SARS患者免疫系统病理改变的研究

目的探讨SARS患者免疫系统的病理改变,确认异型增生细胞的来源.方法采用常规组织病理、免疫组织化学和原位杂交的方法对两例SARS患者的尸检组织淋巴结,脾脏和小肠阑尾的淋巴组织进行研究.结果淋巴结,脾脏结构破坏,淋巴细胞明显减少,淋巴小结结构消失.小血管增生明显.脾脏白髓萎缩,淋巴细胞减少,红髓明显扩张充血.结外淋巴组织萎缩.所有的淋巴组织中见到异型增生的淋巴细胞,此种细胞免疫表型以T细胞为主,且呈现PCNA阳性.结论SARS患者的免疫系统受到了明显的损害,全部免疫细胞减少,以T细胞为主.在淋巴组织中出现的异型增生的细胞,其病理意义有待于进一步探讨.     

伴有明显淋巴滤泡的非特指外周T细胞淋巴瘤

目的　探讨伴有明显淋巴滤泡增生的非特指外周T细胞淋巴瘤的形态学特点和免疫表型。方法　对 3例特殊形态的外周T细胞淋巴瘤进行形态学观察 ,免疫组化EnVision法检测CD3、CD4 5RO、CD4 3、CD2 0、CD79a、cyclinD1、bcl 2、CD4、CD8、S 10 0等抗体 ,并用PCR方法进行T细胞受体(TCR)基因重排检测。结果　 3例患者均以全身浅表淋巴结肿大为主要表现 ,初发部位为颈部和颌下 ,发病过程中出现低热及全身皮疹 ,并有肝、脾肿大。形态学的显著特点为淋巴滤泡增生 ,套区消失 ,边缘区有中等大小、胞浆透亮的瘤细胞浸润生长。免疫表型标志为T细胞淋巴瘤。基因检测有TCRγ基因阳性条带。结论　部分非特指外周T细胞淋巴瘤可伴有明显淋巴滤泡增生 ,应注意与淋巴结反应性增生、滤泡性淋巴瘤、边缘区淋巴瘤及套区淋巴瘤等鉴别     

伴TdT阳性淋巴母细胞增生的Castleman病1例报道

正Castleman病于1956年Castleman等~([1])首次描述并报道,又称血管滤泡性淋巴组织增生或巨大淋巴结增生症,病因尚不明确,临床较少见。Td T全称是末端脱氧核苷酸转移酶,其主要在胸腺皮质细胞和少数骨髓淋巴细胞表达,在淋巴结及脾等成熟淋巴细胞中不表达,在T淋巴母细胞淋巴瘤中阳性率较高。然而,很多淋巴组织增生性疾病也有不同程度的Td T阳性的淋巴母细胞增生、表达;也有报道     

SARS继发曲菌感染死亡1例临床病理学观察

目的 探讨重症急性呼吸综合征(SARS)的死因和病变特征。方法 常规HE染色，组织化学Macchiavello法、MSB、网状纤维、PAS染色法进行观察。结果 SARS增生修复期改变；继发性肺曲菌病伴双肺广泛化脓性炎，严重的肺组织破坏，肺水肿，肺出血，气管、支气管、小支气管血液吸入；霉菌性败血症伴全身器官播散性、多发性曲菌性脓肿、局部组织坏死及出血伴纤维素性坏死性血管炎、血栓及霉菌菌栓形成；免疫器官抑制：脾红髓及白髓等淋巴组织严重减少，淋巴组织灶状坏死；纤维组织增生；淋巴结淋巴滤泡减少，生发中心消失，间质纤维化；骨髓粒细胞系、巨核细胞系减少，红细胞系灶状增生。结论 患者死于免疫功能抑制继发感染性多器官衰竭。提示对SARS的皮质激素治疗要适时视情慎用。     

