CD79A and systemic lupus erythematosus: IgA anti-β2-GP1 were detected in 63 (34%) of the 187 patients: in 22 (41%) of 53 patients with PAPS, in 4 (33%) of 12 with probable APS, in 28 (47%) of 59 with SLE + APS, in 9 (14%) of 63 with SLE in none of the patients in the comparison group, and in one (1%) of the control group.