Characteristics of HLA class I and class II polymorphisms in Rwandan women

Objective: To define HLA class I and class II polymorphisms in Rwandans. Me thods: PCR-based HLA genotyping techniques were used to resolve variants of HLA-A, B, and C to their 2- or 4-digit allelic specificities, and those of DRB1 and DQB1 to their 4- or 5-digit alleles. Results: Frequencies of 14 A , 8 C, and 14 B specificities and of 13 DRB1 and 8 DQB1 alleles were greate r than or equal to0.02 in a group of 280 Rwandan women. These major HLA fac tors produced 6 haplotypes extending across the class I and class II region s: A*01-Cw*04-B* 4501-DRB1*1503-DQB1*0602 (A1-Cw4-B12-DR15 -DQ6), A * 01 - Cw * 04 - B * C 4901 - DRB1 * 1302-DQB1*0604 (A1-Cw4-B21-DR13-DQ6), A*30 - Cw*04-B*15-DRB1*1101-DQB1*0301 (A19-Cw4-B15-DR11-DQ7), A*68-Cw*07-B* 4901-D RB1*1302-DQB1*0604(A28-Cw7-B21-DR13- DQ6), A*30- Cw*07 - B*5703 - DRB1* 130 3-DOB1*0301(A19 - Cw7-B17-DR13-DQ7), and A*74-Cw*07-B*4901-DRB1*1302-DOB1* 0604 (A19-Cw7-B21-DR13-DQ6), respectively. Collectively, these extended hap lotypes accounted for about 19% of the total. Other apparent class I-class II haplotypes (e.g., Cw*17-B*42-DRB1*0302-DQB1*0402, Cw*06-B*58-DRB1*1102 - DQB1*0301, and Cw*03-B*15-DRB1*03011-DQB1*0201) did not extend to the telom eric HLA-A locus, and other 3-locus class I haplotypes (e.g., A*68-Cw*04-B* 15, A*74-Cw*04-B*15, and A*23-Cw*07-B*4901) completely or partially failed to link with any specific class II alleles. Discussion: Frequent recombinat ions appeared to occur between the three evolutionarily conserved HLA block s carrying the class I and class II loci. The HLA class I profile seen in R wandans was not directly comparable with those known in the literature, alt hough the class II profile appeared to resemble those in several African po pulations. These data provide additional evidence for the extensive genetic diversity in Africans. Copyright (C) 2000 S. Karger AG, Basel.