Immunovirologic Characteristics of Human Immunodeficiency Virus-Infected Patients Consisting Mainly of Injecting Drug Users on Highly Active Antiretroviral Treatment with Prolonged Virologic Failure

Immunovirologic parameters of 24 heavily antiretroviral drug-pretreated patients with prolonged virologic treatment failure under highly active antiretroviral therapy, and who harbored highly resistant human immunodeficiency virus (HIV) isolates, were studied in this retrospective cross-sectional study. Most of the patients were injecting drug users (71%) and male (88%). All patients were studied for CD4⁺ cell count, HIV viral load, resistance mutations, and viral phenotype. The patients showed a high accumulation of resistance-associated mutations, their CD4⁺ cell count and viral load directly correlated with their respective values at initiation of therapy, and the presence of K103N was inversely associated with lower viral load. On the other hand, patients with K103N had the same level of CD4⁺ cell count compared with patients without this mutation. Among the patients, a majority with a specific viral phenotype was not present. Rather, a dual-tropic virus was found most frequently, suggesting a preferential suppression of X4-specific strains and less cytopathogenicity during antiretroviral therapy and a greater proportion of R5X4 viruses due to an adaptation to that pressure.