Drug-Associated Resistance Mutations in Plasma and Peripheral Blood Mononuclear Cells of Human Immunodeficiency Virus Type 1-Infected Patients for Whom Highly Active Antiretroviral Therapy Is Failing

In 32 patients for whom highly active antiretroviral therapy was failing, a good agreement between drug resistance-associated mutations in plasma and peripheral blood mononuclear cells (PBMCs) was found (k = 0.85). The mutations with the lowest agreement were 20R, 63P, and 84V in the protease gene and 184V in the reverse transcriptase gene. In eight patients, primary drug resistance mutations were detected only in PBMCs.