CD4 and anal carcinoma: However, by applying the Bruzzi method [38], it is estimated that avoiding having CD4+ T cell counts drop below 200 cells/μL 6–7 years prior to anal cancer diagnosis would prevent 20% of anal cancer cases, this estimate could rise to 49% or 79% by keeping CD4+ T cell counts higher than 350 cells/μL or 500 cells/μL, respectively.