Interaction of a dengue virus NS1-derived peptide with the inhibitory receptor KIR3DL1 on natural killer cells

Killer immunoglobulin-like receptors (KIRs) interact with human leucocyte antigen (HLA) class I ligands and play a key role in the regulation and activation of NK cells. The functional importance of KIR-HLA interactions has been demonstrated for a number of chronic viral infections, but to date only a few studies have been performed in the context of acute self-limited viral infections. During our investigation of CD8(+) T cell responses to a conserved HLA-B57-restricted epitope derived from dengue virus (DENV) non-structural protein-1 (NS1), we observed substantial binding of the tetrameric complex to non-T/non-B lymphocytes in peripheral blood mononuclear cells (PBMC) from a long-standing clinical cohort in Thailand. We confirmed binding of the NS1 tetramer to CD56(dim) NK cells, which are known to express KIRs. Using depletion studies and KIR-transfected cell lines, we demonstrated further that the NS1 tetramer bound the inhibitory receptor KIR3DL1. Phenotypical analysis of PBMC from HLA-B57(+) subjects with acute DENV infection revealed marked activation of NS1 tetramer-binding natural killer (NK) cells around the time of defervescence in subjects with severe dengue disease. Collectively, our findings indicate that subsets of NK cells are activated relatively late in the course of acute DENV illness and reveal a possible role for specific KIR-HLA interactions in the modulation of disease outcomes.

Surgical management of recurrent pyogenic cholangitis: 10 years of experience in a tertiary referral centre in Hong Kong

BACKGROUND

Recurrent pyogenic cholangitis (RPC) is common in Asia. Its management differs from centre to centre.

METHODS

A retrospective review of 80 patients undergoing surgery for RPC was performed. Immediate and longterm outcomes were analysed.

RESULTS

All patients underwent hepaticocutaneousjejunostomy (HCJ) for biliary drainage and stone removal. Additional hepatectomy was performed in 38 patients with intrahepatic ductal stricture or liver segmental atrophy. Twenty-three patients had residual stones and 25 had recurrent stones. All patients with residual stones underwent repeated choledochoscopy (median: four sessions) for stone removal and obtained confirmation of ductal clearance. Four patients developed cholangiocarcinoma, of which two died. The complication rate was 17.5%. Most of the complications were wound infections. No mortality related to surgery occurred. Multivariate analysis found that gender, disease extent (unilobar versus bilobar) and surgery type (HCJ alone versus HCJ with hepatectomy) were not associated with increased risk for residual or recurrent stones. A raised preoperative bilirubin level was the only risk factor identified as associated with an increased risk for recurrent stones (P < 0.001); it was not associated with an increased risk for residual stones.

CONCLUSIONS

Recurrent pyogenic cholangitis is a distinct disease, the management of which requires a high level of surgical expertise. Hepaticojejunostomy is recommended as the primary drainage procedure, but hepatectomy should be reserved for complicated RPC.

Accuracy of BRCA1/2 mutation prediction models for different ethnicities and genders: experience in a southern Chinese cohort

Background

BRCA1/2 mutation prediction models (BRCAPRO, Myriad II, Couch, Shattuck-Eidens, BOADICEA) are well established in western cohorts to estimate the probability of BRCA1/2 mutations. Results are conflicting in Asian populations. Most studies did not account for gender-specific prediction. We evaluated the performance of these models in a Chinese cohort, including males, before BRCA1/2 mutation testing.

Methods

The five risk models were used to calculate the probability of BRCA mutations in probands with breast and ovarian cancers; 267 were non-BRCA mutation carriers (247 females and 20 males) and 43 were BRCA mutation carriers (38 females and 5 males).

Results

Mean BRCA prediction scores for all models were statistically better for carriers than noncarriers for females but not for males. BRCAPRO overestimated the numbers of female BRCA1/2 mutation carriers at thresholds ≥20% but underestimated if <20%. BRCAPRO and BOADICEA underestimated the number of male BRCA1/2 mutation carriers whilst Myriad II underestimated the number of both male and female carriers. In females, BRCAPRO showed similar discrimination, as measured by the area under the receiver operator characteristic curve (AUC) for BRCA1/2 combined mutation prediction to BOADICEA, but performed better than BOADICEA in BRCA1 mutation prediction (AUC 93% vs. 87%). BOADICEA had the best discrimination for BRCA1/2 combined mutation prediction (AUC 87%) in males.

Conclusions

The variation in model performance underscores the need for research on larger Asian cohorts as prediction models, and the possible need for customizing these models for different ethnic groups and genders.

Cross-sectional survey on the knowledge, attitude and practice of male Filipino seafarers on sexual health

The Philippines is currently the world's leading supplier of seafarers aboard foreign vessels, accounting for nearly a quarter of the world's maritime industry. Seafarers, being mobile, have a significant contribution impact on the worldwide spread of infectious diseases such as sexually transmitted infections (STIs). This study aims to determine the level of knowledge, as well as the attitudes and practices (KAP) of male Filipino seafarers regarding sexual health. A cross-sectional survey was administered through convenience sampling of male Filipino seafarers. The respondents showed the least knowledge about prevention, followed by transmission of STIs. The respondents showed adequate knowledge about risk factors such as multiple sex partners, and about transmission such as vertical spread. In addition, the respondents indicated their attitude and level of responsibility in informing their sexual partners in case they contract STIs and avoidance of high-risk partners. They also showed attitudes that predispose them to high-risk behaviour such as decreased sexual sensation caused by use of condoms and added pleasure in having intercourse with strangers. The majority of respondents were sexually active. Most have STI/HIV screening as part of their pre-employment medical exam. Positive practices include use of condoms, voluntary medical evaluation for STI's, and avoidance of high-risk partners. Negative practices include going to bars closely linked with prostitution, and most of the respondents had had sexual intercourse with sex workers overseas. Male seafarers appear to have double standards regarding women as sexual partners - about half had intercourse outside their stable relationships. They perceive protection as their sole discretion.

Family with three apparently balanced t(3;15) (p27;q22) translocation carriers. Association with deficits in language acquisition and mental retardation: a possible example of position effect in man

A father, son, and daughter had a (3;15) (p27;q22) simple reciprocal translocation. No abnormality in the G-banding pattern was noted. The girl was most severely affected; she had an abnormal phenotype, noticeable delay in receptive and expressive language development, bilateral hearing impairment, and definite mental retardation. The boy had a moderate delay in receptive language skills, had moderate hearing impairment in one ear, and showed mild mental retardation. The father has low-set ears, some deficits in receptive language skills, is illiterate, and was found to be borderline mentally retarded. The mother and younger child do not have the translocation and are normal in terms of phenotype, intellect, and verbal skills. The accumulating evidence suggests that balanced translocations are associated with an increased frequency of intellectual deficit and congenital anomalies, and the cytogenetic mechanism may be that of position effect.