Differential effects of single dose FTY720 on CD62L+ B-cells in stable renal allograft recipients

FTY720, a sphingosine-1-phosphate receptor agonist, is the archeotype of a new class of immune modulators, which redirects lymphocytes from the peripheral blood into secondary lymphatic tissue. Previously, it was shown that FTY720 differentially decreases peripheral T-cells, expressing specific chemokine and adhesion receptors. Here, we investigated the effect of single doses FTY720 on peripheral B-cells expressing CD62L, CD11a, CD49d and CXCR4 in stable human renal allograft recipients. Peripheral blood lymphocytes were isolated by Ficoll density centrifugation and stained with monoclonal antibodies against CD3 or CD19 and CD62L, CD11a, CD49d, CXCR4 to determine the percentage of these T- and B-cell subpopulations. Total lymphocyte counts were measured by routine laboratory diagnostics to calculate absolute lymphocyte subset counts. In FTY720 treated patients, total lymphocyte counts decreased by 31.8% (0.25-2 mg) and 60.4% (3.5 mg), and total T-cell counts by 38.8% (0.25-2 mg) and 70.9% (3.5 mg). In comparison, total B-cell counts decreased by 32.2% (0.25-2 mg) and 61.1% (3.5 mg). The reduction of CD62L+ B-cells was less pronounced as compared to CD62L+ T-cells (0.25-2 mg: 15.7% vs. 57.3%; 3.5 mg: 57.2% vs. 86.9%). CD11a+ B-cells decreased by 15.4% (0.25-2 mg) and 57.1% (3.5 mg), and CD49d+ B-cells by 15.0% (0.25-2 mg) and 56.7% (3.5 mg). CXCR4+ B-cells decreased by 19.9% (0.25-2 mg) and 57.2% (3.5 mg). In vitro experiments showed that FTY720 did not change the mean expression of CD62L, CD11a, CD49d and CXCR4 on CD19+ B-cells. In conclusion FTY720 treatment reduces B-cells expressing CD62L to a significant lesser degree than T-cells expressing CD62L.     

Single-dose FTY720 pharmacokinetics, food effect, and pharmacological responses in healthy subjects

AIMS: FTY720 is a sphingosine-1-phosphate receptor agonist that redirects lymphocytes from the circulation to lymph nodes without impairing lymphocyte function. It is being developed as an immunomodulator for the prevention of acute rejection after organ transplantation. This study was performed to provide guidance on administration with respect to meals and to measure pharmacologic responses in healthy subjects. METHODS: In this randomized, two-period, crossover study, 14 healthy subjects received placebo on day -1 of each period with baseline circadian measurements of lymphocyte count and heart rate. Subjects subsequently received a single 1 mg oral dose of FTY720 on day 1 under fasting conditions and after a high fat meal. Blood FTY720 concentrations, lymphocyte count, and supine heart rate were assessed over an 8 day period after each FTY720 dose. The effect of food on FTY720 pharmacokinetics was assessed by standard bioequivalence testing. RESULTS: Both the peak concentration (0.65 +/- 0.17 vs 0.64 +/- 0.18 ng ml(-1)) and total exposure (AUC 149 +/- 65 vs 139 +/- 43 ng ml(-1) h) did not differ significantly between fasting and fed states, respectively. The corresponding fed/fasting ratios and 90% confidence intervals were 1.00 (0.86, 1.17) for Cmax and 0.98 (0.86, 1.11) for AUC. Under both treatment conditions peripheral blood lymphocyte count decreased from baseline by 38 +/- 9% over the first 2 days postdose and then increased towards predose values over the subsequent week. Whereas a circadian rhythm in supine heart rate was preserved in the presence of FTY720, the heart rate vs time curve was shifted downwards by 10% over the first day postdose and then recovered to prestudy values by days 3-5 postdose. These changes were asymptomatic. CONCLUSIONS: Single 1 mg doses of FTY720 were well tolerated in healthy subjects and elicited a moderate decrease in peripheral blood lymphocyte count and a transient decrease in heart rate consistent with its pharmacological mode of action. FTY720 may be administered without regard to the timing of meals or their fat content.     