再生障碍性贫血、骨髓增生异常综合征、急性髓系白血病患者CD8＋T细胞亚群的变化及临床意义

摘要本研究检测再生障碍性贫血（AA）、骨髓增生异常综合征（MDS）和急性髓系白血病（AML）患者细胞毒T细胞亚群平衡及其活性的改变，探讨三种疾病造血异常的细胞免疫机制，为临床治疗选择提供实验室依据。采用流式细胞术检测AA组17例、MDS组35例（其中RA19例，RAEB16例）、AML组15例和正常对照组10例的细胞毒性T细胞（Tc1、Tc2）以及部分T细胞亚群比例并进行对比分析。结果表明：与正常对照组相比，AA组、MDS-RA组Tc1、Tc1／Tc2、CD8＋HLA-DR＋、CD3＋CD8＋CD28＋、CD8＋CIM5RO＋显著升高，Tc2无明显统计学差异，CD8＋CD45RA＋显著减低；MDS-RAEB组Tc1、CD3＋CD8＋CD28＋、CD8＋HLA．DR＋比例显著减低，Tc、Tc1／Tc2无明显变化，CD8＋CD45RA＋减低但差异不明显，CD8＋CD45RO＋显著升高；AML组Tcl、CD3＋CD8＋CD28＋、CD8＋CD45RA＋、CD8＋CD45RO＋、CD8＋HLA。DR＋，Tc1／Tc2显著减低，Tc2显著上升。结论：AA、MDS不同阶段、AML患者的细胞免疫状态不同，在AA和MDS早期阶段，Tc1／Tc2的平衡向Tcl偏移，且伴有T细胞亚群活性增加；而在MDS晚期和AML阶段，则向Tc2偏移，T细胞亚群活性减低。前者可能与骨髓造血衰竭密切相关，而后者可能是恶性克隆免疫挑挽的重要机制之一．     

Castleman病7例临床病理分析

目的探讨Castleman病的临床诊断鉴别诊断及病理组织学特征。方法通过组织学、组织化学、免疫组化及基因重排克隆性分析等方法对Castleman病进行研究，并结合文献加以分析。结果7例Castleman病中5例为透明血管型，表现为增生的淋巴结内均匀的分布着大小相近的小淋巴滤泡；滤泡生发中心变小，其内可见泡状核的滤泡树突状细胞，有透明变性的小动脉穿入；外套层明显增厚，小淋巴细胞呈同心圆排列于血管周围，形成特征性的“洋葱”样同心圆结构，类似胸腺小体；滤泡间毛细血管增加，可有玻璃样变和纤维化；淋巴窦大部分消失或全部消失。2例浆细胞型特点是滤泡间大量的成熟浆细胞增生，有淋巴窦消失改变，滤泡内的毛细血管穿入，“洋葱”样改变不明显，滤泡间可见PAS染色阳性的无定型的嗜酸性物质沉积。其中1例浆细胞型部分区域淋巴细胞显著增生，弥漫成片，免疫组化显示κ链限制性表达，基因重排克隆性分析显示IG受体阳性，表明已转化为B细胞淋巴瘤。结论Castleman病是一种特殊类型的淋巴结增生性疾病，可发生于任何年龄，诊断时要与反应性滤泡性增生、淋巴瘤等进行鉴别，并注意是否发生淋巴瘤等恶性转化。     

淋巴结病理诊断的基本训练

1正掌握淋巴结的基本结构是做好淋巴结病理诊断的基础训练淋巴结的基本结构包括支架、实质、淋巴引流系统和血管系统。淋巴结的实质分为：①皮质（或称浅皮质），由淋巴滤泡（B细胞区）和滤泡间区（T细胞区）组成；②副皮质（或称深皮质，T细胞区），含有被覆立方或低往状内皮细胞（上皮样内皮细胞）的毛细血管后小静脉（PCV），可呈现T小结（或称第三小结，T细胞在其中增生、转化）；③髓质（B细胞区），成于髓索。受抗原刺激处于反应状态的次级淋巴滤泡成于生发中。C（B细胞在其中增生、转化）和套层（帽层），后者成于小淋巴细胞、…     

CD45RO阳性的B细胞性淋巴瘤

目的 研究免疫表型异常淋巴瘤的起源。方法 从48例B细胞淋巴瘤中筛选出3例CD45RO、CD20和CD79a( )，CD3(-)的淋巴瘤。采用免疫组化、PCR和基因扫描技术对其免疫表型，免疫球蛋白重链基因重排(IgH)和T细胞受体基因重排(TCR)进行深入研究。结果 3例淋巴瘤均为结外淋巴瘤。1例为滤泡性淋巴瘤，2例为弥漫性大B细胞性淋巴瘤。PCR和基因扫描显示3例均有IgH克隆性扩增；PCR未显示TCR扩增；高敏感性基因扫描显示低峰值TCR克隆性扩增，提示可能为背景T细胞扩增。结论 CD45RO不是T细胞特异性抗原，CD45RO阳性细胞不能完全等同于T细胞，因此，在研究和临床病理诊断中应选用多种抗体配合使用。     

