No Association Between HLA-B*57:01 and Prevalence and/or Outcome of Progressive Multifocal Leukoencephalopathy in a French Nationwide Human Immunodeficiency Virus Cohort

Among 34,351 patients living with human immunodeficiency virus with available HLA-B*57:01 included in the Dat'AIDS cohort, 194 patients (0.56%) had a history of progressive multifocal leukoencephalopathy (PML) and 1,746 (5.08%) were carriers of HLA-B*57:01. The frequency of HLA-B*57:01 was similar among patients with history of PML compared with patients without a history of PML (6.19% [95% confidence interval, CI 2.8%-9.6%] vs. 5.08% [95% CI 4.8%-5.3%]; p = .48). Among patients with PML, clinical and biological characteristics at PML diagnosis and the PML outcome were not different according to HLA-B*57:01 status.

HLA-B*57:01 typing in a Malaysian cohort: implications of abacavir hypersensitivity in people living with HIV

Background: Abacavir (ABC) in combination with other antiretroviral drugs, is used to treat people living with HIV (PLWH). However, it is linked to a fatal hypersensitivity reaction in susceptible individuals, and is strongly associated with the HLA-B*57:01 allele. Materials & methods: A total of 152 patients, 50 PLWH and 102 HIV-1 negative patients, were assessed for the HLA-B*57:01 allele through a sequence-specific primer PCR. Results: All PLWH tested negative for the HLA-B*57:01 allele, but two HIV-negative patients were found to have HLA-B*57, with one of them expressing the HLA-B*57:01 allele. Conclusion: Given the low prevalence of this risk allele in the population, testing for the presence of HLA-B*57:01 in PLWH may not provide significant benefit for the reported population.

HLA-B*57:01/Carbamazepine-10,11-Epoxide Association Triggers Upregulation of the NFκB and JAK/STAT Pathways

Measure of drug-mediated immune reactions that are dependent on the patient's genotype determine individual medication protocols. Despite extensive clinical trials prior to the license of a specific drug, certain patient-specific immune reactions cannot be reliably predicted. The need for acknowledgement of the actual proteomic state for selected individuals under drug administration becomes obvious. The well-established association between certain HLA molecules and drugs or their metabolites has been analyzed in recent years, yet the polymorphic nature of HLA makes a broad prediction unfeasible. Dependent on the patient's genotype, carbamazepine (CBZ) hypersensitivities can cause diverse disease symptoms as maculopapular exanthema, drug reaction with eosinophilia and systemic symptoms or the more severe diseases Stevens-Johnson-Syndrome or toxic epidermal necrolysis. Not only the association between HLA-B*15:02 or HLA-A*31:01 but also between HLA-B*57:01 and CBZ administration could be demonstrated. This study aimed to illuminate the mechanism of HLA-B*57:01-mediated CBZ hypersensitivity by full proteome analysis. The main CBZ metabolite EPX introduced drastic proteomic alterations as the induction of inflammatory processes through the upstream kinase ERBB2 and the upregulation of NFκB and JAK/STAT pathway implying a pro-apoptotic, pro-necrotic shift in the cellular response. Anti-inflammatory pathways and associated effector proteins were downregulated. This disequilibrium of pro- and anti-inflammatory processes clearly explain fatal immune reactions following CBZ administration.

Rapid Near Point-of-Care Assay for HLA-B*57:01 Genotype Associated with Severe Hypersensitivity Reaction to Abacavir