Evidence that FTY720 induces T cell apoptosis in vivo

The immunosuppressant FTY720 induces a drastic decrease in blood lymphocytes, especially T cells; a decrease which is assumed to be the immunosuppressive mechanism of this drug. FTY720 causes cell death in vitro in lymphocytes and leukemia cells. However, the deletion mechanism of blood lymphocytes in vivo remains unclear. We investigated whether administration of FTY720 induced lymphocyte apoptosis in blood circulation. A marked decrease in the number of blood lymphocytes was observed within an hour after a single oral administration of FTY720 at doses of 5-10 mg/kg in rats and mice. Experiments using fluorescein isothiocyanate (FITC)-Annexin V and APO-BRDU methods revealed that FTY720 induced blood lymphocyte apoptosis in a dose-dependent manner. On the other hand, lymphocyte homing to Peyer's patches was proposed as the mechanism underlying the blood lymphocyte decrease at these doses. However, similar results were obtained when using aly/aly mice, which lack Peyer's patches and lymph nodes. Thus, we concluded that apoptosis of blood lymphocytes was induced immediately after administration of FTY720, and the cells could be immediately scavenged by phagocytes or the reticuloendothelial system in addition to Peyer's patches homing. We also concluded that T cells were highly sensitive to FTY720, which induced apoptosis in vivo.     

Analysis of the mode of action of a novel immunosuppressant FTY720 in mice.

Accelerated lymphocyte homing and apoptosis have been suggested to contribute to potent immunosuppressive effects of FTY720, however, its main mechanism of action remains to be fully elucidated. Here, we examined the mode of action of FTY720 in mice. FTY720, when given at a single dose of 1 mg/kg, markedly decreased the number of peripheral blood lymphocytes (PBL) but moderately increased the lymphocyte numbers in lymph nodes (LN) and Peyer's patches (PP) in normal mice, as previously observed in rats. However, the sharp decrease in PBL numbers was also observed in aly/aly mice lacking LN and PP, indicating that this phenomenon is not explained by accelerated lymphocyte homing to LN and PP. In addition, the finding that a single administration of FTY720 did not suppress proliferative responses of T cells suggested that the PBL reduction could occur without inhibiting lymphocyte functions. However, when administered at the same dose for 2 weeks, FTY720 induced severe systemic lymphopenia, as well as marked suppression of lymphocyte proliferative responses in normal mice. The same treatment also prolonged skin allograft survival in aly/aly mice. Our results suggest that FTY720 suppresses in vivo immune functions mainly by inducing systemic lymphopenia and also by inhibiting T cell functions.     

Dual effect of methylprednsolone pulses on apoptosis of peripheral leukocytes in patients with renal diseases

It is well known that change in apoptosis may modulate the natural story of illness, and that many drugs may act through modulation of apoptosis, but the role of steroids in acting through apoptosis in different settings, including renal diseases, has still to be elucidated. We studied the in vivo effects of steroids by oral assumption (10 to 25 mg/deltacortene) or by intravenous pulses (300 to 1000 mg/dose) on apoptosis and cellular subsets of peripheral lymphocytes, by evaluating DNA-fragmentation and lymphocyte subsets in 79 subjects: 22 controls and 57 patients with various renal diseases (25 Lupus-GN, 19 membranous-GN (MGN), 6 rapidly progressive-GN (RPGN), 2 acute interstitial nephritis (AIN), 5 on chronic dialysis. Baseline apoptosis was present in 1/22 (4.5%) of controls, 3/25 (12%) SLE, 2/6 (33.3%) RPGN and 10/19 (52.6%) MGN. A significant decrease in CD3+CD8+ cell count and a significant increase of the CD3+CD4/CD3+CD8+ ratio were found in apoptosis-positive subjects. DNA fragmentation did not change after oral steroids, paralleling a 22 to 32% decrease in total lymphocytes. Following intravenous methylprednisolone pulses, a deeper drop of all lymphocyte subsets was observed, while DNA fragmentation turned from present to absent in 2 MGN, but not in 2 RPGN, and from absent to present in 1 ARF and 1 SLE, independently of the dosage. We demonstrated that the presence of apoptosis in renal diseases is associated with decreased CD3+CD8+ cell count. Furthermore, steroid intravenous pulses, besides inducing a profound decrease in lymphocyte subsets, do exert a dual effect on baseline leukocyte apoptosis, eventually leading to a reversal of baseline patterns, either turning from negative to positive or from positive to negative. Oral steroid therapy did not influence baseline apoptosis.     

