[Pulmonary pathology in fatal human influenza A (H1N1) infection].

OBJECTIVE: To study the pulmonary pathology in patients died of fatal human influenza A(H1N1) infection. METHODS: Eight cases of fatal human influenza A (H1N1) infection, including 2 autopsy cases and 6 paramortem needle puncture biopsies, were enrolled into the study. Histologic examination, immunohistochemitry, flow cytometry and Western blotting were carried out. RESULTS: The major pathologic changes included necrotizing bronchiolitis with surrounding inflammation, diffuse alveolar damage and pulmonary hemorrhage. Influenza viral antigen expression was detected in the lung tissue by Western blotting. Immunohistochemical study demonstrated the presence of nuclear protein and hemagglutinin virus antigens in parts of trachea, bronchial epithelium and glands, alveolar epithelium, macrophages and endothelium. Flow cytometry showed that the apoptotic rate of type II pneumocytes (32.15%, 78.15%) was significantly higher than that of the controls (1.93%, 3.77%). CONCLUSION: Necrotizing bronchiolitis, diffuse alveolar damage and pulmonary hemorrhage followed by pulmonary fibrosis in late stage are the major pathologic changes in fatal human influenza A (H1N1) infection.

[The pathological feature of primary hepatic carcinoma on explanted liver and its significance].

OBJECTIVE: To investigate the pathological feature of primary hepatic carcinoma and the clinical significance. METHODS: From August 2000 to December 2007, there were 89 patients with cirrhosis and carcinoma of liver who accepted whole liver resection. The whole liver was cut into 10 mm slices to examine the tumor size, number, distribution, capsule, satellite nodes, portal vein tumor thrombi (PVTT). The invaded adjacent tissue and lymph nodes were recorded, the distance from satellite to major tumor was measured, then histological examinations were carried out, and the final diagnosis was made by pathologists. RESULTS: The total of 89 cases included hepatocellular carcinoma in 86 cases and cholangiocarcinoma in 3 cases; 53 cases with multiple tumors and 36 cases with solitary tumor; complete capsule only in 14 cases, no obvious margin in 11 cases, 13 cases had a major tumor in the right lobe and a small tumor in the left lobe; 8 of 25 cases with gross invaded tissue were confirmed by histological examination, 7 of 16 cases with swollen lymph nodes were infiltrated by cancer cells. There were 47 cases with PVTT (47.2%) and 39 cases with satellite nodes (43.8%). PVTT and satellite nodes increased with the increase of sizes and the numbers of the tumors. The distance from satellite node to major tumor mostly were 0.5 - 3.0 cm. CONCLUSIONS: The whole explanted liver can completely reflect the characteristics of growth and infiltration of hepatic carcinoma. Attention must be paid to the small cancer lesions in another lobe, distal satellite nodes from major tumor, and tumor thrombi in a small branch of portal vein, which can not be found by imaging, and might influence the curative effectiveness after liver resection or transplantation.

[Expression of co-stimulators in ulcerative colitis and its pathologic significance].

OBJECTIVE: To study the expression and localization of co-stimulators in the mucosa of patients with ulcerative colitis (UC), and to explore its role in the pathogenesis of UC. METHODS: Expression of co-stimulators CD86 and inducible co-stimulator (ICOS) was studied by immunohistochemistry on paraffin-embedded mucosal tissue from patients with active UC (64 cases), inactive UC (51 cases) and normal controls (20 cases). Immunostaining for CD28 was also carried out on frozen fresh mucosal tissue sampled from patients with active UC (7 cases), inactive UC (2 cases) and normal controls (5 cases). In addition, expression of CD4, CD8 and CD20 were also examined. RESULTS: In active UC, increased expression of CD86 was not only observed in lamina propria mononuclear cells but also in the intestinal epithelial cells, as compared with inactive UC and the normal controls (P < 0.01). Increased ICOS expression in lamina propria mononuclear cells was detected in active UC, as compared with inactive UC and the normal controls (P < 0.01). Increased ICOS expression in intestinal epithelial cells was also seen in active UC, as compared with that of inactive UC (P < 0.01). The expression of CD86 was higher in inactive UC than in the normal controls (P < 0.05 or P < 0.01). However, the expression of ICOS showed no statistically significant difference between inactive UC and normal controls. Increased expression of CD28 in active UC, compared with that in inactive UC and normal controls, was also noticed (P < 0.05 or P < 0.01). The number of CD4 or CD8-positive intraepithelial lymphocytes and lymphocytes infiltrating in the lamina propria and small vessel walls was much higher in active UC than in inactive UC and normal controls (P < 0.01). Moreover, the ratio of CD4/CD8 was highest in active UC (P < 0.01). The number of CD20-positive B lymphocytes in lamina propria was also higher in active UC than in inactive UC and normal controls (P < 0.01). CONCLUSIONS: In active UC, CD86 and ICOS were over-expressed in the intestinal epithelial cells and lamina propria mononuclear cells. The phenomenon suggests that abnormal expression of co-stimulators may contribute to the deregulation of acquired immune responses in UC.

