The paradox of autoimmune thrombocytopenia in common variable immunodeficiency.

Common variable immunodeficiency (CVID) is the most common primary immunodeficiency requiring medical intervention and is heterogeneous in clinical presentation and outcome. Beyond susceptibility to infections, many patients with CVID develop chronic lung disease, enteropathy, granulomatous disease, lymphoproliferation and autoimmunity. Immune thrombocytopenia (ITP) is the most common autoimmune condition associated with CVID, impacting 4%-19% of CVID patients, while CVID is found in 1%-2% of ITP patients. Given that CVID is defined by decreased antibody production, the underlying pathophysiology of CVID-associated ITP remains elusive.