新型免疫抑制剂FTY720对大鼠胶原诱导性关节炎的抑制作用

目的观察新型免疫抑制剂FTY720对大鼠胶原诱导性关节炎发生和发展的影响。方法以胶原诱导大鼠关节炎模型,从第1次免疫造模开始,大鼠分别予以FTY720(0.1、0.6mg·kg-1)和雷公藤多苷(6、12mg·kg-1)灌胃治疗,连续4周。观察记录大鼠活动和关节炎指数、体重、足底厚度和足爪肿胀;血常规分析大鼠外周血淋巴细胞、单核细胞和中性粒细胞变化;流式分析外周血CD4+和CD8+T淋巴细胞变化;组织学及免疫组织化学分析炎性关节病理改变和滑膜组织中CD4+和CD8+T淋巴细胞的变化。结果 FTY720给药后能抑制大鼠关节炎的发生和发展,明显降低大鼠外周血淋巴细胞特别是CD4+T淋巴细胞数量和滑膜组织中CD4+T淋巴细胞数量。结论 FTY720可有效控制大鼠胶原诱导性关节炎的发生和发展,其作用机制可能是通过抑制外周血CD4+T淋巴细胞浸润到滑膜组织。     

T cell selective apoptosis by a novel immunosuppressant,FTY720, is closely regulated with Bcl-2

1. A novel immunosuppressant FTY720 caused a significant decrease in peripheral T lymphocytes, but not in B lymphocytes upon oral administration. This decrease was mainly a result of FTY720-induced apoptosis. In this study, we confirmed FTY720-induced T cell selective apoptosis using lymphoma cell lines in vitro. 2. Viability loss, DNA fragmentation, Annexin V binding, and caspases activation (caspase-3, -8, and -9) were observed in Jurkat cells (T lymphoma cells), but not significantly in BALL-1 cells (B lymphoma cells). These results indicated that FTY720 selectively induced apoptosis in T cell lymphoma to a greater extent than in B cell lymphoma, a finding that is similar to the result observed when FTY720 was treated with T lymphocytes and B lymphocytes in vitro. 3. FTY720 released cytochrome c from mitochondria in Jurkat intact cells as well as from isolated Jurkat mitochondria directly, but not from mitochondria in BALL-1 cells nor from isolated BALL-1 mitochondria. 4. BALL-1 cells and B cells had more abundant mitochondria-localized anti-apoptotic protein Bcl-2 than did Jurkat cells and T cells. 5. FTY720-induced apoptosis is inhibited by the overexpression of Bcl-2, suggesting that the cellular Bcl-2 level regulates the sensitivity to FTY720.     

Dose and dose rate effects of whole-body gamma-irradiation: I. Lymphocytes and lymphoid organs

The major goal of part I of this study was to compare varying doses and dose rates of whole-body gamma-radiation on lymphoid cells and organs. C57BL/6 mice (n = 75) were exposed to 0, 0.5, 1.5, and 3.0 Gy gamma-rays (60Co) at 1 cGy/min (low-dose rate, LDR) and 80 cGy/min (high-dose rate, HDR) and euthanized 4 days later. A significant dose-dependent loss of spleen mass was observed with both LDR and HDR irradiation; for the thymus this was true only with HDR. Decreasing leukocyte and lymphocyte numbers occurred with increasing dose in blood and spleen at both dose rates. The numbers (not percentages) of CD3+ T lymphocytes decreased in the blood in a dose-dependent manner at both HDR and LDR. Splenic T cell counts decreased with dose only in HDR groups; percentages increased with dose at both dose rates. Dose-dependent decreases occurred in CD4+ T helper and CD8+ T cytotoxic cell counts at HDR and LDR. In the blood the percentages of CD4+ cells increased with increasing dose at both dose rates, whereas in the spleen the counts decreased only in the HDR groups. The percentages of the CD8+ population remained stable in both blood and spleen. CD19+ B cell counts and percentages in both compartments declined markedly with increasing HDR and LDR radiation. NK1.1+ natural killer cell numbers and proportions remained relatively stable. Overall, these data indicate that the observed changes were highly dependent on the dose, but not dose rate, and that cells in the spleen are more affected by dose rate than those in blood. The results also suggest that the response of lymphocytes in different body compartments may be variable.     

