儿童系统性EB病毒阳性T细胞淋巴组织增殖性疾病的临床病理观察

目的 探讨儿童系统性EB病毒阳性T细胞淋巴组织增殖性疾病(CSEBV+T-LPD)的临床病理特征、诊断及鉴别诊断要点.方法 经过HE染色观察并采用免疫组织化学、原位杂交技术,结合临床资料,对30例CSEBV+T-LPD病例进行回顾性研究,并进行随访.结果 (1)CSEBV+T-LPD,男19例,女11例,中位年龄9岁;起病至确诊的时间平均14个月;主要临床表现有发热(96.7%),淋巴结增大(83.3%),肝脾肿大(66.7%),常见皮肤损害包括蚊虫叮咬超敏反应(13.3%)和皮疹(20.0%);20例随访患者中6例死亡,4例发展为淋巴瘤.(2)组织病理特点:淋巴结表现为T区扩大,淋巴滤泡缩小、减少甚至消失;病变主要为中小淋巴细胞以及多少不等的组织细胞,大细胞散在其中,轻至中度异型;21例淋巴结的间质及小血管增多,11例包膜增厚;另外,肝、脾和皮肤主要表现为轻至中度异形淋巴细胞浸润;3例可见噬血细胞现象.(3)免疫表型特点:病变中的中小淋巴细胞表达CD3、粒酶B和T细胞胞质内抗原(TIA-1);8例检测病例中7例表达CD8,1例主要表达CIM,也表达CD8;15例检测了CD56,2例阳性并已进展为NK/T细胞淋巴瘤,其余13例阴性.(4)30例均检测出EB病毒编码的小RNA(EBER)阳性细胞,数量5～500个/HPF;EBER在各种淋巴细胞中均阳性,9例以中至大淋巴细胞阳性为主,其余主要是中小淋巴细胞阳性;主要分布在T区,也见于套区、初级滤泡和生发中心内.结论 中国存在CSEBV+T-LPD;主要发生于儿童和青少年,病程为亚急性或慢性伴反复发热;此病为系统性病变,主要累及淋巴结和肝脾,也可累及皮肤,淋巴结以T区扩大和轻中度异形淋巴细胞浸润为主要形式;EB病毒感染的细胞毒性T细胞构成病变主体;是一种危及生命的疾病,患者往往死于严重并发症或进展为恶性淋巴瘤;应综合考虑临床、病理、免疫表形和EB病毒感染4方面信息以获得准确诊断.     

儿童系统性EB病毒阳性T细胞淋巴组织增殖性疾病的临床病理观察

目的 探讨儿童系统性EB病毒阳性T细胞淋巴组织增殖性疾病(CSEBV+T-LPD)的临床病理特征、诊断及鉴别诊断要点.方法 经过HE染色观察并采用免疫组织化学、原位杂交技术,结合临床资料,对30例CSEBV+T-LPD病例进行回顾性研究,并进行随访.结果 (1)CSEBV+T-LPD,男19例,女11例,中位年龄9岁;起病至确诊的时间平均14个月;主要临床表现有发热(96.7%),淋巴结增大(83.3%),肝脾肿大(66.7%),常见皮肤损害包括蚊虫叮咬超敏反应(13.3%)和皮疹(20.0%);20例随访患者中6例死亡,4例发展为淋巴瘤.(2)组织病理特点:淋巴结表现为T区扩大,淋巴滤泡缩小、减少甚至消失;病变主要为中小淋巴细胞以及多少不等的组织细胞,大细胞散在其中,轻至中度异型;21例淋巴结的间质及小血管增多,11例包膜增厚;另外,肝、脾和皮肤主要表现为轻至中度异形淋巴细胞浸润;3例可见噬血细胞现象.(3)免疫表型特点:病变中的中小淋巴细胞表达CD3、粒酶B和T细胞胞质内抗原(TIA-1);8例检测病例中7例表达CD8,1例主要表达CIM,也表达CD8;15例检测了CD56,2例阳性并已进展为NK/T细胞淋巴瘤,其余13例阴性.(4)30例均检测出EB病毒编码的小RNA(EBER)阳性细胞,数量5～500个/HPF;EBER在各种淋巴细胞中均阳性,9例以中至大淋巴细胞阳性为主,其余主要是中小淋巴细胞阳性;主要分布在T区,也见于套区、初级滤泡和生发中心内.结论 中国存在CSEBV+T-LPD;主要发生于儿童和青少年,病程为亚急性或慢性伴反复发热;此病为系统性病变,主要累及淋巴结和肝脾,也可累及皮肤,淋巴结以T区扩大和轻中度异形淋巴细胞浸润为主要形式;EB病毒感染的细胞毒性T细胞构成病变主体;是一种危及生命的疾病,患者往往死于严重并发症或进展为恶性淋巴瘤;应综合考虑临床、病理、免疫表形和EB病毒感染4方面信息以获得准确诊断.     