肾移植后单形性T细胞型淋巴组织增生性疾病1例并文献复习

目的：了解肾移植后淋巴组织增生性疾病（PTLD）的病理形态及鉴别诊断。方法：对1例肾移植后患者发生在右上肢下的PTLD进行大体，光镜，免疫组化观察并结合文献分析。结果：肿瘤镜下为弥漫分布小圆及卵圆形细胞，异型性明显，浸润皮下脂肪组织。免疫组化：肿瘤细胞CD45RO、CD43、CD3和CD68（＋）；EBV、CD20、CD30和CD56（－）。结论：单形性T细胞型PTLD，其发生与使用免疫抑制剂，EBV感染等多种因素有关，预后很差。     

IFN-γ在骨髓增生异常综合征发病中作用

目的 研究骨髓增生异常综合征(MDS)患者骨髓内T细胞亚群水平，T细胞产生IFN-γ能力，及与造血干细胞凋亡的关系，探讨T细胞、IFN-γ在MDS发病中作用。方法 骨髓单个核细胞经短期培养并激活T细胞，采用细胞内因子测定技术，用流式细胞术测定骨髓内T细胞亚群，T细胞IFN-γ水平，RT-PCR技术测定BMMNC凋亡基因Fasm-RNA水平。结果 MDS患者骨髓内异常活化的T细胞(CD3^ CD45RO^ 、CD4^ CD45RO^ 、CD8^ CD45RO^ 细胞)增多，活化的T细胞产生IFN-γ增多，并与Fas-mRNA存在相关性。结论 MDS患者骨髓内活化的T细胞增多，这些细胞产生的IFN-γ可能增加凋亡基因Fas的表达。     

Peripheral engraftment of fetal intestine into athymic mice sponsors T cell development: direct evidence for thymopoietic function of murine small intestine

Adult athymic, lethally irradiated, F1-->parent bone marrow-reconstituted (AT x BM) mice were engrafted bilaterally with day 16-18 fetal intestine or fetal thymus into the kidney capsule and were studied for evidence of peripheral T cell repopulation of 1-12 wk postengraftment. Throughout that time period, both types of grafts were macroscopically and histologically characteristic of differentiated thymus or intestine tissues, respectively. Beginning at week 2 postengraftment, clusters of lymphocytes were present within intestine grafts, particularly in subepithelial regions and in areas below villus crypts. As determined by immunofluorescence staining and flow cytometric analyses, lymphocytes from spleen and lymph nodes of sham-engrafted mice (AT x BM-SHAM) were essentially void of T cells, whereas in AT x BM thymus-engrafted (AT x BM-THG) mice, which served as a positive control for T cell repopulation, normal levels of T cells were present in spleen and lymph nodes by week 3 postengraftment, and at times thereafter. Most striking, however, was the finding that T cell repopulation of the spleen and lymph nodes occurred in AT x BM fetal intestine-engrafted (AT x BM-FIG) mice beginning 3 wk postengraftment. Based on H-2 expression, peripheral T cells in AT x BM-FIG mice were of donor bone marrow origin, and consisted of CD3+, T cell receptor (TCR)-alpha/beta+ T cells with both CD4+8- and CD4-8+ subsets. Peripheral T cells in AT x BM-FIG mice were functionally mature, as demonstrated by their capacity to proliferate after stimulation of CD3 epsilon. Moreover, alloreactive cytotoxic T lymphocytes were generated in primary in vitro cultures of spleen cells from AT x BM-FIG and AT x BM-THG mice, though not in spleen cell cultures from AT x BM-SHAM mice. Histologic studies of engrafted tissues 3-4 wk postengraftment demonstrated that thymus leukemia (Tl) antigens were expressed on epithelial surfaces of intestine grafts, and that both TCR-alpha/beta+ and TCR-gamma/delta+ lymphocytes were present in intestine grafts. Collectively, these findings indicate that the murine small intestine has the capacity to initiate and regulate T cell development from bone marrow precursors, thus providing a mechanism by which extrathymic development of intestine lymphocytes occur.     

T-lymphocyte subset distribution in human spleen

BACKGROUND: When analyzing human cellular immune responses, most focus is placed on the peripheral blood (PB) and, to a lesser extent, the lymph nodes. To date the spleen has not been analyzed with regard to its role in adaptive cellular immunity and more notably not with respect to T-cell immune responses. MATERIALS AND METHODS: We analyzed the splenic lymphocyte compartment in comparison with the PB lymphocyte compartment regarding the number of NK cells, B cells, CD4(+), CD8(+) T cells and CMV-specific CD8(+) T cells. Furthermore, we analyzed the distribution of naive, memory and effector subsets of CD4(+) and CD8(+) T cells in these compartments. RESULTS: The spleen contains proportionally more B cells and less CD4(+) and CD8(+) T cells than PB. The percentage of CD8(+) T cells is greater in the spleen, leading to an inverse CD4/CD8 ratio. Both splenic CD4(+) and CD8(+) T-cell populations show a greater number of activated cells, and splenic CD8(+) T cells show a more differentiated cytotoxic CD27(-)CD45RA(+) memory phenotype. CONCLUSIONS: Our findings show that the distribution of the different lymphocyte subsets is markedly different between the spleen and the PB, thus inferring an important and distinct role for the spleen in CD4(+) and CD8(+) T-cell activation.     

