KIR genotype and haplotype frequencies in the multi-ethnic population of Malaysia.

Killer cell immunoglobulin-like receptors (KIR) genotype and haplotype frequencies have been reported to vary distinctly between populations, which in turn contributes to variation in the alloreactivity of natural killer (NK) cells. Utilizing the diverse KIR genes to identify suitable transplant donors would prove challenging in multi-ethnic countries, even more in resource-limited countries where KIR genotyping has not been established. In this study, we determined the KIR genotypes from 124 unrelated Malaysians consisting of the Malays, Chinese, Indians, and aboriginal people through polymerase chain reaction sequence-specific primer (PCR-SSP) genotyping and employing an expectation-maximization (EM) algorithm to assign haplotypes based on pre-established reference haplotypes. A total of 27 distinct KIR haplotypes were discerned with higher frequencies of haplotype A (55.2%) than haplotype B (44.8%). The most frequent haplotypes were cA01:tA01 (55.2%), cB01:tB01 (18.1%), and cB02:tA01 (13.3%), while the least frequent haplotypes were cB03:tB01 (1.2%), cB04:tB03 (0.4%), and cB03:tA01 (0.4%). Several haplotypes were identified to be unique to a specific ethnic group. The genotype with the highest frequency was genotype AB (71.8%), followed by AA (19.4%), and BB (8.9%). The Indians exhibited the lowest genotype AA but the highest genotype BB, whereas genotype BB was absent in the aboriginal people. Despite the limitations, the genotype and haplotypes in the Malaysian population were successfully highlighted. The identification of ethnic-specific KIR genotypes and haplotypes provides the first step to utilizing KIR in identifying suitable transplant donors to further improve the transplant outcome in the Malaysian population.

Randomised controlled trial to assess and compare the performance and safety of two-piece ostomy appliances.

BACKGROUND: Choice of ostomy appliances is based on multiple factors including economic considerations, individual patient requirements and lifestyle. A recently launched two-piece ostomy collection device with an extended tape border is expected to provide a long wear time and increase patients' sense of security. AIMS AND METHODS: A randomised controlled, non-blinded, cross-over study involving 38 patients (with colostomies and ileostomies) compared the test device to a similar device from the same manufacturer but without the tape border. The main objective was to assess wear time for non-inferiority as a measure of efficacy. Secondary efficacy assessment included peristomal skin condition using the DET (discolouration, erosion and tissue growth) score and patient acceptability, which was assessed through questionnaires using Likert-scale options. Safety was assessed according to the incidence and intensity of device-related adverse events, and the condition of the peristomal skin. RESULTS AND CONCLUSION: Analysis of results in the per-protocol population showed an average wear time of 4.5 days for both devices and demonstrated non-inferiority. DET scores were similar in both groups, and both had low rates of device-related adverse events, all of which related to peristomal skin. Patients said the devices were user friendly. While the two devices are similar, some patients may find one with an adhesive tape more suited to their needs.

Allele HLA-DQB1*06 reduces fibrosis score in patients with non-alcoholic fatty liver disease.

AIM: Human leukocyte antigen (HLA) regions were highlighted as important genetic markers for various liver diseases by hepatology-related genome-wide association studies. Replication studies in non-alcoholic fatty liver disease (NAFLD) are limited and none has investigated the association of HLA alleles with non-alcoholic steatohepatitis (NASH) and other histological characteristics. In the current study, we examined the association of HLA-DQA1 and HLA-DQB1 alleles with NAFLD spectrum and its histological characteristics. METHODS: Consecutive biopsy-proven NAFLD patients (n = 191) and healthy controls (n = 188) were enrolled and genotyped for HLA-DQA1 and HLA-DQB1 alleles using the sequence-specific oligonucleotide-polymerase chain reaction method. RESULTS: No association was found between the HLA alleles and NAFLD or NASH in a case-control setting. Nevertheless, among NAFLD patients, the frequency of HLA-DQB1*06 allele was significantly the lowest in NASH with significant fibrosis (10.4%) and approximately similar for NASH without significant fibrosis (22.9%) and NAFL (22.5%) (P = 0.004). It is noteworthy that the association remains significant after correction for multiple comparisons (Pc = 0.04). Multivariate analysis revealed that HLA-DQB1*06 allele is also associated with fibrosis score (P = 0.001); the result remains significant after correction for multiple comparisons. CONCLUSION: These findings suggest that HLA-DQB1*06 is associated with lower fibrosis score in NAFLD patients.

