慢性乙型病毒性肝炎患者外周血T淋巴细胞CD27和CD45RA表达的研究

目的分析慢性乙型病毒性肝炎患者外周血T淋巴细胞CD27和CD45RA的表达。方法采集分离健康人和慢性乙型病毒性肝炎患者外周血单个核细胞(PBMC),利用多种荧光标记抗体标记细胞表面分子,再用流式细胞仪检测CD8+T淋巴细胞表面CD27和CD45RA表达情况。结果31例慢性乙型病毒性肝炎患者CD8+CD45RA+CD27+T细胞占CD8+T细胞(29.03±13.18)%,低于28例健康对照组的(60.85±14.36)%,P<0.01。而CD8+CD45RA-CD27+T细胞占CD8+T细胞(30.31±24.11)%,显著高于健康对照组的(10.32±5.24)%,P<0.05。慢性乙型病毒性肝炎患者CD4+CD45RA+CD27+T细胞21.12±9.64%低于健康对照组的(60.89±17.93)%,P<0.01,而CD4+CD45RA-CD27+T细胞(54.28±18.75)%显著高于健康对照组的(27.16±9.24)%,P<0.01。结论健康人外周血CD8+和CD4+T淋巴细胞均以CD45RA+CD27+初始细胞表型为主,而慢性乙型病毒性肝炎患者外周血初始细胞减少,CD45RA-CD27+表型的T淋巴细胞明显增加。     

结直肠癌患者与健康受试者外周血CD45RA+/CD45RO+淋巴细胞表型分析

目的 分析结直肠癌患者与健康受试者外周血CD45RA+/CD45RO+系列T淋巴细胞表达的差异.方法 运用流式细胞术(FCM)检测2010年1月至2013年12月解放军总医院收治的109例结直肠癌患者(试验组)与64例健康受试者(对照组)外周血CD45RA+、CD45RO+、CD4+ CD45RA+、CD4+ CD45RO+T淋巴细胞亚群表达情况,统计分析试验组和对照组性别和年龄的分布是否存在差异,然后进一步分析CD45 RA等T淋巴细胞亚群与结直肠癌临床分期的关系.结果Ⅰ+Ⅱ期、Ⅲ期和Ⅳ期结直肠癌患者外周血CD45 RA+细胞百分率[三者分别为(56.23±7.75)％、(58.86±7.66)％和(59.02±9.71)％]明显高于对照组[(48.94±12.66)％],差异具有统计学意义(F=11.128,P＜0.001);Ⅲ期和Ⅳ期患者的CD45RO+细胞百分率[分别为(47.19±8.30)％和(45.41±10.45)％]则明显低于对照组[(53.43±11.75)％],差异具有统计学意义(F=5.817,P=0.00083);Ⅲ期和Ⅳ期患者CD45RA+/CD45RO+的比值(分别为1.32 ±0.46和1.43±0.63)明显高于对照组(1.00±0.47),差异具有统计学意义(F=6.986,P=0.000185);Ⅰ+Ⅱ期患者CD4+ CD45 RO+细胞百分率[(31.37±6.39)％]明显高于对照组[(27.49±7.19)％],差异具有统计学意义(F=2.368,P=0.009);Ⅳ期患者CD4+ CD45RA+/CD4+ CD45RO+的比值(0.66±0.39)明显高于Ⅰ+Ⅱ期的患者(0.49±0.23),差异具有统计学意义(F=1.812,P=0.029);各组之间CD4+ CD45RA+细胞百分率无明显统计学差异(F=0.637,P=0.592).结论 随着临床分期的增加,结直肠癌患者外周血CD45RA+细胞逐渐增加而CD45RO+细胞逐渐减少,反映出结直肠癌患者随着肿瘤的进展其免疫功能逐渐抑制、逐渐降低的动态过程;CD4+ CD45RA+细胞和CD4+ CD45RO+细胞在反映结直肠癌患者机体免疫功能方面不如CD45RA+细胞和CD45RO+细胞敏感.     

