Re-testing and misclassification of HIV-2 and HIV-1&2 dually reactive patients among the HIV-2 cohort of the West African Database to evaluate AIDS collaboration

Are Confirmatory Assays Reliable for HIV-1/HIV-2 Infection Differentiation? A Multicenter Study

Immunoblots remain the gold standard for HIV-1/HIV-2 infection confirmation. However, their ability to differentiate HIV-1 from HIV-2 infection on an antigenically diversified HIV-1 and HIV-2 panel remain uncommon. We performed a multicenter study on 116 serum samples accounting for most of the diversity of HIV-1 (9 different subtypes in group M, 17 circulating recombinant forms (CRFs), and 3 group O) and HIV-2 (groups A and B), evaluating seven confirmatory assays (six commercially available assays and one in-house assay) with genotyping as the reference. The assays were INNO-LIA HIV I/II score, HIV-2 blot 1.2, HIV blot 2.2, New Lav blot I and II, Geenius, and an in-house serotyping enzyme-linked immunosorbent assay (ELISA). Among the HIV-1 samples, INNO-LIA, HIV blot 2.2, New Lav blot I, Geenius, and serotyping had comparable high sensitivities, from 98% to 100%, whereas HIV-2 blot 1.2 and New Lav blot II had high rates of "undetermined" results (85% and 95%, respectively). HIV-2 blot 1.2 and New Lav blot II misclassified 7% and 5% of HIV-1 samples as HIV-2, respectively, and HIV-2 blot 1.2 had an 8% false-negative rate. Among the HIV-2 samples, INNO-LIA, New Lav blot II, HIV-2 blot 1.2, and serotyping had high sensitivities, from 96% to 100%. HIV blot 2.2 misclassified 17% of HIV-2 samples as HIV-1/HIV-2 dual infections. New Lav blot I misclassified 19% of HIV-2 samples as HIV-1 with a high (81%) undetermined rate, and Geenius misclassified 2% as HIV-1 and 7% as untypeable HIV positive. For HIV-1/HIV-2 dual infection, the results were less sensitive, with at most 87.5% for INNO-LIA and Geenius and 75% for HIV blot 2.2 and serotyping. Overall, confirmatory assays remain useful for most cases, with the exception of HIV-1/HIV-2 dual-infection suspicion.

Early Diagnosis of HIV-1 and HIV-2 Using Cobas HIV-1/HIV-2 Qualitative Test: A Novel Qualitative Nucleic Acid Amplification Test for Plasma, Serum, and Dried Blood Spot Specimens

BACKGROUND

Nucleic acid amplification tests (NATs) minimize the time from HIV infection to diagnosis, reducing transmission during acute HIV. NATs are especially useful for diagnosing HIV in children younger than 18 months and discriminating between HIV-1 and HIV-2.

METHODS

We evaluated the performance of the cobas HIV-1/HIV-2 qualitative (cobas HIV-1/2 Qual) test for use on cobas 6800/8800 Systems. The results of adult plasma and serum samples and pediatric dried blood spots were compared with those of the recomLine HIV-1 & HIV-2 Immunoglobulin G serological test and COBAS AmpliPrep/COBAS TaqMan HIV-1 qualitative test, v2.0. Genotype inclusivity and limits of detection were determined, and sensitivity on seroconversion panels was compared with that in the Bio-Rad Geenius HIV 1/2 Confirmatory Assay, Abbott ARCHITECT HIV Ag/Ab Combo serological test, and cobas TaqScreen MPX, v2.0.

RESULTS

Concordance of cobas HIV-1/2 Qual test with the comparator serological test and COBAS AmpliPrep/COBAS TaqMan test was ≥99.6% with all sample types. Reactivity with all HIV genotypes was 100%. LOD in plasma samples was 14.8, 12.6, and 27.9 copies/mL for HIV-1 group M, HIV-1 group O, and HIV-2, respectively, with similar results for serum samples. LOD in dried blood spots was 255 copies/mL for HIV-1 and 984 copies/mL for HIV-2. HIV infection was detected 18.9 days and 8.5 days earlier than the confirmatory and serological assays, respectively, and at a similar time to the NAT.

