Objective　To investigate the impact of rheumatoid arthritis (RA)-associated HLA-DRβ1*0401,*0402,*0403 and*0404 subtypes on protein kinase A (PKA) signaling. Methods　To detect the activities of adenylate cyclase (AC), cAMP and PKA in transfectants expressing rheumatoid arthritis-associated HLA-DRβ1 subtypes and their mutants. Results　The levels of AC, cAMP and PKA of HLA-DRβ1*0401 and*0404 transfectants were significant lower than that of HLA-DRβ1*0402 and*0403 transfectants (P＜0.01). The mutant HLA-DRβ1*0403 tranfectants expressing DRRAE or QRRAA secreted lower levels of PKA, cAMP and AC (P＜0.01). Conclusion　RA-associated HLA-DRβ1*0401 and*0404 expression suppressed intracelluar PKA signaling pathway, and may mediate abnormal intracellular signaling in rheumatoid arthritis.