慢性乙型肝炎患者CD4~+和CD8~+T细胞亚群的研究

目的:比较不同感染状态慢性乙型肝炎(CHB)患者外周血CD4+和CD8+T细胞亚群的差异。方法:收集CHB患者78例,根据感染状态分为乙型肝炎e抗原(HBeAg)阳性且肝功能正常、HBeAg阳性且肝功能异常和HBeAg阴性3组。13例健康志愿者(正常对照组)来自曙光医院体检中心。应用流式细胞术(FCM)检测不同感染状态CHB患者外周血中CD4+CD25+、CD8+CD28-、CD4+CD95+、CD8+CD95+细胞亚群的分布情况,并对各亚群分布情况与HBeAg和HBVD-NA水平的相关性进行分析。结果:与正常对照组相比,HBeAg(+)肝功能正常组的CD4+CD25+/CD4+和CD4+CD95+/CD4+明显升高(P<0.01,P<0.05),3个感染组CD8+CD28-/CD8+值均明显升高(P<0.01);与HBeAg(+)肝功能正常组相比,HBeAg(+)肝功能异常组和HBeAg(-)组的CD4+CD25+/CD4+明显降低(P<0.01),HBeAg(-)组CD8+CD95+/CD8+明显降低(P<0.05),HBeAg(+)肝功能异常组的CD8+CD95+/CD8+明显降低(P<0.01)。CD4+CD25+/CD4+,CD4+CD95+/CD4+与HBVDNA呈正相关(P<0.01,P<0.05),CD8+CD28-/CD8+与HBVDNA和HBeAg均呈正相关(P<0.01)。结论:CHB患者外周血中CD4+CD25+、CD8+CD28-T、CD4+CD95+细胞表达频率增加,可能对慢性乙肝病毒感染过程中的免疫耐受起一定作用。     

慢性乙型肝炎患者外周血细胞CD40+、CD40L+及CD8+/CD28+表达的研究

目的检测慢性乙型肝炎(简称慢乙肝)患者外周血淋巴、单核细胞表面CD40+、CD40L+及淋巴细胞表面CD8+/CD28+、CD8+/CD28-的表达,评价患者的细胞免疫状态,为临床治疗提供指导.方法流式细胞仪测定慢乙肝患者单核细胞、淋巴细胞表面CD40+、CD40L+表达的百分率及淋巴细胞表面CD8+/CD28+、CD8+/CD28-表达的百分率.结果慢乙肝组外周血淋巴、单核细胞表面CD40+、CD40L+及淋巴细胞表面CD8+/CD28+的表达明显低于正常对照组(P＜0.01,P＜0.05,P＜0.01,P＜0.05,P＜0.01),乙肝肝硬化组(简称肝硬化)均明显低于正常对照组(均P＜0.01),而慢乙肝组、肝硬化组CD8+/CD28-的表达高于正常对照组(P＜0.05,P＜0.01).慢乙肝组与肝硬化组均无显著差异(均P＞0.05).慢乙肝轻、中、重度和肝硬化三组间均无显著差异(均P＞0.05).相关性分析结果显示,慢乙肝患者淋巴、单核细胞表面CD40+和CD40L+的表达之间存在正相关,淋巴细胞CD40+、CD40L+表达与CD8+/CD28+表达存在正相关,而与CD8+/CD28-表达相关性不明显.结论慢乙肝患者外周血淋巴、单核细胞CD40+、CD40L+及淋巴细胞CD8+/CD28+表达低下,而CD8+/CD28-的表达增加.检测外周血CD40+、CD40L+及CD8+/CD28+的表达可评估患者的细胞免疫状态,对临床的抗病毒治疗提供新思路.     

