Immunodeficiency presenting as hypergammaglobulinaemia with IgG2 subclass deficiency.

Recurrent bacterial infections, lymphadenopathy, and failure to thrive are unlikely to be attributed to immune deficiency if they occur in the presence of hypergammaglobulinaemia, and other explanations will usually be sought. We describe eight patients who presented with all these features in infancy or early childhood. Deficiencies of immunoglobulin and antibody production were initially discounted, and the children were referred for investigation of possible lymphoma, autoimmune disease, or chronic viral infection. The patients were later referred to us for more detailed immunological investigation, which revealed low levels of IgG2 and poor specific antibody production to common pathogens. Treatment with intravenous immunoglobulin resulted in resolution of signs and symptoms in all patients. Thus we have shown that hypergammaglobulinaemia does not preclude the presence of immunoglobulin/antibody deficiency. We suggest that investigation of children with high levels of IgG and features of immunodeficiency should include IgG subclass analysis.