SLE and infections.

Infections are common in systemic lupus erythematosus (SLE), and remain a source of mortality. The types of infections (such as pneumonia, urinary tract infection, cellulitis, and sepsis) in SLE patients are similar to the general population and include the same pathogens (Gram-positive and Gram-negative). SLE patients may also develop opportunistic infections, especially when treated with immunosuppressive agents. As a high-risk population, identification and treatment of chronic infections such as tuberculosis, hepatitis B, or human immunodeficiency virus (HIV), are important prior to the institution of immunosuppression to prevent reactivation or exacerbation of the infection. A common caveat is to distinguish between a lupus flare and an acute infection; judicious use of corticosteroids and cytotoxic drugs is critical in limiting infectious complications. The risk factors associated with susceptibility to disease include severe flares, active renal disease, treatment with moderate or high doses of corticosteroids and/or immunosuppressive agents, and others. Genetic factors (complement deficiencies, mannose-binding lectin, Fcgamma III, granulocyte macrophage colony-stimulating factor [GM-CSF], osteopontin) may predispose certain SLE patients to develop infections. Parameters including C-reactive protein (CRP) and adhesion molecules may help to differentiate an infectious disease from an exacerbation of the disease. Finally, the mechanism of molecular mimicry by specific microbial agents may play a role in the induction of SLE.