The nucleoside reverse transcriptase inhibitor abacavir (ABC) is used commonly to treat young children with HIV infection and is a component of the fixed-dose-combination Triumeq^®. ABC can trigger a severe hypersensitivity reaction in people who are homozygous or heterozygous for HLA-B*57:01. Testing for HLA-B*57:01 before ABC initiation is standard-of-care in high-resource settings, but current tests are costly or difficult to access in resource-limited settings. To address these gaps, we developed an inexpensive simple-to-use rapid assay to detect HLA-B*57:01. We designed and optimized a multiplexed polymerase chain reaction (PCR) to amplify HLA-B*57 subtypes and the human beta-globin gene; employed probes and ligation to specifically tag the HLA-B*57:01 allele with biotin. Tagged-ligated products were detected by immunocapture in an enzyme-linked immunosorbent assay plate or lateral flow strip. Cell lines with known HLA genotypes were used to optimize the assay. The optimized assay was then compared with genotypes of clinical specimens (n = 60) determined by sequencing, with specimens enriched for individuals with HLA-B*57:01. The optimized assay utilizes 40-min 35-cycle multiplex PCR for B*57 and beta-globin; 20-min ligation reaction; and 15-min detection. Evaluation of the HLA-B*57:01 oligonucleotide ligation assay using clinical specimens had a sensitivity of 100% (n = 27/27 typed as B*57:01) and specificity of 100% (n = 33/33 typed as non-B*57:01) by visual interpretation of lateral flow strips. The cost is US$5.96/specimen. This rapid and economical assay accurately detects HLA-B*57:01 in clinical specimens. Use of this assay could expand access to HLA-B*57:01 genotyping and facilitate safe same-day initiation of ABC-based treatment.

Prevalence of human leukocyte antigen HLA-B*57:01 in individuals with HIV in West and Central Africa

BACKGROUND

The presence of the human leukocyte antigen HLA-B*57:01 is associated with the development of a hypersensitivity reaction to abacavir (ABC). Limited data exist on HLA-B*57:01 prevalence in individuals with HIV-1 in Africa. This study aimed to estimate HLA-B*57:01 prevalence in individuals with HIV-1 in West and Central Africa.

METHODS

A cross-sectional study was conducted in four countries in West and central Africa (Burkina-Faso, Côte d'Ivoire, Gabon, and Togo) from January 2016 to February 2020 to determine the status of HLA-B*57:01 in adults with HIV-1. The presence of HLA-B*57:01 was determined by using Single Specific Primer-Polymerase Chain Reaction (SSP-PCR) in blood samples. Prevalence rates were stratified based on country.

RESULTS

A total of 4016 (69.8% women) individuals with HIV were enrolled. Their median age was 45, and the interquartile range was 38-52. We included 500 (12.4%) patients in Burkina-Faso, 1453 (36.2%) in Côte d'Ivoire, 951 (23.7%) in Gabon, and 1112 (27.7%) in Togo. The overall HLA-B*57:01 prevalence was 0.1% [95% CI: 0.0-0.2%]. The prevalence of HLA-B*57:01 was similar according to the four countries. Only one case was reported in each country except Togo, with no cases.

CONCLUSIONS

HLA-B*57:01 prevalence is low in individuals with HIV in West and central Africa, and there is no difference among countries. This study does not confirm the utility of HLA-B*57:01 allele testing for abacavir use in this region.

Alterations in the HLA-B*57:01 Immunopeptidome by Flucloxacillin and Immunogenicity of Drug-Haptenated Peptides

Neoantigen formation due to the interaction of drug molecules with human leukocyte antigen (HLA)-peptide complexes can lead to severe hypersensitivity reactions. Flucloxacillin (FLX), a β-lactam antibiotic for narrow-spectrum gram-positive bacterial infections, has been associated with severe immune-mediated drug-induced liver injury caused by an influx of T-lymphocytes targeting liver cells potentially recognizing drug-haptenated peptides in the context of HLA-B*57:01. To identify immunopeptidome changes that could lead to drug-driven immunogenicity, we used mass spectrometry to characterize the proteome and immunopeptidome of B-lymphoblastoid cells solely expressing HLA-B*57:01 as MHC-I molecules. Selected drug-conjugated peptides identified in these cells were synthesized and tested for their immunogenicity in HLA-B*57:01-transgenic mice. T cell responses were evaluated in vitro by immune assays. The immunopeptidome of FLX-treated cells was more diverse than that of untreated cells, enriched with peptides containing carboxy-terminal tryptophan and FLX-haptenated lysine residues on peptides. Selected FLX-modified peptides with drug on P4 and P6 induced drug-specific CD8⁺ T cells in vivo. FLX was also found directly linked to the HLA K146 that could interfere with KIR-3DL or peptide interactions. These studies identify a novel effect of antibiotics to alter anchor residue frequencies in HLA-presented peptides which may impact drug-induced inflammation. Covalent FLX-modified lysines on peptides mapped drug-specific immunogenicity primarily at P4 and P6 suggesting these peptide sites as drivers of off-target adverse reactions mediated by FLX. FLX modifications on HLA-B*57:01-exposed lysines may also impact interactions with KIR or TCR and subsequent NK and T cell function.

