A baboon syndrome induced by intravenous human immunoglobulins: Report of a case and immunological analysis

Following the second series of intravenous human immunoglobulins (IVIg; 0.4 g/kg) prescribed to treat a sensorimotor polyneuritis, a 28-year-old woman developed pompholyx that recurred after each of the following monthly trea tments with IVIg. During the administration of the 10th series, the patient developed a typical baboon syndrome. Immunohistochemical studies of a skin biopsy revealed an unexpected epidermal expression of P-selectin, usually expressed by endothelial cells. Patch, prick and intradermal tests performe d with IVIg on the back, arms and buttocks gave negative results on immedia te and delayed readings. IVIg were re-administered, with the informed conse nt of the patient, and induced a generalized maculopapular rash. This is th e first reported case of baboon syndrome induced by IVIg. Although extensiv e skin testing was performed, all test sites remained negative. We wonder w hether IVIg could reproduce immunological mechanisms involved in the 3 type s of systemic contact dermatitis (pompholyx, baboon syndrome and maculopapu lar rash), including the epidermal expression of P-selectin. Baboon syndrome is a systemic contact-dermatitis-type reaction in which the pathogenesis remains unknown. In order to determine the mechanisms involve d in a case of baboon syndrome induced by intravenous immunoglobulins (IVIg ), immunophenotyping and extensive skin testing were performed.