Some specific human leukocyte antigen (HLA)-DR/DQ haplotypes are more important than individual HLA-DR and -DQ phenotypes for the development of mucocutaneous type of Behcet's disease and for disease shift from recurrent aphthous stomatitis to mucocutaneous type of Behcet's disease

The phenotype and haplotype frequencies of human leukocyte antigens (HLA)-D R and -DQ in 32 Chinese patients with the mucocutaneous (MC) type of Behcet 's disease (BD) were calculated and compared with those in 310 healthy cont rol Chinese and with those in 80 Chinese patients with recurrent aphthous s tomatitis (RAS). We found that the phenotype frequency of HLA-DRw8 [correct ed P (P-c)<0.005] and the haplotype frequencies of HLA-DRw8/DQw1 (P-c<0.005 ), -DRw8/DQw5(w1) (P-c<0.0005), -DRw12(5)/DQw1 (P-c<0.005), -DRw12(5)/DQw1( w1) (P-c<0.0005), and -DRw52/ DQw1 (P-c<0.005) in patients with the MC type of ED were significantly greater than those in healthy control subjects. T his finding suggests that individual Chinese with HLA-DRw8 antigen and HLA- DRw8/DQw1, -DRw8/DQw5(w1), -DRw12(5)/DQw1, -DRw12(5)/DQw6(w1) and -DRw52/DQ w1 haplotypes are more likely to have the MC type of ED. Furthermore, the r elative risks (RRs) of HLA-DRw8/DQw1 (5.6), -DRw8/DQw5 (w1) (10.0), and -DR w12(5)/DQw6(w1) (14.4) haplotypes in patients with the MC type of ED were e qual to or higher than the RR of HLA-DRw8 phenotype (5.6), suggesting that some of the HLA-DR/DQ haplotypes may play more important roles than the ind ividual HLA-DR and -DQ phenotypes for the development of the MC type of ED. The phenotype frequencies of HLA-DR5 (P-c<0.01), -DRw8 (P-c<0.005) and -DQ w1 (P-c<0.05) as well as the haplotype frequencies of HLA-DR5/DQw1 (P-c<0.0 05) and -DRw8/DQw1 (P-c<0.00005) in patients with the MC type of ED were si gnificantly higher than those in patients with RAS. Moreover, the RRs of HL A-DR5/DQw1(29.1) and -DRw8/DQw1(47.4) haplotypes were greater than the RRs of HLA-DR5 (10.4), -DRw8 (23.4) and -DQw1 (4.0) antigens. These results sug gest that some specific HLA-DR/DQ haplotypes may be more important than the individual HLA-DR and -DQ phenotypes in the disease shift from RAS to the MC type of ED.