Comparison of abacavir-specific effector and proliferating functions of CD8 T cells in abacavir-treated HIV-1 patients

Susceptibility to abacavir hypersensitivity (ABH) in HIV-1-positive patients is strongly linked to the carriage of HLA-B*57:01 and the potential mechanism includes drug-specific activation of cytokine producing CD8 T cells exclusively in individuals carrying HLA-B*57:01. Here, we report a detailed characterization of abacavir-induced functional response of CD8 T cells in HLA-B*57:01^pos individuals. Peripheral blood mononuclear cells (PBMNCs) from HLA-B*57:01^pos ABH^pos and HLA-B*57:01^neg ABH^neg individuals were stimulated with abacavir. Multicolor flow cytometry was performed to assess the cytokine (IFNγ) production and degranulation (CD107a expression) after 6-18 hr culture and to enumerate proliferating CD4/CD8 T cells by culturing carboxyfluorescein diacetate succinimidyl ester-loaded PBMNCs for 7 days. CD8 T cells from HLA-B*57:01^pos ABH^pos individuals were multifunctional: proliferating, IFNγ producing, degranulating (CD107a^pos ), and both degranulating and IFNγ producing (CD107a^pos IFNγ^pos ). Degranulating CD8 T cells in general and both degranulating and IFNγ producing CD8 T cells in particular dominated abacavir-specific immune response. All functional responses were partially blocked by addition of HLA-B*57:01-reactive Bw4 mAb, but not by non-HLA-B*57:01-reactive Bw6 mAb. In conclusion, the study demonstrates that abacavir-specific CD8 T-cell-restricted immune response in HLA-B*57:01^pos ABH^pos HIV-1 patients has multiple effector and proliferating functions, where the primary effector response appears to be the release of cytolytic granules. The findings have implications for immunotherapy of HLA-related drug hypersensitivities.

HLA-B*57:01 allele prevalence in treatment-Naïve HIV-infected patients from Colombia

BACKGROUND

The HLA-B*57:01 allele is associated with a hypersensitivity reaction to abacavir. Due to the lack of knowledge of HLA-B*57:01 prevalence in Colombia, routine screening is not performed and is not recommended by the national guidelines. We aimed to determine the prevalence of HLA-B*57:01 in HIV population from Colombia.

METHODS

This cross-sectional study included naïve HIV-infected adults from 13 cities of the country. The presence of HLA-B*57:01 was determined by using SSP-PCR in blood samples. Prevalence rates were stratified by sex, race, and region of origin.

RESULTS

HLA-B*57:01 allele prevalence in Colombian HIV-infected individuals was 2.7%. When stratifying for the race, the prevalence was 4% for whites, 2.6% for other race (mainly mestizo), and 1.9% for Afro-Colombians. The prevalence varied from 0% up to 11.4% depending on the department of origin. The highest prevalence rates were found in Caldas (11.4%), Antioquia (5%), Risaralda (4.8%), and Valle del Cauca (4.3%). When distributed by country zones, the central, with a racial predominance of Caucasians and mestizos, was the highest (6.0%, 0R = 4.1, CI 1.2-12.8, p = 0,016).

CONCLUSIONS

The overall prevalence of HLA-B*57:01 in Colombia was lower than the reported rates for other Latin American countries such as Brazil, Costa Rica, and Argentina, but similar in comparison to Chile and Mexico. The diversity in the racial and ethnic heritage shown in our data supports the recommendation to implement routine screening for the HLA-B*57:01 allele before initiation of abacavir-containing antiretroviral therapy in the Colombian HIV management guidelines.

