SARS病人外周血T淋巴细胞的动态变化及其在发病进程和发病机理中的意义

目的 :通过研究严重急性呼吸综合征 (SevereAcuteRespiratorySyndrome,SARS)患者外周血免疫细胞的动态变化 ,探讨外周血免疫细胞在SARS发病进程中的意义 ,初步探讨SARS的发病机理 ,并为SARS的诊断和治疗提供有力的实验室依据。方法 :回顾性动态观察我院收治的已治愈SARS病例和SARS死亡病例外周血CD4 + 和CD8+ T淋巴细胞 ,评估外周血免疫细胞在SARS发病进程及预后中的作用。实验方法为流式细胞术检测和分析免疫细胞表面特异性荧光抗体标记 ,T细胞表面标志组合为CD3 CD8 CD4 5 CD4。结果 :所有治愈的SARS病人的CD4 + 和CD8+ T淋巴细胞都有不同程度的可逆性下降 ,而所有的死亡病例有不可逆性显著下降 ,直至死亡。T细胞下降程度和维持的时间与病情密切相关。普通型SARS病例最低CD4 + T淋巴细胞数为 30 5± 15 0cells μl(P <0 .0 0 1)、重型为 139± 6 9cells μl(P <0 .0 0 1) ,普通型SARS病例最低CD8+ T淋巴细胞数为 2 2 3± 89cells μl(P <0 .0 0 1)、重型为 171± 92cells μl(P <0 .0 0 1)。所有普通型病例和大部分重型病例T淋巴细胞恢复正常 ,个别重型病例低于正常或接近正常 ,恢复后普通型平均为 991± 2 86cells μl,重型平均为 5 4 5± 2 2 5cells μl。恢复时间有所不同 ,普通型平均为 17± 5天     

SARS患者淋巴细胞亚群和Th1/Th2细胞因子的检测与意义

为了解SARS患者糖皮质激素治疗后细胞免疫状况 ,系列观察我院 7例SARS确诊者 (5男 2女 ,2 8～ 6 8岁 )淋巴细胞亚群及细胞因子变化 ,病程 0～ 6 1d。另选 31例HIV感染者作疾病对照 ,2 4例健康献血员作正常对照。用流式细胞术检测外周血CD3、CD4和CD8细胞 ,以ELISA法检测血清Th1/Th2类细胞因子 (IFN γ/IL 4 )含量。结果是SARS组CD3、CD4、CD8均值 (5 2 9 80、 313 0 9、 195 94 /μl)都低于正常组均值 (14 2 0 95、 80 9 80、 5 30 95 /μl) ,P均 <0 0 0 1;与HIV组均值(813 2 3、 176 81、 6 0 3 10 /μl)比较 ,CD4、CD8偏低 (P <0 0 0 6、P <0 0 0 1)。SARS组CD4 /CD8比值与正常组相比 ,差异不显著。淋巴细胞亚群数目与病程密切相关。SARS组Th1/Th2类细胞因子水平 (A均值 0 0 5 8/0 0 31)均低于HIV组 (A均值0 0 79/0 0 33)和正常组 (A均值 0 111/0 0 35 ) ,细胞因子含量与病程无关。提示我们所观察的SARS患者细胞免疫功能低下。     

北京市不同转归SARS患者免疫学指标的比较性研究

目的 :探讨不同转归 (治愈 死亡 )严重急性呼吸综合征 (severeacuterespiratorysyndrome,SARS)患者病程中免疫学指标变化趋势的差异 ,以指导临床诊治和判断预后。方法 :应用SARS病历数据库 ,收集治愈和死亡SARS患者病程前 4周CD3、CD4、CD8淋巴细胞绝对值 ,CD4 CD8比值 ,淋巴细胞百分比数据 ,比较不同转归SARS患者免疫学指标的变化趋势及差异。结果 :治愈组和死亡组SARS患者CD3,CD4 ,CD8计数在起病的 1～ 2周内明显低于正常值。但治愈组各免疫学指标从第 2周起呈逐渐恢复趋势 ,而死亡组则一直呈明显降低趋势 ,第 2周仍无恢复且显著低于治愈组 (P <0 0 5 ) ,并随病程延长显著性差异更大 (P <0 0 1,P <0 0 0 1) ;CD4 CD8比值在病程中基本不变 ,无显著性组间差别。结论 :CD3、CD4、CD8淋巴细胞亚群绝对值的动态变化是判断疗效和预后的重要依据     