CONCLUSIONS

The cobas HIV-1/2 Qual test enables early and accurate diagnoses of HIV-1 and HIV-2 in adults and children across sample types. The assay could help avert transmission during acute HIV, simplify HIV diagnostic algorithms, and promote the survival of HIV-infected children.

Long-term immunological responses to treatment among HIV-2 patients in Côte d'Ivoire

BACKGROUND

Studies indicate that responses to HIV-2 treatment regimens are worse than responses to HIV-1 regimens during the first 12 months of treatment, but longer-term treatment responses are poorly described. We utilized data from Côte d'Ivoire's RETRO-CI laboratory to examine long-term responses to HIV-2 treatment.

METHODS

Adult (≥15 years) patients with baseline CD4 counts < 500 cells/μl that initiated treatment at one of two HIV treatment centers in Abidjan, Côte d'Ivoire between 1998 and 2004 were included in this retrospective cohort study. Patients were stratified by baseline CD4 counts and survival analyses were employed to examine the relationship between HIV type and time to achieving CD4 ≥ 500 cells/μl during follow up.

RESULTS

Among 3487 patients, median follow-up time was 4 years and 57% had documented ART regimens for > 75% of their recorded visits. Kaplan-Meier estimates for achievement of CD4 ≥ 500 cells/μl after 6 years of follow-up for patients in the lower CD4 strata (< 200 cells/μl) were 40% (HIV-1), 31% (HIV-dual), and 17% (HIV-2) (log-rank p < 0.001). Cox Regression indicated that HIV-1 was significantly associated with achievement of CD4 ≥ 500 cells/μl during follow-up, compared to HIV-2.

CONCLUSIONS

Sub-optimal responses to long-term HIV-2 treatment underscore the need for more research into improved and/or new treatment options for patients with HIV-2. In many West African countries, effective treatment of both HIV-1 and HIV-2 will be essential in the effort to reach epidemic control.

Discriminatory rapid tests cause HIV-type misclassification-evaluation of three rapid tests using clinical samples from Guinea-Bissau

BACKGROUND

Discrimination among HIV types is important because HIV-2 is naturally resistant to some of the first-line drugs used in the treatment of HIV-1. We evaluated three assays for HIV-type discriminatory capacity: SD Bioline HIV 1/2 3.0 (Bioline), First Response HIV 1-2-0 Card Test (First Response) and Genie III HIV-1/HIV-2 (Genie III).

METHODS

Based on results from the Bioline assay, samples from 239 HIV-infected patients from the Bissau HIV cohort in Guinea-Bissau were retrospectively selected for evaluation. Genie III and First Response were scored by three independent readers and compared with a reference test (INNO-LIA HIV I/II Score) confirmed by HIV RNA as well as DNA detection.

RESULTS

The best performing test was Genie III, with an average agreement with the reference test of 93.4%, followed by First Response (86.1%) and Bioline (72.4%). First Response and Bioline were scored with a false high number of HIV-1/2 dual infections. For both First Response and Genie III, there were discrepancies among independent readers, and some tests were scored as HIV non-reactive.

CONCLUSIONS

Using these rapid tests with a suboptimal performance will presumably result in a high rate of false HIV-1/2 dual diagnoses, depriving patients of alternative treatment options in cases of treatment failure.

Performance of Bio-Rad HIV-1/2 Confirmatory Assay in HIV-1, HIV-2 and HIV-1/2 dually reactive patients - comparison with INNO-LIA and immunocomb discriminatory assays

BACKGROUND

Being able to discriminate between HIV-1, HIV-2 and HIV-1/2 dual infection is imperative for the appropriate selection of antiretroviral therapy (ART) in regions with high HIV-2 endemicity.

OBJECTIVES

To evaluate Bio-Rad Geenius HIV-1/2 Confirmatory Assay against INNO-LIA HIV 1/2 Score and ImmunoComb HIV 1/2 BiSpot with an emphasis towards ability to discriminate between HIV-1, HIV-2 and HIV-1/2 dual infection.

