Activated PI3 Kinase Delta Syndrome Revealed by Vasculitis and Disseminated Toxoplasmosis

Excerpt

Activated phosphoinositide-3kinase delta syndrome (APDS) includes two monogenic immunodeficiencies leading to constitutional activation of the PIK3 pathway. APDS-1 is caused by heterozygous gain-of-function mutation in PIK3CD that induce hyperactivation of the protein subunit p110δ whereas APDS-2 result from the loss of function in PIK3R1 that encodes for p85α regulatory subunit [1, 2]. Clinical manifestations include a lymphoproliferative syndrome with benign lymphadenopathy, splenomegaly, and an increased risk of B cell lymphoma. Infectious complications are common with recurrent respiratory tract infections, bronchiectasis, and opportunistic infections such as chronic Herpes virus infections. Associated autoimmune diseases are also frequent. We herein describe a case of APDS-1 revealed in the adulthood by disseminated toxoplasmosis and vasculitis, both rare and poorly described manifestations of APDS. …