One SSc patient received rituximab because of the development of a microscopic polyangiitis (MPA) starting 44 months after aHSCT with positivity for myeloperoxidase anti-neutrophil cytoplasmic antibodies (MPO-ANCA) and with renal involvement proven by renal biopsy [for details, see the formerly published case report (17)]. The gene discussed is MPO; the disease is systemic sclerosis.