Purpose of review: To provide an update on infections in systemic lupus erythematosus (SLE) and Sjögren's syndrome, particularly addressing their role as triggers of autoimmunity, their impact on mortality, the main microorganisms, the approaches to differential diagnosis with disease flares and recommendations for vaccination.
Recent findings: New mechanisms for autoimmunity triggered by Epstein-Barr virus and human commensal microbiota have been described. The increased risk for tuberculosis was recently demonstrated for the first time in Sjögren's syndrome. C-reactive protein was reported to be a more sensitive and specific marker for bacterial infections in SLE than procalcitonin and phagocyte-specific S100A8/A9 protein. Inactivated vaccines are well tolerated and efficacy was demonstrated for influenza vaccine. Immunogenicity is generally reduced but adequate in SLE. Prednisone or immunosuppressants are associated with decreased vaccine serological response, whereas hydroxicloroquine seems to improve vaccine immunogenicity. Other infection-preventive measures for these diseases include antimalarials and prophylaxis for tuberculosis or Pneumocystis jirovecii.
Summary: Advances in the role of infectious agents as triggers for SLE and Sjögren's syndrome have provided new insights into disease development. Knowledge on vaccine immunogenicity, safety and efficacy has improved with evidence of a generally reduced but adequate response for inactivated vaccines in SLE. Other preventive measures comprise infection prophylaxis and antimalarials.