Neuronal infection is a major pathogenetic mechanism and cause of fatalities in human acute Nipah virus encephalitis.

OBJECTIVES: Acute Nipah (NiV) encephalitis is characterised by a dual pathogenetic mechanism of neuroglial infection and ischaemia-microinfarction associated with vasculitis-induced thrombotic occlusion. We investigated the contributions of these two mechanisms in fatal cases. MATERIALS AND METHODS: We analysed brain tissues (cerebrum, brainstem and cerebellum) from 15 autopsies using light microscopy, immunohistochemistry (IHC), in situ hybridisation and quantitative methods. RESULTS: Three types of discrete plaque-like parenchymal lesions were identified: Type 1 with neuroglial IHC positivity for viral antigens and minimal or no necrosis; Type 2 with neuroglial immunopositivity and necrosis; and Type 3 with necrosis but no viral antigens. Most viral antigen/RNA-positive cells were neurons. Cerebral glial immunopositivity was rare, suggesting that microinfarction played a more important role in white matter injury. Type 1 lesions were also detected in the brainstem and cerebellum, but the differences between cerebral cortex and these two regions were not statistically significant. In the cerebral cortex, Type 1 lesions overwhelmingly predominated, and only 14% Type 1 vs 69% Type 2 lesions were associated with thrombosis. This suggests that neuronal infection as a mechanism of pathogenesis was more important than microinfarction, both in general and in Type 1 lesions in particular. Between the 'early' group (<8-day fever) and the 'late' group (≥8-day fever), there was a decrease of Type 1 and Type 2 lesions with a concomitant increase of Type 3 lesions, suggesting the latter possibly represented late-stage microinfarction and/or neuronal infection. CONCLUSION: Neuronal infection appears to play a more important role than vasculopathy-induced microinfarction in acute NiV encephalitis.

HER2 testing by immunohistochemistry in breast cancer: A multicenter proficiency ring study.

BACKGROUND: Human epidermal growth factor receptor 2 (HER2) over-expression in breast cancer is associated with aggressive tumor behavior and predicts response to targeted therapy. Accurate HER2 result is paramount for optimal patient management. However, routine HER2 immunohistochemistry (IHC) testing are subjected to intra- and inter-laboratory variability. OBJECTIVE: This study aims to determine inter-laboratory variation in HER2 IHC testing through a slide-exchange program between five main reference laboratories. METHOD: A total of 20 breast carcinoma cases with different known HER2 expression and gene status were selected by the central laboratory in five testing rounds. Three unstained tissue sections from each case were sent to participating laboratories, which immunostained and interpreted the HER2 immunohistochemistry result. One of the stained slides was sent to one designated participating laboratory for evaluation. Results were analyzed by the central laboratory. RESULTS: A complete concordance was achieved in six IHC-positive and six IHC-negative cases, its gene status of which was confirmed by in-situ-hybridization (ISH) study. The discordant results were observed in six equivocal cases, one negative case and one positive case with a concordance rate of 50-88.3%. Interestingly, the negative discordant case actually displays tumor heterogeneity. Good inter-observer agreement was achieved for all participating laboratories (k = 0.713-1.0). CONCLUSION: Standardization of HER2 testing method is important to achieve optimum inter-laboratory concordance. Discordant results were seen mainly in equivocal cases. Intra-tumoral heterogeneity may impact the final HER2 IHC scoring. The continuous quality evaluation is therefore paramount to achieve reliable HER2 results.

Programmed Death Ligand 1: A Poor Prognostic Marker in Endometrial Carcinoma.

Endometrial carcinoma is the only gynaecologic malignancy with a raising incidence and mortality, posing a major health concern worldwide. The upregulation of programmed death ligand 1 (PD-L1) on tumour cells causes T-cell suppression, which impedes antitumour immunity, promotes immune cell evasion and enhances tumour survival. The aim of this study was to evaluate PD-L1 expression in endometrial carcinoma and to correlate it with survival rate. A total of 59 cases of endometrial carcinoma were evaluated. Thirty-two cases of non-neoplastic endometrial tissue were included as control. PD-L1 immunohistochemistry was performed on all cases. PD-L1 expression was evaluated on tumour cells and immune cells. PD-L1 was positive in 62.7% (37/59) and 28.8% (17/59) of immune cells and tumour cells, respectively. PD-L1 expression in immune cells was significantly higher in endometrial carcinoma than in non-neoplastic endometrium (p < 0.001). Among the patients with endometrial carcinoma, PD-L1 expression in tumour cells was significantly higher in patients who died (10/15, 66.7%) compared to those who survived (7/44, 15.9%) (p < 0.001). It is noteworthy to point out that the expression of PD-L1 in tumour cells was significantly associated with a poor survival. This suggests that immunomodulation using PD-L1 inhibitors may be useful in advanced endometrial carcinoma.