传染性非典型肺炎与常见非典型肺炎T淋巴细胞亚群的差异及意义

目的探讨T淋巴细胞亚群在传染性非典型肺炎(SARS)与常见的非典型肺炎(非典)中的差异及意义.方法定期观察北京地坛医院自2003年3～6月以临床诊断为SARS收治的住院患者100例,从初发病开始共观察3周以上,分为SARS组和常见的非典型肺炎组(非典组),系统观察两组的CD3+、CD4+、CD8+计数.结果SARS组病例65例,男性26例,女性39例,均为普通型,50例使用甲基泼尼松龙(激素)治疗;非典组病例35例,男性21例,女性14例,20例使用激素治疗;两组所有病例均临床治愈.SARS组患者T淋巴细胞亚群计数呈先下降后上升的特点,病程前15 d内CD3+计数均值可降低至(694±568)个/μl,CD4+计数均值可降低至(441±356)个/μl,CD8'计数均值可降低至(309±462)个/μl,在病程第15天以后逐渐回升至正常;常见的非典组患者整个病程中CD3+、CD4+、CD8+计数基本在正常范围;用激素对非典组患者的T淋巴细胞亚群计数影响不太大,用激素的SARS组患者的T淋巴细胞亚群计数的变化规律在病程15 d前与未用激素的同组患者也基本一致,但其细胞免疫功能恢复时间推迟6 d左右.结论SARS患者发病早期CD3+、CD4+、CD8+计数同步降低的特点可作为与常见的非典型肺炎的鉴别诊断的重要依据,即使应用激素也不影响T淋巴细胞亚群计数作为SARS与常见的非典型肺炎早期鉴别诊断的依据.     

SARS患者CD4~+T细胞水平与胸部X线表现的动态变化研究

为探讨SARS患者的CD4 + T淋巴细胞改变与胸部X线表现及临床表现的动态变化关系 ,为SARS的诊断治疗提供相应依据。 (1)通过每天测体温 ,了解热度、热程以及发热规律 ;(2 )入院后行CD4 + T淋巴细胞计数检测 ,此后每隔 2～ 3d进行一次 ;(3)每隔 2 4～ 72h摄胸部正侧位片。结果 2 3例均有发热 ,37 8～ 4 0 1℃。重症患者热程 (12 82± 4 4 9)d ;普通患者为 (7 6 0± 3 14 )d ,(P <0 0 5 )。入院初CD4 + T细胞平均为 17 9%± 5 6 % ;治疗 15～ 30d后为 2 9 4 %± 5 4 %。高峰期CD4 + T细胞最低 12 5 %± 6 2 % ,与其他各期比较 ,差异有显著性意义 (P <0 0 1) ;恢复期 5例肺纤维化患者CD4 + T细胞为2 2 4 %± 4 8% ,较 18例无肺纤维化患者 31 4 %± 4 4 %明显降低 (P <0 0 1) ;5例并发肺纤维化患者恢复时间 (35 8± 12 5 )d ,较 18例无肺纤维化患者 (2 5± 8 6 )d明显延长 (P <0 0 1)。通过CD4 + T细胞和胸部X线的动态观察 ,两者基本呈平行变化 ,但CD4 + T细胞降低较胸部X线改变发生早 ,恢复时间较晚 ,且与肺纤维化的形成有关     