Gaining Insight Into Posttranslationally Modified HIV Antigens and Their Underlying Characteristics

Mass spectrometry (MS)-based immunopeptidomics has developed as one of the leading methodologies for comprehensive characterization of in vivo presented human leukocyte antigen (HLA)-bound peptides. Unveiling the identity of HLA-bound peptides derived from diseased cells is crucial to gain knowledge on the constitution of efficient disease-specific T cell responses. The HLA-presented peptidome reflects the status of the cellular proteome, hence disease-related aberrations of posttranslational modifications (PTMs) might lead to presentation of peptides harboring PTMs. Therefore, characterization of HLA-bound PTM peptides could shed light on their relevance in immune and disease processes. In this issue, Ramarathinam et al. investigate the presentation of HIV envelope (HIVenv) peptides bound to the HLA-B*57:01 allele. Among these peptides, the authors specifically focused on a kynurenine-modified peptide. To this end, they characterize the possible origin of the kynurenine modification, its effect on HLA binding affinity, stability, conformation within the complex, and its immunogenicity compared to the native counterpart.

Identification of Native and Posttranslationally Modified HLA-B*57:01-Restricted HIV Envelope Derived Epitopes Using Immunoproteomics

The recognition of pathogen-derived peptides by T lymphocytes is the cornerstone of adaptive immunity, whereby intracellular antigens are degraded in the cytosol and short peptides assemble with class I human leukocyte antigen (HLA) molecules in the ER. These peptide-HLA complexes egress to the cell surface and are scrutinized by cytotoxic CD8+ T-cells leading to the eradication of the infected cell. Here, naturally presented HLA-B*57:01 bound peptides derived from the envelope protein of the human immunodeficiency virus (HIVenv) are identified. HIVenv peptides are present at a very small percentage of the overall HLA-B*57:01 peptidome (<0.1%) and both native and posttranslationally modified forms of two distinct HIV peptides are identified. Notably, a peptide bearing a natively encoded C-terminal tryptophan residue is also present in a modified form containing a kynurenine residue. Kynurenine is a major product of tryptophan catabolism and is abundant during inflammation and infection. Binding of these peptides at a molecular level and their immunogenicity in preliminary functional studies are examined. Modest immune responses are observed to the modified HIVenv peptide, highlighting a potential role for kynurenine-modified peptides in the immune response to HIV and other viral infections.

Adverse drug reactions triggered by the common HLA-B*57:01 variant: virtual screening of DrugBank using 3D molecular docking

BACKGROUND

Idiosyncratic adverse drug reactions have been linked to a drug's ability to bind with a human leukocyte antigen (HLA) protein. However, due to the thousands of HLA variants and limited structural data for drug-HLA complexes, predicting a specific drug-HLA combination represents a significant challenge. Recently, we investigated the binding mode of abacavir with the HLA-B*57:01 variant using molecular docking. Herein, we developed a new ensemble screening workflow involving three X-ray crystal derived docking procedures to screen the DrugBank database and identify potentially HLA-B*57:01 liable drugs. Then, we compared our workflow's performance with another model recently developed by Metushi et al., which proposed seven in silico HLA-B*57:01 actives, but were later found to be experimentally inactive.

METHODS

After curation, there were over 6000 approved and experimental drugs remaining in DrugBank for docking using Schrodinger's GLIDE SP and XP scoring functions. Docking was performed with our new consensus-like ensemble workflow, relying on three different X-ray crystals (3VRI, 3VRJ, and 3UPR) in presence and absence of co-binding peptides. The binding modes of HLA-B*57:01 hit compounds for all three peptides were further explored using 3D interaction fingerprints and hierarchical clustering.

RESULTS

The screening resulted in 22 hit compounds forecasted to bind HLA-B*57:01 in all docking conditions (SP and XP with and without peptides P1, P2, and P3). These 22 compounds afforded 2D-Tanimoto similarities being less than 0.6 when compared to the structure of native abacavir, whereas their 3D binding mode similarities varied in a broader range (0.2-0.8). Hierarchical clustering using a Ward Linkage revealed different clustering patterns for each co-binding peptide. When we docked Metushi et al.'s seven proposed hits using our workflow, our screening platform identified six out of seven as being inactive. Molecular dynamic simulations were used to explore the stability of abacavir and acyclovir in complex with peptide P3.