Diagnostic Value of the EZH2 Immunomarker in Malignant Effusion Cytology.

BACKGROUND: Differentiating reactive mesothelial cells from metastatic carcinoma in effusion cytology is a challenging task. The application of at least 4 monoclonal antibodies including 2 epithelial markers (Ber-EP4, MOC-31, CEA, or B72.3) and 2 mesothelial markers (calretinin, WT-1, CK5/6, or HBME-1) are often useful in this distinction; however, it is not readily available in many resource-limited developing countries. Aberrant immunoexpression of enhancer of zeste homolog 2 (EZH2), a transcriptional repressor involved in cancer progression, is observed widely in various malignancy. In this study, we evaluate the diagnostic value of EZH2 as a single reliable immunomarker for malignancy in effusion samples. METHODS: A total of 108 pleural, peritoneal, and pericardial effusions/washings diagnosed as unequivocally reactive (n = 41) and metastatic carcinoma (n = 67) by cytomorphology over 18 months were reviewed. Among the metastatic carcinoma cases, 54 were adenocarcinoma and others were squamous cell carcinoma (n = 1), carcinosarcoma (n = 1), and carcinoma of undefined histological subtypes (n = 11). Cell block sections were immunostained by EZH2 (Cell Marque, USA). The percentages of EZH2-immunolabeled cells over the total cells of interest were calculated. Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal cut-off score to define EZH2 immunopositivity. RESULTS: A threshold of 8% EZH2-immunolabeled cells allows distinction between malignant and reactive mesothelial cells, with 95.5% sensitivity, 100% specificity, 100% positive predictive value, and 93.2% negative predictive value (p < 0.0001). The area under the curve was 0.988. CONCLUSION: EZH2 is a promising diagnostic biomarker for malignancy in effusion cytology which is inexpensive yet trustworthy and could potentially be used routinely in countries under considerable economic constraints.

Cutaneous Vasculitis as Early Presentation of Eosinophilic Granulomatosis with Polyangiitis without Systemic Symptoms.

Eosinophilic granulomatosis with polyangiitis (formerly known as Churg-Strauss syndrome) is a rare vasculitis in children. It commonly presents with respiratory symptoms, especially asthma, allergic rhinitis, and peripheral eosinophilia. Involvement of other systems, such as renal and cardiac, may carry a poor prognosis. Anti-neutrophil cytoplasmic antibodies have been found less frequently in children with this condition. We report a case of a 15-year-old male who presented with indurated and pruritic papules on both legs and peripheral eosinophilia without other system involvement. Histopathological findings from a skin biopsy were suggestive of eosinophilic granulomatosis with polyangiitis. Anti-neutrophil cytoplasmic antibodies were negative.

Refractory Adult Onset Still's Disease.

It is often a challenge and a dilemma for clinicians encountering patients with pyrexia of unknown origin. Numerous tests performed to determine the underlying cause often give inconclusive results. We present a 52-year-old man with undulating fever for more than 10 months with persistent hyperferritinaemia, and negative immunological and serological markers. Despite corticosteroids, disease modifying anti-rheumatic agents and immune-modulator therapy, he succumbed to the illness. A diagnosis of refractory Adult onset Still's disease complicated by haemophagocytic lymphohistiocytosis was made.

Helicobacter pylori, ethnicity, and the gastroesophageal reflux disease spectrum: a study from the East.

BACKGROUND: Ethnic differences in gastroesophageal reflux disease (GERD) and its complications as well as racial variations in the prevalence of Helicobacter pylori infection are well documented. Nevertheless, the association between reflux disease, H. pylori, and race has not been adequately explored. AIMS: We estimated the strength of the association between H. pylori, ethnicity, and the gastroesophageal reflux disease (GERD) spectrum, including Barrett's esophagus, in Asian patients presenting for endoscopy in a tertiary referral center. METHODS: Prospectively, we studied 188 consecutive patients with GERD, short- and long-segment Barrett's esophagus, and controls. All patients underwent gastroscopy with gastric biopsies to assess H. pylori, gastritis, and atrophy. CagA status and H. pylori infection were determined by immunoblot assay. RESULTS: The overall prevalence of H. pylori infection was 52.1% (of which 77.6% were cagA(+)) and was lowest in the long-segment Barrett's esophagus group (36.7%) (p = .048). When Barrett's esophagus was present, the length of abnormality was 44.8% shorter in the presence of H. pylori (p = .015). Indians had the highest prevalence of H. pylori (75%) and Malays the lowest (19.6%) (p < .001). In Indians, increased prevalence of H. pylori and cagA-positive strains was associated with reduced severity of GERD (p < .004 and p < .001, respectively), a trend not apparent in the other races. Corpus atrophy, which was almost exclusively associated with H. pylori, was highest in Indians as compared to the other races (p = .013). CONCLUSIONS: Presence of H. pylori was associated with a reduced severity of GERD spectrum disease in Asians, especially Indians. H. pylori infection may protect against complicated reflux disease via induction of corpus atrophy.

