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.