MyD88-dependent expansion of an immature GR-1(+)CD11b(+) population induces T cell suppression and Th2 polarization in sepsis

Polymicrobial sepsis alters the adaptive immune response and induces T cell suppression and Th2 immune polarization. We identify a GR-1(+)CD11b(+) population whose numbers dramatically increase and remain elevated in the spleen, lymph nodes, and bone marrow during polymicrobial sepsis. Phenotypically, these cells are heterogeneous, immature, predominantly myeloid progenitors that express interleukin 10 and several other cytokines and chemokines. Splenic GR-1(+) cells effectively suppress antigen-specific CD8(+) T cell interferon (IFN) gamma production but only modestly suppress antigen-specific and nonspecific CD4(+) T cell proliferation. GR-1(+) cell depletion in vivo prevents both the sepsis-induced augmentation of Th2 cell-dependent and depression of Th1 cell-dependent antibody production. Signaling through MyD88, but not Toll-like receptor 4, TIR domain-containing adaptor-inducing IFN-beta, or the IFN-alpha/beta receptor, is required for complete GR-1(+)CD11b(+) expansion. GR-1(+)CD11b(+) cells contribute to sepsis-induced T cell suppression and preferential Th2 polarization.     

骨髓增生异常综合征骨髓单个核细胞内负调控因子的研究

为研究MDS患者细胞凋亡与骨髓内不同T细胞亚群胞内负调控因子的关系，采用胞内细胞因子染色技术对骨髓内不同亚群T细胞胞内的TNF—α和IFN-γ水平进行检测和分析，用RT—PCR技术测定BMMNC的凋亡基因Fas的mRNA水平。结果表明，MDS患者骨髓内产生TNF-α增多的淋巴细胞为CD4^ CD45RO^ 、CD8^ CD45RO^ 细胞，产生IFN-γ增多的为CD4^ CD45RO^ 、CD8^ CD45RO^ 、CD8^ CD45RA^ 细胞，但均以CD8^ CD45RO^ 细胞为主；MDS患者T淋巴细胞产生的IFN-γ与Fas mRNA存在相关性，而TNF—α与Fas mRNA相关性不强。结论：MDS患者造血微环境中不仅T淋巴细胞亚群失调，而且各亚群分泌负调控因子增多；MDS患者髓内IFN-γ主要来自于T淋巴细胞。     

B cell development in the spleen takes place in discrete steps and is determined by the quality of B cell receptor-derived signals.

Only mature B lymphocytes can enter the lymphoid follicles of spleen and lymph nodes and thus efficiently participate in the immune response. Mature, long-lived B lymphocytes derive from short-lived precursors generated in the bone marrow. We show that selection into the mature pool is an active process and takes place in the spleen. Two populations of splenic B cells were identified as precursors for mature B cells. Transitional B cells of type 1 (T1) are recent immigrants from the bone marrow. They develop into the transitional B cells of type 2 (T2), which are cycling and found exclusively in the primary follicles of the spleen. Mature B cells can be generated from T1 or T2 B cells. Mice with genetic deletions of elements participating in the B cell receptor signaling cascade display developmental arrest at the T1 or T2 stage. The analysis of these defects showed that the development of T2 and mature B cells from T1 precursors requires defined qualitative and quantitative signals derived from the B cell receptor and that the induction of longevity and maturation requires different signals.     

Recombinant adenovirus vaccines can successfully elicit CD8+ T cell immunity under conditions of extreme leukopenia.

We have examined the efficacy of vaccination with recombinant adenovirus under conditions of extreme leukopenia in lethally irradiated mice reconstituted with autologous bone marrow. The expansion of antigen-specific CD8(+) T cells following immunization of lethally irradiated hosts paralleled the recovery of total CD8(+) T cells. Surprisingly, the numbers of antigen-specific CD8(+) T cells in lethally irradiated mice beyond 6 weeks postimmunization were comparable to the numbers found in nonirradiated controls. CD8(+) T cells elicited in the lethally irradiated hosts were functionally indistinguishable from those elicited in normal hosts. Antigen expression and presentation persisted for a longer period of time in the draining lymph nodes of irradiated mice compared to those of nonirradiated animals, suggesting that antigen presentation mechanisms were intact during the reconstitution period. Experiments employing allogeneic bone marrow demonstrated that radioresistant host antigen-presenting cells were responsible for antigen presentation during the process of immune reconstitution. These results demonstrate clear compatibility of adenovirus vaccines and cytotoxic therapy. Furthermore, these observations provide novel insights into the mechanisms of CD8(+) T cell activation following adenovirus immunization.     