ACETYL CHOLINESTERASE IS EXPRESSED IN THE FOLLICULAR DENDRITIC CELLS OF GERMINAL CENTRES: DIFFERENCES BETWEEN NORMAL AND NEOPLASTIC FOLLICLES

Acetyl cholinesterase (AcChE) was demonstrated by histochemistry in the follicular dendritic cells (FDCs) of the germinal centres of lymph nodes, tonsils, and bowel lymphoid tissue. Its presence in the FDCs was confirmed by double immunostaining for CD21 or DRC-1. AcChE-positive FDCs are concentrated in the inner portion of the light zone of the germinal centre, being absent from the dark zone. In the lymphoid tissue surrounding the germinal centres are AcChE-positive blood vessels; double staining shows that the AcChE is present in the pericytes surrounding the endothelium of the blood vessels. In contrast to the reactive follicle, the AcChE reactivity in FDCs of follicle centre lymphoma is absent or minimally expressed, although the dense FDC mesh is well stained with CD21 or DRC-1. This suggests that the AcChE is not constitutively expressed in FDCs but that its expression is influenced by the state and activity of the lymphoid cells in the germinal centre. The reduced level of AcChE staining can be profitably employed in the diagnosis of follicle centre lymphoma.     

Histology and immunohistochemistry of the gut-associated lymphoid tissue of the eastern grey kangaroo, Macropus giganteus

Mesenteric lymph nodes and gut-associated lymphoid tissue (GALT) from juvenile eastern grey kangaroos were investigated. The mesenteric nodes had a similar structure to that described for eutherian mammals. They contained distinct regions of medulla and cortex, with prominent follicles and germinal centres. Gut associated lymphoid tissue consisted of areas of submucosal follicles. These varied from areas of densely packed lymphocytes with darkly staining, prominent coronas to areas with no defined follicles. The distribution of T cells in these tissues was documented by use of species-crossreactive antibodies to the surface markers CD3 and CD5; B cells were identified by antibodies to CD79b. Within the lymph nodes T cells were located mainly in the paracortex and cortex, with limited numbers observed in the follicles; B cells were located on the marginal zone of the follicles. In GALT, T cells were located in the peripheral regions of the germinal centres of secondary follicles, while B cells were abundant in primary follicles. These observations are consistent with those made in a range of other marsupials (metatherian) and eutherian mammals and are indicative of the capacity to respond to antigens entering via the mouth.     

免疫组化技术分析人淋巴组织的多种分化抗原

用间接免疫过氧化物酶和PAP技术检测本室制备的31种抗人分化抗原单抗与淋巴组织的反应性.结果表明,CD3、CD5单抗与扁桃腺和淋巴结的T细胞、大部分成熟髓质胸腺细胞和脾白髓的中央动脉周围淋巴鞘呈非常强的反应.CD4~+细胞在扁桃腺的分布与CD3~+细胞类似,但数量稍少.只有少部扁桃腺和淋巴结T细胞与CD8单抗反应,CD8单抗主要染大部分胸腺皮质细胞,但抗CD8单抗与脾窦的内皮细胞呈强阳性交叉反应.Wu59单抗同时与扁桃腺、淋巴结和脾脏的T、B细胞呈非常强的膜染色,并与胸腺皮质和髓质细胞呈阳性反应,该单抗可能识别白细胞共同抗原或LFA-1.Wu 26.145单抗除与扁桃腺生发中心呈弱阳性反应外,还与脾红髓窦状结构内的血小板呈强阳性反应.此外,抗B细胞及其亚群单抗与扁桃腺、淋巴结、脾白髓生发中心呈强阳性反应.抗IL-2受体单抗与上述组织基本上呈阴性反应。     

