Selective C4 deficiency, systemic lupus erythematosus, and Whipple's disease.

A 45-year-old female with selective deficiency of C4 and systemic lupus erythematosus developed puzzling gastrointestinal and systemic symptoms in the last 6 months of her life. Extensive investigation of the gastrointestinal tract did not yield any diagnosis, and the patient died shortly afterwards. Autopsy revealed evidence of a typical Whipple's disease of the jejunum and lymph nodes. This association has not been previously described. The disease is reviewed with emphasis on its being an opportunistic infection in an immunosuppressed host with a complement deficiency and SLE.