A patient with a Mycobacterium avium complex infection complicated by systemic lupus erythematosus

A 41-year-old woman was admitted to our hospital because of fever and polyarthralgia. A diagnosis of systemic lupus erythematosus (SLE) was made based on the findings of polyarthritis, leukocytopenia, lymphocytopenia, proteinuria, and positive reactions for antinuclear antibody (ANA) and anti-double strand (ds)DNA antibody. She had also been suffering from a pulmonary Mycobacterium avium complex (MAC) infection with such symptoms as cough and sputum for the past 3 years. Antimicrobial drugs for MAC infection were administered first, and later she was given cyclophosphamide pulse therapy, consisting of methylprednisolone (8mg/day) and mizoribine (100mg/day). Owing to these therapeutic regimens, SLE was successfully treated without an exacerbation of the MAC infection. The risk factors for MAC infection and SLE are also discussed.