GD患者外周血CD4+CD28-T细胞亚群的表型特征及临床意义

检测Graves病(GD)患者外周血CD4~+CD28-T细胞水平及其表面CD45RO/CD45RA及ICOS的表达,探讨CD4~+ CD28-T细胞亚群在GD免疫致病机制中的作用。采用三色荧光抗体染色及流式细胞术检测了42例初发GD患者和30例健康者外周血中CD4~+CD28-T细胞的百分率及其表面CD45RO/CD45RA和ICOS表达水平,同时检测其甲状腺功能并进行相关性分析。结果GD患者外周血中CD4~+CD28-T细胞百分率明显高于健康对照组,并高表达ICOS分子,与FT3水平显著正相关;与健康对照组相比,GD患者CD4~+CD28~-CD45RO~+T细胞百分率也显著增高,而CD4~+CD28~-CD45RA~+T细胞呈下降趋势,FT3、FT4水平与CD4~+CD28-T细胞表面CD45RO的表达率呈正相关,而FT3水平与CD45RA表达呈负相关。结论GD患者外周血CD4~+CD28~-T细胞异常增高,表面高表达ICOS分子,具有记忆性细胞的表型特征,与甲状腺功能异常有一定的相关性,CD4~+CD28-T细胞可能是参与GD免疫病理反应的自身反应性T细胞。     

慢性乙肝病毒携带者外周血皮质醇水平与T细胞亚群状态的研究

目的 探讨慢性乙肝病毒(HBV)携带者血浆皮质醇水平与细胞免疫状态的变化.方法 选取符合诊断标准的慢性HBV携带者60例,正常对照10例,放射免疫法测定血浆皮质醇水平,流式细胞仪检测外周血T细胞亚群CD3+、CD4+、CD8+、CD4+/CD8+比例.结果 与正常对照组相比,慢性HBV携带者血浆皮质醇水平相对升高(P＜0.05),CD4+细胞比例无明显变化(P＞0.05),CD8+细胞比例明显增加(P＜0.05),CD4+/CD8+明显下降(P＜0.05).HBeAg阳性组与HBeAg阴性组比较,HBeAg阳性组血浆皮质醇升高较为明显(P＜0.05),CD4+细胞比例无明显变化(P＞0.05).CD8+细胞比例明显增加(P＜0.05),CD4+/CD8+明显下降(P＜0.05).结论 慢性乙肝病毒携带者存在着血浆皮质醇水平的增高及细胞免疫功能的失衡,慢性HBV感染过程中存在内分泌-免疫系统紊乱.     

慢性乙型肝炎患者外周血CD4＋CD25＋、CD8＋CD28＋淋巴细胞的变化及与病毒载量的关系

目的：研究慢性乙型肝炎患者外周血CD4＋CD25＋、CD8＋CD28＋淋巴细胞的表达变化及与病毒载量的关系。方法：利用流式细胞术检测50例慢性乙型肝炎患者外周血CD4＋CD25＋、CD8＋CD28＋淋巴细胞的表达率和绝对数,并与正常对照组30例进行比较;荧光定量PCR检测慢性乙型肝炎患者HBV核酸的载量,并与CD4＋CD25＋、CD8＋CD28＋淋巴细胞的表达进行相关分析。结果：慢性乙型肝炎患者的CD4＋CD25＋表达率和细胞数分别为（15.60±5.86）%和（0.34±0.13）×109/L,明显高于正常对照组（P〈0.01）;而CD4＋CD25-、CD8＋CD28＋为（21.13±5.32）%、（0.47±0.19）×109/L和（9.49±2.57）%、（0.21±0.07）×109/L,均低于正常对照组（均P〈0.01）;不同病毒载量的慢性乙型肝炎患者CD4＋CD25＋T细胞与病毒载量均呈正相关（r分别为0.552、0.588,P均〈0.01）,而CD8＋CD28＋T细胞与病毒载量均无相关性（r分别0.275、-0.092,P均〉0.05）。结论：慢性乙型肝炎患者细胞毒T细胞（CD8＋CD28＋）减少,免疫调节细胞的增加与慢性乙型肝炎患者病毒长期存在,病程迁延不愈有关。     

