C3 and Behcet disease: In 2009, Kose published a paper evaluating IgG, IgM, IgA, and C3 deposits in 108 BD patients by direct immunoflourescence, 44 of the skin samples were obtained from positive pathergy sites, and high deposition rates of IgM, IgA, and C3 were found [8], indicating a probable underlying autoimmune mechanism (see Table 2).