Even both cytokines are secreted by adipose tissue and are involved in inflammation pathways, the salivary level of leptin was not correlated with the IL-6 level (r = 0.07, P = 0.41), six cases of obesity were characterized by elevated IL-6 and normal level of salivary leptin. This evidence concerns the gene IL6 and obesity due to melanocortin 4 receptor deficiency.