Renal Transplant Outcomes in Spousal and Living-Related Donors in Malaysia.

INTRODUCTION: Studies have shown that a compatible human leukocyte antigen (HLA) match can confer a favourable effect on graft outcomes. We examined the outcomes of HLA matching in renal transplant donors in Malaysia. MATERIALS AND METHODS: A total of 140 patients who had compatible ABO blood type with negative T-cell lymphocytotoxicity crossmatch were included in the study and 25% of them were spousal transplant donors. No remarkable differences in acute rejection rate, graft survival, patient survival and serum creatinine level were observed between the spousal and living-related donor groups. RESULTS: The spousal donor group had a higher degree of HLA mismatch than the living-related donor group. HLA-A mismatch was associated with increased rejection risk at 6 months (odds ratio [OR], 2.75; P = 0.04), 1 year (OR, 2.54; P = 0.03) and 3 years (OR, 3.69; P = 0.001). It was also observed in the deleterious effects of HLA-B and HLA-DQ loci when the number of antigen mismatches increased. The risk was 7 times higher in patients with ≥1 mismatch at HLA-A, HLA-B and HLA-DR loci than those who did not have a mismatch at these loci at 6 months (P = 0.01), 1 year (P = 0.03) and 3 years (P = 0.003). CONCLUSION: A good match for HLA-A, HLA-B, HLA-DR and HLA-DQ can prevent acute rejection risk in renal transplant patients. Consequently, spousal donor transplants could be a safe intervention in renal patients.

Association between microRNA-196A2 and microRNA-146A polymorphisms and progression to cirrhosis and hepatocellular carcinoma in patients with viral hepatitis B.

BACKGROUND/AIM: MicroRNAs (miRNAs) are small noncoding RNAs that have been implicated in mechanisms underlying various types of cancers including hepatocellular carcinoma (HCC). Reports have indicated that single nucleotide polymorphisms in miRNA-196A2 and miRNA-146A genes may contribute to the risk of progression of hepatitis B virus (HBV) infection to cirrhosis and HCC. This study aimed to examine the effect of miRNA-196A2 and miRNA-146A polymorphisms on the progression of HBV infection to cirrhosis and/or HCC in HBV patients in the Malaysian population. PATIENTS AND METHODS: This study consists of 423 chronic HBV patients without either cirrhosis or HCC and 103 chronic HBV patients diagnosed with liver cirrhosis or with cirrhosis and HCC. The single nucleotide polymorphisms of miRNA-196A2 (rs12304647 and rs11614913) and miRNA-146A (rs2910164) were genotyped using the Sequenom MassARRAY platform. RESULTS: The genotype distribution in chronic HBV without either cirrhosis or HCC, relative to chronic HBV patients diagnosed with liver cirrhosis or with cirrhosis and HCC revealed that rs12304647 has a protective effect from the development of HCC (odds ratio=0.37, 95% confidence interval=0.15-0.89, P=0.027). However, rs11614913 and rs2910164 were not significantly associated with progression of the HBV infection. CONCLUSION: In summary, rs12304647 is associated with a reduced risk of progression to HCC in patients with chronic HBV infection.

Histocompatibility testing after fifty years of transplantation.

