Multicenter evaluation of methods to quantitate human immunodeficiency virus type 1 RNA in seminal plasma

HIV-1 RNA levels and antiretroviral drug resistance in blood and non-blood compartments from HIV-1-infected men and women enrolled in AIDS clinical trials group study A5077

BACKGROUND

Detectable HIV-1 in body compartments can lead to transmission and antiretroviral resistance. Although sex differences in viral shedding have been demonstrated, mechanisms and magnitude are unclear. We compared RNA levels in blood, genital-secretions and saliva; and drug resistance in plasma and genital-secretions of men and women starting/changing antiretroviral therapy (ART) in the AIDS Clinical Trials Group (ACTG) 5077 study.

METHODS

Blood, saliva and genital-secretions (compartment fluids) were collected from HIV-infected adults (≥ 13 years) at 14 United-States sites, who were initiating or changing ART with plasma viral load (VL) ≥ 2,000 copies/mL. VL testing was performed on all compartment fluids and HIV resistance genotyping on plasma and genital-secretions. Spearman rank correlations were used to evaluate concordance and Fisher's and McNemar's exact tests to compare VL between sexes and among compartments.

RESULTS

Samples were available for 143 subjects; 36% treated (23 men, 29 women) and 64% 'untreated' (40 men, 51 women). RNA detection was significantly more frequent in plasma (100%) than genital-secretions (57%) and saliva (64%) (P<0.001). A higher proportion of men had genital shedding versus women (78% versus 41%), and RNA detection was more frequent in saliva versus genital-secretions in women when adjusted for censoring at the limit of assay detection. Inter-compartment fluid VL concordance was low in both sexes. In 22 (13 men, 9 women) paired plasma-genital-secretion genotypes from treated subjects, most had detectable resistance in both plasma (77%) and genital-secretions (68%). Resistance discordance was observed between compartments in 14% of subjects.

CONCLUSIONS

HIV shedding and drug resistance detection prior to initiation/change of ART in ACTG 5077 subjects differed among tissues and between sexes, making the gold standard blood-plasma compartment assessment not fully representative of HIV at other tissue sites. Mechanisms of potential sex-dependent tissue compartmentalization should be further characterized to aid in optimizing treatment and prevention of HIV transmission.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00007488.

Reproductive assistance in HIV serodiscordant couples

BACKGROUND

Three quarters of individuals infected with human immunodeficiency virus (HIV) are in their reproductive years and may consider pregnancy planning. Techniques have been developed which can minimize the risk of HIV transmission in these couples, and the current literature on this topic is reviewed here.

METHODS

We reviewed the literature for the following topics: risk of HIV transmission, effects of HIV infection on fertility, reproductive assistance in industrialized and low-income countries, pre-exposure chemoprophylaxis (PrEP) and timed intercourse in HIV-discordant couples for both male and female positivity. Relevant publications were identified through searches of the EMBASE Medline and PubMed databases, the Google-indexed scientific literature and periodic specialized magazines from the on-line Library Service of the University of Milan, Italy.

RESULTS

In serodiscordant couples in which the man is positive, the primary method used to prevent HIV transmission is 'sperm washing', followed by IUI or IVF. Data show that sperm washing in HIV-positive men has not produced seroconversion in women or their offspring; however, the evidence is limited. Recently, increasing evidence describing PrEP for HIV prevention has been published and PrEP could be an alternative to ART for fertile couples. Usually HIV-infected women undergo self-insemination around the time of ovulation. Few studies have been published on IVF outcome in HIV-infected women.

CONCLUSIONS

Assisted reproduction programmes should be integrated into global public health services against HIV. For HIV serodiscordant couples with infected men, sperm washing should be the first choice. However, timed intercourse and PrEP for HIV prevention has been reported. Recent data highlight the possible impairment of fertility in HIV-infected women. Efforts to design a multicentric study should be strengthened.

Efficient methodologies for sensitive HIV-1 RNA quantitation from plasma and vaginal secretions

BACKGROUND

Quantifying HIV levels in mucosal secretions is essential to study compartmentalized expression of HIV and facilitate development of intervention strategies to prevent disease progression and transmission.

OBJECTIVES

To develop a sensitive, reliable, and cost-effective technique to quantify HIV from blood and vaginal secretions that is compatible with efficient implementation in clinical research environments.

