The median (IQR) of the absolute change in CD4 counts from baseline among patients who developed NNRTI-skin rash compared with those did not develop this event at 6 and 12 months were 172 (108–283) versus 159 (85–248) cells/mm3 p = 0.02, and 237 (148–336) versus 199 (114–304) cells/mm3, p = 0.0008 respectively. The gene discussed is CD4; the disease is exanthem.