HLA-DPB1 and systemic sclerosis: A protective association between the carrier frequency of DQB1*03:01 (P = 0.0009, Pc = 0.0150, OR 0.56, 95% CI 0.40–0.79, Table 3) or DPB1*02:01 (P = 5.16X10-6, Pc = 8.77X10-5, OR 0.52, 95% CI 0.39–0.69, Table 3) and SSc was detected.