MATERIAL AND METHODS

131 samples from ART naïve HIV infected patients in Guinea-Bissau were selected retrospectively and tested with Geenius, INNO-LIA and Immunocomb. HIV-1/2 RNA were measured in all samples and HIV-1/2 DNA in 59 samples.

RESULTS

The Geenius reader typed 62 samples as HIV-1 reactive, 37 samples as HIV-2 reactive and 32 samples as HIV-1/2 dually reactive. Geenius manual reading classified 10% more samples as HIV-1/2 dually reactive (n = 35). INNO-LIA typed 63 samples as HIV-1 reactive, 36 samples as HIV-2 reactive and 32 samples as HIV-1/2 dually reactive while Immunocomb classified a large proportion of samples as HIV-1/2 dually reactive (n = 45). The measurement of agreement of the Geenius reader compared with INNO-LIA and Immunocomb was 92.4% and 84.0% respectively while the measurement of agreement of Geenius manual reading compared with INNO-LIA and Immuncomb was 93.1% and 89.3% respectively.

CONCLUSIONS

Geenius has similar performance characteristics as INNO-LIA, and performs considerably better than Immunocomb, for differentiating between HIV types. This is especially true when using the Geenius reader while manual reading of the Geenius assay seemed to overestimate the numbers of HIV-1/2 dually reactive samples.

Evaluation of Two HIV Rapid Diagnostic Tests in a Context of Strains' Genetic Diversity in Mali

The rapid diagnostic tests used in most resource-limited countries offer little specificity in the differentiation of HIV-1, HIV-2, and HIV-1 + 2. World Health Organization (WHO) does periodically evaluate rapid tests in use in the South Countries. Despite the prequalification from WHO, it is necessary at local level to conduct comparative studies between the available tests. To do this in Mali, we conducted a cross-sectional study at the University Teaching Hospital Gabriel Touré and the Research and Training Center (SEREFO) of Bamako on 172 samples from retrospective and prospective studies. The goal of this project was to compare the following rapid tests: "HIV TRI-DOT" and OnSite HIV1/2 Ab Plus Combo Rapid Test for screening HIV-1 and HIV-2 to "ImmunoComb II BiSpot" (gold standard). The sensibility and specificity of "HIV TRI-DOT" for HIV-1 detection were 100% each [95% confidence interval (CI): 87.13-100 and 95.31-100]. Its performance for HIV-2 detection was 95.24% (95% CI: 84.21-98.68) (sensibility) and 100% (95% CI: 72.25-100) (specificity). The positive and negative predictive values were, respectively, 100% (95% CI: 91.24-100) and 83.33% (95% CI: 55.20-95.30). The sensibility and specificity of OnSite HIV1/2 Ab Plus Combo Rapid Test assay performance were 100% (95% CI: 87.13-100 and 95.31-100). Overall, OnSite HIV ½ Ab Combo Rapid Test proved to be a good test for warm countries and does not require refrigeration in these settings. Blood and its products can be used to perform the test, unlike "ImmunoComb II BiSpot" and "HIV TRI-DOT," which must be kept cold and cannot be done with whole blood.

HIV rapid screening tests and self-tests: Be aware of differences in performance and cautious of vendors

BACKGROUND

Rapid tests for HIV testing are essential tools to achieve the 90-90-90 target of the World Health Organization. Many tests are available, some directly from websites. Evaluation of the performance of rapid tests, under close to real-life usage, is therefore needed to ensure accurate diagnosis in the context of the recommendation for their more widespread use.

METHOD

Nine third- (3G) or fourth-generation (4G) rapid screening tests or self-tests (two bought on websites), were evaluated on an extensive panel of 200 HIV-negative and 312 HIV-positive samples, representative of a wide variety of clinical situations and HIV genetic diversity. A whole blood reconstitution protocol was designed to simulate real-life usage of these tests in community-based and private settings.