CONCLUSIONS

This study reports on the extensive docking of the DrugBank database and the 22 HLA-B*57:01 liable candidates we identified. Importantly, comparisons between this study and the one by Metushi et al. highlighted new critical and complementary knowledge for the development of future HLA-specific in silico models.

High Frequency of Human Leukocyte Antigen-B*57:01 Allele Carriers among HIV-Infected Patients in Serbia

Abacavir is an effective antiretroviral drug and one of the most commonly used nucleoside reverse transcriptase inhibitors in Serbia. А percentage of the treated patients experience a potentially life-threatening hypersensitivity reaction, which was shown to be associated with the presence of the class I MHC allele, HLA-B*57:01; hence genotyping for HLA-B*57:01 prior to starting abacavir is nowadays recommended in international HIV treatment guidelines. In Serbia, this testing became available in 2013. This study was designed to estimate the prevalence of the HLA-B*57:01 allele in Serbian HIV-1-infected patients. The presence of the HLA-B*57:01 allele was analyzed in 273 HIV-1-infected patients aged 18 years or more, who were abacavir naïve. Buccal swab samples were obtained from all participants and assayed for the presence of HLA-B*57:01 using a commercially available HLA-B*57:01 real-time PCR kit. The presence of the HLA-B*57:01 allele was found in 22 of 273 tested individuals (8%; 95% CI 5.4-11.9%). This is the first study that estimated the HLA-B*57:01 prevalence among HIV-infected patients in Serbia. The very high prevalence of HLA-B*57:01 found in our study strongly supports HLA-B*57:01 genotyping, which should be implemented prior to the initiation of an abacavir-containing therapy to reduce the risk of potentially life-threatening hypersensitivity reactions.

Rapid and Reliable Genotyping of HLA-B*57:01 in Four Chinese Populations Using a Single-Tube Duplex Real-Time Polymerase Chain Reaction Assay

HLA-B*57:01 is strongly associated with severe adverse drug reaction induced by the anti-HIV drug abacavir (ABC) and antibiotic flucloxacillin. This study was dedicated to establishing a new method for HLA-B*57:01 genotyping and investigating the HLA-B*57:01 distribution pattern in four Chinese populations. A single-tube duplex real-time polymerase chain reaction (PCR) system was established by combining the amplification refractory mutation system and TaqMan probe. The reliability of this assay was validated by comparing the genotyping results with those by sequence-based typing. With this assay, the distribution of HLA-B*57:01 in 354 blood samples from four ethnic groups, namely, Han, Tibetan, Uighur, and Buyei, was determined. A 100% concordance was observed between the results of real-time PCR and sequence-based typing in 50 Uighur samples. As low as 0.016 ng DNA that carried HLA-B*57:01 could be detected with this assay. HLA-B*57:01 carriers identified in 100 Northern Han Chinese, 104 Buyeis, 100 Tibetans, and 50 Uighurs were 0, 1 (0.96%), 3 (3%), and 6 (12%), respectively. The carrier rate of HLA-B*57:01 in Uighur was significantly higher than those in Northern Han (p = .001) and Buyei (p = .005). The newly established real-time PCR assay provides a rapid and reliable tool for HLA-B*57:01 allele screening before the prescription of ABC and flucloxacillin in clinical practice.

HLA-B*57:01 allele prevalence in HIV-infected North American subjects and the impact of allele testing on the incidence of abacavir-associated hypersensitivity reaction in HLA-B*57:01-negative subjects

Background

The presence of the HLA-B*57:01 allele in HIV-infected subjects is associated with a higher risk of abacavir-associated hypersensitivity reaction (ABC HSR). HLA-B*57:01 allele prevalence varies in different populations, but HLA-B*57:01 testing with immunological confirmation has had a negative predictive value for ABC HSR between 97 and 100%.