STUDY DESIGN

A sensitive, reliable, internally-controlled real-time reverse transcriptase (RT) PCR assay, which uses the HIV-1 pol gene as a target (Hpol assay) was developed to quantify HIV levels in plasma and genital secretions, and compared to the widely used Roche Amplicor HIV-1 Monitor assay. In addition, a simplified method of sample collection and processing of genital secretions (self-collection and use of RNAlater with batch processing) was compared to provider collection of samples and immediate processing.

RESULTS

The sensitivity and reliability of HIV levels detected by the assay described herein correlate well with measurements from Roche Amplicor HIV-1 Monitor assay for both plasma and vaginal secretions (R(2)=0.9179 and R(2)=0.942, respectively). The Hpol assay reproducibly quantifies a lower limit of 5 HIV-1 RNA copies per reaction, with low-levels of inter-assay and intra-assay variation. Additionally, vaginal viral levels and detection frequency did not differ significantly between the two the collection and processing methods.

CONCLUSIONS

The methodologies developed here provide sensitive, reliable, and cost-effective quantification of HIV levels in plasma and mucosal secretions, and are compatible with efficient use in clinical research studies.

HIV dynamics in seminal plasma during primary HIV infection

HIV dynamics in seminal plasma during primary HIV infection was evaluated through an observational study of individuals with primary HIV infection at the University of Washington Primary Infection Clinic. Seminal plasma HIV RNA was quantified using a real-time reverse transcription PCR assay. Blood plasma RNA was quantified by bDNA or PCR-based assays. Longitudinal analyses of HIV RNA levels over time used random effects regression analysis. From 1993 to 2005, 110 men collected 327 semen specimens. Initial blood and seminal plasma RNA levels in untreated men were only moderately correlated (Spearman r = 0.38, p = 0.0002). Estimated peak and set point levels were lower in semen than blood by 0.8 (p = 0.001) and 0.7 (p < 0.001) log(10) copies/ml, respectively. RNA decay rates were similar in the two compartments (p = 0.4). For 2 months after infection, mean HIV RNA levels in seminal plasma remained above a threshold level (3.8 log(10) copies/ml) that has been associated with recovery of infectious virus in vitro. HIV-positive men are likely to be most infectious in the first months following HIV acquisition. However, the modest relationship between HIV RNA levels in blood and seminal plasma suggests that the relative risk of HIV transmission during primary infection may vary from current estimates that are solely based on blood levels. Incorporating seminal plasma HIV levels into future mathematical models may increase the accuracy of these models.

Biological and technical variables affecting immunoassay recovery of cytokines from human serum and simulated vaginal fluid: a multicenter study

The increase of proinflammatory cytokines in vaginal secretions may serve as a surrogate marker of unwanted inflammatory reaction to microbicide products topically applied for the prevention of sexually transmitted diseases, including HIV-1. Interleukin (IL)-1beta and IL-6 have been proposed as indicators of inflammation and increased risk of HIV-1 transmission; however, the lack of information regarding detection platforms optimal for vaginal fluids and interlaboratory variation limit their use for microbicide evaluation and other clinical applications. This study examines fluid matrix variants relevant to vaginal sampling techniques and proposes a model for interlaboratory comparisons across current cytokine detection technologies. IL-1beta and IL-6 standards were measured by 12 laboratories in four countries, using 14 immunoassays and four detection platforms based on absorbance, chemiluminescence, electrochemiluminescence, and fluorescence. International reference preparations of cytokines with defined biological activity were spiked into (1) a defined medium simulating the composition of human vaginal fluid at pH 4.5 and 7.2, (2) physiologic salt solutions (phosphate-buffered saline and saline) commonly used for vaginal lavage sampling in clinical studies of cytokines, and (3) human blood serum. Assays were assessed for reproducibility, linearity, accuracy, and significantly detectable fold difference in cytokine level. Factors with significant impact on cytokine recovery were determined by Kruskal-Wallis analysis of variance with Dunn's multiple comparison test and multiple regression models. All assays showed acceptable intra-assay reproducibility; however, most were associated with significant interlaboratory variation. The smallest reliably detectable cytokine differences ( P < 0.05) derived from pooled interlaboratory data varied from 1.5- to 26-fold depending on assay, cytokine, and matrix type. IL-6 but not IL-1beta determinations were lower in both saline and phosphate-buffered saline as compared to vaginal fluid matrix, with no significant effect of pH. The (electro)chemiluminescence-based assays were most discriminative and consistently detected <2-fold differences within each matrix type. The Luminex-based assays were less discriminative with lower reproducibility between laboratories. These results suggest the need for uniform vaginal sampling techniques and a better understanding of immunoassay platform differences and cross-validation before the biological significance of cytokine variations can be validated in clinical trials. This investigation provides the first standardized analytic approach for assessing differences in mucosal cytokine levels and may improve strategies for monitoring immune responses at the vaginal mucosal interface.

