We examined MLR about one-mismatched HLA DRB 1 to each other, for the purpose of selection of better matching donor in the HLA one-haplotype matched relation. Each DR・DRB1 type has different strength of MLR. DR 1 DR 2 showed strong stimulation and DR 8 DR 9 did weaker one. Occurrence rate of acute rejection showed similar tendency. But DR4 subtype mismatched pairs showed high occurrence rate of acute rejection in spite of low MLR.

PCR-MPH (micro plate hybridization) low resolution plate provided with 16 SSOs is a convenient DNA-based typing method for HLA-DR. A large number of samples were treated to define their HLA-DR types using this method in a short term. However it is known that some identifications like DR 13/-, DR 11/- and DR 1403/- are unable to ascertain whether DR 14 antigen is present or not. Of 139 1typed samples, we had the 60 samples to be not ascertained (4.3 %). The details of them were 42 DR13/ -, 8 DR11/ -and 10 DR 1403/ -. By PCR-SSCP we confirmed the existences of DR 14 antigens in these samples and their DRB1 alleles consequently. The DR 13/ - samples were identified with DRB1^* 1302/ -, DRB1^* 1302/DRB1^* 1401, DRB1^* 1302/ DRB1^* 1405 and DRB1^* 1302/DRB1^* 1406. The numbers of them were 8, 18, 9 and 7 respectively. The DR 11/ - samples were typed to, one DRB1^* 1101/ -, five DRB1^* 1101/DRB1^* 1401, one DRB1^* 1101/ DRB1^* 1405 and one DRB1^* 1101/DRB1^* 1406. The DR1403 -samples were defined, one DRB1^* 1403/ -, six DRB1^* 1403/ DRB1^* 1401 and three DRB1^* 1403/ DRB1^* 1405. As a result of this study, DRB1^* 14 antigens existed in 50 samples (83%) and we recognized the necessity of further testing in regard to the uncomfirmed DR types from the PCR-MPH low resolution plate.