Lupus and Infections

Infections remain a significant source of morbidity and mortality in systemic lupus erythematosus (SLE). Both the underlying disease process and therapeutic immunosuppression can increase susceptibility to a wide variety of pathogens while influencing the clinical course of infections. Because of the atypical presentation of many infections and the varied array of baseline symptoms, distinguishing an acute infection from a lupus flare is a common clinical challenge in treating SLE patients. This challenge is compounded by the need to suppress the immune system enough to prevent autoimmune complications without making patients overly vulnerable to infection. This chapter reviews the impact of infections on lupus morbidity and mortality, risk factors for infection, the clinical spectrum of infections in lupus, proposed mechanisms of infection susceptibility, and biomarkers or other factors that may assist the clinician when differentiating active infection from an SLE disease flare.