FINDINGS

The specificity was high (98.5-100%) and sensitivity excellent (100%) for samples from patients chronically infected with the pandemic strains. The performance for infrequent situations with a major epidemiological and clinical impact, such as infection with divergent viruses or primary infection, was highly variable, depending on the test. One of the two 4G tests allowed detection of additional positive samples from early stages of infection, whereas the second (sold as a 4G test on a website) corresponded in reality to a 3G test.

INTERPRETATION

Our study showed that not all tests are equal for the detection of major HIV variants or early stages of HIV infection; adding the detection of specific p24Ag improved the latter point. This study also showed, for the first time, that buying through web-based vendors can be risky, due to the varying performance of the tests and questionable sales practices. Our results are of particular importance in the context of the increasing use of rapid tests in an "outside laboratory" settings. FUND: Santé Publique France, COREVIH - Normandie, and Rouen University Hospital.

Prevalence of hepatitis C among HIV-1, HIV-2 and dually reactive patients: A multi-country cross-sectional survey in West Africa

Little is known on the impact of HIV-2 infection on HCV viral replication. The aim of the study was to compare HCV prevalence and viral replication based on HIV types in West Africa. A cross-sectional survey was conducted within the IeDEA HIV-2 West Africa cohort from March to December 2012. All HIVinfected adult patients who attended participating HIV clinics during the study period were included. Blood samples were collected and re-tested for HIV type discrimination, HCV serology and viral load. A total of 767 patients were enrolled: 186 HIV-1, 431 HIV-2 and 150 HIV-1&2 dually reactive. At time of sampling, 531 (69.2%) were on ART and median CD4+ cell count was 472/mm³. Thirty (3.9%, 95% CI 2.7-5.5) patients were anti-HCV positive (4.3% in HIV-1, 4.0% in HIV-1&2 dually reactive and 3.7% in HIV-2; p=0.91). Detectable HCV RNA was identified in 21 (70.0%) patients (100% in HIV-1 and HIV- 1&2 dually reactive vs. 43.8% in HIV-2; p=0.003). Systematic screening should be promoted and performed in this population, since HCV is now potentially curable in sub- Saharan Africa.

In Vitro Antiviral Activity of Cabotegravir against HIV-2

We examined the antiviral activity of the integrase inhibitor (INI) cabotegravir against HIV-2 isolates from INI-naive individuals. HIV-2 was sensitive to cabotegravir in single-cycle and spreading-infection assays, with 50% effective concentrations (EC₅₀s) in the low to subnanomolar range; comparable results were obtained for HIV-1 in both assay formats. Our findings suggest that cabotegravir should be evaluated in clinical trials as a potential option for antiretroviral therapy and preexposure prophylaxis in HIV-2-prevalent settings.

The challenge of discriminating between HIV-1, HIV-2 and HIV-1/2 dual infections

OBJECTIVES

Discrimination between HIV-1 and HIV-2 is important to ensure appropriate antiretroviral treatment (ART) and epidemiological surveillance. However, serological tests have shown frequent mistyping when applied in the field. We evaluated two confirmatory tests, INNO-LIA HIV I/II Score and ImmunoComb HIV 1/2 BiSpot, for HIV type discriminatory capacity.

METHODS

Samples from 239 ART-naïve HIV-infected patients from the Bissau HIV Cohort in Guinea-Bissau were selected retrospectively based on the initial HIV typing performed in Bissau, ensuring a broad representation of HIV types. INNO-LIA results were interpreted by the newest software algorithm, and three independent observers read the ImmunoComb results. HIV-1/HIV-2 RNA and DNA were measured for confirmation.