慢性乙型肝炎患者外周血CD4~+CD25~+Treg与CD4~+和CD8~+ T淋巴细胞亚群的相关研究

目的:探讨慢性乙型肝炎患者外周血中CD4+CD25+调节性T细胞的含量和CD4+CD8+T淋巴细胞亚群分布,两者之间相关性及与HBV的相关性。方法:采用流式细胞术检测50例慢性乙型肝炎患者和20例健康对照者外周血中CD4+CD25high、CD4+CD25+Foxp3+Treg细胞表达及CD3/CD4/CD8 T淋巴细胞亚群,荧光定量PCR法检测HBV DNA含量。结果:慢性乙型肝炎患者外周血中CD4+CD25highTreg明显高于健康对照组(P0.01),且随HBV DNA载量增加,患者外周血中CD4+CD25highTreg细胞的水平逐渐升高。慢性乙型肝炎患者外周血中CD4+CD25+Foxp3+Treg细胞也相应增高,且与CD4+CD25highTreg细胞的变化成正相关(r=0.890,P0.001)。与健康对照组比较,患者组CD4+T细胞百分率及CD4+/CD8+比值均降低,而CD3+T细胞和CD8+T细胞百分率差异无显著性(P0.05)。CD4+CD25highTreg细胞与HBV DNA取对数后成正相关(r=0.782,P0.001),与谷丙转氨酶(ALT)成正相关(r=0.432,P0.005);与CD3+、CD4+、CD8+T细胞水平及CD4+/CD8+比值均无相关性(P0.05)。CD3+、CD4+、CD8+T淋巴细胞及CD4+/CD8+比值与HBV DNA载量之间亦无相关性(P0.05)。结论:慢性乙型肝炎患者外周血中CD4+CD25+Treg细胞增高,且与HBV的复制水平及ALT增高具有一致性,而T细胞亚群是否可作为监测CHB患者免疫状态的指标需进一步探讨。     

低剂量辐射对不同岗位男性放射人员外周血T淋巴细胞亚群的影响

目的:探讨低剂量辐射对不同岗位男性放射人员T淋巴细胞亚群水平的影响.方法:检测168例男性放射人员CD3+T、CD3+/CD4+T、CD3+/CD8+T、CD4+/CD45RA+T、CD4+/CD45RO+T、CD8+/CD45RA+T、CD8+/CD45RO+T、CD8+/CD28+T、CD8+/CD95+T、CD8...     

替比夫定对慢性乙型肝炎患者外周血CD4~+ CD25~+ CD127~(low) T和CD8~+ CD25~+ T细胞频率的影响及临床意义

目的探讨核苷类药物替比夫定对慢性乙肝患者(CHB)外周血中CD4+CD25+CD127lowT细胞和CD8+CD25+T细胞比例的影响,并结合临床指标分析其临床意义。方法替比夫定抗病毒治疗22例CHB患者,在治疗前及治疗后3,6个月时,分别以流式细胞仪检测外周血中CD4+CD25+CD127lowT细胞和CD8+CD25+T细胞比例,实时荧光定量RT-PCR检测Foxp3 mRNA的表达水平,荧光定量PCR检测血清HBV DNA水平,酶联免疫吸附法检测HBV标志物,全自动生化分析仪检测ALT水平。结果 CHB患者外周血中CD4+CD25+CD127lowT细胞和CD8+CD25+T细胞比例显著高于对照组。替比夫定治疗3个月时,这两群细胞比例显著下降,Foxp3 mRNA的表达也显著下降;HBV DNA水平降至检测水平以下的CHB患者,其CD4+CD25+CD127lowT细胞也降至正常水平。治疗3、6个月时,HBeAg阴转率分别为9.1%和18.2%,发生HBeAg血清学转换者的CD4+CD25+CD127lowT细胞和CD8+CD25+T细胞比例均降至正常水平。结论替比夫定能快速有效抑制CHB患者的病毒复制...     

