Quantifying Adaptive And Innate Immune Responses In Hiv-Infected Participants Using A Novel High Throughput Assay

ObjectivesHIV infection is characterised by persistent immune dysfunction of both the adaptive and innate immune responses. The aim of this study was to evaluate these responses using a novel high throughput assay in healthy controls and HIV-infected individuals prior to and following anti-retroviral treatment (ART).DesignCross-sectional study.MethodsWhole blood was assessed using the QuantiFERON Monitor (R) (QFM) assay containing adaptive and innate immunostimulants. Interferon (IFN)-gamma levels (IU/mL) were measured by enzyme-linked immunosorbent assay (ELISA).ResultsWe recruited HIV-infected participants (n = 20 off ART and viremic; n = 59 on suppressive ART) and HIV-uninfected controls (n = 229). Median IFN-gamma production was significantly higher in HIV-infected participants compared to controls (IFN-gamma 512 vs 223 IU/ml, p<0.0001), but within the HIV-infected participants there was no difference between those on or off ART (median IFN-gamma 512 vs 593 IU/ml p = 0.94). Amongst the HIV-infected participants, IFN-gamma production was higher in individuals with CD4 count>350 compared to <350 cells/mu L (IFN-gamma IU/ml 561 vs 259 p = 0.02) and in males compared to females (IFN-gamma 542 vs 77 IU/ml p = 0.04). There were no associations between IFN-gamma production and age, plasma HIV RNA, nadir CD4 count or duration of HIV infection. Using a multivariable analysis, neither CD4 nor sex were independently predictive of IFN-gamma production.ConclusionUsing a high throughput assay which assesses both adaptive and innate immune function, we showed elevated IFN-gamma production in HIV-infected patients both on and off ART. Further research is warranted to determine if changes in QuantiFERON Monitor (R) are associated with clinical outcomes.