Double-Negative T Cell Number and Phenotype Alterations Before and After Effective Antiretroviral Treatment in Persons Living with HIV

Double-negative (DN) T cells represent a small and phenotypically heterogeneous population that display regulatory functions. In HIV infection, DN T cells are decreased in peripheral blood and have been negatively associated with T cell activation. This study was aimed at describing the dynamics and phenotypic characteristics of DN T cells in peripheral blood of people living with HIV (PLHIV) before and after antiretroviral therapy (ART) initiation. We included 41 newly diagnosed, ART-naive individuals with advanced HIV infection, who were followed up for 6 months after ART initiation. The control group included 34 people without HIV (PWHIV), on preexposure prophylaxis for HIV infection. DN T cells in peripheral blood were characterized by flow cytometry. The absolute counts of DN T cells were lower in PLHIV than in PWHIV (p = 0.0223), and were particularly low in individuals with advanced HIV disease (p = 0.0311). Activation of DN T cells before ART initiation was directly associated with viral load (VL) (p = 0.0081, r = 0.4083) and inversely associated with CD4⁺ T cell counts (p = 0.0004, r = -0.4041). Compared with PWHIV, DN T cells of PLHIV expressed higher levels of CD57 (p = 0.0019), Ki67 (p = 0.0065), PD-1 (p = 0.0187), and CD38/HLA-DR (p < 0.0001). After 6 months on ART, expression of Ki67, PD-1, and CD38/HLA-DR on DN T cells returned to similar levels to those observed in PWHIV (p > 0.05 in all cases). However, expression of CD57 decreased only in individuals that start ART with high VL (p = 0.0127). DN T cell counts are decreased in HIV infection. Low DN T cell counts remained despite ART-induced immune reconstitution and viremia control. DN T cell phenotype is altered during chronic untreated infection with a high proportion of proliferating, activated, exhausted, and senescent cells. Most markers return to levels similar to those observed in PWHIV after ART. The impact of altered phenotype of DN T and their regulatory functions warrants further exploration.

A Summary of the Fourth Annual Virology Education HIV Microbiome Workshop

Each year, a growing international collection of researchers meets at the NIH to share and discuss developments in the microbiome HIV story. This past year has seen continued progress toward a detailed understanding of host-microbe interactions both within and outside the field of HIV. Commensal microbes are being linked to an ever-growing list of maladies and physiologic states, including major depressive disorder, chronic kidney disease, and Parkinson disease. PubMed citations for "microbiome" are growing at an exponential rate with over 11,000 in 2018. Various microbial taxa have been associated with HIV infection, and some of these taxa associated with HIV infection have also been associated with systemic markers of inflammation in HIV infected individuals. Causality remains unclear however as environmental and behavioral factors may drive HIV risk, inflammation, and gut enterotype. Much of the work currently being done addresses potential mechanisms by which gut microbes influence immune and inflammatory pathways. No portion of the microbiome landscape has grown as rapidly as study of the interplay between gut microbes and response to cancer immunotherapy. As Dr. Wargo discussed in her keynote address, this area has opened the door to better understanding on how commensal microbes interact with the human immune system.

Determination of human neutrophil antigen-1, -3, -4 and -5 allele frequencies in English Caucasoid blood donors using a multiplex fluorescent DNA-based assay

BACKGROUND AND OBJECTIVES

A number of DNA-based methods to genotype the alleles coding for HNA have been described, but all require the separate amplification and analysis of each allele. The aim was to develop a DNA-based method for simultaneous detection of HNA-1, HNA-3, HNA-4 and HNA-5 alleles.

MATERIALS AND METHODS

An allele-specific primer extension method was used in combination with magnetic beads from Luminex technology. PCR-sequence-specific primers (SSP) was used to resolve the presence of the HNA-1b allele in samples assigned by the Luminex bead assay as HNA-1a/-1b/-1c or HNA-1b/-1c. HNA allele frequencies were determined in a panel of 140 randomly selected English Caucasoid blood donors.

RESULTS

HNA allelic types were compared with historical results, and 100% concordance was found. Only eight of the 97 samples used in the validation required additional testing by PCR-SSP. Allele frequencies were determined in the blood donor population as follows: 0·318 for HNA-1a, 0·668 for HNA-1b, 0·014 for HNA-1c, 0·768 for HNA-3a, 0·232 for HNA-3b, 0·882 for HNA-4a, 0·118 for HNA-4b, 0·736 for HNA-5a and 0·264 for HNA-5b.

CONCLUSION

A multiplex Luminex bead assay for the simultaneous detection of HNA-1, HNA-3, HNA-4 and HNA-5 alleles is described that enables rapid typing of donors to support HNA alloimmunized patients who require HNA-compatible blood products.

Simultaneous detection of HFE C282Y, H63D and S65C mutations associated with type 1 haemochromatosis using a multiplex luminex bead assay

Type 1 hereditary haemochromatosis (HH) is a common genetic disorder in Caucasoids resulting from mutations in the HFE gene. Routine diagnostic testing for type 1 HH involves genotyping for two of these described HFE mutations, C282Y and H63D. In some cases typing of a third mutation, S65C is also performed. Several techniques have been reported for HFE genotyping and these include polymerase chain reaction (PCR)-sequence-specific primers (SSP), PCR-restriction fragment length polymorphism (RFLP), PCR-sequence-specific oligonucleotide probe (SSOP), real-time PCR followed by melting curve analysis and TaqMan assay. The aim of this study was to develop an alternative method to both conventional PCR and real-time PCR/TaqMan assay to detect all three HFE mutations in a single assay using Luminex technology. DNA controls of known genotypes (n = 109) were used to evaluate this approach. These controls were selected to represent the three possible genotypes (wild type, mutant, heterozygous) for each mutation. Subsequently, blind DNA samples (n = 100) were used to validate this method. This new assay was then compared with current techniques (in-house PCR-SSP and TaqMan assay). Comparison of genotypes obtained with the Luminex method with those previously reported by both in-house PCR-SSP and TaqMan assay showed 100% concordance for both DNA controls and blind DNA samples and no discrepancies were observed. Allelic frequency for C282Y, H63D and S65C mutations were 22%, 16% and 2%, respectively. We report here a high-throughput, accurate and robust multiplex luminex bead assay for routine clinical testing of C282Y, H63D and S65C mutations in the HFE gene.

Identification of two novel single nucleotide polymorphisms in the promoter of the human interleukin-18 receptor alpha

Single-strand conformational polymorphism (SSCP) was used to identify single nucleotide polymorphisms (SNPs) in the promoter region of the human interleukin-18 receptor alpha (IL-18Ralpha). Two SNPs were identified at positions -69 and -638 relative to the transcriptional start site. Two-way comparison of the two SNPs revealed strong linkage disequilibrium (chi2 = 63.45, P < 0.001). Three haplotypes were identified, namely C-69C-638, T-69C-638 and C-69T-638, with frequencies of 0.26, 0.39 and 0.35, respectively.