HLA-B27-associated acute anterior uveitis in the University Referral Centre in North Thailand: clinical presentation and visual prognosis.

BACKGROUND: Acute anterior uveitis (AAU) is the most frequent type of uveitis encountered in the west. Although human leucocyte antigen (HLA)-B27-associated ankylosing spondylitis was reported in South East Asia, it is not known whether HLA-B27-associated ocular disease is prevalent in Thailand. METHODS: A prospective study of 100 unrelated blood donors and 121 consecutive patients with AAU was carried out. All people underwent HLA-B27 typing and full ocular examination. Radiological examination of the sacroiliac joints was conducted in patients with low back pain or arthralgias. RESULTS: The prevalence of HLA-B27 was 10% among the blood donors in contrast with 44% in the AAU group (p<0.001). The clinical characteristics of HLA-B27-associated AAU were similar to those published throughout the world (unilaterality in 74%, hypopyon in 31%, recurrent AAU in 64%). However, the increased intraocular pressure (IOP) was more common in the HLA-B-27-negative group (p = 0.03) than in their HLA-B27-positive counterparts. At least 15% of the HLA B27-positive group had radiological signs of ankylosing spondylitis. CONCLUSION: The prevalence of HLA-B27 in the population without uveitis in Thailand is about 10% and clinical characteristics of HLA-B27-positive AAU are similar to those reported in the west. In contrast with earlier reports, HLA-B27-negative AAU in Thailand was associated with increased IOP and should be further studied.

HLA class I serotypes and cytotoxic T-lymphocyte responses among human immunodeficiency virus-1-uninfected Thai volunteers immunized with ALVAC-HIV in combination with monomeric gp120 or oligomeric gp160 protein boosting.

Antigen-induced cellular immunogenicity may vary between populations due to differences in human leukocyte antigen (HLA) diversity and, hence, may play a critical role in the protection afforded by vaccines. In the setting of two, phase I/II human immunodeficiency virus-1 vaccine trials of a recombinant canarypox prime, and boosting with either recombinant monomeric gp120 or oligomeric gp160, we assessed the association between specific human leukocyte antigen (HLA) class I serotypes and the presence of cytotoxic T-lymphocyte response measured by 51Cr-release assay. HLA class I serotypes A11, A24, A33, B46, and B75 were the most common, present in 10% or more of 245 individuals studied. Forty of 187 (21.4%) Thai adults who received either ALVAC-HIV with gp120 or oligomeric gp160 or ALVAC alone had a precursor cytolytic CD8 T-cell response (pCTL). HLA-B44 was positively and significantly associated with a pCTL response (odds ratio 7.6, 95% CI: 2.7-21.2), whereas B46 was negatively associated but not robust when adjusted for multiple comparisons. Responses to Env proteins accounted for the majority (nine of 11) of pCTL activity among those persons with B44. This HLA class I serotype occurred in 9.4% of participants overall (including the placebo group), less commonly than what is reported from populations of European ancestry. These results strengthen the importance of assessing HLA class I distributions in conjunction with studies of vaccines designed to elicit cellular immunity in different populations.

HLA gene frequencies of northern Thais.

We investigated the distribution of HLA-A and B locus, gene frequency (GF), antigen frequency (AF), haplotype frequency (HF) and non detectable antigens in Northern Thais. Of 289 native northern Thai people residing in Chiang Mai province for many generations were tested using lymphocytotoxicity test and 146 unrelated subjects were selected for analysis. The common alleles were A2, A11 and A24 for A locus with GF of 36.4%, 35.4% and 15.6%, respectively and B46, B40 and B13 for B locus with GF of 21.1%, 15.7% and 8.6%, respectively. The frequent linkage disequilibrium haplotypes were A2,B46; A33,B17 with HF of 15.9%; 5.0% and LD of 8.3%; 4.6%, respectively (p < 0.0001). The undetectable antigens (blanks) occurred with GF = 11.64% at A locus and GF = 4.92% at B locus. Comparing the GFs to other Thai ethnic groups, showed that the Northern Thais shared several alleles such as A2, A11, B46, and B62 in common with Dai Lue (Thai-speaking people who lived in the southern part of China), (p > 0.05), more than Thais, Thai/Chinese or present-day Thais (p < 0.001). Especially, HLA-B46 with the GF of 21.1% is considered to be a very typical antigen for Southern Mongoloids. These similarities will support the root of migration and origin of Northern Thais.

The value of HLA-ABC common typing tray in relation to bone marrow transplantation.

Bone marrow transplantation (BMT) is one of the most effective procedures to cure the previously uncured hematologic diseases. However, it is costly and HLA typing to select the compatible donors contributed to its cost. A total of 53 prospective patients for BMT and their 114 siblings were analyzed to evaluate the use of locally prepared HLA-ABC common typing tray (ABCCT) during Mar 1988-Mar 1992. The 16, 9, 7, 5, 5 and 12 patients were diagnosed as aplastic anemia, CML, thalassemia, ALL, ANLL and other blood diseases, respectively. It was found that 18 patients were HLA-identical (HLA-ID) with one of their siblings except one patient had 2 HLA-ID sibs. All of those who appeared to be HLA-ID were further tested for the HLA-ABCDR typings. It was observed that 16 (88.89%) of 18 patients and 17 (89.47%) of 19 sibs were confirmed as HLA-ID. After careful clinical screening, only 13 HLA-ID pairs were able to proceed to the mixed lymphocyte culture and confirmed their status of HLA-ID by this test. Finally, only 6 (46.15%) of 13 patients received BMT with a high rate of success, ie all patients have survived with bone marrow engraftment. Thus, ABCCT is very useful for related BMT. It was highly efficient to exclude HLA-non-ID and haplo-ID yet the cost and workload were greatly reduced.