RESULTS

INNO-LIA results showed 123 HIV-1 positive samples, 69 HIV-2 positive and 47 HIV-1/2 dually reactive. There was agreement between INNO-LIA and HIV-1/HIV-2 RNA and DNA detection, although not all HIV-1/2 dually reactive samples could be confirmed by the nucleic acid results. Overall, the observers found that the ImmunoComb results differed from the INNO-LIA results, with agreements of 90.4, 91.2 and 92.5%, respectively, for HIV-1, HIV-2 and HIV-1/2. The combined kappa-score for agreement between the three observers was 0.955 (z-score 35.1; P < 0.01). Of the HIV-2 mono-reactive samples (INNO-LIA), the three observers interpreted 24.6-31.9% as HIV-1/2 dually infected by ImmunoComb. None of these samples had detectable HIV-1 RNA or DNA.

CONCLUSIONS

There was accordance between INNO-LIA calls and nucleic acid results, whereas ImmunoComb overestimated the number of HIV-1/2 dually infected patients. Confirmatory typing is needed for patients diagnosed with HIV-1/2 dual infection by ImmunoComb.

To err is human, to correct is public health: a systematic review examining poor quality testing and misdiagnosis of HIV status

INTRODUCTION

In accordance with global testing and treatment targets, many countries are seeking ways to reach the "90-90-90" goals, starting with diagnosing 90% of all people with HIV. Quality HIV testing services are needed to enable people with HIV to be diagnosed and linked to treatment as early as possible. It is essential that opportunities to reach people with undiagnosed HIV are not missed, diagnoses are correct and HIV-negative individuals are not inadvertently initiated on life-long treatment. We conducted this systematic review to assess the magnitude of misdiagnosis and to describe poor HIV testing practices using rapid diagnostic tests.

METHODS

We systematically searched peer-reviewed articles, abstracts and grey literature published from 1 January 1990 to 19 April 2017. Studies were included if they used at least two rapid diagnostic tests and reported on HIV misdiagnosis, factors related to potential misdiagnosis or described quality issues and errors related to HIV testing.

RESULTS

Sixty-four studies were included in this review. A small proportion of false positive (median 3.1%, interquartile range (IQR): 0.4-5.2%) and false negative (median: 0.4%, IQR: 0-3.9%) diagnoses were identified. Suboptimal testing strategies were the most common factor in studies reporting misdiagnoses, particularly false positive diagnoses due to using a "tiebreaker" test to resolve discrepant test results. A substantial proportion of false negative diagnoses were related to retesting among people on antiretroviral therapy. Conclusions HIV testing errors and poor practices, particularly those resulting in false positive or false negative diagnoses, do occur but are preventable. Efforts to accelerate HIV diagnosis and linkage to treatment should be complemented by efforts to improve the quality of HIV testing services and strengthen the quality management systems, particularly the use of validated testing algorithms and strategies, retesting people diagnosed with HIV before initiating treatment and providing clear messages to people with HIV on treatment on the risk of a "false negative" test result.

Prevalence of hepatitis B and delta according to HIV-type: a multi-country cross-sectional survey in West Africa

Background

In West Africa where HIV-1 and HIV-2 co-circulate, the co-infection with hepatitis B virus (HBV) and hepatitis Delta virus (HDV) is not well described. This study aimed at estimating the prevalence of HBV and HBV/HDV co-infection according to HIV types and risk factors for HBV infection among West African HIV-infected patients.

Method

A cross-sectional survey was conducted within the IeDEA West Africa cohort from March to December 2012 in Côte d’Ivoire (three sites), Burkina Faso and Mali (one site each). All HIV-infected adult patients on antiretroviral therapy (ART) or not who attended one of the participating HIV clinics during the study period and agreed to participate were included. Blood samples were collected and re-tested for HIV type discrimination, HBV and HDV serology as well as HBV viral load. Logistic regression was used to identify risk factors for HBV infection.

