Kaposi's sarcoma (KS) usually occurs when CD4+ lymphocyte counts are:

When CD4 count falls less than 200/L, the patient develops full-blown AIDS. This stage is characterized by the development of HIV wasting syndrome with weight loss and diarrhea for 1 month. The patients with AIDS show a marked susceptibility to the development of malignancies.  Human herpes virus-8–associated Kaposi’s sarcoma is the most noted malignancy associated with AIDS. ​Parija SC. Textbook of Microbiology & Immunology. Elsevier Health Sciences; 2014. Page:571