大鼠皮肤移植排异反应中T淋巴细胞亚群的观察

为了了解在皮肤移植组织排异反应中浸润的不同T淋巴细胞亚群 ,分析其与排异反应的关系。采用HE及免疫组化方法观察大鼠III度烫伤后 2 0例同种异体 自体皮肤混合移植和 15例大张同种异体皮肤移植组织在移植后 4或 5、 7、 14、 2 1和 2 8d时CD4+ 和CD8+ 淋巴细胞的比例。结果表明同种异体 自体皮肤混合移植组 7～ 14d时CD8+ 淋巴细胞明显高于大张同种异体皮肤移植组 (P <0 0 5 ) ,在移植后 4或 5dCD4+ 淋巴细胞明显高于CD8+ 淋巴细胞。大张同种异体皮肤移植组在移植后 7～ 14dCD4+ 淋巴细胞明显高于CD8+ 细胞 ,在植皮后 7～ 2 8d高于同种异体 自体皮肤混合移植组 ,2 1d时差异有统计学意义 (P <0 0 5 )。在 7～ 14d时CD4/CD8比值高于同种异体 自体皮肤混合移植组 (P <0 0 5 )。提示同种异体 自体皮肤混合移植排异反应以CD8+ 淋巴细胞为主 ,而在大张同种皮肤移植排异反应中CD4+ 淋巴细胞起主要作用。     

免疫学指标在轻/重症SARS患者中的不同及意义

目的　研究免疫学指标在严重急性呼吸综合征(severeacuterespiratorysyndrome,SARS)患者病程中的变化趋势及轻 重症患者各指标的差异。方法　收集12 91例SARS患者的临床资料,建立病历数据库,记录轻症及重症患者发病1～5周各周的白细胞(WBC)计数,淋巴细胞计数,CD3+ 、CD4 + 及CD8+ T淋巴细胞绝对值,C3、C4、血沉(ESR)及C反应蛋白(CRP)等数据,研究各免疫学及炎性指标在轻重症SARS患者中的不同及意义。结果　SARS患者的淋巴细胞数、CD8+ T细胞绝对值在发病初期即达到最低值,随病程的进展缓慢回升,CRP、C4在发病初期即维持较高水平,随时间的进展缓慢下降,重症患者淋巴细胞水平及CD8+ T细胞绝对值明显低于轻症患者(P <0 .0 1) ,而CRP、C4水平明显高于轻症患者(P <0 .0 1)。结论　淋巴细胞,CD8+ T细胞绝对值及CRP、C4等免疫炎性指标均可作为评价病情轻重及变化的基本指标用于指导临床诊断及治疗。     

重症肌无力患者外周血CD5~+B细胞和CD4~-CD8~-T细胞的变化

研究重症肌无力 (MG )患者外周血CD5 + B细胞和CD4 CD8 T细胞的变化 ,以探讨这两种细胞与MG的关系。采用流式细胞仪分析MG患者和对照组外周血中CD5 + B细胞和CD4 CD8 T细胞的频率 ,同时以ELISA方法检测这些患者的血清AchR、PsmR抗体水平。结果 :2 8例MG患者的CD5 + B细胞为 19 75 %± 10 8% ,高于对照组的 15 4 %± 9 6 7% (P <0 0 1) ;胸腺未切除MG患者的CD5 + B细胞为 2 2 31%± 7 4 7% ,显著高于对照组 (P <0 0 0 1) ;两种抗体阳性MG患者的CD5 + B细胞为 2 4 96 %± 13 1% ,显著高于对照组 (P <0 0 0 1) ;以上各组MG患者的CD4 CD8 T细胞与对照组均无显著区别 ;两种抗体阴性组的CD5 + B细胞和CD4 CD8 T细胞亦与对照组均无显著区别 ;两种抗体阴性组的CD5 + B细胞和CD4 CD8 T细胞亦与对照组无明显差异。本研究提示MG患者外周血的CD5 + B细胞频率增高 ,与胸腺切除与否以及突触前后膜抗体的阳性程度密切相关 ,而CD4 CD8 T细胞是否与MG有关还需进一步研究证实。     