Methods

In the ASSURE study (EPZ113734), the HLA-B*57:01 prevalence in virologically suppressed, antiretroviral treatment–experienced, HIV-infected subjects from the United States, including Puerto Rico, was assessed.

Results

Three hundred eighty-five subjects were screened; 13 were HLA-B*57:01 positive and 372 were negative. Only HLA-B*57:01-negative, abacavir-naive subjects were eligible to enroll into the ASSURE trial. Eleven of the 13 subjects who possessed the HLA-B*57:01 allele were white, the other 2 were African-American. There was no geographic clustering of HLA-B*57:01-positive subjects, and the incidence correlated roughly with those states with the greatest numbers of subjects screened. Similarly, there was no statistically significant correlation between subjects who possessed or lacked the allele and age, gender, ethnicity or CD4+ T-cell numbers. The incidence of ABC HSR following abacavir initiation was also evaluated. Only 1 of 199 HLA-B*57:01-negative subjects (an African-American male) randomized to receive abacavir-containing treatment developed symptoms consistent with suspected ABC HSR; ABC HSR was not immunologically confirmed.

Conclusions

These findings confirm the utility of HLA-B*57:01 allele testing to reduce the frequency of ABC HSR. The prevalence of HLA-B*57:01 positivity was higher in white than in African-American subjects. In HLA-B*57:01-negative subjects, suspected ABC HSR is very rare, but should lead to discontinuation of abacavir when ABC HSR cannot be definitively excluded from the differential diagnosis.

Trial registration

The ASSURE (EPZ113734) study was registered on ClinicalTrials.gov registration on April 8th 2010 and the registration number is NCT01102972.

Prevalence of abacavir-associated hypersensitivity syndrome and HLA-B*5701 allele in a Portuguese HIV-positive population

Background

Human Immunodeficiency Virus (HIV)-positive patients treated with the antiretroviral drug abacavir (ABC) may develop a potentially fatal ABC-associated hypersensitivity syndrome (ABC-HS), typically characterized by fever, malaise, rash, vomiting/diarrhoea and/or dyspnoea/cough. ABC-HS has been strongly associated with HLA-B*57:01 carriage and screening for this allele is recommended.

Objective

To determine the prevalence of HLA-B*57:01 and to characterize suspected ABC-HS in the adult HIV population from our hospital during a 7-year period.

Methods

Clinical data on patients under ABC treatment from January 2006 to December 2012 were analyzed to search for symptoms of ABC-HS. Reactions of suspected ABC-HS were characterized. HLA-B*57:01 and patch tests (1% and 10% ABC in petrolatum) with readings at 48 h were performed in those without previous testing. From January 2008 routine HLA-B*57:01 screening was implemented.

Results

From January 2006 to December 2007, 186 patients began treatment with ABC (data from 163 were available): 7 (4%) patients stopped ABC for suspected ABC-HS (71% males, median age 45 years) and the median time for onset of the reaction after starting ABC was 7 days. Four of the 7 patients had the HLA-B*57:01 allele and 2 of these 4 had positive patch tests. After HLA-B*57:01 screening implementation (January 2008), 573 patients were evaluated and 35 (6.1%) were HLA-B*57:01 positive; no suspected ABC-HS were observed since then.

Conclusion

Four patients with suspected ABC-HS (of 6 screened) were HLA-B*57:01 positive. No ABC-HS occurred since January 2008, after HLA-B*57:01 screening was implemented.

Validation of a rapid test for HLA-B*58:01/57:01 allele screening to detect individuals at risk for drug-induced hypersensitivity

AIM

In prevention of allopurinol and abacavir hypersensitivity, screening HLA-B*58:01/57:01 has been highly recommended prior to commencing these therapies. Therefore, we aimed at developing and validating a rapid and robust screening method for HLA-B*58:01/57:01.

MATERIALS & METHODS

Real-time polymerase chain reaction with TaqMan probes was employed to detect HLA-B*58:01/57:01.