Myeloid‐Lymphoid Ontogeny in the Rhesus Monkey (Macaca mulatta)

Establishment of a functional immune system has important implications for health and disease, yet questions remain regarding the mechanism, location, and timing of development of myeloid and lymphoid cell compartments. The goal of this study was to characterize the ontogeny of the myeloid‐lymphoid system in rhesus monkeys to enhance current knowledge of the developmental sequence of B‐cell (CD20, CD79), T‐cell (CD3, CD4, CD8, FoxP3), dendritic cell (CD205), and macrophage (CD68) lineages in the fetus and infant. Immunohistochemical assessments addressed the temporal and spatial expression of select phenotypic markers in the developing liver, thymus, spleen, lymph nodes, gut‐associated lymphoid tissue (GALT), and bone marrow with antibodies known to cross‐react with rhesus cells. CD3 was the earliest lymphoid marker identified in the first trimester thymus and, to a lesser extent, in the spleen. T‐cell markers were also expressed midgestation on cells of the liver, spleen, thymus, and in Peyer's patches of the small and large intestine, and where CCR5 expression was noted. A myeloid marker, CD68, was found on hepatic cells near blood islands in the late first trimester. B‐cell markers were observed mid‐second trimester in the liver, spleen, thymus, lymph nodes, bone marrow spaces, and occasionally in GALT. By the late third trimester and postnatally, secondary follicles with germinal centers were present in the thymus, spleen, and lymph nodes. These results suggest that immune ontogeny in monkeys is similar in temporal and anatomical sequence when compared to humans, providing important insights for translational studies. Anat Rec, 297:1392–1406, 2014. © 2014 Wiley Periodicals, Inc.     

Phenotypic analysis of lymphocyte populations in the lungs and regional lymphoid tissue of sheep naturally infected with maedi visna virus.

We have analysed the phenotype of lymphocytes in lung and regional lymph node of symptomatic and asymptomatic sheep infected with the ovine lentivirus, maedi visna virus (MVV). Compared to equivalent tissues from age-matched, non-infected controls, MVV-infected sheep show increased numbers of lymphocytes in the lung, both in the bronchus-associated lymphoid tissue (BALT) and in the alveolar septae. Both CD8+ and CD4+ T lymphocyte numbers in alveolar septae were increased, particularly in animals with clinical respiratory disease. The ratio of CD8+ to CD4+ lymphocytes was similar to that in normal lung. In both MVV-infected and uninfected animals a high proportion of pulmonary lymphocytes, particularly in the alveolar septae, did not express the CD5 antigen, suggesting that they were activated. The number of activated cells was higher in infected sheep. Variable numbers of alveolar macrophages containing MVV-core protein were present in alveolar lumina, the majority of positive cells showing morphological evidence of activation. In regional lymphoid tissue there were increased numbers of CD8+ and gamma delta expressing T cells in lymphoid follicles and germinal centres of infected animals. The specificity of these cells is unknown and we could find no evidence for the presence of cells productively infected with the virus in these structures. This study shows that activated T lymphocytes, particularly of the CD8 subset, play a major part in the pathogenesis of MVV-induced pulmonary and regional lymph node lesions.     

Morphology of colorectal lymphoid aggregates in cancer, diverticular and inflammatory bowel diseases.

