Immunoglobulin G Subclasses in Childhood Systemic Lupus Erythematosus and Systemic Onset Juvenile Rheumatoid Arthritis

Abstract

Twenty patients with childhood systemic lupus erythematosus (SLE) and 20 with systemic onset juvenile rheumatoid arthritis (JRA) had immunoglobulin G (IgG) subclasses measured by immunoradiometric assay and total IgG measured by nephelometry. These IgG subclass measurements were obtained also on age- and gender-matched controls for each patient group. A significant increase in total IgG (p < 0.01), IgG₁ (p < 0.005), and IgG₃ (p < 0.05) was identified in the SLE and JRA patients versus controls. A decrease in IgG₄ (p < 0.05) was identified in the SLE patients versus JRA patients. In evaluating the SLE patients with respect to cerebritis, nephritis, disease activity, disease duration, age of onset, medications, or infection, no difference was found in the subclasses relating to these variables.