共刺激分子CD40L在RA患者T细胞亚群中的异常表达

目的　探讨共刺激分子CD4 0L在类风湿关节炎 (RA)患者的T细胞亚群上的表达异常与免疫功能紊乱的关系。方法　用流式细胞仪采用直接免疫荧光法测定 4 6例RA患者和 2 0例健康对照人外周血T细胞表面标志CD3、CD4、CD8的表达情况及CD4 0L在CD4 + T和CD8+ T细胞上的表达。用IMMAGE免疫分析仪 ,速率散射比浊法测定血清中免疫球蛋白的水平。结果　RA患者CD3+ CD4 + 细胞较正常对照组显著增高 (P <0 .0 5 ) ,CD3+ CD8+ 细胞较正常对照组显著降低 (P <0 .0 5 ) ,CD4 + T细胞和CD8+ T细胞上的CD4 0L的表达都较对照组显著增高 (P <0 .0 5 ) ;血清中 3种免疫球蛋白IgG、IgA、IgM的水平均较对照组显著增高 (P <0 .0 5 )。结论　RA患者以CD4 + T细胞活化为主 ,CD4 + T细胞和CD8+ T细胞上高表达的CD4 0L为T细胞活化提供第二信号 ,促使RA患者的细胞免疫功能亢进 ,同时诱导B细胞增生 ,产生大量免疫球蛋白。CD4 0 CD4 0L途径在RA免疫功能紊乱中起了重要作用     

NOD/Ltj小鼠Ⅰ型糖尿病不同发病阶段细胞免疫状态研究

目的:通过对NOD/Ltj小鼠在未发病、发病初期与发病末期不同组织器官中CD4~+T、CD8~+T细胞,Th1、Th2、Th17亚群,iNKT细胞频率及亚群,细胞因子、相关转录因子进行观察分析,进一步了解NOD/Ltj小鼠Ⅰ型糖尿病不同发病阶段细胞免疫功能状态。方法:选用雌性NOD/Ltj小鼠为实验对象。血糖仪检测小鼠空腹血糖值,根据尿糖阳性且连续2次≥11. 1 mmol/L作为T1D发病标准将动物分为未发病组、发病初期组、发病末期组。流式细胞技术(FCM)检测各组小鼠外周血、胸腺、脾脏、肝脏中CD4~+T、CD8~+T细胞,Th1、Th2、Th17亚群,iNKT细胞频率及亚群比例以及腹股沟淋巴结CD4~+T、CD8~+T细胞; CBA检测IFN-γ、TNF-α、IL-2、IL-6、IL-17A、IL-4、IL-10; WB检测PLZF、T-bet、GATA-3、ROR-γt。结果:①与未发病组比较,发病初期组CD4~+、CD8~+T细胞频率在脾脏、肝脏、胸腺、腹股沟淋巴结中均显著增加(P0. 05);与发病初期组比较,发病末期CD4~+T细胞频率在肝脏、胸腺、腹股沟淋巴结及外周血中均显著降低(P0. 05)。②在脾脏、肝脏中,与未发病组和发病初期组比较,发病末期组Th1亚群比例显著增加(P0. 05);在肝脏中,与发病初期组比较,发病末期组Th2、Th17亚群水平显著升高(P0. 05)。③与未发病组比较,发病初期组肝脏、腹股沟淋巴结中iNKT细胞频率均显著增高(P0. 05);与发病初期组比较,发病末期组外周血、肝脏中iNKT细胞频率显著降低(P0. 05);与未发病组比较,发病初期组和发病末期组胸腺iNKT1亚群比例均显著增加,iNKT2亚群比例均显著降低(P0. 05),脾脏、肝脏、腹股沟淋巴结iNKT1及iNKT2亚群比例三组两两比较均差异均无统计学意义(P0. 05)。④在脾脏和腹股沟淋巴结中致炎性细胞因子和抑炎性细胞因子水平在发病初期较未发病组和发病末期组均显著升高(P0. 05);在肝脏中致炎性细胞因子水平随小鼠病情进展逐渐升高,两两比较差异均有统计学意义(P0. 05);抑炎性细胞因子水平在发病初期最高,发病末期显著降低(P0. 05)。⑤胸腺PLZF相对表达量,三组两两比较差异均无统计学意义(P0. 05);脾脏和肝,与未发病组和发病初期组比较,发病末期组T-bet相对表达量显著增加(P0. 05)。结论:①发病初期CD4~+T和CD8~+T细胞的增加,特别是CD4~+T细胞的增加以及Th亚群的失衡是导致胰岛炎重要的免疫基础;②发病初期iNKT细胞频率的增加以及胸腺iNKT1/iNKT2亚群比例的翻转,提示了iNKT细胞在NOD/Ltj小鼠发病初期可能参与了T1D的发生。     