In vivo modulation of the circulating lymphocyte subsets and monocytes by androgen

Androgens influence some immunological processes, including alternation of the number and function of the circulating lymphocytes and monocytes. In the present study, the effects of three different doses of testosterone on the numbers and percentages of the peripheral blood cells were investigated; the lymphocyte subsets were determined and the proliferation of lymphocyte was detected. Groups of Sprague-Dawley rats were treated with 0.5, 2.5, 12.5 mg/kg or only vehicle, respectively. Compared with controls, the results of complete blood counts showed that the absolute and relative numbers of monocytes decreased. The lymphocyte subpopulations determined by flow cytometry indicated an increase in CD8+ T cells, whereas the CD3+, CD4+ and CD4+CD8+ T cells remained unchanged. Thus, the immunoregulatory index (CD4+/CD8+ ratio) decreased. The proliferative activities determined by MTT assay were down-regulated. In conclusion, the immunosuppressive effects of testosterone may be attributed to a decline in number of monocytes, CD4+/CD8+ ratio and proliferative activities together with an increase of CD8+ T cells in Sprague-Dawley rats.     

自身免疫相关疾病患者外周血淋巴细胞亚群检测及其意义

目的探讨自身免疫相关疾病患者淋巴细胞亚群的变化特点。方法采用流式细胞术检测23例自身免疫病患者及20例正常人的外周血中T淋巴细胞(CD3+细胞)、辅助性T细胞(CD4+细胞)、T抑制性细胞毒细胞(CD3+/CD8+)、NK细胞(CD3-/CD16+56)和NKT细胞(CD3+/CD16+56),对两者百分比进行比较分析。结果患者组中T抑制性细胞毒细胞(CD3+/CD8+)的百分比和绝对值高于正常对照组(P<0.05)。而患者组中CD4/CD8数值上低于正常对照组,但无明显差异。NK细胞(CD3-/CD16+56)的百分比和绝对值明显低于对照(P<0.01),有显著统计学差异。结论可通过对淋巴细胞亚群的检测了解自身免疫病在其发生发展的过程中免疫系统的变化,并为采用的相关治疗提供依据。     

Overview of FTY720 clinical pharmacokinetics and pharmacology

Drug discovery programs are actively exploring for therapeutic agents targeting enzymes and receptors regulating sphingolipid metabolism and biologic functions. FTY720 is a close structural analogue of sphingosine with immunomodulatory properties. After oral administration, FTY720 is phosphorylated by sphingosine kinase to form the active moiety FTY720-phosphate, which subsequently binds to the sphingosine-1-phosphate receptor. In characterizing the safety and pharmacological effects of FTY720, detailed clinical pharmacology studies in healthy subjects and renal transplant recipients have focused on cardiac responses and lymphocyte trafficking. After the first dose, FTY720 causes a mild, transient decrease in heart rate that returns to baseline in approximately 1 to 2 weeks despite continued administration of the drug. FTY720 elicits a prompt and dose-dependent decrease in peripheral blood lymphocytes by redirecting them from the circulation to the lymph nodes without impairing lymphocyte functions. An association among FTY720 blood concentration, decrease in lymphocyte counts, and freedom from acute rejection episodes has been observed in early clinical development trials in de novo kidney transplantation.     

类风湿关节炎患者外周血T淋巴细胞亚群与临床相关性分析

目的 探讨类风湿关节炎(RA)患者外周血T细胞亚群的变化情况,了解其变化在RA发病及炎症活动中的意义.方法 采用流式细胞仪荧光抗体标记法分别对197例RA患者的外周血淋巴细胞进行CD3/CD8/CD45/CD4及CD3/CD16+56/CD45/CD19四色荧光抗体(B.D)标记,分析比较RA患者外周血淋巴细胞比例情况,并与RA疾病活动性评分(DAS28-4)、压痛关节数、肿胀关节数、晨僵时间、医生和患者对疼痛程度的视觉模糊评分(VAS)、血红细胞沉降率、C反应蛋白及血清学抗体行相关分析.结果 RA患者外周血淋巴细胞中CD3+CD19-、CD3+CD4+和CD3+CD8+T细胞占总淋巴细胞的百分率分别为(71.06±12.07)%、(45.13±36.14)%和(26.56±9.54)%,RA患者CD3+CD19-T细胞与DAS28-4、压痛关节数、肿胀关节数及患者VAS存在负相关(P<0.05).RA患者外周血CD3+CD4+T(Th)淋巴细胞与抗环瓜氨酸肽抗体呈明显负相关(r=-0.156,P=0.029),与抗角蛋白抗体、人抗核周因子抗体、类风湿因子无明显相关.合并肺间质病变组与未合并肺间质病变组T细胞和Ts细胞差异有统计学意义(Z=-2.159和-2.031,P=0.031和0.042),合并干燥综合征组与未合并干燥综合征组的免疫功能差异无统计学意义(P>0.05).结论 RA思者外周血T淋巴细胞存在比例的失衡,T淋巴细胞数量的异常可能是RA发病及炎症活动的重要影响因素.

