INTRODUCTION Unlike most high-income countries where subtype B viruses predominate, the Cuban HIV-1 epidemic is characterized by a great diversity of subtypes and circulating recombinant forms. Some studies have shown that HIV variants exhibiting a preference for the CXCR4 co-receptor (X4-tropic) could have impacts on disease pathogenesis, with clinical implications for antiviral treatment plans. Determination of HIV co-receptor tropism is crucial for clinicians in deciding whether maraviroc is an appropriate antiviral.

OBJECTIVE Characterize V3 sequence variability and its relation to viral tropism across different subtypes circulating in Cuba and explore how this may affect treatment success with maraviroc.

METHODS We designed a cross-sectional study that included 72 plasma samples obtained at the Pedro Kourí Tropical Medicine Institute in Havana, Cuba. We sequenced the C2V3 env region and assessed subtype based both on env and pol sequences; tropism was predicted by Geno2pheno analysis. Additionally, 35 V3-loop Cuban sequences, obtained from a previous study, were incorporated into the analysis. Statistical associations among virological, clinical and epidemiological variables were assessed by a chi-square test.

RESULTS Tropism prediction for 72 variants revealed that CRF19_cpx was associated with dual-tropic R5X4 viruses (p = 0.034). Moreover, when 35 sequences from a former study were added, the association was significant not only for R5X4 (p = 0.019) but also for X4-tropic variants (p = 0.044). Alignment of 107 V3-loop sequences showed wide diversity among the different HIV-1 subtypes circulating in Cuba.

CONCLUSIONS In accordance with G2P, CRF19_cpx is a genetic variant with a high proportion of X4 and R5X4-tropic viruses. The results from the present study suggest that the Cuban recombinant could be a more pathogenic variant and that maraviroc may not be suitable for patients infected with CRF19_cpx.

KEYWORDS HIV, CCR5 receptor antagonists, maraviroc, HIV envelope glycoprotein gp120, Cuba

INTRODUCTION By the end of 2017, there were more than 28,000 individuals living with HIV in Cuba, over 80% receiving antiretroviral therapy, which dramatically reduces viral replication, improves immune status and decreases risk of transmission. These results could be jeopardized by emergence of HIV-1 drug resistance. In 2009, a test for HIV-1 genotypic resistance was introduced in routine clinical practice in Cuba.

OBJECTIVE Investigate antiretroviral resistance and its relation to subtype distribution in HIV-1 treatment-naïve and previously treated patients in Cuba.

METHODS Resistance and HIV-1 subtype distribution were determined in 342 antiretroviral treatment-naïve patients and 584 previously treated for HIV-1 whose blood specimens were sent to the Pedro Kourí Tropical Medicine Institute during 2009–2014. Transmitted drug resistance was determined using the Calibrated Population Resistance Tool v.6. Drug resistance analysis was conducted using the algorithm Rega v9.1.0.

RESULTS Prevalence of transmitted drug resistance was 11.4%, and 41% of mutated viruses exhibited dual-class resistance to nucleoside reverse transcriptase inhibitor and non-nucleoside reverse transcriptase inhibitor. Overall, 84.9% of patients had ≥1 resistance mutation, 80% had ≥1 nucleoside reverse transcriptase inhibitor mutation, 71.4% had ≥1 non-nucleoside reverse transcriptase inhibitor mutation and 31.7% had ≥1 protease inhibitor mutation. K65R and K101E mutations were significantly more frequent in subtype C, L210W in CRF19_cpx, and M47V/I in CRF BGs (20, 23, 24). Full class resistance to nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors, protease inhibitors and multidrug resistance were detected in 21.2%, 32.4%, 8% and 4.1% of patients, respectively. Average percentage resistance to nucleoside reverse transcriptase inhibitor, protease inhibitor, full class resistance to nucleoside reverse transcriptase inhibitor, protease inhibitor and multidrug resistance increased in patients failing two or more regimens. Nevertheless, after 2011, a declining trend was observed in the frequency of multidrug resistance and full class resistance to nucleoside reverse transcriptase inhibitors and protease inhibitors.

CONCLUSIONS Detected levels of transmitted drug resistance highlight the need for a national surveillance study in treatment-naïve patients. Resistance prevalence is high in previously treated patients but appears to be decreasing over time. The frequency of resistance mutations in recombinant forms of HIV in Cuba needs further study.

KEYWORDS Antiretroviral therapy, highly active antiretroviral therapy, HIV, anti-HIV agents, drug resistance, multiple drug resistance, Cuba

INTRODUCTION The use of highly active antiretroviral therapy has reduced progression to AIDS and increased survival among seropositive persons; yet, appearance of resistant viruses may jeopardize these benefits. In Cuba, HIV mainly affects adults; at the end of 2009 of the 41 children infected, 25 were still alive; of these, 22 were under antiretroviral treatment. Until now, nothing was known about HIV-1 antiviral resistance and viral subtypes in the pediatric population in Cuba.

OBJECTIVE This study aims to identify presence of antiretroviral-resistant HIV-1 strains in Cuban children and their mothers, and to provide a phylogenetic characterization and comparison of pol gene sequences in the same.

METHODS Plasma samples were collected from 22 children and their mothers, all HIV-1–infected, from 2004 through 2009. Reverse transcription polymerase chain reaction was used to amplify the pol gene fragment coding for HIV protease and reverse transcriptase enzymes; this was then sequenced and subjected to phylogenetic analysis of HIV subtypes and recombinant forms to compare sequences between mothers and children. HIV mutations conferring antiretroviral resistance were determined.

RESULTS Viral amplification was achieved in samples from 11 children and 8 mothers. Subtypes detected were: CRF19_cpx in five children, subtype B in three, CRF18_cpx in two, and subtype C in one child. In all mother–child pairs, samples were grouped within the same viral subtype in the phylogenetic tree. One mother was under treatment and five children had been treated before the sample was collected. In viruses amplified from samples of children under treatment, resistance was most frequently found to lamivudine (3 cases) and nevirapine (4 cases). Two untreated children carried resistant viruses possibly acquired from their mothers.

CONCLUSIONS This is the first study to describe HIV-1 antiviral resistance in the pediatric population in Cuba; it also identified viral subtypes infecting the mother−child pairs studied. We recommend antiretroviral resistance assays before initiating treatment in pregnant seropositive women and their newborns.

KEYWORDS HIV, AIDS, antiretroviral therapy, antiviral drug resistance, phylogeny, infectious disease transmission, vertical, Cuba

The following errata have been corrected in all versions of this article

Page 24: Byline, ”Joan Alemán” should read “Yoan Alemán.”

Page 31, The Authors: ”Joan Alemán” should read “Yoan Alemán Campos.”