SARS患者急性期外周血CD3+、CD4+及CD8+细胞数量的变化

目的 探讨SARS患者外周血T淋巴细胞亚群的变化及其临床意义。方法 用全自动血细胞分析仪检测44例SARS患者外周血白细胞计数及分类，用流式细胞仪检测SARS患者外周血T淋巴细胞亚群；并与正常对照组比较。结果 与对照组比较，SARS组患者白细胞总数显著下降，淋巴细胞百分数和绝对数显著下降，粒细胞绝对数显著下降，粒细胞百分数显著增加；CD3^ 、CD4^ 和CD8^ 细胞绝对数显著下降，CD3^ 、CD4^ 及CD8^ 细胞百分数和CD4^ /CD8^ 比值与对照组比较无显著性差异。结论 SARS冠状病毒感染损伤患者细胞免疫功能。     

严重急性呼吸综合征的临床病理及发病机制研究

目的　研究严重急性呼吸综合征 (SARS)的病理学特征及临床治疗的病理学基础 ,并探讨SARS的发病机制。方法　采用光、电镜观察 ,对 2例SARS系统尸检病例和 4例多器官多部位穿刺标本进行病理学观察 ;应用免疫组化标记并分析肺组织及免疫器官中各淋巴亚群的分布及数量变化 ;核酸原位杂交结合电镜观察 ,作SARS冠状病毒 (SARS CoV)在体病原学定位及定量检测。结果　 6例SARS肺组织均呈弥漫性肺泡上皮损伤 ,2例尸检肺组织呈急性间质性炎和区域性肺水肿 ,2例尸检和1例穿刺肺组织中肺泡腔内透明膜形成 ,1例尸检和 2例穿刺肺组织呈脱屑性终末细支气管炎及肺泡炎 ,2例穿刺病例见早期肺纤维化及肺泡腔机化。SARS肺外器官 ,2例病程 <12dSARS病例免疫器官呈较广泛的出血坏死性炎 ,组织细胞及单核细胞样免疫母细胞反应性增生 ,骨髓组织内单核 粒细胞系统相对抑制 ,而 4例病程 >2 1dSRAS病例脾脏中央动脉周围T淋巴细胞增生 ,骨髓像大致正常。体内SARS CoV存在多种感染靶细胞和靶器官 ,其中肺脏为主要靶器官 ,支气管、肾、肾上腺、心肌、胃肠道、淋巴组织及睾丸等也为靶器官。肺组织内以CD8+ 细胞浸润为主 ,杂以少数CD4 + 细胞 ;淋巴结及脾脏中CD3+ 、CD4 + 、CD8+ 和CD2 0 + 淋巴细胞亚群呈不同程度减少及比例失衡 ,而     