Control of lymphocyte function through CD27–CD70 interactions

In contrast to the expression of other TNFR/TNF family members, expression of CD27 and its ligand CD70 is predominantly confined to lymphocytes. High expression levels of CD27 appear to be dependent on proper ligation of antigen receptors, whereas for the induction of CD70 expression additional (co–stimulatory and/or pro–inflammatory) signals are required. Next to membrane–bound CD27 also a soluble form of CD27 is produced in the course of the immune response. Soluble CD27 (sCD27) is found in body fluids and can be used to monitor local and systemic immune activation. In addition, elevated serum concentrations of sCD27 are found in patients with B cell malignancies and levels of sCD27 strongly correlate with tumor load. Based on functional experiments andin vitroexpression regulation data, we propose that interactions between activated lymphocytesin vivocan result in CD27–CD70 interactions that may regulate the size and function of antigen–primed lymphocyte populations.     

CD8+ T cells and not CD4+ T cells are hyporesponsive to CD28- and CD40L-mediated activation in HIV-infected subjects

T cell dysfunction in HIV-infected subjects could be the consequence of altered sensitivity of CD4⁺ or CD8⁺ T cells to various costimulatory signals. Therefore, we studied proliferation and cytokine production in highly purified CD8⁺ and CD4⁺ T cells from HIV-infected and HIV⁻ subjects, induced by co-activation via cell-bound CD80, CD86 and CD40 or by allo-activation. Regardless of the nature of the first and the costimulatory signal, CD8⁺ T cells from patients proliferated consistently less than controls, while responses from CD4⁺ T cells were similar in patients and controls. This phenomenon was observed after ligation of CD28 combined with anti-CD3 or phorbol myristate acetate (PMA), but also after allogeneic stimulation and after activation by CD40 and anti-CD3. Anti-CD3 combined with CD80 or CD86 induced a mixed Th1/Th2-type cytokine profile in both CD4⁺ and CD8⁺ T cells from controls, whereas anti-CD3 plus CD40 induced only low levels of Th2-type cytokines and no interferon-gamma (IFN-γ) in CD4⁺ T cells. Compared with controls, CD4⁺ T cells from patients produced slightly lower levels of IL-10 but equal amounts of IFN-γ, IL-4 and IL-5, while CD8⁺ T cells from patients produced less of all cytokines tested. In conclusion, responses of purified CD4⁺ T cells from HIV⁺ subjects to various costimulatory pathways are relatively intact, whereas CD8⁺ T cells are hyporesponsive at the level of proliferation and cytokine production. A generalized intrinsic CD8⁺ T cell failure might contribute to viral and neoplastic complications of HIV infection.     

Kikuchi病中检测出全T细胞相关抗原丢失

目的 观察全T细胞相关抗原CD2、CD3、CD5、CD7在Kikuchi病中是否存在丢失,探讨将全T细胞相关抗原丢失作为鉴别T细胞良、恶性病变辅助诊断依据的局限性.方法 收集33例明确诊断为Kikuchi病和15例淋巴组织反应性增生病例,通过复习HE切片并应用免疫组织化学EliVision法检测病变中CD2、CD3、CD5、CD7的表达情况.结果 72.7％ (24/33)的Kikuchi病患者中存在一种或几种全T细胞相关抗原的丢失,其中13例仅CD5丢失,1例仅CD7丢失,1例仅CD2丢失,2例CD2和CD7丢失,4例CD5和CD7丢失,2例CD2和CD5丢失,1例CD2、CD5和CD7丢失.以CD5丢失最多见(60.6％,20/33),其次为CD7(24.2％,8/33)和CD2( 18.2％,6/33).抗原的丢失多见于增生型及坏死型.经随访,抗原的丢失与Kikuchi病的预后无明显相关性.15例淋巴组织反应性增生病例中无明显抗原丢失现象.结论 Kikuchi病中存在一种或几种全T细胞相关抗原的丢失.因此,将全T细胞相关抗原丢失作为T细胞淋巴瘤辅助诊断依据不适用于Kikuchi病.     

