In conditions of hyperleptinemia, as occurs in obesity, an expansion of the Th1 cells in the adipose tissue and an increase in pro-inflammatory cytokine secretion (as TNF-α, IL6 and IL12) have been described together with an increase of CD8+ T cells, macrophages and mast cells. The gene discussed is IL6; the disease is obesity due to melanocortin 4 receptor deficiency.