[Expression of co-stimulatory molecule CD86 and its inducible co-stimulator in Crohn disease and their pathologic significance].

OBJECTIVE: To investigate the expression of co-stimulatory molecule CD86 and inducible co-stimulator(ICOS) in the intestinal mucosa of Crohn disease (CD) and to exlpore its pathologic significance. METHODS: Expression of co-stimulator CD86 and ICOS was examined by immunohistochemistry on paraffin embedded tissue from patients with CD (30 cases) and normal controls (20 cases). The subsets of lamina propria mononuclear cells (LPMC) were also analysed via immunostaining for CD4, CD8 and CD20. RESULTS: Increased amount of CD86 or ICOS positive LPMC was observed in the lesional area of CD when compared with the essentially normal area of CD and normal controls (q=9.23,P<0.01 and q=5.46,P<0.01). In addition, the expression of CD86 or ICOS was higher in intestinal epithelium of CD than that in normal controls(H=24.93,P<0.01 and H=4.66,P<0.01), whereas no significant difference was seen between the diseased and the essentially normal area of CD. The amount of CD4 or CD8 positive lymphocytes in lamina propria, epithelium and small vascular walls was also significantly increased in CD than that in normal controls (P<0.05 or P<0.01). CONCLUSION: Increased amount of CD86 or ICOS positive LPMC and enterocytes in CD suggests that co-stimulatory molecules may play a role in the pathogenesis of CD. The enterocytes may act as non-specific antigen presenting cells in the process of cellular immunity activation in CD.

[Molecular confirmation of enterovirus type 71 infection: a post-mortem study of two cases].

OBJECTIVE: To investigate the diagnostic application of molecular detection of enterovirus type 71 (EV71) infection using post-mortem paraffin-embedded tissue. METHODS: Two autopsy cases of EV71 infection were studied by histopathological and immunohistochemical methods. Reverse transcription polymerase chain reaction (RT-PCR) was performed to detect the viral RNA in paraffin-embedded tissue samples. RESULTS: Characteristic features of acute encephalitis were seen in the brain, with most prominent lesions found in the brain stem in both cases. Inflammatory cells were largely CD68-positive microglia with a few CD15-positive neutrophils in the areas of neuronal necrosis. The 5'-untranslated region of EV71 was detected in the medulla by RT-PCR using paraffin-embedded tissues of both cases. Sequencing analysis of the RT-PCR products showed 100% homology to the EV71 strain, recently submitted to the GenBank database from Fuyang, Anhui province. CONCLUSIONS: Molecular detection of EV71 can be performed on formalin-fixed, paraffin-embedded tissue samples from fatally infected patients. Timely and accurate diagnosis of the infection by such molecular approach is crucial for the proper clinical and public health intervention.

[Expression of SARS-CoV in various types of cells in lung tissues].

OBJECTIVE: To investigate the cell types infected by severe acute respiratory syndrome-associated coronavirus (SARS-CoV) in lung tissues and explore the mechanism of lung injury in SARS. METHODS: In-situ hybridization(ISH) and immunohistochemistry(IHC) double staining was applied to study the lung tissues from 7 SARS cases of Beijing and one of Anhui province. According to SARS-CoV genome sequence, the cDNA probe was synthesized and labelled by digoxin. Immunohistochemically, antibodies of cytokeratin(CK), CD34, CD68, Vimentin and CD3 were applied to demonstrate bronchial epithelial cells, type II pneumocytes, endothelial cells, macrophages, fibroblasts and T cells respectively. RESULTS: The positive results of in-situ hybridization showed that the lung tissues of all cases expressed SARS-CoV RNA, and positive signals displayed in cytoplasms (purple-blue, NBP-BCIP. ISH-IHC double staining showed that positive signals of both ISH (purple-blue NBT-BCIP and IHC (red-brown, AEC expressed in the cytoplasms (purple and red). The positive results of double staining indicated that bronchial epithelial cells, type II pneumocytes, endothelial cells, macrophages, fibroblasts and T lymphocytes were diffusely infected by SARS-CoV. CONCLUSION: This study of ISH-IHC double staining in lung tissues of SARS patients showed that bronchial epithelial cells, type II pneumocytes, endothelial cells, macrophages, T lymphocytes and fibroblasts were attacked diffusely in SARS lungs. Various types of cells damaged by SARS-CoV and inflammatory mediators released by those cells play an important role in the pathogenesis of lung injury in SARS.