Abstract：

Objective To study the change of T cell subsets in peripheral blood of patients with rheumatoid arthritis (RA) and investigate the significance of T cell 1 subsets change in the incidence and inflammatory activity of RA. Methods Four-color fluorescence flow cytometry was used to detect the CD3/CD8/CD45/CD4 and CD3/CD16 +56/ CD45/CD19 markers in the peripheral blood lymphocytes of 197 RA patients. The proportion of peripheral blood lymphocytes in RA patients was compared and correlation analysis was conducted between T cell subsets and disease activity indices which include disease activity score(DAS28-4) ,tender joint count (TJC) .swollen joint count(SJC) , time of morning stiffness, patient's global assessment of disease activity on a 100 mm VAS by doctor and patients, erythrocyte sedimentation rate, C-reactive protein and serum antibody. Results The proportions of CD3+CD19- , CD3+ CD4+ and CD3+ CD8+ T cells in peripheral lymphocytes were (71.06 ±12.07)% , (45.13 ±36.14)% and (26.56 ±9.54)% respectively in RA group. Correlation analysis indicated significant negative correlations of the proportions of CD3+ CD19- cells with DAS28-4, TJC, SJC and patient's global assessment of disease activity a 100 mm VAS by patients (P <0.05 ). Furthermore, CD3+ CD4+ T cells still showed significant negative correlation with the anti-CCP antibody (r =-0. 156,P =0. 029) , and no correlation with AKA, APF and RF. CD3+ CD19-and CD3+CD8 + T cells showed significant differences between the interstitial lung disease group and control group (Z=-2. 159 and -2.031, P= 0. 031 and 0.042). There was no significant difference between the Sj(o)gren' s Syndrome group and control group(P>0.05). Conclusion The proportion of T lymphocytes in peripheral blood of patients with RA and the abnormality of T lymphocytes may play an important role in the incidence and inflammatory activity of RA.     

Pharmacodynamic monitoring of the conversion from mycophenolate mofetil to enteric-coated mycophenolate sodium in stable kidney-allograft recipients

BACKGROUND: The formulations of mycophenolic acid, i.e., mycophenolate mofetil (MMF) and enteric-coated mycophenolate sodium (EC-MPS), seem to have different pharmacokinetic profiles. The aim of this study was to compare the effects MMF and EC-MPS on T-cell proliferation, T-cell activation, T-cell function, and lymphocyte subsets. CLINICAL STUDY AND METHODS: Ten stable kidney-transplant patients on standard maintenance therapy of tacrolimus and MMF (1 g/d), with or without steroids, were converted from MMF to EC-MPS at equivalent dose (720 mg/d). Tacrolimus and steroid doses remained unchanged before, and at 1, 2, 3, and 6 months (M) after conversion. Intra T-lymphocyte cytokines IL-2 and TNF-alpha, lymphocyte-activation surface markers (CD25 and CD71), T-cell proliferation (PCNA+ PI(high)), total lymphocyte count, as well as lymphocytes subsets (CD2, CD3, CD4, CD8, CD19, NK cells) were measured by flow cytometry before conversion and at M1, M2, M3, and M6. RESULTS: We found no significant differences of MMF versus EC-MPS on lymphocyte function. T-cell proliferation and T-cell activation (CD25 and CD71 expression), but not cytokine expression (TNF-alpha and IL-2), showed a trend to increase after conversion from MMF to EC-MPS. Total lymphocyte, CD2, CD3, CD4, CD8, and NK cells counts were not significantly modified. CONCLUSION: This study revealed a trend to a lower immunosuppression with EC-MPS as compared to MMF in stable renal transplant patients.     

