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Analysis of the mean increase in CD4 cell counts and viral load decrease between different subtypes C, CRF31_BC, B and F after initial antiretroviral therapy in a Porto Alegre HIV clinic, southern of Brazil
C. Nunes1, C. Dias1, I. Lamego1, L. Brigido2
1Porto Alegre City Bureau of Healthy, HIV Clinic, Porto Alegre, Brazil, 2Adolfo Lutz, Virology Laboratory, Sao Paulo, Brazil
Background: In Brazil HIV-1 subtype B is predominant, but there has been an increase in detection of non-B and recombining subtypes in the south of Brazil. The aims of this study were to assess the increase CD4 cell counts and viral load (VL) decrease in antiretroviral (ARV) naïve patients with different subypes: C, CRF31_BC, B and F in Specialist Assistance Service for STD/AIDS of Porto Alegre.
Methods: The study concerns prospective cohort of 56 patients followed in the period 16 to 24 weeks after initial ARV therapy. Blood samples were sequenced (partial pol,dye terminator,ABI)after retrotranscription and nested PCR following plasmatic RNA. The analysis comprised a partial genetic sequencing of viral polimerasis. Subtype was evaluated at the NCBI, Stanford and Rega sites. Plasma HIV viral load was quantified using bDNA method. The CD4 counts were analysed by four colour flow-citometry. Mean changes from baseline to week 16-24 were compared using ANOVA test and variation of p< 0.05 was considered signicant.
Results: Of the 56 ARV-naïve patients 33.95% were subtype C, 26.8% B, 26.8% CRF31_BC,12.5% F.The ARV regimen included Atazanavir/ritonavir , lopinavir/ritonavir or efavirenz .Median baseline HIV VL(log10 copies/ml) and CD4 count(cells/mm³) were respectively 4.5 log , 174 in subtype B;4.8 log,138 in C; 4.3 log,105 in CRF31 and 4.4 log,177 in F.Mean increase CD4 count from baseline at week 16-24 was 129 in subtype B, 85 in C, 111 in CRF31_BC, 135 in F. Mean decrease in VL was 3.1 log in B, 2.8 in C, 2.0 in CRF31_BC, 2.2 in F.Mean changes CD4 counts and VL were not statistic significant from baseline at week 16-24 between subtypes (p=0.5; 0.1respectively).
Conclusions: Despite of viral diversity in this study (subtypes C, CRF31_BC ,B ,F) the mean increase in CD4 count and viral load decrease was similar after initial ARV therapy among them.
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