SARS患者脾淋巴细胞免疫组织化学的定量分析

目的对严重急性呼吸综合征（SARS）患者脾淋巴细胞进行定量分析,为SARS的病理变化和发病机制的探讨提供证据。方法通过免疫组织化学技术对6例SARS死亡患者脾和6例意外死亡者正常脾CD3^＋、CD4^＋、CD8^＋T细胞及CD20^＋B细胞的分布进行观察,并进行图像分析。结果SARS患者脾内的脾小体及动脉周围淋巴鞘（白髓）均遭到严重损害。动脉周围淋巴鞘的数量减少90．39％;脾小体减少80％左右,有的甚至完全消失;脾红髓广泛出血坏死。红髓内的CD3^＋T细胞平均数较正常减少71．76％,有的甚至完全消失,CD4^＋T细胞和CD8^＋T细胞分别平均减少86％和84％。CD20^＋B细胞减少80％以上。结论定量分析显示,SARS死亡患者脾中T细胞和B细胞普遍严重减少,提示SARS患者免疫系统遭到严重破坏,并可能是疾病的原发性损伤。     

Long-term in vivo depletion of functional CD4+ T lymphocytes from calves requires both thymectomy and anti-CD4 monoclonal antibody treatment

In vivo depletion of lymphocyte subsets is a direct approach used for dissection of the mechanisms of protective immunity. Long-term in vivo depletion of bovine T lymphocyte subpopulations with monoclonal antibody (mAb) treatment alone has been difficult to achieve. The objective of this study was to determine whether both thymectomy and anti-CD4 mAb treatment would optimize long-term in vivo depletion of functional bovine CD4+ T lymphocytes. Calves were thymectomized and treated with high doses of anti-CD4 mAb (approximately 5 mg/kg) over 4 days followed by subsequent lower doses (approximately 0.3 mg/kg) administered twice weekly for an additional 7 weeks. Depletion of CD4+ T lymphocytes from blood, spleen and peripheral lymph nodes was significantly improved in thymectomized calves compared to thymus-intact anti-CD4 mAb-treated calves. Significant differences in percentages of CD4+ T lymphocytes between thymectomized and thymus-intact calves were sustained for the duration of the 8-week study. Depletion of CD4+ T lymphocytes from thymectomized calves resulted in complete abrogation of lymphoproliferative responses to ovalbumin. In addition, thymectomized calves treated with anti-CD4 mAb had significantly reduced immunoglobulin G1 and no detectable immunoglobulin G2 ovalbumin-specific antibody responses compared to thymus-intact anti-CD4 mAb-treated calves. The results of this study demonstrate that both thymectomy and treatment with anti-CD4 mAb are required for long-term in vivo depletion of functional bovine CD4+ T lymphocytes.     

Immunological examination of peripheral blood in patients with colorectal cancer compared to healthy controls

ABSTRACT

Background: The objective of this study was to investigate serum levels of immunosuppressive cytokines TGF beta 1 and VEGF and count of immune cells in peripheral blood in stage II and III colorectal cancer patients.

Methods: Blood samples were collected from 22 colorectal patients and 25 healthy controls before the start of treatment. All patients were examined by a clinical immunologist to exclude patients with immune disorders and autoimmune diseases. TGF beta 1 and VEGF were measured by ELISA, and anti-tumor cellular immunity cells (CD4, CD8, B cells, NK cells) were measured by flow cytometry.

Results: TGF beta 1 and VEGF plasma levels were significantly increased in stage II and III colorectal patients compared with control group (both p < 0.0001). A decrease in the cellular immunity was shown in the absolute numbers of cytotoxic T lymphocytes (CD8+ ; p = 0.0240), helper T lymphocytes (CD4+ ; p = 0.0019), and natural killer cells (CD16 + CD56+; p < 0.0001) in both stage II and stage III patients. On the contrary, B lymphocyte (CD19+) serum levels were increased in colon cancer patients (p < 0.0001) compared to the control group.

Conclusions: Our results show peripheral blood levels of TGF beta and VEGF were significantly increased in colorectal patients and changes in cellular anticancer immunity in comparison to control group. These results will be compared with results from Immunoscore.     