RESULTS

The newly developed assay has the sensitivity of 100% (95% CI: 79.4-100.0%), the specificity of 98.8% (95% CI: 93.6-99.9%), the positive predictive value of 94.1% (95% CI: 71.3-99.9%) and the negative predictive value of 100.0% (95% CI: 95.7-100.0%). The lowest limit of detection is 0.04 ng/µl of DNA.

CONCLUSION

The present method is a rapid and robust assay that is appropriate for screening of HLA-B*58:01/*57:01 alleles.

Enhancing capacitive DNA biosensor performance by target overhang with application on screening test of HLA-B*58:01 and HLA-B*57:01 genes

A highly sensitive label-free DNA biosensor based on PNA probes immobilized on a gold electrode was used to detect a hybridization event. The effect of a target DNA overhang on the hybridization efficiency was shown to enhance the detected signal and allowed detection at a very low concentration. The sensors performances were investigated with a complementary target that had the same length as the probe, and the signal was compared to the target DNAs with different lengths and overhangs. A longer target DNA overhang was found to provide a better response. When the overhang was on the electrode side the signal enhancement was greater than when the overhang was on the solution side due to the increased thickness of the sensing surface, hence produced a larger capacitance change. Using conformationally constrained acpcPNA probes, double stranded DNA was detected sensitively and specifically without any denaturing step. When two acpcPNA probes were applied for the screening test for the double stranded HLA-B*58:01 and HLA-B*57:01 genes that are highly similar, the method differentiated the two genes in all samples. Both purified and unpurified PCR products gave comparable results. This method would be potentially useful as a rapid screening test without the need for purification and denaturation of the PCR products.

Diagnostic accuracy of HLA-B*57:01 screening for the prediction of abacavir hypersensitivity and clinical utility of the test: a meta-analytic review

AIM

To determine diagnostic accuracy of HLA-B*57:01 testing for prediction of abacavir-induced hypersensitivity and to quantify the clinical benefit of pretreatment screening through a meta-analytic review of published studies.

METHODS

A comprehensive search was performed up to June 2013. The methodological quality of relevant studies was assessed by the QUADAS-2 tool. The pooled diagnostic estimates were calculated using a random effect model.

RESULTS

Despite the presence of heterogeneity in sensitivity or specificity estimates, the pooled diagnostic odds ratio to detect abacavir-induced hypersensitivity on the basis of clinical criteria was 33.07 (95% CI: 22.33-48.97, I(2): 13.9%), while diagnostic odds ratio for detection of immunologically confirmed abacavir hypersensitivity was 1141 (95% CI: 409-3181, I(2): 0%). Pooled analysis of risk ratio showed that prospective HLA-B*57:01 testing significantly reduced the incidence of abacavir-induced hypersensitivity.

CONCLUSION

This meta-analysis demonstrates an excellent diagnostic accuracy of HLA-B*57:01 testing to detect immunologically confirmed abacavir hypersensitivity and corroborates existing recommendations.

The Pharmacogenomic HLA Biomarker Associated to Adverse Abacavir Reactions: Comparative Analysis of Different Genotyping Methods

Many pharmacogenomic biomarkers (PGBM) were identified and translated into clinical practice, affecting the usage of drugs via label updates. In this context, abacavir is one of the most brilliant examples of pharmacogenetic studies translated into clinical practice. Pharmacogenetic studies have revealed that abacavir HSRs are highly associated with the major histocompatibility complex class I. Large studies established the effectiveness of prospective HLA-B*57:01 screening to prevent HSRs to abacavir. Accordingly to these results the abacavir label has been modified: the European Medicines Agency (EMA) and the FDA recommend/suggested that the administration of abacavir must be preceded by a specific genotyping test. The HLA locus is extremely polymorphic, exhibiting many closely related alleles, making it difficult to discriminate HLA-B*57:01 from other related alleles, and a number of different molecular techniques have been developed recently to detect the presence of HLA-B*57:01. In this review, we provide a summary of the available techniques used by laboratories to genotype HLA-B*57:01, outlining the scientific and pharmacoeconomics pros and cons.