Killer cell immunoglobulin-like receptors in Thai patients with multiple myeloma.

BACKGROUND: Natural killer (NK) cells have been implicated in the immune response against multiple myeloma (MM) cells. Killer cell immunoglobulin-like receptors (KIRs) regulate NK cell activity by recognizing specific human leukocyte antigen (HLA) class I as ligands. OBJECTIVE: To investigate the association of KIR genes and ligands with MM in the Thai population. METHODS: KIR gene polymorphisms and their HLA ligands were investigated in 66 Thai patients with MM and 200 healthy controls. RESULTS: The frequencies of KIR3DL1 and 2DS4 were significantly lower in myeloma patients than in controls (P = 0.02). The frequencies of KIR3DL1, 2DS4, 2DL1 with C2, and 3DL1 with Bw4 were significantly higher in the patients achieving > very good partial response (VGPR) than those achieving ≤ VGPR after treatment with bortezomib (P = 0.009, 0.009, 0.01, and 0.02, respectively). CONCLUSIONS: This study suggests the association of KIR genes with the protection against MM and the association of inhibitory KIR and ligands with the response to treatment in MM.

Major Histocompatibility Complex Class I Chain-Related A and B (MICA and MICB) Gene, Allele, and Haplotype Associations With Dengue Infections in Ethnic Thais.

BACKGROUND: Major histocompatibility complex class I chain-related (MIC) A and B (MICA and MICB) are polymorphic stress molecules recognized by natural killer cells. This study was performed to analyze MIC gene profiles in hospitalized Thai children with acute dengue illness. METHODS: MIC allele profiles were determined in a discovery cohort of patients with dengue fever or dengue hemorrhagic fever (DHF) (n = 166) and controls (n = 149). A replication cohort of patients with dengue (n = 222) was used to confirm specific MICB associations with disease. RESULTS: MICA*045 and MICB*004 associated with susceptibility to DHF in secondary dengue virus (DENV) infections (odds ratio [OR], 3.22; [95% confidence interval (CI), 1.18-8.84] and 1.99 [1.07-2.13], respectively), and MICB*002 with protection from DHF in secondary DENV infections (OR, 0.41; 95% CI, .21-.68). The protective effect of MICB*002 against secondary DHF was confirmed in the replication cohort (OR, 0.43; 95% CI, .22-.82) and was stronger when MICB*002 is present in individuals also carrying HLA-B*18, B*40, and B*44 alleles which form the B44 supertype of functionally related alleles (0.29, 95% CI, .14-.60). CONCLUSIONS: Given that MICB*002 is a low expresser of soluble proteins, these data indicate that surface expression of MICB*002 with B44 supertype alleles on DENV-infected cells confer a protective advantage in controlling DENV infection using natural killer cells.

HLA Class I Supertype Associations With Clinical Outcome of Secondary Dengue Virus Infections in Ethnic Thais.

BACKGROUND: Human leukocyte antigen (HLA) supertypes are groups of functionally related alleles that present structurally similar antigens to the immune system. OBJECTIVES: To analyze HLA class I supertype associations with clinical outcome in hospitalized Thai children with acute dengue illness. METHODS: Seven hundred sixty-two patients and population-matched controls recruited predominantly in Bangkok were HLA-A and -B typed. HLA supertype frequencies were compared and tested for significant dengue disease associations using logistic regression analyses. Multivariable models were built by conducting forward stepwise selection procedures. RESULTS: In the final logistic regression model, the HLA-B44 supertype was protective against dengue hemorrhagic fever (DHF) in secondary infections (odds ratio [OR] = 0.46, 95% confidence interval [CI], .30-.72), while the HLA-A02 supertype (OR = 1.92, 95% CI, 1.30-2.83) and the HLA-A01/03 supertype (OR = 3.01, 95% CI, 1.01-8.92) were associated with susceptibility to secondary dengue fever. The B07 supertype was associated with susceptibility to secondary DHF in the univariate analysis (OR = 1.60, 95% CI, 1.05-2.46), whereas that was not retained in the final model. CONCLUSIONS: As the HLA-B44 supertype is predicted to target conserved epitopes in dengue, our results suggest that B44 supertype-restricted immune responses to highly conserved regions of the dengue proteome may protect against secondary DHF.

