Neutrophil ageing and immunesenescence

As humans age, their morbidity and mortality from infection increases, their response to vaccination declines and they have an increased incidence of inflammatory diseases and cancer. The reasons for these effects are clearly complex, but reduced efficiency of the innate and adaptive immune system is likely to be important in the pathology of old age. Age-related changes in the adaptive immune system are well-documented and include alterations in T cell phenotype and effector functions and a reduced ability of B cells to produce high affinity antibody. In contrast, the innate immune system has been less well researched and the perception amongst many immunogerontologists is that this branch of the immune system is only moderately affected by age. However, it is becoming increasingly clear that the adaptive and innate immune systems co-operate at several levels to ensure the optimal immune response and any decline in adaptive immunity will impact upon the function of the innate immune system and vice-versa. Here, we review the literature concerning intrinsic age-related changes in neutrophil responses and consider how changes in lymphocyte function with age might further compromise efficiency of neutrophil function.