Microsporidiosis in Patients with Autoimmune Diseases Undergoing Monoclonal Antibody Associated Therapy.

We present Enterocytozoon bieneusi infection in four patients with autoimmune diseases undergoing prolonged monoclonal antibody therapies. Two patients suffered from inflammatory bowel disease and received anti-TNF therapies, whereas two other patients suffered from systemic lupus erythematosus with renal involvement and received anti-CD20 or anti-BLyS protein therapies. Three out of four patients consulted for diarrhea with abdominal pain without intestinal inflammation or bleeding at the time of sampling. The fourth patient did not declare intestinal troubles. Microsporidia genotype detected in this study were S9, C, Wildboard3 with one patient harboring 2 genotypes S6 and EBCMAP-038. Management of microsporidia infection included albendazole and reduction of immunosuppression treatment, but no specific treatment was implemented in two other patients. In conclusion, microsporidia infection occurs in patients with autoimmune diseases undergoing prolonged monoclonal antibody therapies. Diagnosis should be carefully assessed in this population and a thorough benefit-risk analysis is essential prior to initiating therapeutic interventions.