水平。结果与T0时比较,C组T2～T4时血清IL-6和T2、T3时血浆Cor浓度升高(P<0.05);T1～T5时CD3+、CD4+、CD8+、CD4+/CD8+显著下降(P<0.05);D组血清IL-6及血浆Cor浓度无明显变化,T2和T3时CD3+、CD4+、CD8+、CD4+/CD8+显著上升(P<0.05)。结论全麻期间持续静脉输注右美托咪定可有效抑制胃癌根治术患者围术期的应激反应,减少细胞免疫功能的抑制。     

Increased donor CD86+CD14+ cells in the bone marrow and peripheral blood of patients with chronic graft-versus-host disease

BACKGROUND: Based on experimental models, chronic graft-versus-host disease (cGVHD) may depend on activated donor antigen-presenting cells presenting host antigens to donor T cells. METHODS: Peripheral blood (PB) and marrow samples from 24 patients with cGVHD and 17 patients without GVHD after an allogeneic hematopoietic stem-cell transplant were analyzed by flow cytometry. The absolute number of myeloid dendritic cells (mDC) (BDCA1+CD19-), plasmacytoid DC (pDC) (BDCA2+CD123+) and monocytes (CD45+CD14+), and mean fluorescence intensity of costimulatory molecules and chemokine receptors were assessed in each antigen-presenting cell population. RESULTS: Patients with cGVHD showed increased numbers of marrow monocytes when compared with patients without cGVHD (P=0.006). Moreover, monocytes of cGVHD patients had greater CD86 mean fluorescence intensity in marrow (P=0.02) and PB (P=0.04). Treatment with prednisone resulted in decreased CD86 expression in marrow (P=0.02) and PB (P=0.04) monocytes. The number and phenotype of mDC and pDC were similar in patients with or without cGVHD. Full-donor chimerism was detected in the PB of all patients, and in purified CD14+ monocytes from three cGVHD patients. CONCLUSION: Our results show an increased activation of donor-derived marrow and blood monocytes in patients with cGVHD, possibly suggesting the need to target monocytes in the treatment of cGVHD.     

Recipient memory-like lymphocytes remain unresponsive to graft antigens after CAMPATH-1H induction with reduced maintenance immunosuppression

BACKGROUND: Treatment with CAMPATH-1H at the time of transplantation allows reduced maintenance immunosuppression. We hypothesized that CAMPATH-1H induction would modulate the response of repopulating leukocytes to donor alloantigens. METHODS: The phenotype, proliferative and stimulatory capacity of peripheral blood leukocytes from 14 renal transplant recipients treated with CAMPATH-1H and reduced immunosuppression with mycophenolate mofetil and tacrolimus were investigated for the first six months after transplantation. The impact of immunosuppressive drugs on leukocytes that escape depletion was also evaluated in vitro. RESULTS: CAMPATH-1H therapy caused a significant decrease in the number of B and T cells, with CD4 T central memory cells being the most resistant to depletion. The recovery of CD8 T cells was faster than that of CD4 T cells. Lymphopenia correlated with a decrease in both proliferative and effector responses, however, the recipient T cells remained responsive to third-party antigens. Dendritic cells (DC) were also depleted but to a lesser extent than lymphocytes; lymphoid DC were more resistant than myeloid DC; these changes correlated with decreased allostimulatory capacity. One of the patients experienced rejection that was treated successfully. The rejection was associated with a high proportion of CD4 T effector memory cells and myeloid DC, increased proliferation and enhanced effector activity to donor antigens. In vitro studies confirmed that the reduced dose of immunosuppressive drugs used could prevent activated T cells from switching to the effector compartment, suppressing both their proliferation and effector activity. CONCLUSIONS: CAMPATH-1H induction combined with reduced maintenance immunosuppression is sufficient to control the effector phase of immune response to donor antigens.