INTERELATIONSHIP BETWEEN THE DURATION OF HIV-INFECTION, THE VIRAL LOAD AND THE CD4+ LYMPHOCYTE COUNT

BACKGROUND: The decline in CD4+ lymphocytes occurs at different rates in patients with HIV infection. A longer duration of HIV infection and a higher level of viral replication, represented by the viral load, a re associated with a lower CD4+ lymphocyte count. However, the interel ationship between these variables is still not well known. PATIENTS AN D METHODS: 107 HIV-infected patients for whom the date of infection wa s known, were included in a transversal study, in which the CD4+ lymph ocyte count and the plasma viral load were analysed, the last using an isothermal amplification method (NASBA). Patients were not receiving antiretroviral drugs or suffered intercurrent infections at the time o f the study. RESULTS: The mean duration of HIV infection was 8.6 +/- 2 .9 years. The mean CD4+ lymphocyte count was 366 +/- 264 x 10(6)/l. Th e mean plasma viraemia was 4.3 +/- 0.9 logs. In a linear regression mo del, the CD4+ lymphocyte count was explained in 21.7% of cases by the duration of HIV infection, meanwhile the viral load justified up to 36 .2 of CD4+ cell variability. When both parameters were combined, up to 58.4% of CD4+ lymphocyte values were explained. In this model, change s of 1 log in viral load had a 4-fold higher effect on the CD4+ cell c ount than each year of HIV infection. CONCLUSIONS: The duration of HIV infection and, particularly the viral load strongly influences the cu rrent CD4+ lymphocyte count, although other variables should exist (vi rus with syncytium-inducing phenotype, age of the patient and his immu negenetic repertoire) influencing the different decline seen in CD4+ T -cells.