Results

A total of 791 patients were included: 192 HIV-1, 447 HIV-2 and 152 HIV-1&2 dually reactive. At time of sampling, 555 (70.2%) were on ART and median CD4+ cell count was 472/mm³ (inter-quartile range [IQR]: IQR: 294–644). Sixty-seven (8.5%, 95% CI 6.6–10.6) patients were HBsAg positive without any difference according to HIV type (7.9% in HIV-1, 7.2% in HIV-1&2 dually reactive and 9.4% in HIV-2; p = 0.61). In multivariate logistic analysis, age ≤ 30 years old (adjusted odds ratio [aOR] 5.00, 95% CI 1.96–12.76), age between 31 and 49 years old (aOR 1.78, 95% CI 1.00–2.21) and male gender (aOR 2.15, 95% CI 1.25–3.69) were associated with HBsAg positivity. HBV DNA testing was performed in 36 patients with blood sample available (25 on ART) and 8 (22.2%) had detectable HBV DNA. Among the HBsAg-positive individuals, 14.9% (95% CI 7.4–25.7) were also positive for anti-HDV antibody without any difference according to HIV type (28.6% in HIV-1, 14.3% in HIV-2 and 0.0% in HIV-1&2 dually reactive; p = 0.15).

Conclusion

HBV and HBV/HDV co-infection are common in West Africa, irrespective of HIV type. Therefore, screening for both viruses should be systematically performed to allow a better management of HIV-infected patients. Follow-up studies are necessary to determine the impact of these two viruses on HIV infection.

Effect of sex and age on outcomes among HIV-2-infected patients starting antiretroviral therapy in West Africa

OBJECTIVES

HIV-2-infected individuals usually initiate antiretroviral therapy (ART) at an advanced age compared with HIV-1 patients, with a potential impact on treatment outcomes. This study aimed to investigate the effect of sex and age on mortality and loss to follow-up (LTFU) among HIV-2-infected individuals initiating ART.

METHODS

Analyses were conducted using the database of the International Epidemiological Databases to Evaluate AIDS's collaboration in West Africa. LTFU was considered if the interval between the last visit and the closing date for this analysis was more than 180 days. Probability of death and LTFU were estimated with Kaplan-Meier methods. A Cox regression model was used to identify factors associated with death and LTFU over the first 24 months on ART.

RESULTS

A total of 1825 HIV-2-infected individuals, including 60% women were considered for this analysis. The median age, baseline CD4 cell count, and follow-up duration were 45 years [interquartile range (IQR; 38-52)], 185 cells/μl [IQR (95-297)], and 28.8 months [IQR (9.8-58.9)], respectively. Over the first 24 months, the mortality rate was 5.2/100 person-years of observation [95% confidence interval (CI; 4.4-6.1)] and 469 (25.7%) were LTFU. Male sex [hazard ratio (HR) = 1.9; 95% CI (1.4; 2.8)], baseline CD4 cell count less than 100 cell/μl [HR = 4.4 95% CI (1.7; 11.1); ref at least 350 cell/μl], haemoglobin 7.5-10 g/dl [HR = 2.4 95% CI (1.3; 4.4); ref at least 12 g/dl], and BMI less than 18 kg/m [HR = 2.1 95% CI (1.3; 3.4); ref = 18-25 kg/m] were associated with higher mortality over the first 24 months. Similar associations were found for LTFU.

CONCLUSION

Mortality and LTFU are high among ART-receiving HIV-2-infected individuals and higher in men than in women. There is a critical need to further determine the causes of poor retention and implement sex-specific solutions that improve outcomes in HIV-2 ART programmes.

Hiv-2 molecular epidemiology

The Simian Immunodeficiency Virus of sooty mangabeys (SIVsmm) has been revealed to be at the origin of Human Immunodeficiency Virus type 2 (HIV-2) in humans, firstly detected from two Portuguese patients in 1986. HIV-2 is mainly restricted to West Africa where it infects up to 1 to 2 million people. HIV-2 is also present in Europe, mainly Portugal and France, India and United States of America. Two major HIV-2 groups, groups A and B, were generated by two independent transmission events involving infected sooty mangabeys from the Taï forest in Ivory Coast. Seven other HIV-2 groups have been described, but each has only been identified in one patient. To date, no subtypes have been formally described but some preliminary data suggest that HIV-2 group A may be divided in two distinct subtypes with distinct geographical origins. To date only two recombinant forms have been described: one circulating recombinant form (CRF01_AB) and one unique recombinant form. In this review, we focused mainly on molecular data available and their insights about HIV-2 origins, diversity, drug resistance and global epidemiology.