Analysis of KIR genes in HLA-identical sibling hematopoietic stem cell transplantation in Thai patients with leukemia.

BACKGROUND: Killer cell immunoglobulin-like receptors (KIRs) are members of a group of regulatory molecules found on the natural killer (NK) cells that regulate NK cells function by interacting with the human leukocyte antigen (HLA) class I molecules or ligands. The effects of KIR genes on the outcome of hematopoietic stem cell transplantation (HSCT) are still controversial. OBJECTIVE: To investigate the distribution of KIR genes in HLA-identical sibling and the effect of KIR genes on the outcome of HSCT. MATERIAL AND METHOD: The present study included 74 patients and their HLA-identical sibling donors. KIR genes and HLA ligands typing were determined by polymerase chain reaction-sequence specific primer (PCR-SSP). A retrospective study was carried out to analyze the outcomes of the recipients. RESULTS: There was no effect of KIR gene mismatch and missing ligand on the outcome regarding graft-versus host disease (GVHD), relapse, and overall survival (OS) (p > 0.05). However the presence of donor activating KIR2DS5 was associated with decreased aGVHD (p = 0.01). CONCLUSION: Our findings suggest an important role of donor activating KIR in identical sibling HSCT.

Prevalence of G6PD deficiency in Thai blood donors, the characteristics of G6PD deficient blood, and the efficacy of fluorescent spot test to screen for G6PD deficiency in a hospital blood bank setting.

BACKGROUND: Transfusion of blood from glucose-6-phosphate dehydrogenase (G6PD) enzyme deficient donors could cause a potentially unfavorable outcome, especially in newborns and those with hemoglobinopathies. AIMS: To determine the prevalence of G6PD deficiency in Thai blood donors, the characteristics of G6PD deficient blood, and the efficacy of fluorescent spot test (FST) to screen for G6PD deficiency in a hospital blood bank setting. METHODS: Blood samples were obtained from 514 Thai blood donors who donated blood at Siriraj Hospital (Bangkok, Thailand) during December 2020-February 2021. G6PD deficiency status was screened using FST, and in vitro hemolysis of red blood cell parameters of G6PD deficient blood units was compared with those of normal control units at different time points during 35 days of refrigerated storage. RESULTS: The prevalence of G6PD deficiency was 7.59% (35 [8.73%] males, 4 [3.54%] females). The sensitivity of FST was 100% (95% confidence interval [CI]: 90.97-100%), and the specificity was 99.58% (95%CI: 98.49-99.95%). In vitro hemolysis was not significantly different between G6PD deficiency and normal controls. CONCLUSION: The prevalence of G6PD deficiency in this study was 7.59%. FST was demonstrated to be an effective and reliable method for G6PD deficiency screening among Thai blood donors in a hospital blood bank setting.

Killer cell immunoglobulin-like receptors and response to antiviral treatment in Thai patients with chronic hepatitis C virus genotype 3a.

Genetic factors of the host have been shown to influence the outcome of treatment for hepatitis C virus (HCV) infection. Killer cell immunoglobulin-like receptors (KIR) regulate natural killer (NK) cell activity by interaction with specific human leukocyte antigen (HLA) class I. In this study, KIR gene polymorphisms and their HLA ligands were investigated in 110 Thai patients with chronic HCV genotype 3a. Seventy-six patients were sustained virological responders and 34 patients were virological non-responders. KIR typing and HLA-C typing were performed using PCR-SSP (polymerase chain reaction with sequence specific primer). The frequency of HLA-C1C2 was significantly higher in sustained responders than in non-responders (P = 0.04). However, the frequencies of KIR2DL2/2DL3 genotype and KIR2DL2/2DL3-HLA-C1C1 genotype were significantly higher in non-responders than in sustained responders (P = 0.02, 0.004, respectively). In summary, this study showed the association of KIR genes and ligands with the outcome of antiviral treatment in chronic hepatic C virus genotype 3a infection.

