Necrotizing vasculitis with a polyarteritis nodosa-like pattern and selective immunoglobulin A deficiency: case report and review of the literature.

Selective immunoglobulin A deficiency (IgAD) is a primary immunodeficiency disease characterized by low levels (< 7 mg/dl) of serum immunoglobulin (Ig) A and normal serum levels of IgG and IgM. Patients with IgAD have increased risk for recurrent respiratory and gastrointestinal infections, autoimmune disease, asthma and allergy. A 26-year-old woman was admitted with sudden onset of painful cutaneous lesions on her lower extremities, pyrexia and arthromyalgia. Her medical history was remarkable for recurrent respiratory tract infections, self-limited episodes of acute diarrhea, atopy, splenomegaly and a 4-year history of a lung granulomatous lesion. Laboratory and imaging tests ruled out severe life-threatening infection, connective tissue disease and neoplasm. Serum protein electrophoresis showed a low IgA serum level (6.67 mg/dl), with normal serum levels of IgG and IgM, conducting to a diagnosis of selective IgAD. A skin biopsy showed necrotizing vasculitis without any sign of internal organ disease. We report a patient with IgAD and granulomatous involvement of lungs, spleen and medium-sized arteries of the skin. Although IgAD results from a failure of B-cell differentiation, we propose that deregulated immune response with production of cross-reactive antibodies and hyperstimulation of T cells and macrophages could contribute to this widespread granulomatous reaction.