Therapeutic Plasma Exchange Management for a Pediatric Patient Presenting With Immune Thrombotic Thrombocytopenic Purpura in a Setting of Common Variable Immunodeficiency.

Common variable immunodeficiency (CVID) is a disorder characterized by hypogammaglobulinemia resulting in recurrent infections. While autoimmune disorders are common in patients with CVID, no association has been reported between CVID and immune thrombotic thrombocytopenic purpura (iTTP), a disorder most often caused by autoantibodies that compromise the activity of the enzyme ADAMTS13. Reduced ADAMTS13 activity results in the accumulation of large von Willebrand factor multimers that can consume platelets and cause microvascular thrombosis and organ injury, ultimately resulting in mortality in most cases of untreated iTTP.