Finally, the 52 HAART users who developed KS were individually reviewed and classified into the following groups: (1) no antiretroviral drug in the 3 months before KS diagnosis; (2) recent initiation of HAART (<6 months before KS diagnosis); (3) severe immunodeficiency (CD4 cell count <100 cells μl−1 at KS onset while on HAART for ⩾6 months); and (4) none of the above (data not shown). Here, CD4 is linked to Kaposi's sarcoma.