虫草多糖调节小鼠T淋巴细胞及其亚群数量的机制研究

目的 研究冬虫夏草菌丝体多糖（虫草多糖）对正常小鼠T淋巴细胞及其亚群数量的影响及可能的机制。方法 ICR小鼠,随机分成空白对照组、阳性组（香菇多糖1 mg·kg^-1）和虫草多糖高、中、低剂量（200,100,50 mg·kg^-1）组,连续腹腔注射10 d后,流式细胞仪检测外周血T淋巴细胞（CD³⁺细胞）及其亚群细胞CD4⁺CD8^-和CD4-CD8+数量、CD³⁺细胞凋亡率;MTT法测定小鼠脾淋巴细胞转化功能;实时荧光定量PCR检测脾脏组织Bcl-2 mRNA、Bax mRNA的转录水平,并测定胸腺和脾脏指数。结果 与空白对照组比较,虫草多糖能提高小鼠脾脏质量、促进未经ConA诱导的脾淋巴细胞增殖转化能力,并呈现剂量依赖性;虫草多糖高剂量组能明显增加外周血CD³⁺细胞和CD4⁺CD8^-细胞亚群的数量,降低CD4^-CD8⁺细胞亚群数量,显著提高CD4⁺CD8^-/CD4-CD8⁺的比值;高剂量虫草多糖能明显降低小鼠外周血CD³⁺细胞凋亡率,显著升高脾组织Bcl-2 mRNA转录水平和Bcl-2/Bax比值,而对Bax mRNA转录水平没有明显影响。结论 虫草多糖可刺激小鼠主要免疫器官（胸腺和脾脏）增生,提高T淋巴细胞及CD4^-CD8⁺亚群的数量,其作用机制可能与上调抑制凋亡基因Bcl-2 mRNA的转录,提高Bcl-2/Bax比值,从而抑制淋巴细胞凋亡有关。     

Individual radiosensitivity and its relevance to health physics

Radiation protection regulations have been established to reduce exposure of individuals to acceptable safe levels. These limits assume that people have similar responses to ionizing radiation and that there is no variation in individual radiation risk. The purpose of this research was to determine if apoptosis in lymphocytes can be used to assess individual sensitivity to ionizing radiation. Blood samples were taken from 54 males ranging in age from 19-85 years. Apoptosis was measured using modified flow cytometry based Annexin-FITC/7AAD and DiOC(6)/7AAD assays in different populations of lymphocytes (total mixed lymphocyte population, subset CD4+ or CD8+ lymphocytes) after exposure to in vitro doses of 0, 2, 4 or 8Gy (dose rate 0.1Gy/min). The variation in individual responses to radiation was large. The variation was the largest in the CD4+ lymphocyte sub-population. Radiation-induced apoptosis decreased with age of donor demonstrating that as people age their lymphocytes may become relatively more resistant to radiation. This research shows that individuals have marked differences in their sensitivity to radiation and protection policies may someday need to be tailored for some individuals.     

Activation-induced T cell apoptosis by monocytes from stem cell products.

We recently found that mobilized peripheral blood stem cell (PSC) products (from both cancer patients and normal donors) contain high levels of CD14+ monocytes, which can inhibit the proliferation of allogeneic and autologous T cells. We found in our studies that using CD14+ monocytes from mobilized PSC products (from normal and cancer patient donors), normal apheresis products or normal peripheral blood (PB) can affect lymphocyte function and apoptosis-dependent T cell activation. However, it appears that the apoptosis is dependent on the frequency of monocytes, which is increased by both mobilization and apheresis. Both phytohemagglutinin (PHA)- and interleukin (IL)-2-induced proliferation of steady-state peripheral blood mononuclear cells (PBMC) were markedly inhibited by co-culture with irradiated CD14+ monocytes, although inhibition was significantly greater with PHA than with IL-2 stimulation. IL-2 (predominately CD56+ NK cells) or anti-CD3 monoclonal antibody (mAb) and IL-2-expanded lymphocytes (activated T cells) were inhibited by PSC monocytes to a significantly greater level as compared to steady-state lymphocytes. Indeed, no inhibition of T cell proliferation was observed when lymphocytes were co-cultured in the absence of mitogenic or IL-2 stimulation. In contrast, an increased proliferation was observed in co-cultures of CD14+ monocytes and steady-state or activated lymphocytes without mitogenic stimulation. Cell cycle analysis by flow cytometry revealed a significant increase in hypodiploid DNA, in a time-dependent manner, following co-culture of monocytes and PBMC in PHA, suggesting that T cell apoptosis occurred during PHA-induced activation. These results demonstrate that PSC-derived monocytes inhibit T cell proliferation by inducing the apoptosis of activated T cells and NK cells, but not steady-state cells. This suggests a potential role for monocytes in the induction of peripheral tolerance following stem cell transplantation.     

