Susceptibility to infection in patients with neutropenia: the role of the innate immune system

Chemotherapy-induced neutropenia increases the risk of infection. There appears to be a wide variability in the severity and length of infective episodes. Susceptibility to infections is determined by the underlying malignant disease and its treatment, environmental factors (e.g. nutritional state of the patient and hygiene) and genetically determined variations of the immune system. The majority of primary immunodeficiencies are rare (c. frequency one in 10 000), whereas some genetic polymorphisms in the innate immune system, such as profound mannose-binding lectin deficiency, are much more common (c. frequency one in 10). Here, we review the potential role of the innate immune system in determining susceptibility to infections in patients with neutropenia.