Eculizumab for rescue of thrombotic microangiopathy in PM-Scl antibody-positive autoimmune overlap syndrome.

A 46-year-old female with interstitial lung disease presented with proximal muscle weakness, worsening hypertension, microangiopathic hemolysis, thrombocytopenia and deteriorating renal function. She had no sclerodactyly, but had abnormal capillaroscopy. She tested positive for PM-Scl antibodies, and a renal biopsy showed an acute thrombotic microangiopathy consistent with scleroderma renal crisis (SRC). She failed to respond to corticosteroids, plasmapheresis and renin-angiotensin pathway inhibitors. She recovered quickly with the anti-C5 antibody, eculizumab. She had no genetic abnormalities associated with atypical hemolytic uremic syndrome except a DNA variant of unknown significance in C3. This case suggests that eculizumab may be effective for SRC.