Novel agents for the treatment of immune-mediated diseases such as systemic lupus erythematosus (SLE) have been increasingly used as an alternative to or in combination with conventional therapies. Belimumab, a human monoclonal antibody that inhibits B-cell activating factor (BAFF), has demonstrated efficacy in moderate-to-severe SLE with similar adverse effects when compared to other biologic agents and conventional SLE therapies. Here, we describe a woman with SLE and diabetes mellitus (DM) on immunosuppressive therapy for five years who was admitted to the hospital for pneumonia but had a complicated hospital course with multiple infections and, most notably, a nosocomial algaemia due to Prototheca wickerhamii, which was treated successfully with amphotericin B. She had recently received three belimumab infusions as an outpatient prior to admission to the hospital. To the best of our knowledge no cases of human protothecosis in patients receiving belimumab have been described in the English literature; however, unusual infections have to be considered in all patients undergoing immunosuppressive therapies who persist with fever despite conventional antimicrobials.

A 59-year-old male presented with 1 month of progressive dyspnea, 30-lb weight loss, and skin changes on the digits of the hands. In the 4 weeks prior to admission, he was admitted and treated twice for pneumonia at another hospital and received intravenous (IV) vancomycin, ceftriaxone, and azithromycin for a total of 10 days. After admission, he underwent computed tomography imaging of chest, which revealed findings suggestive of interstitial lung disease but given the fact that infection was not ruled out, empiric antibiotics were initiated. The skin lesions on the fingers were felt to be consistent with Gottron’s papules, and his overall constellation of findings were felt to be consistent with dermatomyositis (DM). Over the following 3 days, he developed diffuse, violaceous skin lesions, elevation of liver transaminases, and severe thrombocytopenia. The skin lesions progressed to epidermal necrosis. He developed erosions of the oral mucosa and scrotum. Before skin biopsy results were finalized, IV immunoglobulin and IV dexamethasone were started empirically for suspected DM and immune-mediated thrombocytopenia. His laboratory abnormalities normalized within a week. Biopsy results of the skin were consistent with Stevens-Johnson syndrome (SJS). Autoantibody test for anti-MDA5 were positive, confirming a diagnosis of anti-MDA5 associated DM. Subsequent development of SJS was likely due to antibiotic exposure in the preceding month. Simultaneous development of anti-MDA5 DM and SJS raises the question of a link between the 2 conditions. To our knowledge, this is the first reported association of these 2 conditions reported in the literature.

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