Infections during Immunosuppression Abstract. Immunomodulating and immunosuppressive therapies are being used more and more frequently. Depending on the mechanism of action and the underlying disease, there is an increased risk of infection with these therapies. In everyday clinical practice, the individual risk of infection depends on a large number of patients, and environmental as well as pathogen-specific factors. Elderly and multimorbid patients are at particular risk of infection. Classical bacterial infections with possible atypical manifestation, hepatitis B virus, herpes viruses, mycobacteria and other granulomatous infections are prevalent. Typical clinical signs of infections may be missing and laboratory chemical parameters may fail as diagnostic tools. Systematic screening for latent or chronic infections prior to initiation and close monitoring of patients during immunomodulatory or immunosuppressive therapy are necessary to reduce morbidity and mortality.