C4A and alopecia areata: We did not find any differences between patients with and without vitiligo/alopecia areata in terms of sex of the donor, transplant cell source, prior acute GVHD, cGVHD onset, cGVHD classification, or organ involvement (except skin), global NIH score, and the majority of laboratory data (C reactive protein, albumins, complement components C3 and C4, etc), including antibodies (anticardiolipin IgG, anticardiolipin IgM, rheumatism factor).