Brief Report: CXCR4 or CCR5 Tropism of Human Immunodeficiency Virus Type 1 Isolates Does Not Determine the Immunological Milieu in Patients Responding to Antiretroviral Therapy

Abstract

Here we address whether CCR5 or CXCR4 tropism of the predominant viral strain detected before or on combination antiretroviral therapy (ART) explains why some human immunodeficiency virus (HIV)-infected patients who begin ART with advanced HIV disease retain low interferon (IFN)-γ responses, despite recovery of CD4⁺ T cell counts. Tropism was determined by culture and confirmed by gp120 V3 loop sequence of multiple plasma samples in eight adult male patients who began treatment with <50 CD4⁺ T cells/µL. Four patients had mixed infections, one had only R5 HIV, and three had only X4 HIV. Of these, two carried CCR5Δ32. Viral tropism was not related to CD4⁺ T cell counts or HIV RNA levels. When immunological responses were monitored over several years, IFN-γ responses to cytomegalovirus were below the median value of uninfected controls and similar in patients with R5, X4, or mixed infection. Interleukin-5 responses were low and plasma soluble CD30 levels were high at treatment onset, but resolved with control of HIV replication irrespective of HIV tropism. Levels of LAG-3 (lymphocyte activation gene-3 protein) were elevated in patients with uncontrolled HIV replication. Hence the immunological milieu did not reflect HIV tropism.