[Microbiological diagnosis of HIV infection]

Currently, there are around 150,000 HIV-infected patients in Spain. This number, together with the fact that this disease is now a chronic condition since the introduction of antiretroviral therapy, has generated an increasing demand on the clinical microbiology laboratories in our hospitals. This increase has occurred not only in the diagnosis and treatment of opportunistic diseases, but also in tests related to the diagnosis and therapeutic management of HIV infection. To meet this demand, the Sociedad de Enfermedades Infecciosas y Microbiología Clinica (Spanish Society of Infectious Diseases and Clinical Microbiology) has updated its standard Procedure for the microbiological diagnosis of HIV infection. The main advances related to serological diagnosis, plasma viral load, and detection of resistance to antiretroviral drugs are reviewed in this version of the Procedure.

Validation of an automated real-time PCR protocol for detection and quantitation of HIV and HCV genomes in semen

The ability to detect and quantify HIV and HCV genomes is important for checking spermatozoid preparation protocols also known as "sperm washing". But no commercial assay is available. A method was developed for detecting HIV and HCV in semen fractions using the COBAS Ampliprep and COBAS Taqman instruments. It will detect fewer than 200 copies of HIV RNA per ml of semen plasma and fewer than 200 copies/3 x 10(6) semen cells. The sensitivity for HCV is similar at more than 200 IU/ml and below 200 IU/3 x 10(6) semen cells. No inhibitor of PCR amplification was detected. This automated protocol permits a convenient, standardized testing for HIV and HCV in semen. The performance is the same as that of the previous generation of automated assays but the cost and operating time are both reduced.

Use of a novel washing method combining multiple density gradients and trypsin for removing human immunodeficiency virus-1 and hepatitis C virus from semen

OBJECTIVE

To determine the effectiveness of a novel treatment designed to remove human immunodeficiency virus (HIV) -1 and hepatitis C virus (HCV) from spiked semen and to evaluate sperm motility and viability after treatment.

DESIGN

A prospective clinical laboratory-based study.

SETTING

The human studies were conducted in academic and national research environments. The bovine study was conducted in an accredited research facility.

PATIENT(S)

Healthy volunteers provided the semen samples used in the human studies; abattoir-derived material was used for the bovine embryo production study.

INTERVENTIONS(S)

None.

MAIN OUTCOME MEASURE(S)

Cytopathic, reverse transcriptase-polymerase chain reaction, and branched DNA assays were used to test the efficacy of the procedure for inactivating or removing viruses from spiked semen; standard semen evaluation criteria were used to assess the effects of the procedures on sperm motility and viability.

RESULT(S)

Trypsin exposure significantly reduced the infectivity of HIV-1. The triple density gradient treatment, with or without trypsin, had no detrimental affect on fresh or cryopreserved/thawed sperm 2-48 hours after treatment. The treatment of semen spiked with HIV-1 or HCV indicated that the procedure was effective for reducing viral copies to undetectable levels or below levels of clinical relevance.

CONCLUSION(S)

The procedure was effective for significantly inactivating or reducing HIV-1 and HCV in spiked semen without adversely affecting sperm quality.

Multicenter quality control of the detection of HIV-1 genome in semen before medically assisted procreation

Couples in whom the man is HIV-1-positive may use medically assisted procreation in order to conceive a child without contaminating the female partner. But, before medically assisted procreation, the semen has to be processed to exclude HIV and tested for HIV nucleic acid before and after processing. The performance was evaluated of the technical protocols used to detect and quantify HIV-1 in 11 centers providing medically assisted procreation for couples with HIV-1 infected men by testing panels of seminal plasma and cells containing HIV-1 RNA and/or DNA. The performance of these tests varied due to the different assays used. False positive results were obtained in 14-19% of cases. The sensitivity for RNA detection in seminal plasma was 500-1,000 RNA copies/ml, over 500 RNA copies/10(6) cells in semen cells, and for DNA detection in semen cells 50-500 DNA copies/10(6) cells. The use of silica-based extraction seemed to increase the assay performance, whereas the use of internal controls to detect PCR inhibitor did not. This first quality control highlights the need for technical improvements of the assays to detect and quantify HIV in semen fractions and for regular evaluation of their performance.

