Altered neutrophil extracellular traps in response toMycobacterium tuberculosisin persons living with HIV with no previous TB and negative TST and IGRA

Abstract

AbstractPersons living with HIV (PLWH) have an increased risk for tuberculosis (TB). After prolonged and repeated exposure, some PLWH never develop TB and test persistently negative in tests of immune sensitization tuberculin skin test (TST) and interferon gamma release assays (IGRA) forMycobacterium tuberculosis(Mtb). This group has been identified and defined as HIV+ persistently TB, tuberculin and IGRA negative (HITTIN). To investigate potential innate mechanisms unique to individuals with the HITTIN phenotype we compared their neutrophilMtbinfection response to that of PLWH, with no TB history, but who test persistently IGRA positive, and tuberculin positive (HIT). Neutrophil samples from 17 HITTIN (PMNHITTIN) and 11 HIT (PMNHIT) were isolated and infected withMtbH37Rv for 1h and 6h. RNA was extracted and used for RNAseq analysis. At 1h ofMtbinfection, PMNHITTINdisplayed 151 significantly upregulated and 40 significantly downregulated differentially expressed genes (DEGs) and PMNHIT98 significantly upregulated and 11 significantly downregulated DEGs. At the 6h timepoint, PMNHITTINdisplayed 3106 significantly upregulated and 3548 significantly downregulated DEGs while PMNHIThad 3816 significantly up- and 3794 significantly downregulated DEGs. There was no significant differential transcriptional response at 1h between infected PMNHITTINand PMNHIT.However, when contrasting the log2FC 6h infection response toMtbfrom PMNHITTINagainst PMNHIT, 2285 genes showed significant differential response between the two groups. Apoptosis and NETosis were key pathways linked to the enrichment of genes in PMNHITTINwhen contrasted to PMNHITafter 6h infection withMtb. Fluorescence microscopy revealed relatively lower neutrophil extracellular trap formation and cell loss in PMNHITTINcompared to PMNHIT, showing that PMNHITTINhave a distinct response toMtb.