A functional analysis of recombinant soluble CD46 in vivo and a comparison with recombinant soluble forms of CD55 and CD35 in vitro

The human cell surface complement regulatory proteins CD46 (MCP), CD55 (DAF) and CD35 (CR1) protect autologous cells from complement-mediated damage by inhibiting C3 and C5 convertases. This regulatory potential has previously been exploited in the treatment of some models of inflammatory injury by the generation of recombinant soluble (rs) proteins, such as rsCD55 and rsCD35. More recently, we have shown that rsCD46 inhibits complement activation in the fluid phase. In this report, the ability of rsCD46, rsCD55 and rsCD35 to regulate human complement activation mediated by the classical and alternative pathways was directly compared. Regulation of the classical pathway in vitro was clearly demonstrated by all three soluble proteins; however, rsCD35 was a more effective inhibitor than either rsCD46 or rsCD55. A combination of rsCD46 + rsCD55 was more potent than either of these proteins alone. Cell lysis via alternative pathway activation in vitro was efficiently regulated by rsCD46 and rsCD35 to a similar extent, whereas rsCD55 was not as effective. Assays of rsCD46 in vivo have previously not been possible due to difficulties in expressing sufficient quantities of protein. This limitation has been overcome and now we report the ability of rsCD46 to inhibit immune complex-mediated inflammation in a rat using the reverse passive Arthus reaction model. Administration of rsCD46 significantly reduced the size of lesion, and histological examination showed a reduction in inflammatory infiltrate and edema. These data suggest that rsCD46, in addition to rsCD55 and rsCD35, may be a useful therapeutic agent.     

Costimulation of CD3/TcR complex with either integrin or nonintegrin ligands protects CD4+ allergen-specific T-cell clones from programmed cell death

An optimal stimulation of CD4⁺ cells in an immune response requires not only signals transduced via the TcR/CD3 complex, but also costimulatory signals delivered as a consequence of interactions between T-cell surface-associated costimulatory receptors and their counterparts on antigen-presenting cells ‘APC). The intercellular adhesion molecule-1 ‘ICAM-1, CD54) efficiently costimulates proliferation of resting, but not antigen-specific, T cells. In contrast, CD28 and CD2 support interleukin ‘IL)-2 synthesis and proliferation of antigen-specific T cells more efficiently than those of resting T cells. The molecular basis for this differential costimulation of T cells is poorly understood. Cypress-specific T-cell clones ‘TCC) were generated from four allergic subjects during in vivo seasonal exposure to the allergen. Purified cypress extract was produced directly from fresh collected pollen and incubated with the patients' mononuclear cells. Repeated allergen stimulation was performed in T-cell cultures supplemented with purified extract and autologous APC. The limiting-dilution technique was then adopted to generate allergen-specific TCC, which were also characterized by their cytokine secretion pattern as ThO ‘IL-4 plus interferon-gamma) or Th2 ‘IL-4). Costimulation-induced proliferation or apoptosis was measured by propidium iodide cytofluorometric assay. By cross-linking cypress-specific CD4⁺ and CD8⁺ T-cell clones with either anti-CD3 or anti-CD2, anti-CD28, and anti-CD54 monoclonal antibodies, we demonstrated that CD4+ clones ‘with ThO- or Th2-type cytokine production pattern) undergo programmed cell death only after anti-CD3 stimulation, whereas costimulation with either anti-CD54 or anti-CD28 protects target cells from apoptosis. The costimulation-induced protection from apoptotic death was associated with a significant rise in IL-4 secretion in both Th0 and Th2-type clones. In contrast, cypress-specific Th0 CD8⁺ clones were more susceptible to stimulation-induced apoptosis via either anti-CD3 or anti-CD2, alone or in combination with anti-CD54 or anti-CD28, thus displaying only slight but nonsignificant modifications in the pattern of IL-4 secretion. The death-promoting costimulatory effects were not observed with highly purified normal resting CD4⁺ or CD8⁺ lymphocytes. Taken together, these results suggest that TcR engagement by an allergen in the context of functionally active APC induces activation-dependent cell death of some, perhaps less specific, cells, and this may be an important homeostatic mechanism through which functional expansion of allergen-specific T cells is regulated during an ongoing immune response.     