Mutation of ABO gene in Thai blood donors with A3 phenotype.

The ABO system is the most important of all blood group systems in transfusion practice. The subgroup gives a weak reaction when treated with anti-A or anti-B. The most common subgroup found in Thai blood donors is subgroup A3, which is characterized by mixed-field agglutination when reacted with anti-A and anti-A,B, was caused by mutation in the ABO gene, especially in the exon 7. In the present study mutation in A3 were charactered in exon 7 of the ABO gene in 10 A3 phenotype Thai blood donors from the National Blood Centre, Thai Red Cross Society by PCR amplification and DNA sequencing. Mutations in exon 7 were identified in the A allele of six cases. In four cases, mutations were detected at positions 646T > A, 681G > A, 771C > T and 829G > A. One case showed a double mutations at positions 467C > Tand 745C > T and one case showed a mutation at position 467C > T. Four cases showed wild type exon 7 as A101 allele. These mutations were previously reported in BGMUT database and no novel mutation was identified These data suggest genetic heterogeneity in A3phenotype in Thai blood donors.

TNF alpha and NRAMP1 polymorphisms in leprosy.

OBJECTIVE: To determine the association of TNF alpha and NRAMP1 polymorphisms in leprosy. MATERIAL AND METHOD: The polymorphisms of TNF alpha at -238, -308, and NRAMP1 at INT4, D543N, and3' UTR were examined in 37 patients with leprosy (24 multibacillary and 13 paucibacillary) and 140 healthy controls. PCR-SSP and PCR-SSO method were used to type TNF and NRAMP1 polymorphisms. RESULTS: The genotype frequency of TNF-308 G/A was significantly increased in all leprosy patients compared to the controls (p = 0.04, OR = 2.69). When leprosy types were divided, the allele frequency of TNF-308A was significantly increased in multibacillary leprosy compared to the normal controls (p = 0.04, OR = 2.93). There was no significant difference in the distribution of the genotypes and allele frequencies of TNF -238 and NRAMP1 polymorphisms between the patients and controls. CONCLUSION: TNF-308A was associated with susceptibility to multibacillary leprosy.

Association between HLA class II alleles and autoimmune hepatitis type 1 in Thai patients.

OBJECTIVE: To investigate the association between HLA class II alleles and autoimmune hepatitis (AIH) type I in Thai patients. MATERIAL AND METHOD: The clinical data of 50 autoimmune hepatitis patients type I (AIH) at Siriraj hepatitis clinic were analysed, 37 of whom were tested for HLA class II genotyping using polymerase chain reaction and sequence-specific oligonucleotide technique (PCR-SSO). RESULTS: AIH is an uncommon chronic hepatitis in Thailand with females predominant. The HLA DRB1*0301, and DQA1*0101 were significantly associated with AIH patients when compared to controls; (OR = 3.92 [1.18-13.30], p 0.021, OR = 2.31 [1.13-4.73], p 0.019, respectively). When 18 patients with "definite" AIH were analysed, only HLA DRB1*0301 was still significantly associated with AIH (OR = 5.22, 95%CI = 1.28-20.92, p 0.015). CONCLUSION: HLA genotyping has shown that HLA DRB1*0301 and HLA DQA1*0101 were significantly associated with AIH.

HLA Class I Alleles Associated with Mortality in Thai Military Recruits with HIV-1 CRF01_AE Infection.

