Different etiologies of graft loss and death in Asian kidney transplant recipients: a report from Thai Transplant Registry

Background

Kidney transplantation is the most performed solid organ transplantation in Thailand. Over 4000 patients have received kidney transplantation from 23 centers within the kingdom. This study sought to demonstrate the causes of graft loss and death in Thai patients receiving kidney transplant during the past decade.

Patients and Methods

The Thai Transplant Registry database was used to evaluate the causes of graft loss and death. This database was established since 1997, a total of 2298 kidney transplants were available for analysis. Graft loss was defined as return to dialysis, graft removal, retransplantation, or death of the recipients. Patient survival was analyzed by all deaths.

Results

Among 2298 recipients, 59% received organs from deceased donors. The mean age at transplantation was 42 years (SD 12) and 61% were male. The most common identified causes of the end-stage renal disease were chronic glomerulonephritis (25.3%) and hypertensive nephropathy (11.3%); half of those were unknown. Actuarial graft survival rates at 1 and 5 years were 89% and 73%, respectively. The common causes of graft loss were chronic allograft nephropathy (53%), acute rejection (15%), death with a functioning graft (15%), and transplant renal artery diseases (7%). The greatest proportion (64%) of deaths was infection owing to septicemia and/or pulmonary infection. The others were from cardiovascular deaths (12%), liver disease (6%), and malignancy (4%).

Conclusion

Graft survival rates were comparable with previous reports. However, the proportion of death with functioning graft and cardiovascular death as a cause of graft and patient loss is lower than that of Caucasian populations.     

Hypomethylation of LINE-1 but not Alu in lymphocyte subsets of systemic lupus erythematosus patients

BackgroundT lymphocytes from SLE patients have a global decrease in the 5-methylcytosine content. Previous studies have identified hypomethylation in the promoter of several genes but there is limited study in the interspersed repetitive sequences (IRSs).MethodsWe examined and compared the methylation levels of long interspersed nuclear element 1 s (LINE-1) and Alu elements in normal and SLE CD4+ T lymphocytes, CD8+ T lymphocytes and B lymphocytes by the combined bisulfite restriction analysis-interspersed repetitive sequences (COBRA-IRS).ResultsHypomethylation of LINE-1 but not Alu was found in CD4+ T lymphocytes, CD8+ T lymphocytes, and B lymphocytes of SLE patient (P = 0.005, 0.002, and 0.007, respectively). Moreover, when the SLE patients were divided into active and inactive groups, LINE-1 hypomethylation was more significantly distinguished in both CD4+ and CD8+ T lymphocytes of patients from the active SLE group when compared to the controls. Surprisingly, Alu hypomethylation was also observed in CD8+ T lymphocytes from the inactive SLE group when compared to the normal controls (P = 0.0056).ConclusionsThe hypomethylation in each lymphocyte subset of SLE was IRSs specific, mainly found in LINE-1 rather than Alu.     

Correlates of Forced Sex Among Populations of Men Who Have Sex with Men in Thailand

Although forced sex is a correlate of HIV infection, its prevalence and associated risks are not well described among men who have sex with men (MSM) in developing-country settings. Between March and October 2005, we assessed the prevalence of forced sex and correlates among populations of MSM (this includes general MSM, male sex workers, and male-to-female transgender persons) in Thailand using a community-based sample. Participants were enrolled from venues around Bangkok, Chiangmai, and Phuket using venue day-time sampling. Handheld computer-assisted self-interviewing was used to collect demographic and behavioral data and logistic regression evaluated factors associated with forced sex, defined as ever being forced to have sexual intercourse against one’s will. Of the 2,049 participants (M age, 24.8 years), a history of forced sex was reported by 376 (18.4%) men and, of these, most were forced by someone they knew (83.8%), forced more than once (67.3%), and had first occurrence during adolescence (55.1%). In multivariate analysis, having a history of forced sex was significantly associated with being recruited in Phuket, classification as general MSM or transgender (versus classification as male sex worker), drug use, increased number of male sexual partners, and buying sex. The findings in our assessment were consistent with assessments from Western countries. Longitudinal studies are needed to understand the mechanisms of the relationships between forced sex correlates found in our assessment and HIV acquisition and transmission risks.     

A comparative study of antimicrobial properties of crustinPm1 and crustinPm7 from the black tiger shrimp Penaeus monodon

Several isoforms of crustin have been identified in the black tiger shrimp Penaeus monodon. These cationic cysteine-rich antimicrobial peptides contain a single whey acidic protein (WAP) domain at the C-terminus and exhibit antimicrobial activity against both Gram-positive and Gram-negative bacteria. In this paper, we investigate the binding properties and antimicrobial actions of crustinPm1 and crustinPm7, the two most abundant crustin isoforms found in the haemocyte of P. monodon. Previously, crustinPm1 showed strong inhibition against Gram-positive bacteria, whilst crustinPm7 acted against both Gram-positive and Gram-negative bacteria. A binding study showed that both crustins can bind to Gram-positive and Gram-negative bacterial cells. Enzyme-linked immunosorbent (ELISA) assay suggested that crustins bind to the cell wall components, lipoteichoic acid (LTA) and lipopolysaccharide (LPS) with positive cooperativity of Hill slope (H) > 2. This indicates that at least two molecules of crustins interact with one LTA or LPS molecule. In addition, both crustins can induce bacterial agglutination and cause inner membrane permeabilization in Escherichia coli. Scanning Electron Microscopy (SEM) revealed the remarkable change on the cell surface of Staphylococcus aureus, Vibrio harveyi and E. coli after the bacteria were treated with the recombinant crustinPm7. Meanwhile, crustinPm1 can cause a visible change on the cell surface of S. aureus and E. coli only. This is in agreement with the fact that crustinPm1 has shown no antimicrobial activity against V. harveyi. It is likely that the antimicrobial activity of crustins mainly relies on their ability to agglutinate bacterial cells and to disrupt the physiochemical properties of bacterial surface.     

