IL1A and obesity due to melanocortin 4 receptor deficiency: Interestingly, both IL-1α and IL-1β are reduced in Cluster 2 subjects, similar to gene expression patterns reported for innate immune challenge of peripheral blood lymphocytes of aged adults (≥ 65 years) compared to younger adults (< 40 years) [47], supporting interpretations that metabolically unhealthy obesity resembles some inflammatory features of aging [39–41].