The present study compares the characteristics of colorectal lymphoid aggregates in patients with carcinoma, diverticular disease, Crohn's disease, or ulcerative colitis of the large bowel. A total of 77 patients (41 colorectal cancer, 27 diverticular disease, six ulcerative colitis, three Crohn's disease) undergoing colorectal resection were included. Acetic acid staining, hematoxylin and eosin staining, CD3, CD20, and MIB1 immunostaining were employed in order to assess density, diameter, subepithelial or basal location, cellular profile, and proliferation of lymphoid aggregates in normal-appearing and actively inflamed large bowel. In normal-appearing tissue, mean density of lymphoid aggregates was lower in patients with ulcerative colitis and Crohn's disease than in those with colorectal cancer or diverticular disease. A larger mean diameter of aggregates was observed in patients with Crohn's disease. In inflammatory bowel diseases, a marked increase of the mean density of lymphoid aggregates was observed in actively affected specimens. In Crohn's disease more than in ulcerative colitis, the aggregates had a predominant basal or transmural distribution. In diverticular disease, active inflammation determined a less significant increase of subepithelial aggregates harboring a lower proportion of germinal centers. No significant variations of CD3, CD20, and MIB1 were recorded among the four disease groups. The lymphoid aggregate derangements observed not only in the actively affected mucosa but also in the unaffected colorectal lining of patients with Crohn's disease and ulcerative colitis support a relevant involvement of lymphoid aggregate system in the pathogenesis of inflammatory bowel diseases.     

Lymphoid hyperplasia of the large intestine: a case report with immunohistochemical and gene analysis

A case of lymphoid hyperplasia arising in the large intestine of a 54-year-old woman is described. Barium enema X-ray and colonoscopic examination revealed multiple small polyps in the right side of the colon. Pathological findings from forceps biopsy revealed similar features to a mucosa-associated lymphoid tissue (MALT) lymphoma. A right hemicolectomy with mesenteric lymph node dissection was carried out. Histological sectioning demonstrated hypertrophic lymphoid follicles with well-formed germinal centers. Occasionally, lymphocytes infiltrated the crypts, in a way similar to that found in lymphoepithelial lesions, which was suggestive of a MALT lymphoma diagnosis. Cryptitis was also observed in the lamina propria. Immunohistochemically, proliferating lymphocytes were positive for CD20 (L26) and negative for CD45RO (UCHL-1). Analyses of immunoglobulin gene (IgHJH) rearrangement could not detect any monoclonality in these cells. These findings suggested that the present case should be categorized as lymphoid hyperplasia rather than lymphoma.     

Podoplanin (d2-40): a new immunohistochemical marker for reactive follicular dendritic cells and follicular dendritic cell sarcomas

The diagnosis of follicular dendritic cell (FDC) sarcoma can be challenging because of its morphologic overlaps with many other spindle cell neoplasms and, therefore, new phenotypic markers will be helpful in its differential diagnosis. Podoplanin is a mucin-type transmembrane glycoprotein that has recently been detected in reactive FDCs. In this study, we investigated the expression patterns of podoplanin using a new mouse monoclonal antibody D2-40, and compared them with CD21, a well-established FDC marker, in a comprehensive panel of cases. The panel included 4 FDC sarcomas, 38 spindle cell neoplasms of other types, 25 reactive lymphoid hyperplasia, and 117 lymphoid and 5 myeloid malignant hematopoietic neoplasms. Our study revealed that D2-40 strongly stained 3 of 4 FDC sarcomas. In contrast, D2-40 stained only 2/38 other spindle cell neoplasms tested. Furthermore, we observed that D2-40 highlighted more FDC meshworks than CD21 in Castleman's disease, follicular lymphoma, nodular lymphocyte predominance Hodgkin lymphoma, and residual reactive germinal centers in a variety of lymphoma types. D2-40 and CD21 stained an equal number of cases of reactive lymphoid hyperplasia, progressively transformed germinal centers and angioimmunoblastic T-cell lymphoma. No expression of podoplanin was detected in normal or neoplastic lymphoid and myeloid cells. We conclude that podoplanin (D2-40) is a sensitive and specific FDC marker, which is superior or equal to CD21 in evaluating both reactive and neoplastic FDCs. In addition, our results suggest that podoplanin (D2-40) can be used to support the diagnosis of FDC sarcoma.     

