HIV-1 VIREMIA CHANGES IN PATIENTS WITH AND WITHOUT SYNCYTIUM-INDUCINGPHENOTYPE TREATED WITH NUCLEOSIDE ANALOGS - A CASE-CONTROL STUDY

The objective of the present study was to investigate the effect of th e nucleoside analogue treatment on serum viraemia, CD4(+) cell count a nd disease progression in patients with and without syncytium-inducing (SI) HIV-I variants. To achieve this in a case-control study, 11 nucl eoside-naive patients harbouring SI variants who started treatment wit h zidovudine or zidovudine plus didanosine were matched with 11 contro l patients who never formed SI variants during a follow-up of 48 weeks . The matching criteria were age, CD4(+) cell count and CDC clinical c ategory at the start of the study and exposure to the same antiretrovi ral treatment. During the follow-up there were no significant differen ces in the changes of serum HIV-1 RNA viral load and CD4(+) cell count s between the two groups. In contrast, AIDS or new AIDS-defining event s were observed in five SI cases but in none of the non-SI controls (P = 0.002). The emergence of a zidovudine-resistant mutation at codon 2 15 was observed in all the patients harbouring SI strains and in six o f the subjects with non-SI variants (P = 0.03). The results of the pre sent study show that in patients carrying SI virus, measurements of CD 4(+) count or RNA viral burden are neither related to the virulence of the virus strains nor able to predict the clinical course of the dise ase, at least under antiretroviral drug conditions. Thus; determinatio n of SI phenotype should be considered in the evaluation and monitorin g of HIV-I therapies.