CLEC4D and granulomatosis with polyangiitis: A disruption in the balance between type I (part of the Ig receptor superfamily that includes FcγRI, II and III) and type II (C-type lectin receptors) Fc receptor signaling also very likely occurs in several autoimmune diseases such as rheumatoid arthritis and granulomatosis with polyangiitis (GPA), in which changes in autoantibody-specific glycosylation have been observed.