IL17A and obesity due to melanocortin 4 receptor deficiency: One of the mechanisms leading to worse outcomes in obese COVID-19 patients includes a dysfunction of specific fat-resident regulatory T cells (Treg) and TH17 (T-cell sub-lineage), as a result of high circulating IL-6, IL-23/IL-17, as well as other obesity-associated plasma cytokines, contributing to the ‘cytokine storm’ described in more serious cases [5].