Ethnic differences in the prevalence of endoscopic esophagitis and Barrett's esophagus: the long and short of it all.

Recent studies indicate that the prevalence of gastroesophageal reflux disease in Asia is either increasing or better recognized. There is a paucity of reliable data on the prevalence of reflux disease in the various races in general and in Malaysia, in particular. The prevalence of erosive esophagitis and Barrett's esophagus in a multiethnic Malaysian population was studied, as well as the relationship of various factors associated with reflux disease. Chinese, Malay, and Indian patients undergoing gastroscopy in a tertiary referral center were assessed for the presence of esophagitis, hiatus hernia, and Barrett's esophagus. Patient demographics and risk factors associated with gastroesophageal reflux disease were also documented. The prevalence of endoscopically documented esophagitis among 1985 patients was 6.1%, the majority of which were mild, Grade I or II (88%). There was a preponderance of Indians with esophagitis, as well as males (P < 0.05) and those with the presence of a hiatus hernia (P < 0.01). Long-segment Barrett's esophagus was found in 1.6% of patients, and short-segment Barrett's in 4.6%. Indians had the highest prevalence of Barrett's esophagus compared with Chinese (P < 0.05) or Malays (P < 0.01). Hiatus hernia and erosive esophagitis were both positively associated with Barrett's metaplasia (P < 0.01). A significant proportion of Malaysian patients undergoing endoscopy has mild reflux esophagitis and Barrett's esophagus. Indian ethnicity and the presence of a hiatus hernia were significantly associated with endoscopic esophagitis and Barrett's metaplasia. These observed racial differences warrant further study.

Flat colonic adenomas in Malaysia: fact or fancy?

BACKGROUND: Some two-thirds of colorectal carcinomas arise from adenomatous polyps, and as such, screening by colonoscopy and polyp removal should significantly reduce colorectal cancer. This has not been the case, as evidenced by recent studies, which revealed that endoscopy failed to prevent up to 50% of all subsequent carcinomas. Flat or depressed adenomas, frequently reported from Japan but rarely elsewhere, might explain the 'missed carcinomas.' Detection of flat adenomas has not been previously reported from Malaysia. METHODS: In the present prospective study, 426 consecutive patients underwent colonoscopic examination between March 1997 and January 2000, for a variety of bowel symptoms. The examinations were performed by an experienced endoscopist using a standard colonoscope and methylene blue dye spraying technique. Macroscopically, flat adenomas were defined using the criteria proposed by Sawada. RESULTS: Twenty-nine adenomas were identified in 12 patients, of which 15 were polypoid and 14 were flat, with no depressed lesions. Eight polypoidal lesions and all the flat adenomas contained mild or moderate areas of epithelial dysplasia. Seven severely dysplastic polyps were identified. One Duke's A polypoidal cancer and two advanced carcinomas were also found. All the severely dysplastic lesions and Duke's A carcinomas were found in polyps greater than 10 mm in mean size. The flat adenomas were all less than 5 mm in size. CONCLUSIONS: A significant proportion of colonic adenomas in Malaysian patients appear as small flat lesions, which could easily be missed during endoscopy. Increased recognition and treatment of flat adenomas among colonoscopists is warranted.

Epstein-Barr virus (EBV) and gastric carcinoma in Malaysian patients.

Epstein-Barr virus (EBV) has consistently been detected in the tumour cells of nasopharyngeal carcinoma and lymphoepithelial-like carcinoma of the salivary glands, and have occasionally been found in similar tumours at other sites. Moreover, recent studies from various parts of the world including the Orient have shown about 10% of gastric carcinomas to be EBV-associated. We studied 50 gastric carcinomas from Malaysia to investigate its association with EBV in the Malaysian population. They comprised 37 intestinal and 13 diffuse type carcinomas from 32 male and 18 female patients, age range from 29 to 86 years with an ethnic distribution of Malay: Chinese: Indian with the ratio of 4: 27: 19. EBV gene and gene-expression were examined in sections of formalin-fixed, paraffin-embedded tissue using commercially available probes for detecting EBV encoded RNAs (EBERs) by in situ hybridization and monoclonal antibodies to EBV latent membrane protein-1 (LMP-1) by standard immunohistochemistry. Five of 50 gastric carcinomas showed EBER intranuclear positivity in all tumour cells but no cases expressed LMP-1. The EBV-associated cases were classified as intestinal type in 4 and diffuse type in one case and all were histologically unremarkable. EBV-positive tumours were found in 3 Chinese and 2 Indian patients with none in the small Malay group. Four EBV-positive tumours were in male patients, with age-range of 65 to 86 years. We conclude that our findings of about 10% of Malaysian gastric carcinomas being EBV-associated is in line with the results from other parts of the world and from other ethnic groups.