Obesity and the associated accumulation of bone marrow adipocytes disrupt normal hematopoiesis and immune function by creating a pro-inflammatory environment mediated by TLR4 activation, leading to impaired immune responses and increased morbidity/mortality during infections.

This accumulation of adipocytes can disrupt the normal haematopoietic processes and therefore directly impact on the production of mature blood cells in the steady state and the response to infection (65, 66)... Obesity has been associated with systemic chronic low-level inflammation (69), at least partially mediated by chronic activation of toll TLR 4 (20, 70)... The consequences of this on the BM microenvironment and immune function include increases in haematopoiesis affecting both myeloid and lymphoid lineages (65, 69), and changes in the innate and adaptive immune responses, with disrupted immediate responses observed in the BM (70) as well as impaired memory T-cells responses (72).