Correlation of protection against Japanese encephalitis virus and JE vaccine (IXIARO(®)) induced neutralizing antibody titers

Immune sera from volunteers vaccinated in a blinded Phase 3 clinical trial with JE-VAX^® and a new Japanese encephalitis virus (JEV) vaccine (IC51 or IXIARO), were tested for the ability to protect mice against lethal JEV challenge. Sera from IXIARO vaccinated subjects were pooled into four batches based on neutralizing antibody measured by plaque reduction neutralization test (PRNT₅₀ titer): high (∼200), medium (∼40-50), low (∼20) and negative (<10). Pooled sera from JE-VAX^® vaccinated subjects (PRNT₅₀ titer ∼ 55) and pooled JEV antibody negative pre-vaccination sera were used as controls. Groups of ten 6- to 7-week-old female ICR mice were injected intraperitoneally with 0.5 ml of each serum pool diluted 1:2 or 1:10, challenged approximately 18 h later with a lethal dose of either JEV strain SA14 (genotype III) or strain KE-093 (genotype I) and observed for 21 days. All mice in the non-immune serum groups developed clinical signs consistent with JEV infection or died, whereas high titer sera from both IXIARO and JE-VAX^® sera protected 90-100% of the animals. Statistical tests showed similar protection against both JEV strains SA14 and KE-093 and protection correlated with the anti-JEV antibody titer of IXIARO sera as measured by PRNT₅₀. Ex vivo neutralizing antibody titers showed that almost all mice with a titer of 10 or greater were fully protected. In a separate study, analysis of geometric mean titers (GMTs) of the groups of mice vaccinated with different doses of IXIARO and challenged with JEV SA14 provided additional evidence that titers ≥ 10 were protective.     

Large transmission cluster of acute hepatitis C identified among HIV‐positive men who have sex with men in Bangkok,Thailand

A rapidly emerging and highly concentrated hepatitis C virus (HCV) outbreak has recently been observed among both acute and chronic HIV‐positive men who have sex with men (MSM) in Bangkok, Thailand. NS5B regions of the HCV genome were amplified using nested PCR and sequenced. Phylogenetic inference was constructed by Maximum Likelihood methods and clusters were identified with support and genetic distance thresholds of 85% and of 4.5%. Forty‐eight (25 acute HIV and 23 chronic HIV) MSM with incident HCV infection were included in the analysis. HCV genotype (GT) was 85% GT 1a and 15% GT 3a or 3b. Median age at HCV diagnosis was 34 (interquartile range, 28‐41) years. 83.3% (40/48) had history of syphilis infection and 36% (16/44) reported crystal methamphetamine use. Only 2 (4%) reported ever injecting drugs, both crystal methamphetamine. In the phylogenetic clustering analysis, 83% belonged to one of two clusters: one large (75%) and one small (8%) cluster. All clusters were GT 1a. MSM with acute HIV infection were more likely to be in a cluster (92%) than those with chronic infection (74%). HCV screening should be regularly performed for MSM in ART clinics, and offering direct‐acting antiviral agents to all MSM with HCV infection might contain the HCV epidemic from expanding further.     

Azathioprine-induced fatal myelosuppression in systemic lupus erythematosus patient carrying TPMT*3C polymorphism

Azathioprine (AZA) is a commonly used immunosuppressant for systemic lupus erythematosus (SLE). Myelosuppression is a serious adverse reaction due to AZA and its metabolites. Thiopurine S-methyltransferase (TPMT) is the rate-limiting enzyme. Variations of TPMT enzyme activity may be responsible for myelosuppression. However, a correlation between certain mutant alleles of low TPMT enzyme activity and myelotoxicity has also been suggested as a factor. We describe herein a case of AZA-induced severe myelosuppression associated with TPMT*3C heterozygous mutant allele in a SLE patient. The patient presented with pancytopenia, sepsis, typhlitis and disseminated intravascular coagulopathy after a short period of AZA therapy. The patient had low TPMT activity and TPMT*3C genotype. Measurement of TPMT activity and determination of TPMT variant allele may identify patients at risk for AZA-induced myelosuppression.     

Melanization reaction products of shrimp display antimicrobial properties against their major bacterial and fungal pathogens

Melanization is a rapid defense mechanism in invertebrates. The substrate specificity of phenoloxidases (POs) and the role of melanization reaction products were investigated in the black tiger shrimp, Penaeus monodon. Two PmPOs (PmproPO1 and PmproPO2) were found to display a substrate specificity towards monophenols and diphenols, and exhibit relatively weak activity against 5,6-dihydroxyindole (DHI). Systemic infection of the PmproPO1/2 co-silenced shrimp with the fungus, Fusarium solani, led to a significantly increased mortality, suggesting an important role of PmproPOs in shrimp’s defense against fungal infection. Using l-DOPA, dopamine or DHI as a substrate, the melanization reaction products exhibited in vitro antimicrobial activities towards Gram-negative bacteria (Vibrio harveyi and Vibrioparahaemolyticus) and Gram-positive bacteria (Bacillus subtilis), whereas the lower effect was detected against the fungus (F. solani). SEM analysis revealed the morphological changes and damage of cell membranes of V. harveyi and F. solani after treatment with shrimp melanization reaction products. Together, these findings demonstrate the crucial functions of the proPO system and the importance of melanization reaction products in the shrimp’s immune defense.