Chronic lymphocytic thyroiditis in a cynomolgus macaque (Macaca fascicularis)

Chronic lymphocytic thyroiditis characterized by multifocal follicular lymphoid cell infiltrates with germinal centers, thyroid acinar atrophy and pituitary cell hyperplasia/hypertrophy of the adenohypophysis was detected in a vehicle control, 4-year-old female Cynomolgus macaque in a routine toxicology study. Lymphoid cells of germinal centers were positive for the B-cell marker CD20 by immunohistochemistry (IHC), while remaining lymphocytes were positive for the T-cell marker CD3. Hypertrophied/hyperplastic pituitary cells were positive for thyroid stimulating hormone (TSH) by IHC, consistent with an adaptive response due to removal of hormonal negative feedback from the diseased thyroid gland. Features of this case are similar to chronic lymphocytic thyroiditis in humans, an autoimmune disorder also known as Hashimoto's disease. Chronic lymphocytic thyroiditis with compensatory pituitary changes may occur spontaneously in young, clinically normal cynomolgus macaques and its presence in drug treated animals should be interpreted with caution.     

成年人系统性EB病毒阳性T/NK细胞淋巴组织增殖性疾病的临床病理研究

目的 探讨成年人系统性EB病毒阳性T/NK细胞淋巴组织增殖性疾病(ASEBV+ T/NK-LPD)的临床病理特征、免疫表型和EBV感染特征,以提高对其的认识及诊断水平.方法 经过HE染色观察并采用免疫组织化学、原位杂交及基因重排技术,结合临床资料,对20例ASEBV+ T/NK-LPD患者病理资料进行回顾性研究,并进行随访.结果 (1)男15例,女5例,中位年龄34岁;起病至确诊时间平均8.7个月;主要临床表现有发热(18/20)、肝脾大(18/20)、淋巴结肿大(17/20);17例随访中11例死亡,平均生存时间2.9个月.(2)组织病理学特点:淋巴结T区明显增宽至弥漫成片,淋巴滤泡不同程度地减少或消失.病变中细胞种类多样至相对单一,以中小淋巴细胞增多为主,大细胞散在其中.淋巴细胞多数异型性不明显,少数轻或中度异型.6例被膜增厚,9例可见局灶或片状坏死及核碎;3例可见噬血细胞现象;另外,肝、脾、肠黏膜、扁桃体和骨髓主要表现为轻至中度异型淋巴细胞浸润.(3)免疫表型特点:20例都表现出T细胞明显多于B细胞,很多细胞表达颗粒酶B或T细胞胞质内抗原(TIA)-1,仅1例CD56阳性.14例CD4/CD8检测病例中8例以CD8阳性细胞为主,5例以CD4阳性细胞为主,1例CD8和CD4阳性数量相当.(4)全部病例EBER均阳性.阳性细胞最多的区域数量在30～300个/HPF,绝大多数病例中EBER阳性细胞包括大、中、小淋巴细胞,主要分布在扩大的T区.(5)TCR基因重排显示该病细胞群体中既有多克隆(4/7)也有单克隆(3/7).结论 ASEBV+T/NK-LPD呈亚急性或慢性经过,主要表现为反复发热伴淋巴结及肝脾大;淋巴结以T区扩大和轻中度异型淋巴细胞浸润为主;EBV感染的细胞毒性T细胞构成病变主体.它是一种危及生命的疾病,患者往往死于器官衰竭和出血.

