The risk of obesity may be increased by two blood cell traits, high light scatter reticulocyte count (WHR, WHRadjBMI) and platelet count (WHR, WHRadjBMI), and three immune cell traits, CD14+ CD16– monocyte absolute count (BMI, WHR), CD28– CD8+ T cell absolute count (Obesity classes 1 and 3), and monocytic myeloid-derived suppressor cells absolute count (Obesity classes 1 and 2). Here, CD28 is linked to obesity due to melanocortin 4 receptor deficiency.