CD44+/CD24-细胞在乳腺癌组织及细胞系中的数量与分布

目的 检测CD44+/CIY24-细胞在乳腺癌组织及细胞系中的分布及数量,探讨其与乳腺癌常用标志物表达和乳腺癌分子亚型的关系.方法 采用免疫组织化学SP双染及单染法,分别检测了60例乳腺浸润性导管癌中的CD44及C1724的共表达情况和ER、PR、HER2、人雌激素诱导蛋白PS2、bcl-2、nm23的单独表达情况,同时检测了三种乳腺痛细胞系(MCF-7、MDA-MB-468及MDA-MB-231)中CD44及CD24的表达情况.结果 不同病例标本中CD44+/C1724-细胞的数量差异较大,分布无明显规律,总阳性率为65.0%;CD44+/CD24-细胞数量与患者年龄、肿瘤大小、淋巴结转移情况及ER、PR、HER-2、人雌激素诱导蛋白PS2、bcl-2、nm23表达情况无关(P均>0.05);CD44+/CD24-细胞数量与乳腺癌分子亚型无关.CD44+/CIY24-细胞在MCF-7、MDA-MB-468及MDA-MB-231细胞系中的比例分别为<1%、5%及>80%.结论 CD44+/CD24-细胞存在于部分乳腺癌组织及细胞系中,其数量及分布与乳腺癌的分子亚型和临床病理参数无直接关系.     

CD4+ lymphocytes from HIV-infected patients display impaired CD45-associated tyrosine phosphatase activity which is enhanced by anti-oxidants

It has been proposed that signal transduction defects may, at least partially, account for the functional impairment of CD4⁺ lymphocytes during HIV-1 infection. Recently, we have demonstrated that unresponsive CD4⁺ lymphocytes from these patients had reduced protein tyrosine phosphorylation after CD3 engagement, and that this defect was associated with constitutively altered levels of p56^lck and p59^fynkinases. Since CD45 is essential for T cell receptor (TCR) and CD2-mediated activation of protein tyrosine kinases, we study here CD45-associated tyrosine phosphatase activity in resting and activated CD4 T cells from HIV-infected patients. We found a significant decrease in the basal and post-activation phosphatase activity of CD45 which correlated well with impairment of proliferative responses. In addition, decreased levels of cellular thiols observed in resting CD4⁺ lymphocytes from these patients suggested a disturbed redox status. Although expression levels of CD45 were decreased in most patients, a significant recovery of phosphatase activity and proliferative responses was observed in most patients by preincubating cells with N-acetyl-l-cysteine and β₂-mercaptoethanol. In some patients, anti-oxidant treatment failed to significantly enhance phosphatase activity and proliferative responses. The low responses of purified CD4⁺ lymphocytes from these patients were associated with a high ratio of apoptotic cell death which did not appear to be influenced by anti-oxidant treatment.     

Anomalies of the CD8+ T cell pool in haemochromatosis: HLA-A3-linked expansions of CD8+CD28− T cells