Abstract：

Objective To study the clinicopathologic features, immunophenotype, clonality and Epstein-Barr virus (EBV) status of systemic EBV-positive T/NK-cell lymphoproliferative disease in adults (ASEBV + T/NK-LPD). Methods Twenty cases of ASEBV + T/NK-LPD were analyzed retrospectively with histopathologic review, immunohistochemistry and in-situ hybridization for EBV-encoded RNA (EBER).The follow-up data were collected. Results There were altogether 15 males and 5 females. The median age of the patients was 34 years. The average duration from onset of symptoms to diagnosis was 8. 7 months.Fever (18/20), hepatosplenomegaly (18/20) and lymphadenopathy (17/20) were the main clinical manifestations. Eleven of the 17 patients died during follow-up, with a mean survival of 2. 9 months.Histologically, there was obvious expansion of T zone of the involved lymph nodes, associated with diminished lymphoid follicles. The interfollicular areas were widened and infiltrated by small to median-sized lymphoid cells which showed only mild atypia. Scattered large lymphoid cells were not uncommon. The nodal capsule was thickened in 6 cases. Focal necrosis was seen in 9 cases. Sinus histiocytic proliferation with erythrophagocytosis was observed in 3 cases. In addition, there were mild atypical lymphoid cells infiltrate into the liver, spleen, intestinal mucosa and bone marrow. Immunohistochemical study and in-situ hybridization showed that the EBER-positive cells were of T-cell lineage, with CD3 expression. They were also positive for cytotoxic molecules (granzyme B or TIA-I) . Only 1 case was CD56 positive. A predominance of CD8-positive cells was demonstrated in 8 of the 14 cases studied, while CD4-positive cells predominated in the remaining 5 cases. One case showed similar proportion of CD8 and CD4-positive cells.The number of EBER-positive cells ranged from 30 to more than 300 per high-power fields. These EBERpositive cells were of small to large size and located mainly in the expanded T zone and occasionally in the germinal centers. Three of the 7 cases exhibited clonal rearrangement of T-cell receptor gamma gene, while the other 4 cases exhibited polyclonal rearrangement of T-cell receptor gamma gene. Conclusions ASEBV +T/NK-LPD is a systemic disease with a subacute or chronic clinical course. Most patients suffer from relapsing fever, lymphadenopathy and hepatosplenomegaly. The disease is characterized by proliferation of EBV-infected cytotoxic T cells. The T zone of the involved lymph nodes shows expansion by mildly atypical lymphoid cells. The disease is associated with poor clinical outcome and can be life-threatening. The patients often die of multiorgan failure and bleeding.     

Histological Development of the Immune Tissues of a Marsupial,the Red‐Tailed Phascogale (Phascogale calura)

Red‐tailed phascogale (Phascogale calura) pouch young at birth were relatively underdeveloped in comparison with their eutherian counterparts, and the lymphoid tissues of the immune system were found to be histologically immature. The phascogale thymus rapidly developed in the first few days of pouch life and was quickly populated with lymphocytes. By the end of pouch life, involution of the thymus was underway. The bone marrow started to develop in the early stage of pouch life, although adipocytes and megakaryocytes were not observed until slightly later. The liver was hematopoietic from birth and reached histological maturity toward the end of pouch life. The lymph nodes were difficult to detect macroscopically because of their small size, but were easily identified microscopically later in pouch life, particularly in the mesentery, and these lymph nodes exhibited germinal centers by the end of pouch life. The early spleen was predominately mesenchymal, but exhibited some erythropoiesis. Follicles with well‐developed germinal centers were not observed until the latest stage of pouch life. Although intraepithelial lymphocytes were detected in the intestines early in pouch life, the discrete lymphoid aggregates and Peyer's patches characteristic of the gut‐associated lymphoid tissue (GALT) were not detected until later in pouch life. This is the first report of histological development in phascogale pouch young, as well as the first report of the thymus, bone marrow, and lymph nodes in this dasyurid species at any age. Anat Rec, 299:207–219, 2016. © 2015 Wiley Periodicals, Inc.     

LAV-like viral particles in lymph node germinal centers in patients with the persistent lymphadenopathy syndrome and the acquired immunodeficiency syndrome-related complex: an ultrastructural study of 30 cases

The detection of LAV- or HTLV III-type viral particles in lymph node germinal centers from patients with the persistent lymphadenopathy syndrome (LAS) or the acquired immunodeficiency syndrome (AIDS)-related complex (ARC) is an important diagnostic factor in the prodromal stages of AIDS. These particles, the morphology of which is defined, are situated solely in the extracellular spaces delimited by cytoplasmic extensions of the dendritic reticular cells. Often few in number, they were found in 26 of the 30 lymph nodes studied, selected uniquely on the basis of light microscopic criteria (predominantly follicular lymphoid hyperplasia). The four negative nodes contained no, or fewer than two, germinal centers in the samples taken for ultrastructural study. The diagnosis of the LAS or the ARC was always confirmed clinically and biologically. Thus, lymph node biopsy and the corresponding ultrastructural study are important steps in the diagnosis of AIDS.     

