TYPICAL RECURRENT CHILDHOOD INFECTIONS OR PRIMARY IMMUNODEFICIENCY?

Abstract

Introduction Hyper IgM syndromes involve lack of class switch recombination leading to high levels of serum IgM and low levels of IgG, IgA, and IgE. While the absence of high affinity antibodies predisposes patients with X-linked Hyper IgM syndrome to opportunistic infections, this is not so for the less common Hyper IgM syndrome type 2, often making diagnosis difficult. Case Description A 20-month old girl with a six month history of recurrent viral infections presented with persistent high-grade fevers, rash, intermittent diarrhea, and decreased appetite. Physical exam revealed left sided erythematous maculopapular rash, cervical lymphadenopathy and erythematous posterior pharynx. A thorough infectious workup was negative and the patient was initially diagnosed with systemic onset Juvenile Idiopathic Arthritis. Afterwards, a humoral immune panel revealed: IgM 1590 mg/dL,IgA. Discussion Hyper IgM type 2 patients have three common findings: absence of immunoglobulin class switch recombination, lack of immunoglobulin somatic hypermutations, and lymph node hyperplasia secondary to AID gene expression in germinal center B cells. Our patient presented with all of these findings, but given the complexity of this condition, suffered a significant delay in diagnosis. It is important to include primary immunodeficiency in the differential diagnoses of patients with autoimmune manifestations and recurrent infections.