CD4+ Tcell transfer into obese mice reversed weight gain and insulin resistance [67], iNKT transfer decreased body fat, triglyceride levels, leptin, fatty liver and insulin sensitivity [31], while T reg expansion alone was able to reduce TNF-α-related inflammation [75] but was unable to restore overall metabolic function in obesity [77]. The gene discussed is TNF; the disease is obesity due to melanocortin 4 receptor deficiency.