[Lung pathology and pathogenesis of severe acute respiratory syndrome: a report of six full autopsies].

OBJECTIVE: Severe acute respiratory syndrome (SARS) is an emerging infectious disease that first manifested in humans in November 2002. The SARS-associated coronavirus (SARS-CoV) has been identified as the causal agent, but the pathology and pathogenesis are still not quite clear. METHODS: Post-mortem lung samples from six patients who died from SARS from April to July 2003 were studied by light and electron microscopy, Masson trichromal staining and immunohistochemistry. Evidence of infection with the SARS-CoV was determined by reverse-transcription PCR (RT-PCR) , serological examination and electron microscopy. RESULTS: Four of six patients had serological and RT-PCR evidence of recent infection of SARS-CoV. Morphologic changes are summarized as follows: (1) Diffuse and bilateral lung consolidation was seen in all patients (6/6) with increasing lung weight. (2) Diffuse alveolar damage was universal (6/6) with hyaline membrane formation (6/6), intra-alveolar edema/hemorrhage (6/6), fibrin deposition (6/6), pneumocyte desquamation (6/6). A marked disruption in the integrity of the alveolar epithelium was confirmed by immunostaining for the epithelial marker AE1/AE3 (6/6). (3) Type II pneumocytes, with mild hyperplasia, atypia, cytomegaly with granular amphophilic cytoplasm and intracytoplasmic lipid accumulation (5/6). (4) Giant cells in the alveoli were seen in five of 6 patients (5/6) , most of which were positive for the epithelial marker AE1/AE3 (5/6), but some cells were positive for the macrophage marker CD68(2/6). (5) A pronounced increase of macrophages were seen in the alveoli and the interstitium of the lung (6/6), which was confirmed by histological study and immunohistochemistry. (6) Haemophagocytosis was present in five of the 6 patients(5/6). (7) Lung fibrosis was seen in five patients(5/6), with alveolar septa and interstitium thickening(5/6), intraalveolar organizing exudates (6/6) and pleura thickening (4/6). Proliferation of collagen was confirmed by Masson trichromal staining, most of which was type III collagen by immunostaining. The formation of distinctive fibroblast/myofibroblast foci was seen in five patients (5/6) by light microscopy and immunochemistry. (8) Squamous metaplasia of bronchial mucosa was seen in five patients(5/6). (9) Thrombi was seen in all patients(6/6). (10) Accompanying infection was present in two patients, one was bacteria, the other was fungus. In addition, electron microscopy revealed viral particles in the cytoplasm of alveolar epithelial cells and endothelial cells corresponding to coronavirus. CONCLUSION: Direct injury of SARS-CoV on alveolar epithelium, prominent macrophage infiltration and distinctive fibroblast/myofibroblast proliferation may play major roles in the pathogenesis of SARS.

Pathophysiological significance of a reaction in mouse gastrointestinal tract associated with delayed-type hypersensitivity.

AIM: To explore the pathophysiological significance of delayed type hypersensitivity (DTH) reaction in mouse gastrointestinal tract induced by an allergen 2,4-dinitrochlorobenzene (DNCB). METHODS: BALB/c mice were randomly divided into control and DTH(1-6) groups. After sensitized by DNCB smeared on the abdominal skin, the mice were challenged with DNCB by gavage or enema. The weight, stool viscosity and hematochezia were observed and accumulated as disease active index (DAI) score; the gastrointestinal motility was represented by active charcoal propulsion rate; the colon pathological score was achieved by macropathology and HE staining of section prepared for microscopy; and the leukocyte migration inhibitory factor (LMIF) activity was determined by indirect capillary assay of the absorbance (A) of migrated leukocytes. RESULTS: Active charcoal propulsion rates of small intestine in the DNCB gavages groups were significantly higher than that in the control group (P<0.01). The DAI scores and pathological score in DNCB enema groups were also higher than that in the control group (P<0.05), and there were significant rises in LMIF activity in DNCB enema groups as compared with control groups (P<0.01). CONCLUSION: Mouse gastrointestinal DTH reaction could be induced by DNCB, which might facilitate the mechanism underlying the ulcerative colitis.