CD40LG and autoimmune disease: Hs1.2 allele *2 in the distal 3′RR1 is significantly more frequent in patients with several autoimmune diseases, such as celiac disease, psoriasis, systemic sclerosis, rheumatoid arthritis, and lupus erythematosus with respect to healthy control group [12-15], and is associated with high levels of IgM in peripheral blood [16].