不同剂量糖皮质激素对外周血CD4+T淋巴细胞凋亡的影响

目的 观察不同浓度糖皮质激素对外周血CD4 T淋巴细胞凋亡的影响.方法 取健康志愿者10名的全血样本,用RPMI 1640培养液稀释一倍.分为五组,加入不同浓度氢化可的松:A组,0.3mg/L;B组,1.2mg/L,C组,36mg/L,D组,200mg/L,E组(对照组),0mg/L.以5%CO2培养箱培养4 h,分离淋巴细胞,流式细胞术检测CD4 T淋巴细胞凋亡.结果 0.3 mg/L和1.2mg/L糖皮质激素致CD4激素致CD4 T淋巴细胞凋亡率分别为(8.74±1.3)%和(8.15±1.7)%,明显低于对照组的(10.84±2.1)%(P＜0.05).36 mg/L和200 /mgL糖皮质激素致淋巴细胞凋亡率分别为(11.59±2.2)%和(12.56±2.87)%,明显高于对照组(P＜0.05).结论 低剂量糖皮质激素致T淋巴细胞凋亡率下降,而大剂量糖皮质激素则促淋巴细胞凋亡.     

Effects of single intravenous doses of recombinant human interleukin-10 on subsets of circulating leukocytes in humans

Recombinant human interleukin-10 (rhIL-10) is a potent and specific immunomodulatory agent which inhibits endotoxin-stimulated pro-inflammatory cytokine production by monocytes, blocks T-lymphocyte activation by antigen presenting cells, and modulates T(H)1/T(H)2 balance in immune responses. In previous clinical trials, rhIL-10 administered to healthy volunteers induced rapid and transient elevations of neutrophil and monocyte counts and reductions of lymphocyte counts in addition to suppression of endotoxin-stimulated whole blood cytokine synthesis. We sought to better characterize the effects of rhIL-10 on immunophenotypically defined subsets of circulating leukocytes that could be relevant to its immunomodulatory effects. Healthy volunteers were given single doses of 10 microg/kg rhIL-10 (n = 8) or equivalent placebo (n = 4) by intravenous injection. Significant changes of circulating leukocytes included transiently increased neutrophils and monocytes with parallel increases of CD33+ and CD14+ cells. Total lymphocytes as well as total CD3+, CD3+/CD4+ and CD3+/CD8+ cells transiently decreased. Mean fluorescence intensity of CD11a (integrin alpha-chain subunit of lymphocyte function antigen-1, LFA-1) on lymphocytes transiently but significantly decreased, suggesting a mechanism for transient alteration of lymphocyte trafficking. In addition, mean fluorescence intensity of HLA-DR (major histocompatibility class II) on CD14+ cells (predominantly monocytes) transiently but significantly decreased, implying a possible alteration of antigen presenting function. Further study will be required to elucidate the immunomodulatory roles and potential clinical significance of these hematologic changes in therapeutic trials of rhIL-10 in patients with chronic inflammatory and autoimmune diseases.     

Evaluation of stem cell administration in a model of kidney ischemia-reperfusion injury

Ischemia-reperfusion injury is a common early event in kidney transplantation and contributes to a delay in organ function. Acute tubular necrosis, impaired kidney function and organ leukocyte infiltration are the major findings. The therapeutic potential of stem cells has been the focus of recent research as these cells possess capabilities such as self-renewal, multipotent differentiation and aid in regeneration after organ injury. FTY720 is a new synthetic compound that has been associated with preferential migration of blood lymphocytes to peripheral lymph nodes instead of inflammatory sites. Bone marrow stem cells (BMSC) and/or FTY720 were used as therapy to promote recovery of tubule cells and avoid inflammation at the renal site, respectively. Mice were submitted to renal ischemia-reperfusion injury and were either treated with two doses of FTY720, 10x10(6) BMSC, or both in order to compare the therapeutic effect with non-treated and control animals. Renal function and structure were investigated as were cell numbers in peripheral blood and spleen. Activation and apoptosis markers were also evaluated in splenocytes using flow cytometry. We found that the combined therapy (FTY720+BMSC) was associated with more significant changes in renal function and structure after ischemia-reperfusion injury when compared with the other groups. Also a decrease at cell numbers and prevention of spleen cells activation and apoptosis was observed. In conclusion, in our model it was not possible to demonstrate the potential of stem cells alone or in combination with FTY720 to promote early kidney recovery after ischemia-reperfusion injury.