In HIV-1-infected patients, variation at the HLA class I locus is associated with disease progression, but few studies have assessed the influence of HLA alleles on HIV-1 CRF01_AE infection, which is dominant in Thailand. We hypothesized that alleles predicted to confer more effective immune responses, such as HLA-B*46, would protect against disease progression. HLA typing was performed on HIV-1 incident cases surviving until 1998-1999 and HIV-1-negative matched controls from Thai army cohorts enrolled between 1991 and 1995. We assessed associations between class I alleles and disease progression subsequent to HLA typing. Ninety-nine HIV-1-incident cases were followed for a median of 3.7 years after HLA typing; during this time, 58 participants died. Two alleles were associated with mortality: HLA B*51 was protective (3-year survival B*51(pos) vs. B*51(neg): 75% vs. 52%; p = 0.034) whereas Cw*04 was deleterious (3-year survival Cw*04(pos) vs. Cw*04(neg): 39% vs. 60%; p = 0.027). HLA-B*46 was not associated with disease progression. Alleles present at different frequencies in HIV-1-incident compared with HIV-1-negative men included HLA-A*02:03, B*35, B*15, and C*08. 1. In conclusion in this Thai army cohort, HLA-B*51 was associated with lower mortality, confirming that this allele, which is protective in clade B HIV-1 infection, has a similar effect on HIV CRF01_AE infection. The deleterious effect of HLA-Cw*04 must be interpreted with caution because it may be in linkage disequilibrium with disease-susceptible HLA-B alleles. We did not find that HLA-B*46 was protective. These findings may inform vaccine development for areas of the world in which HIV-1 CRF01_AE infection is prevalent.

Flow cytometric crossmatch for kidney transplantation.

Serum samples from 49 patients with panel reactive antibodies of greater than 15% and 17 patients who have related donor pairs were collected at the Department of Transfusion Medicine, Faculty of Medicine Siriraj Hospital. Crossmatching was performed by three methods, flow cytometry crossmatch (FCXM), the standard National Institutes of Health (NIH), and the antihuman globulin (AHG) microlymphocytotoxicity. 28.9% Spell out of both T- and B-cell crossmatch was positive by FCXM and negative by NIH and AHG. When the T-cell and B-cell crossmatches were negative by FCXM, they were negative by both NIH- and AHG method. There was significant difference of the crossmatch result between FCXM and NIH and between FCXM and AHG (p < 0.0001). In addition, FCXM was about 4-16 and 8-32 times more sensitive than AHG- and NIH method, respectively. In conclusion, the result of FCXM is clear and this method is more sensitive than NIH- and AHG method FCXM should be used together with the NIH- and AHG method for kidney transplantation.

Killer cell immunoglobulin-like receptors in Thai patients with leukemia and diffuse large B-cell lymphoma.

Natural killer (NK) cells are key components of the innate immune system that have been implicated in the immune response against tumor cells. Killer cell immunoglobulin-like receptors (KIR) regulate NK cell activity by interaction with specific human leukocyte antigen (HLA) class I. In this study, KIR gene polymorphisms and their HLA ligands were investigated in Thai patients with chronic myelogenous leukemia (CML) (n=60), acute myelogenous leukemia (AML) (n=60), acute lymphoblastic leukemia (ALL) (n=55), and diffuse large B-cell lymphoma (DLBCL) (n=60) compared with 150 healthy controls. The frequency of KIR3DL1 with HLA-Bw4 was significantly lower in DLBCL patients than in controls (P=0.0006, Pc=0.02), whereas no significant differences were seen in KIR gene frequencies and their ligands between leukemia patients and controls. This study suggest a role of inhibitory KIR with its ligand in the protection against DLBCL.

TNF and LTA gene, allele, and extended HLA haplotype associations with severe dengue virus infection in ethnic Thais.