The present study consists of a phenotypic and functional characterization of peripheral blood T lymphocytes in a group of 21 patients with hereditary haemochromatosis (HH), an MHC class I-linked genetic disease resulting in iron overload, and a group of 30 healthy individuals, both HLA-phenotyped. The HH patients studied showed an increased percentage of CD8⁺ CD28⁻ T cells with a corresponding reduction in the percentage of CD8⁺ CD28⁺ T cells in peripheral blood relative to healthy blood donors. No anomalies of CD28 expression were found in the CD4⁺ subset. The presence of the HLA-A3 antigen but not age accounted for these imbalances. Thus, an apparent failure of the CD8⁺ CD28⁺ T cell population ‘to expand’, coinciding with an ‘expansion’ of CD8⁺ CD28⁻ T cells in peripheral blood of HLA-A3⁺ but not HLA-A3⁻ HH patients was observed when compared with the respective HLA-A3-matched control group. A significantly higher percentage of HLA-DR⁺ but not CD45RO⁺ cells was also found within the peripheral CD8⁺ T cell subset in HH patients relative to controls. Phytohaemagglutinin (PHA) stimulation of peripheral blood mononuclear cells (PBMC) for 5 days showed: (i) that CD8⁺ CD28⁺ T cells both in controls and HH were able to expand in vitro; (ii) that CD8⁺ CD28⁻ T cells decreased markedly after activation in controls but not in HH patients. Moreover, functional studies showed that CD8⁺ cytotoxic T lymphocytes (CTL) from HH patients exhibited a diminished cytotoxic activity (approx. two-fold) in standard ⁵¹Cr-release assays when compared with CD8⁺ CTL from healthy controls. The present results provide additional evidence for the existence of phenotypic and functional anomalies of the peripheral CD8⁺ T cell pool that may underlie the clinical heterogeneity of this iron overload disease. They are of particular relevance given the recent discovery of a novel mutated MHC class I-like gene in HH.     

CD26 expression on CD4+T cells in patients with cutaneous leishmaniasis

Surrogate marker(s) of protection in human leishmaniasis is not well defined. In this study, T helper 1 (Th1) and Th2 cytokine profiles and CD26 expression on CD4(+) T cells in peripheral blood mononuclear cells of patients with healing or non-healing forms of cutaneous leishmaniasis (CL) stimulated with Leishmania antigens were assessed. The level of interferon (IFN)-gamma production was significantly higher in patients with healing or non-healing forms of CL than in healthy controls, but it was not significantly different between the two patient groups. The level of interleukin-5 production was significantly higher in patients with the non-healing form of CL than in the two other groups. There was a significant increase in the level of CD26 expression on CD4(+) T cells in patients with healing (P < 0.001) or non-healing (P = 0.025) forms of CL compared with the control group, but no significant difference was seen between the two patient groups. A weak positive correlation was seen between IFN-gamma production and CD26 expression on CD4(+) T cells of patients with the healing form of lesion (r = 0.54, P = 0.008), but this correlation was not observed in patients with the non-healing form of CL (r = 0.53, P = 0.078). Surface CD26 is not correlated with the clinical manifestation of CL or IFN-gamma production. Therefore, CD26 is not a surrogate marker for IFN-gamma production in CL.     

Use of complement regulators,CD35, CD46, CD55, and CD59, on leukocytes as markers for diagnosis of viral and bacterial infections

Several complement regulatory proteins exist on self-cells to prevent damage by the serum complement system. In the present study, we aimed to perform quantitative analysis of membrane-bound complement regulators, CR1 (CD35), MCP (CD46), DAF (CD55), and MIRL (CD59), on peripheral blood neutrophils, monocytes, and lymphocytes from healthy controls (n = 36) and febrile patients diagnosed with either bacterial (n = 21) or viral (n = 26) infections. Our results show that: (a) increased CD35 and CD55 levels on neutrophils and monocytes present potent markers of bacterial infection, (b) increased expression of CD46 on monocytes is an indicator of viral infection, and (c) increased CD59 expression on neutrophils and monocytes is a general infection marker. Additionally, CD19-positive B-lymphocytes represent practically the only lymphocyte population capable of expressing CD35. We further developed two novel clinical flow cytometric markers (indices), specifically, clinical mononucleosis (CM)-INDEX (incorporating CD35, CD55, and CD59 expression on lymphocytes) and clinical bacterial infection (CBI)-INDEX (incorporating CD35 and CD55 expression on neutrophils and lymphocytes), for the effective detection of viral mononucleosis and bacterial infection, respectively. In summary, bacterial and viral infections induce different expression patterns of membrane-bound complement regulators in human leukocytes, which may be effectively exploited in clinical differential diagnosis.