Histocompatibility testing has been used in support of solid organ and hematopoietic stem cell transplantation for over fifty years and transplantation has clearly served as a major stimulus for interest in the human major histocompatibility complex, the HLA system. Until the 1990s, typing and definition of antibodies to HLA antigens was performed primarily by serologic techniques using cell-based assays. Two major technological advances have greatly increased knowledge of HLA alleles and HLA-specific antibodies, namely the introduction of DNA based molecular typing and solid phase immunoassays using purified HLA antigens as targets. By virtue of these advances, the number of recognized HLA alleles has increased from a few hundred to greater than 6000 and definition of the specificities of antibodies to HLA antigens is now possible at the level of individual epitopes. The technological advancements have also raised new challenges. The vast and ever increasing number of HLA alleles has resulted in ambiguities in allele assignments which confound matching for hematopoietic stem cell transplants. Similarly, the ability to detect extremely low levels of HLA-specific antibodies has raised questions about whether such low levels are clinically relevant. Next generation DNA sequencing methods likely will offer the solution to many of the HLA typing ambiguities and future studies on the nature of both HLA and non-HLA-specific antibodies will clarify their impact on transplant outcomes.

Donor human leukocyte antigen specific antibodies predict development and define prognosis in transplant glomerulopathy.

The pathogenesis of transplant glomerulopathy (TG) remains unclear, with evidence of human leukocyte antigen (HLA) antibodies as important contributors to the disease. We studied the risk factors and the associations of HLA antibodies in the development of TG. Sixty-one cases with morphologic features of TG were identified and compared with contemporaneous matched patients (without TG) from a 17-year period, all undergoing renal biopsy in a single center. Univariate risk factors for TG were previous glomerulitis [odds ratio (OR) 3.3, 95% confidence interval (95% CI) [1.2-9.4], p = 0.025), delayed graft function (OR 2.3 [1.0-5.1], p = 0.042), HLA class I presensitization defined by Luminex solid-phase immunoassays (OR 5.0 [2.3-11.0]. p < 0.001), and de novo posttransplant development of donor HLA specific antibody (DSA) (OR 4.7 [1.7-13.2], p = 0.002). Only DSA remained significantly associated with TG after adjustment (OR 3.8 [1.1-12.9], p = 0.032). DSA was detected in >50% of TG patients, suggesting HLA antibodies play a critical role in TG pathogenesis. TG patients with DSA had increased risk of graft loss (median graft survival 4.4-5.2 years), whereas patients with morphologic features of TG without DSA had similar graft survival compared with the non-TG group (median graft survival 15 years). Thus, DSA is a useful predictor for graft failure in TG patients.

Clinical significance of anti-HLA antibodies detected by Luminex: enhancing the interpretation of CDC-BXM and important post-transplantation monitoring tools.

B-cell crossmatch (BXM) was originally introduced to increase the sensitivity to detect anti-HLA antibodies of conventional CDC crossmatch in renal transplantation. Newer techniques such as Luminex((R)) have greater sensitivity in detecting anti-HLA antibodies but have not been directly evaluated versus BXM. We discuss our experience with Luminex testing and the significance of donor-specific antibodies (DSA) defined by Luminex in three populations, as compared with the CDC crossmatch. In the general transplant population, Luminex-defined DSA were found in only one third of positive CDC-BXM and were associated with graft rejection. Luminex testing enhanced the interpretation of CDC-BXM and identified patients with clinically relevant BXM. In the highly sensitized transplant population, Luminex-defined DSA were found in two thirds of positive BXM and were a better predictor of graft rejection. Therefore, Luminex assays rather than CDC-BXM should be used to facilitate kidney allocation in highly sensitized patients. In the post-transplantation population, Luminex antibody monitoring for DSA was shown to be important, as it defined low-level de novo DSA that were associated with development of transplant glomerulopathy and a significant predictor of graft loss in those patients. Thus Luminex testing facilitated the interpretation of CDC-BXM and provided a useful predictive tool for the detection of clinically significant DSA in post-transplantation antibody monitoring.