Evaluation of the NucliSens Basic Kit assay for detection of Norwalk virus RNA in stool specimens

Norwalk-like viruses (NLVs) are a genetically diverse group of human caliciviruses that are the most common cause of epidemic gastroenteritis and are detected typically in stool by reverse transcription (RT)-PCR or electron microscopy (EM). The application of a rapid nucleic acid sequence-based amplification (NASBA) assay for the detection of NLV RNA in stool is described using the NucliSens Basic Kit. Primers and probes for the NLV Basic Kit assay were based on the RNA polymerase region of the prototype NLV, Norwalk virus (NV) genome and could consistently detect 10(4) RT-PCR detectable units of NV RNA in a stool filtrate. When compared directly with RT-PCR on a dilution series of NV stool filtrate, the NucliSens Basic Kit assay was equally sensitive. Cross-reactivity studies with a representative panel of other enteric pathogens were negative. When applied to 15 stool specimens from NV-challenged volunteers, the NASBA Basic Kit application for NV detection yielded 100% sensitivity, 50% specificity, and 67% concordance, using RT-PCR as the 'gold standard'. Despite the specificity of the NASBA primer/probe sequences for NV, other representatives from both NLV genogroups I and II could be detected by the Basic Kit assay in outbreak stool specimens, although the results were inconsistent. Our results suggest that the NucliSens Basic Kit assay provides a rapid and sensitive alternative to RT-PCR for detecting NV RNA in stool specimens. However, improvements in test specificity and primer design will be needed before the assay can be used routinely in the clinical setting.

Multicenter quality control for the detection of hepatitis C virus RNA in seminal plasma specimens

The discrepant results available in the literature about the presence of hepatitis C virus (HCV) RNA in seminal plasma of men chronically infected by this agent are related, at least in part, to the molecular techniques used and particularly to the wide range of protocols dedicated to RNA extraction. In order to evaluate these protocols and to standardize the method of detection of HCV RNA in this fluid, a panel of coded specimens was tested blindly in 12 French laboratories; it included 14 seminal plasma specimens and four water controls spiked with HCV RNA ranging from 10 to 20000 IU/ml and two HCV-negative seminal plasma specimens. The extraction step was performed according to methods using either silica beads (NucliSens [Organon Teknika S.A., Fresnes, France]; RNA viral kit [Qiagen, Courtaboeuf, France]) or guanidinium thiocyanate (Amplicor HCV assay; Roche Diagnostics, Meylan, France), preceded or not by a centrifugation of the seminal plasma. For the amplification step, all the laboratories performed the same reverse transcription-PCR technique (Amplicor HCV Cobas assay). The percentage of correct results ranged from 53.3 to 100, the poorest results being obtained when no centrifugation step preceded the Amplicor extraction protocol. The rate of correct results was significantly higher in laboratories using a preliminary centrifugation of the specimen (P = 0.034 by chi-square test). By contrast, the overall number of correct results was not correlated to the initial volume of sample used for the test. These results allowed us to validate standardized techniques adapted to the performance of this test on a routine basis, especially in men infected with HCV and involved in programs of medically assisted reproduction.

Comparison of the RNA-amplification based methods RT-PCR and NASBA for the detection of circulating tumour cells

Increasingly, reverse transcriptase polymerase chain reaction (RT-PCR) is used to detect clinically significant tumour cells in blood or bone marrow. This may result in a redefinition of disease-free and clinical relapse. However, its clinical utility may be limited by lack of automation or reproducibility. Recent studies have suggested nucleic acid sequence-based amplification of target RNA may be more robust. In this study, nucleic acid sequence-based amplification was established to detect melanoma, colorectal and prostate cancer cells. Nucleic acid sequence-based amplification and RT-PCR both successfully amplified target RNA in peripheral blood samples from patients with melanoma and colorectal cancer, but only RT-PCR detected PSA in blood samples from patients with prostate cancer. There was relatively good agreement between sample replicates analyzed by RT-PCR (Kappa values of one for tyrosinase, 0.67 for CK-20 and one for PSA), but less agreement when analyzed by nucleic acid sequence-based amplification. This may limit the routine use of NASBA for the detection of clinically significant disease. In summary, RT-PCR appears at present to be the most reliable and reproducible method for the detection of low-level disease in cancer patients, although prospective studies are warranted to assess the clinical utility of different molecular diagnostic methods.