Follicular B helper T cells express CXC chemokine receptor 5, localize to B cell follicles, and support immunoglobulin production

Chemokines and their receptors have been identified as major regulators controlling the functional organization of secondary lymphoid organs. Here we show that expression of CXC chemokine receptor 5 (CXCR5), a chemokine receptor required for B cell homing to B cell follicles, defines a novel subpopulation of B helper T cells localizing to follicles. In peripheral blood these cells coexpress CD45RO and the T cell homing CC chemokine receptor 7 (CCR7). In secondary lymphoid organs, CD4(+)CXCR5(+) cells lose expression of CCR7, which allows them to localize to B cell follicles and germinal centers where they express high levels of CD40 ligand (CD40L), a costimulatory molecule required for B cell activation and inducible costimulator (ICOS), a recently identified costimulatory molecule of the CD28 family. Thus, when compared with CD4(+)CD45RO(+)CXCR5(-) cells, CD4(+)CD45RO(+)CXCR5(+) tonsillar T cells efficiently support the production of immunoglobulin (Ig)A and IgG. In contrast, analysis of the memory response revealed that long-lasting memory cells are found within the CD4(+)CD45RO(+)CXCR5(-) population, suggesting that CXCR5(+)CD4 cells represent recently activated effector cells. Based on the characteristic localization within secondary lymphoid organs, we suggest to term these cells "follicular B helper T cells" (T(FH)).     

Expression of interleukin (IL)-2 and IL-7 receptors discriminates between human regulatory and activated T cells

Abnormalities in CD4(+)CD25(+)Foxp3(+) regulatory T (T reg) cells have been implicated in susceptibility to allergic, autoimmune, and immunoinflammatory conditions. However, phenotypic and functional assessment of human T reg cells has been hampered by difficulty in distinguishing between CD25-expressing activated and regulatory T cells. Here, we show that expression of CD127, the alpha chain of the interleukin-7 receptor, allows an unambiguous flow cytometry-based distinction to be made between CD127(lo) T reg cells and CD127(hi) conventional T cells within the CD25(+)CD45RO(+)RA(-) effector/memory and CD45RA(+)RO(-) naive compartments in peripheral blood and lymph node. In healthy volunteers, peripheral blood CD25(+)CD127(lo) cells comprised 6.35 +/- 0.26% of CD4(+) T cells, of which 2.05 +/- 0.14% expressed the naive subset marker CD45RA. Expression of FoxP3 protein and the CD127(lo) phenotype were highly correlated within the CD4(+)CD25(+) population. Moreover, both effector/memory and naive CD25(+)CD127(lo) cells manifested suppressive activity in vitro, whereas CD25(+)CD127(hi) cells did not. Cell surface expression of CD127 therefore allows accurate estimation of T reg cell numbers and isolation of pure populations for in vitro studies and should contribute to our understanding of regulatory abnormalities in immunopathic diseases.     

Reconstruction of lymph follicles in the mouse popliteal lymph node after X-irradiation damage

In order to suppress possible "de novo" formation of follicles in the node after irradiation, animals to be irradiated received surgical operations to block the afferent lymphatics to the popliteal node on one side, the corresponding node on the other side left intact. 600 R whole body X-irradiation severely destroyed lymph follicles in the nodes of both sides, but the number of follicles in the node on either side recovered toward normal by 3 weeks after irradiation, regardless of whether they contained germinal centers or not. In animals exposed to 1,000 R whole body X-irradiation and infused with bone marrow cells, no lymph follicles were observed in the nodes on day 9. If such treated animals were given 1.0 X 10(8) lymph node cells on day 5, lymph follicles were reconstructed in the nodes of both sides on day 9. In animals irradiated with 1,000 R to the lower half of the body, the number of follicles in the node on either side remained comparable to that of the unirradiated control node. The results favor the interpretation that although X-irradiation destroys the lymphoid elements of the follicles, the stromata of follicles persist and preserve the ability to collect small lymphocytes, and that lymph follicles are reconstructed at the sites of the stromata persisting from damaged follicles.