A preliminary study of the distribution of blood group systems in Thai blood donors determined by the gel test.

Two hundred blood samples obtained from volunteer blood donors at the Blood Bank, Army Institute of Pathology were studied for red cell groupings in the ABO, Rh, MNSs, Duffy, Lewis. P. Kell, Lutheran and Kidd Systems. Each sample was tested by the gel test using five cards; the ABO-Rh card, Diaclon Rh sub groups + K card, Antigen profile I card (P, Le(a), Le(b), Lu(a), Lu(b)), Antigen profile II card (k, Kp(a), Kp(b), Jk(a), Jk(b)) and Antigen profile III card (M, N, S, s, Fy(a), Fy(b)). For the ABO System, group O is the most common (40.5%) followed by group B (30.5%), group A (20.5%) and group AB (8.5%). The most common Rh gene complex was CCDee (51.5%), which was similar to other studies. The incidence of MMss and MNss gene complexes were the most common in the MNSs System. Fy(a) is very common as in other Asians. In the Lewis System, the incidence of Le (a-b-) was 23.5%, which is consistent with other findings in the Thai population. Sixty (30%) were positive with anti-P1. For the Kell System, only kk and Kp(b) positive types were observed in this study, as well as Lu (a-b+) in the Lutheran System. Jk (a-b-) was not found, which is considered a rare phenotype among Thai people. This study reveals the blood group distribution in 200 Thai volunteers using the gel test. Because of its simplicity and efficacy, this test is practical in population studies. Moreover, it is useful for mass screening and application in emergency situations.

HLA class I antibodies in thalassemic patients.

This study was undertaken to demonstrate the prevalence of HLA class I antibodies among 62 polytransfused patients. The diagnosis included beta-thalassemia major, beta-thalassemia/Hb E disease and severe Hb H disease. Their ages ranged from 1 year to 23 years with the mean age of 10.7 years. The number of packed red cell transfusions ranged from 3 to 235 with the mean of 60 episodes per patient. The standard microlymphocytotoxicity test was performed using 50 panels of lymphocytes which specifically identified the majority of HLA class I antibodies. 31/62 cases (50%) were positive for HLA class I antibodies. The detection of single or multiple antibodies depended upon the number of blood transfusions and the patients' ages. These antibodies were induced by the leukocytes present in the transfused packed red cells. Therefore, leukocyte-reduced packed red cells prepared by either additional inverted centrifrugation or leukocyte filter is suggested for the routine blood bank service.