CD8A and obesity due to melanocortin 4 receptor deficiency: Furthermore, a strong negative correlation between plasma IL-6 concentrations and expression of the CD8+ T-cell genes network, in sputum samples from obese adult patients has been found, compared to healthy controls; the authors speculate that obesity-related systemic inflammation may lead to CD8+ cytotoxic T-cell dysfunction, possibly by means of T-cell exhaustion [30].