The relatively high frequency of non-R5 strains determined in the current study for patients with RHI deserves attention because of the restricted number of patients eligible to therapy with CCR5 antagonist, maraviroc, as well as in the light of the established correlation between infection with the CXCR4-using strains and faster disease progression15,54, or first-line treatment failure19. The gene discussed is CXCR4; the disease is infection.