Two Cases of Anti-D Alloimmunization in D-Negative Thai Patients as a Result of the Asian-Type DEL on Transfused Red Cells.

Introduction: DEL is known to be one of the weakest D variants, which can be detected by the adsorption-elution technique or by molecular study. Currently, in Thailand, we do not routinely test for DEL variants serologically or genetically among serologic RhD-negative blood donors. Case Presentation: We reported 2 cases of alloimmunization after transfused with Rh DEL, RHD*DEL1 allele, in the Thai population. The first case was a 73-year-old male with anemia who presented with post-cardiac arrest and septic shock. The patient was group B, RhD-negative, and was transfused with RhD-negative red blood cells (RBCs). Antibody screening and identification found that the patient developed anti-D and anti-Mia during the admission course. The second case was a 38-year-old woman with pseudomyxoma peritonei who developed anti-D after receiving four units of RhD-negative RBCs during cytoreductive surgery with hyperthermic intraperitoneal chemotherapy. Both patients did not receive anti-D immunoglobulin and had no previous history of anti-D detection. We retrospectively investigated and found two units of RHD*DEL1 among the RBCs transfused to these patients. Discussion: Previous reports of several cases of anti-D alloimmunization in RhD-negative recipients transfused by RHD*DEL1, an Asian-type DEL, are limited only to East Asia. We first identified 2 patients with anti-D alloimmunization after receiving the RHD*DEL1 RBCs in the Thai population. This raises concern about Rh DEL screening among D-negative Thai blood donors and whether to remove DEL units from the D-negative inventory to improve patient safety.

HLA-B*27:04 associated with enthesitis and younger age of onset, and HLA-B allele profile in patients with ankylosing spondylitis in Thailand: A cross-sectional study.

AIM: The aims of this study were to estimate human leukocyte antigen (HLA)-B allele frequency, to identify alleles associated with ankylosing spondylitis (AS), and to explore manifestations in various HLA-B*27 in Thai AS patients. METHODS: This was a cross-sectional study. Thai patients older than 18 years with diagnosed AS according to modified New York criteria who visited Siriraj Hospital (Bangkok, Thailand) were consecutively enrolled. HLA-B alleles were determined by reverse sequence-specific oligonucleotide assays, and were assigned at a 4-digit resolution. HLA-B alleles of 334 unrelated healthy Thai donors who participated in a previous phase 2b dengue vaccine clinical trial were included as controls. Odds ratio (OR) and Fisher's exact test were used to estimate association between allele and AS. The P value significance threshold was calculated according to Bonferroni. RESULTS: Among the 88 patients who were recruited, 34 HLA-B alleles were identified, and all patients were heterozygous. The prevalence of HLA-B*27 was 89.8%, and 4 alleles of HLA-B*27 were identified. HLA-B*27:04 (OR: 39.4, P < .0001) and HLA-B*27:05 (OR: 13.8, P = .0011) were associated with AS. In contrast, HLA-B*27:06 was not found to be associated with AS (OR: 0.4, P = .241). AS patients carrying HLA-B*27:04 were more likely to have enthesitis and younger age at onset than those carrying HLA-B*27:05. CONCLUSIONS: HLA-B*27:04 and HLA-B*27:05 were both found to be strongly associated with Thai AS. HLA-B*27:06 showed a neutral allele for Thai AS. AS patients with HLA-B*27:04 had more enthesitis and younger age at onset than those with HLA-B*27:05.

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.

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.

Characterization of 2-deoxy-D-glucose uptake in fibroblast cultures derived from patients with A3243G mitochondrial DNA mutation.

We investigated cellular glucose uptake of fibroblast cultures derived from seven patients with mitochondrial DNA (mtDNA) A3243G mutation and from six healthy controls with no mtDNA mutations. Heteroplasmy of fibroblast cultures were shifted by culturing for 5 days in galactose-containing medium. The proportion of mutant mtDNA decreased by 7.7% to 10% in three patient fibroblast cultures, whereas 2-deoxy-D-glucose uptake increased 1.8-2.1-fold at basal state, 1.9-2.3-fold in the presence of 60 ng/ml of insulin, and 1.8-2.1-fold in 100 ng/ml of insulin. No significant changes in level of heteroplasmy or glucose uptake were observed in the other patients samples and control samples. This study showed that alteration in the proportion of fibroblast mtDNA A3243G mutation content directly affected basal and insulin-stimulated glucose uptake.

Transmission of heteroplasmic G11778A in extensive pedigrees of Thai Leber hereditary optic neuropathy.

Leber hereditary optic neuropathy (LHON) is characterized by the acute or subacute bilateral painless loss of central vision, predominantly in young males. G11778A is the most common mitochondrial DNA mutation responsible for the disease. Thirty-seven percent of our LHON pedigrees (which is a much higher prevalence than that generally found) carried heteroplasmic G11778A. Analyses of four large Thai LHON pedigrees spanning four to six generations strongly suggested that the transmission of the heteroplasmic G11778A mutation is under selective pressure in favour of the mutated allele and that heteroplasmy influences the disease expression.

Mitochondrial DNA haplogroup distribution in pedigrees of Southeast Asian G11778A Leber hereditary optic neuropathy.

To investigate the association of mitochondrial DNA (mtDNA) haplogroups and Leber hereditary optic neuropathy (LHON) in the Southeast Asian population, mtDNA haplogroup determination was performed by high-resolution restriction fragment length polymorphism in 42 patients with LHON who were carrying the G11778A mutation and in control subjects drawn from a Thai urban population unaffected by LHON. The patients with LHON were of Thai, Thai-Chinese, and Indian origin. Three mtDNA haplogroups, M, B*, and B, were found in LHON patients in a frequency similar to that in control subjects. mtDNA haplogroup F was found in none of the patients with LHON but was the second most common haplogroup in control subjects. The G11778A mutation must have arisen in our population independently from the mutation in Caucasians. In contrast to Caucasians, no specific mtDNA haplotype was associated with the patients with LHON in the Southeast Asian population. The mitochondrial polymorphisms that modify the expression of LHON in Southeast Asians could not be identified in this study. The lack of haplogroup F in our patients with LHON may indicate the protective effect of this haplogroup in the expression of this disorder.