Tonsillar crypt epithelium is an important extra-central nervous system site for viral replication in EV71 encephalomyelitis.

Enterovirus 71 (EV71; family Picornaviridae, species human Enterovirus A) usually causes hand, foot, and mouth disease, which may rarely be complicated by fatal encephalomyelitis. We investigated extra-central nervous system (extra-CNS) tissues capable of supporting EV71 infection and replication, and have correlated tissue infection with expression of putative viral entry receptors, scavenger receptor B2 (SCARB2), and P-selectin glycoprotein ligand-1 (PSGL-1). Formalin-fixed, paraffin-embedded CNS and extra-CNS tissues from seven autopsy cases were examined by IHC and in situ hybridization to evaluate viral antigens and RNA. Viral receptors were identified with IHC. In all seven cases, the CNS showed stereotypical distribution of inflammation and neuronal localization of viral antigens and RNA, confirming the clinical diagnosis of EV71 encephalomyelitis. In six cases in which tonsillar tissues were available, viral antigens and/or RNA were localized to squamous epithelium lining the tonsillar crypts. Tissues from the gastrointestinal tract, pancreas, mesenteric nodes, spleen, and skin were all negative for viral antigens/RNA. Our novel findings strongly suggest that tonsillar crypt squamous epithelium supports active viral replication and represents an important source of viral shedding that facilitates person-to-person transmission by both the fecal-oral or oral-oral routes. It may also be a portal for viral entry. A correlation between viral infection and SCARB2 expression appears to be more significant than for PSGL-1 expression.

[A histopathological study on Influenza A H1N1 infection in humans].

OBJECTIVE: To find histopathological changes on major organs of Influenza A H1N1-infected patients and its relationship to clinical symptoms. METHODS: The autopsies were performed following conventional protocols and strict safety procedures. Tissue samples from all major organs of three cases were collected and fixed in 4% formalin. The histopathological changes on these samples were observed under a light microscope. RESULTS: The lungs of some damaged areas of three cases showed diffuse alveolar damage (DAD) with hyaline membranes formation and intra-alveolar edema and/or fibrin. Most areas of the lungs in the three cases showed necrotizing bronchiolitis, hemorrhage, secondary infection, thrombosis and focal alveolar necrosis. The lungs exhibited proliferation of pneumocytes and fibrosis of the interstitium in one case. In one case, the brain showed focal hemorrhage and focal liquefactive necrosis. In one case, the heart showed edema. CONCLUSION: The respiratory tract is the major target of influenza A H1N1 virus. The changes of DAD with secondary infection in the lung resulted in hypoxia, leading to multiple organ failure and death.

[Pathology of enterovirus 71 infection: an autopsy study of 5 cases].

OBJECTIVE: To study the clinicopathologic features of fatal enterovirus 71 (EV71) infection. METHODS: Autopsy was performed in 5 neonates died of EV71 infection. Tissue samples from major organs were collected, formalin-fixed and examined under light microscopy. Immunohistochemical study was carried out in selected examples. RESULTS: Four of the 5 cases showed predominant changes in central nervous system, with encephalitis and encephalomyelitis identified mainly in brainstem and upper cervical spinal cord. Histologic findings included neuronal degeneration and necrosis, neuronophagia, perivascular cuffing and diffuse or nodular hyperplasia of macrophages/microglia. Cerebral edema, brain herniation and aseptic meningitis were also noted. The lungs showed mainly pulmonary congestion, neurogenic pulmonary edema and focal hemorrhage. There were minimal changes in the intestinal epithelium. The intestinal lymphoid tissue however was hyperplastic and associated with apoptosis of follicular center cells. The remaining case had cerebral edema and mild meningitis. The lung alveolar septa were thickened with lymphocytic infiltrates. Some alveolar cells were hyperplastic and associated with diffuse hyaline membrane formation. No specific abnormalities were identified in gastrointestinal tract. In all the 5 cases studied, there was enlargement of lung hilar and mesenteric lymph nodes, coupled with apoptosis of follicular center cells. In general, no significant pathologic changes were demonstrated in heart, liver and kidneys. CONCLUSIONS: In fatal EV71 infection, the major pathologic changes lie in the central nervous system. The pulmonary lesions are mainly secondary in nature. The usual cause of death is cerebral edema complicated by brain herniation and pulmonary edema. It is also noteworthy that some cases show only lung damages, without classic neurologic changes.

[The clinical significance of a new classification algorithm in Chinese DLBCL cases].

OBJECTIVE: To investigate the clinicopathologic features, pathogenesis, diagnostic criteria and the relationship between different classification models and prognosis in Chinese patients with DLBCL, and try to look for the most appropriate classification model to predict clinical prognosis and therapeutic responses for Chinese patients with DLBCL. METHODS: 181 cases of Chinese DLBCLs diagnosed according to the WHO 2008 classification were collected. Standard two-step Envision method of immunohistochemical staining was used to assess the expressions of CD20, CD3ε, CD79a, CD10, Mum-1, Bcl-6, GCET-1, FOXP1 and Ki-67. The phenotypic classifications were assessed according to the standard of Hans model and Chan model. Data were analyzed by χ(2) test and Life Table survival analysis with the SPSS14.0 statistical package. RESULTS: The ratio of male to female in this cohort was 1.26:1. The median age of all patients was 57 yrs with the average age of 53.5 yrs. Of 61 cases (33.7%) primarily showed lymph node involvement. Gastrointestinal tract as the most involved extra-nodal organ was observed in 43 cases (35.8%). All patients with complete clinical follow-up materials survived from 1 - 120 months. The patients showed a high risk for death in the initial one and half years. Three year survival rate was 49.7% (90/181). Three year survival of 44 cases received R-CHOP (Rituximab, cyclophosphamide, doxorubicin, vincristine, bolus) was 76.9% (20/26), whereas 61.9% (60/97) in 119 cases received CHOP alone, R-CHOP group showed better prognosis (P = 0.017). All cases expressed one or more pan B cell markers, such as CD20 (176/179, 98.3%) and CD79a (62/77, 80.5%). For Hans model, 78 cases were classified as GCB group, while 103 cases as Non-GCB group. The ratio of Non-GCB to GCB was 1.32 without difference on the survival (P > 0.05). For the Chan's algorithm, 68 cases belonged to GCB subgroup, while 113 cases non-GCB subgroup. The ratio of non-GCB to GCB was 1.66. GCB subtype showed much better prognosis than non-GCB subtype according to Life Table survival analysis (P < 0.05). CONCLUSION: The epidemiology and clinicopathologic features of Chinese DLBCLs were similarly with the western cases. Chan's algorithm was a significant tool to predict the cell origin and clinical biology of Chinese DLBCLs.

