When grouped based on haemoglobin concentration, participants with anaemia had a significantly lower CD4/CD3 lymphocyte count (P < 0.0001 each) with corresponding lower mean values of red cell indices (HCT, P < 0.0001; MCV, P < 0.0001; MCH, P < 0.0001; MCHC, P = 0.0017). The gene discussed is CD4; the disease is anemia.