Hodgkin''s disease presenting with the histological features of Castleman''s disease

Three cases are reported in which an initial diagnosis of the plasma cell variant of Castleman's disease was made, but in which a second lymph node biopsy within a year showed evidence of Hodgkin's disease. Review of the initial biopsy indicated that atypical CD15 and CD30 positive cells were present in the initial biopsy. This illustrates the difficulty in making the diagnosis of Castleman's disease and suggests that the lymphoid reaction to the presence of Hodgkin's disease may result in similar histological appearances. The need for re-evaluation of the diagnosis of Castleman's disease in the face of persistent or recurrent disease is stressed.     

Lack of Shiga-like toxin binding sites in germinal centres of mouse lymphoid tissues

B cells in germinal centres are known to express carbohydrate antigen CD77 in human lymphoid tissues. The CD77 antigen is specifically recognized by Shiga-like toxins (SLTs) that are produced by enterohaemorrhagic Escherichia coli O157:H7. To determine whether the binding subunits of Shiga-like toxin-1 (SLT-1B) could have adverse effects on the murine immune system when used as an immunogen, we investigated whether SLT-1B could bind to germinal centres of mouse lymphoid tissues. Frozen sections of peripheral lymph nodes and Peyer's patches from immunized mice were tested for the presence of SLT-1B-binding sites by immunohistological methods. Germinal centres were not stained with SLT-1B, while they were intensely stained with peanut agglutinin (PNA), another marker of germinal centres. On the other hand, SLT-1B specifically bound to renal tubules and collecting ducts in frozen sections of mouse kidney. This is consistent with results from human tissues. We also demonstrated that B220/PNA double-positive populations in lymph nodes from immunized mice exhibited only marginal staining with SLT-1B. The present results suggest that SLTs would not impede germinal centre functions of the murine immune system.     

The life and death of the germinal center

The formation, development and dissolution of germinal centers is a major part of immune system function. It is important to differentiate neoplastic processes from follicular hyperplasia and regressive follicular changes. Better understanding of germinal center development and dissolution also provides diagnostic clues to the underlying pathologic process. It is also important in identifying the immune basis of different pathologic entities as well as in immunotherapy decision making and follow up. In this study, we characterize the immunoarchitecture of lymphoid follicles with a focus on germinal center in one representative case, each of commonly encountered benign and malignant lymph node disorders, with morphologic and immunohistochemical alterations of germinal centers. The cases include reactive follicular hyperplasia (FH), florid follicular hyperplasia (FFH), follicular lymphoma (FL), angioimmunoblastic T-cell lymphoma (AITL), hyaline-vascular Castleman disease (HVCD), progressive transformation of germinal centers, nodular lymphocyte predominant Hodgkin lymphoma (NLPHL), lymphocyte-rich classic Hodgkin lymphoma (LR-CHL), human immunodeficiency virus (HIV)-associated follicular dissolution and chronic lymphocytic leukemia (CLL) with proliferation centers (PC). A panel of antibodies were used namely CD3, CD20, CD10, BCL2, BCL6, CD21, CD23, CD35, FOXP1, GCET1, HGAL/GCET2, LMO2, MUM1, IgD, Ki67, PD1 and PD-L1. We found that these entities show distinct immunoarchitectural patterns of germinal center formation, development and regression, particularly, the distribution of mantle zone B-cells, follicular helper T cells (Tfh) and FDC meshworks, confirming the influence of antigenic stimulation and status of immune system in these changes. This also confirms the interrelationship of underlying immunologic mechanisms in these disease processes.