ERVW-1 and autoimmune thrombocytopenic purpura: The recent finding that high plasma concentrations of IgA to HIV-1 Env inhibit protective responses mediated by IgG is supportive of an inhibitory role played by plasma IgA (Haynes et al, 2012), a phenomenon that has been observed with other pathogens (Griffiss & Goroff, 1983; Shi et al, 2011), in the regulation of autoantibodies (Quan et al, 1998), and in cancer (Mathew et al, 1981) or idiopathic thrombocytopenic purpura (ITP) (Arnason et al, 2012).