A Multiplex PCR Approach for Detecting Dual Infections and Recombinants Involving Major HIV Variants

The cocirculation of different HIV types and groups can lead to dual infections and recombinants, which hinder diagnosis and therapeutic management. We designed two multiplex PCRs (mPCRs) coupled with capillary electrophoresis to facilitate the detection of such infections. The first, MMO2, targets three variants (HIV-1/M, HIV-1/O, and HIV-2), and the second, MMO, targets HIV-1/M and HIV-1/O. These mPCRs were validated on DNA and RNA extracts from 19 HIV-1/M, 12 HIV-1/O, and 13 HIV-2 cultures and from mixtures simulating dual infections. They were then assessed with DNA and RNA extracts from samples of 47 clinical monoinfections and HIV-1/M+O dual infections or infections with HIV-1/MO recombinants. Both mPCRs had excellent specificity. Sensitivities ranged from 80 to 100% for in vitro samples and from 58 to 100% for clinical samples, with the results obtained depending on the material used and the region of the genome concerned. Sensitivity was generally lower for DNA than for RNA and for amplifications of the integrase and matrix regions. In terms of global detection (at least one target gene for each strain), both mPCRs yielded a detection rate of 100% for in vitro samples. MMO2 detected 100% of the clinical strains from DNA and 97% from RNA, whereas MMO detected 100% of the strains from both materials. Thus, for in vitro and clinical samples, MMO2 was a useful tool for detecting dual infections with HIV-1 and HIV-2 (referred to as HIV-1+HIV-2) and HIV-1/M+O, and MMO was useful for detecting both MO dual infections and MO mosaic patterns.

Plasma HIV-2 RNA According to CD4 Count Strata among HIV-2-Infected Adults in the IeDEA West Africa Collaboration

Background

Plasma HIV-1 RNA monitoring is one of the standard tests for the management of HIV-1 infection. While HIV-1 RNA can be quantified using several commercial tests, no test has been commercialized for HIV-2 RNA quantification. We studied the relationship between plasma HIV-2 viral load (VL) and CD4 count in West African patients who were either receiving antiretroviral therapy (ART) or treatment-naïve.

Method

A cross sectional survey was conducted among HIV-2-infected individuals followed in three countries in West Africa from March to December 2012. All HIV-2 infected-patients who attended one of the participating clinics were proposed a plasma HIV-2 viral load measurement. HIV-2 RNA was quantified using the new ultrasensitive in-house real-time PCR assay with a detection threshold of 10 copies/ mL (cps/mL).

Results

A total of 351 HIV-2-infected individuals participated in this study, of whom 131 (37.3%) were treatment naïve and 220 (62.7%) had initiated ART. Among treatment-naïve patients, 60 (46.5%) had undetectable plasma HIV-2 viral load (<10 cps/mL), it was detectable between 10-100 cps/mL in 35.8%, between 100-1000 cps/mL in 11.7% and >1000 cps/mL in 6.0% of the patients. Most of the treatment-naïve patients (70.2%) had CD4-T cell count ≥500 cells/mm³ and 43 (46.7%) of these patients had a detectable VL (≥10 cps/mL). Among the 220 patients receiving ART, the median CD4-T cell count rose from 231 to 393 cells/mm³ (IQR [259-561]) after a median follow-up duration of 38 months and 145 (66.0%) patients had CD4-T cell count ≤ 500 cells/mm³ with a median viral load of 10 cps/mL (IQR [10-33]). Seventy five (34.0%) patients had CD4-T cell count ≥ 500 cells/mm³, among them 14 (18.7%) had a VL between 10-100 cps/mL and 2 (2.6%) had VL >100 cps/mL.

Conclusion

This study suggests that the combination of CD4-T cell count and ultrasensitive HIV-2 viral load quantification with a threshold of 10 cps/mL, could improve ART initiation among treatment naïve HIV-2-infected patients and the monitoring of ART response among patients receiving treatment.