Immunoglobulins in idiopathic thrombocytopenic purpura in childhood.

Levels of immunoglobulins G, A and M were determined in 55 children with idiopathic thrombocytopenic purpura (ITP) (32 acute, 18 chronic and 5 recurrent). Mean IgG levels tended to be low in acute ITP and returned to normal with recovery. In contrast, chronic and recurrent ITP had persistently low IgG and IgA levels. C3 complement levels in 10 cases of acute ITP were normal. Seven patients with chronic ITP had their spleens removed, and IgG and IgA levels tended to rise, while IgM levels decreased in 4 patients after the operation. Low IgA levels observed at the onset of purpura in a child might favor the diagnosis of chronic or recurrent ITP.