Low Number of Peripheral Blood B Lymphocytes in Patients with Pulmonary Tuberculosis

The cellular immune response plays a critical role in the containment of persistent Mycobacterium tuberculosis infection; however, the immunological mechanisms that lead to its control are not completely identified. The goal of this study was to evaluate B (CD19+) and T (CD3+) peripheral blood lymphocyte profiles and T-cell subsets (CD4+ and CD8+) in patients with pulmonary tuberculosis (TB). Percentages (p = 0.02) and absolute numbers (p = 0.005) of B cells were significantly lower in patients with pulmonary TB than in healthy donors. In contrast, percentages (p = 0.12) and absolute numbers (p = 0.14) of T cells were similar in TB patients and healthy donors. No significant differences in percentages of CD4+ (p = 0.19) or CD8+ (p = 0.85) T cells between patients and healthy donors were observed. In summary, patients with pulmonary tuberculosis had a lower number of peripheral blood B lymphocytes than healthy controls.     

Hematological findings in SARS patients and possible mechanisms (review)

Severe acute respiratory syndrome (SARS) is a new human infectious disease. The causative agent of SARS is a novel coronavirus (SARS-CoV). This report summarizes the hematological findings in SARS patients and proposes the possible mechanisms of SARS-CoV related abnormal hematopoiesis. Hematological changes in patients with SARS are common and include lymphopenia, thrombocytopenia and occasionally leukopenia. A significant decrease was also observed in peripheral CD4+ and CD8+ T lymphocyte subsets and it was related to onset of SARS. A number of potential mechanisms may be involved. The development of auto-immune antibodies or immune complexes triggered by viral infection may play a major role in inducing lymphopenia and thrombocytopenia. Moreover, SARS-CoV may also directly infect hematopoietic stem/progenitor cells via CD13 or CD66a inducing their growth inhibition and apoptosis. The receptor for group I and III CoV is aminopeptidase N (CD13). CD13 has been identified in human bone marrow CD34+ cells, platelets, megakaryocytes, myeloid cells, and erythroid cells, but not in lymphocytes. The common receptor for group II CoV is CEACAM1a (CD66a). CD66a is an adhesion molecule expressed on bone marrow CD34+ cells, platelets, granulocytes and activated lymphocytes. In addition, glucocorticoids could induce lymphopenia and the use of steroids may account for the decrease of lymphocytes in some SARS patients. The increased consumption of platelets and/or the decreased production of platelets in the damaged lungs are a potential alternative but often overlooked mechanism that can contribute to thrombocytopenia in severe critical pulmonary conditions.     

Sex difference in the CD4 + CD45R+ T lymphocytes in normal individuals and its selective decrease in women with idiopathic thrombocytopenic purpura

Chronic idiopathic thrombocytopenic purpura (ITP) is a well-defined autoimmune hematologic disorder. It is more common in women than men. We have shown that patients with active disease have abnormal T cell subsets which are more perturbed in women than in men and functional abnormalities that are confined to the T lymphocytes. In the current study, the anti-2H4 (CD45R) monoclonal antibody was used to divide the CD4 subset into their CD4+ CD45R+ and CD4+ CD45R- T lymphocytes. The subpopulations were measured in the peripheral blood of 26 women and 15 men with active ITP, 16 women and 8 men with disease in remission, and 33 normal healthy women and men. Normal women had increased percentages (P less than 0.0001) and numbers (P less than 0.005) of the CD4+ CD45R+ lymphocytes compared to normal men. Women with active disease had reduced percentages and numbers of CD4+ CD45R+ lymphocytes compared to normal women (P less than 0.0001) and women with disease in remission (P less than 0.001). Those women with decreased CD4+ CD45R+ lymphocytes had a significantly depressed lymphocyte response to polyclonal T cell mitogens. In contrast, men with active disease had neither such phenotypic changes nor functional correlations. The percentages and numbers of CD4+ CD45R- lymphocytes were not changed in either sex with active disease. In conclusion, women, but not men, with active ITP appear to possess a reduced subpopulation of CD4+ CD45R+ T lymphocytes.