[Clinicopathologic analysis of nodal marginal zone B cell lymphoma].

OBJECTIVE: To investigate the clinicopathologic features of primary nodal marginal zone B-cell lymphoma (NMZL). METHODS: Hematoxylin-Eosin staining and immunohistochemistry were used to evaluate the histological and immunophenotypic characteristics of lymph node (LN) tissue in 22 NMZL cases. Additionally, interphase fluorescence in-situ hybridization (FISH) was carried out to detect the presence of t(11;18) (q21;q21)/API2-MALT1 and/or t(14;18)(q32;q21)/IGH-MALT1 in 9 cases. RESULTS: The median age of the 22 patients was 62 (16 - 77) ys. The male-to-female ratio was 1.2:1. All patients exhibited asymptomatic lymphadenopathy with the cervical region as the most often site to be involved (n = 11), followed by axillary (n = 9), inguinal (n = 7), submandibular (n = 6), mediastinal (n = 4), supraclavicular (n = 2) and retroperitoneal lymph nodes (n = 1). The Ann Arbor stages were I/II in 13 (59%) cases and III/IV in 9 (41%). Immunohistochemical study showed a consistently strong expression of CD20 and an absence in the expression of CD3ε, CD10, CD21, CD23, CyclinD1 and BCL6 by the tumor cells in all the cases. Frequency of expression of CD5 and BCL2 were 39% (7/18) and 30% (3/14) respectively. Among the 9 cases performed with FISH, 2 cases harbored t(14;18)and another 1 case positive for t(11;18) and t(14;18). Complete follow-up data were available for 13 cases. The follow-up time was 6 to 44 months. 3 of them died. 3-year cumulative survival rate was 67%. CONCLUSIONS: NMZL patients are often elderly, which mainly present with multiple lymphadenopathy, rare involvement of extranodal organ and early stage. The diagnosis must be based on a combination of clinicopathologic features, especially those patients detected t(11;18) and/or t(14;18).

Morphological, immunophenotypic and molecular characterization of mature aggressive B-cell lymphomas in Chinese pediatric patients.

Differential diagnosis of Burkitt lymphoma (BL), diffuse large B-cell lymphoma (DLBCL) and B cell lymphoma, unclassifiable, with features intermediate between BL and DLBCL (intermediate BL/DLBCL) can be difficult. We studied 97 Chinese pediatric mature aggressive B-cell lymphomas including 81 BL cases, eight DLBCL cases and eight intermediate BL/DLBCL cases using immunohistochemistry, interphase fluorescence in situ hybridization (FISH) and Epstein-Barr virus (EBV) in situ hybridization. Our results showed that there were no significant differences in the expression of CD10 and BCL6 among cases of BL (91% and 86%, respectively), DLBCL (75% and 63%, respectively) and intermediate BL/DLBCL (75% and 63%, respectively) (p > 0.05). The expression of BCL2 (3% in BL, 50% in DLBCL, 50% in intermediate BL/DLBCL), expression of MUM1 (17% in BL, 63% in DLBCL, 63% in intermediate BL/DLBCL) and mean Ki-67 proliferation index (PI) (93% in BL, 83% in DLBCL, 80% in intermediate BL/DLBCL) were significantly different between BL and DLBCL and between BL and intermediate BL/DLBCL. The frequency of an extra copy of BCL6 (0% in BL, 37.5% in DLBCL, 25% in intermediate BL/DLBCL) and EBV-encoded RNA (EBER) positivity (48% in BL, 0% in DLBCL and intermediate BL/DLBCL) were also significantly different between BL and DLBCL and between BL and intermediate BL/DLBCL. The frequency of C-MYC rearrangement in BL (98%) was much higher than in DLBCL (37.5%) and intermediate BL/DLBCL (50%). Our findings suggest that diagnosis of the mature aggressive B-cell lymphomas in pediatrics should be based on the comprehensive review and integration of morphological, immunohistochemical and molecular genetic features. The expression of CD10 and BCL6 but not BCL2, a high Ki-67 PI (>90%) and a C-MYC rearrangement but not BCL2 or BCL6 rearrangement are the features of BL. MUM1 is not an exclusionary diagnostic marker for BL. As the immunophenotype and molecular genetic features of DLBCL and intermediate BL/DLBCL are similar, intermediate BL/DLBCL is more likely a subgroup of DLBCL in the pediatric population. Regardless of the expression of CD10 and BCL6, strong staining for BCL2, Ki-67 PI below 90% and the presence of extra copies of BCL6 favor a diagnosis of DLBCL or intermediate BL/DLBCL.