Severe dengue virus (DENV) infection is characterized by a cascade of cytokine production, including the production of tumor necrosis factor-alpha (TNF-alpha) and lymphotoxin-alpha (LT-alpha). We have analyzed a variety of polymorphisms in the TNF and LTA genes of 435 ethnic Thais who had subclinical DENV infection, primary or secondary dengue fever (DF), or primary or secondary dengue hemorrhagic fever (DHF). The TNF -238A polymorphism marking the TNF-4,LTA-3 haplotype occurred in a significantly greater number of patients with secondary DHF (20 [15.2%] of 132) than patients with secondary DF (7 [4.1%] of 169) (P < .001; P corrected by use of Bonferroni adjustment, .022; odds ratio, 4.13 [95% confidence interval, 1.59-11.17]). In a subset of patients, the LTA-3 haplotype was associated with in vivo intracellular production of LT-alpha and TNF-alpha during the acute viremic phase of infection. Two extended human major histocompatibility complex (MHC) haplotypes containing TNF-4 and LTA-3, together with HLA-B48, HLA-B57, and HLA-DPB1*0501, were detected only in patients with secondary DHF. These observations indicate that polymorphism in functionally distinct MHC-encoded proteins contributes to the risk of developing severe secondary DENV infection and warrants further investigation.

NRAMP1 and TNF-alpha polymorphisms and susceptibility to tuberculosis in Thais.

OBJECTIVE AND BACKGROUND: Polymorphisms in the natural resistance-associated macrophage protein gene 1 (NRAMP1) and tumour necrosis factor (TNF)-alpha gene have been found to be associated with susceptibility to tuberculosis in different populations. However, the results are inconsistent. This study aimed to determine whether NRAMP1 and TNF-alpha variants are associated with tuberculosis in Thais. METHODS: Polymorphisms of NRAMP1 at INT4, D543N and the 3' untranslated region, and of TNF-alpha at +488, -238, and -308, were examined in 149 tuberculosis patients and 147 healthy controls. PCR using sequence-specific oligonucleotides and sequence-specific priming were used to genotype the NRAMP1 and TNF polymorphisms, respectively. RESULTS: There were no significant differences in the distribution of the genotype frequencies for the NRAMP1 and TNF-alpha polymorphisms between the patients and controls. CONCLUSIONS: The NRAMP1 and TNF-alpha genes are not associated with susceptibility to tuberculosis in Thais.

Tumor necrosis factor-alpha gene promoter polymorphism is not associated with smoking-related COPD in Thailand.

OBJECTIVE: Susceptibility to COPD is, in part, genetically determined. Tumour necrosis factor (TNF)-alpha gene promoter polymorphisms have been investigated in different populations with inconsistent results. This study aimed to determine the genetic predisposition in Thai smoking-related COPD patients. METHODOLOGY: The polymorphism at position -308 of the TNF-alpha gene promoter was examined in 57 patients with smoking-related COPD, 67 smoker control subjects, and 116 control anonymous blood donors. Genomic DNA from peripheral blood lymphocytes was used for genotypic analysis by polymerase chain reaction with sequence specific primers. RESULTS: TNF-alpha-308*2 allele frequency was not significantly different between the population control subjects and the smoking-related COPD patients (4.7% vs. 7.9%, P= 0.14). This allele frequency was also not significantly different between smokers with and without COPD (7.9% vs. 7.5%, P= 0.46). CONCLUSIONS: Although it has been speculated that TNF-alpha might have a causal relationship with COPD, a role for the TNF-alpha gene promoter polymorphism in disease development in Thailand was not demonstrated.

Immunoglobulin GM and KM genotypes in hepatitis C virus infection.

Hepatitis C virus (HCV) is a major health problem, affecting over 170 million people worldwide. HCV causes a wide spectrum of liver disease, varying from persistent to asymptomatic infection. To evaluate the role of immunoglobulin (Ig) GM and KM genes in HCV infection, 191 HCV-infected Thai subjects were studied. These included 43 individuals with transient HCV infection and 148 individuals with persistent chronic HCV infection. The controls consisted of 134 healthy individuals. Several GM and KM alleles were determined by polymerase chain reaction-based methods. The frequency of G1M(f) homozygotes was lower (52.4% vs. 64.2%, P = 0.03) and the frequency of G1M(z) homozygotes was higher (10.5% vs. 3.7%, P = 0.02) in patients than the respective frequencies in controls. These results suggest that GM genotypes make a significant contribution to the risk of acquiring HCV infection.