Many immunedeficiency syndromes are associated with autoimmune disorders. We here report on a girl with a systemic lupus erythematosus-like disease who suffered from both hyperimmunoglobulin M syndrome (HIGMS) and C1q deficiency. Despite severe central nervous system-lupus like disease, probably due to C1q deficiency, kidney function was relatively spared. IgM autoantibody might play a protective role against lupus-glomerulonephritis.