Higher PIK3C2B gene expression of H1N1+ specific B-cells is associated with lower H1N1 immunogenicity after trivalent influenza vaccination in perinatally HIV infected children

Abstract

Abstract Perinatally HIV-infected children (PHIV), despite effective antiretroviral treatment (ART), present chronic immune activation and suboptimal memory B-cell response to vaccinations compared to healthy controls (HC). Here we aimed at identifying frequency and transcriptional profiles of H1N1-specific B-cells (H1N1-Sp) in PHIV differentially responding to Trivalent Influenza Vaccination (TIV) and HC. H1N1-Sp were FACS-sorted from PBMCs collected 21 days after TIV, and analysed by multiplexed RT-PCR (Fluidigm). Differentially induced genes after H1N1 in vitro stimulation were further assessed on sorted memory B cells. H1N1 response was measured by hemagglutination inhibition assay (HIA) and B-cell ELISpot. 10 out of 19 PHIV were non-responders (NR) while all HC (n=8) correctly responded to TIV (≥4 fold change HIA and >80 ELISpot/106PBMCs). Our results showed no differences in H1N1-Sp frequencies and absolute counts between the groups. H1N1-Sp of PHIV showed higher expression of genes related to apoptosis susceptibility (PPP1R13B (logFC=12.77, p=0.01) and immune activation (CD28 (logFC=10.64, p=0.02) compared to HC. Among PHIV, lower PIK3C2B (logFC=−6.67, p=0.02) expression was found in vaccine responders (R) vs NR. In addition, only R showed a reduction in PIK3C2B expression after in vitro H1N1 stimulation in resting memory B cells (CD19+IgD-CD27+CD21+) (FC=−2.6, p<0.05). In conclusion, a gene expression perturbation, underlying immune activation, persists in H1N1-Sp from PHIV despite ART. Also, a higher expression of PIK3C2B may lead to a lower H1N1 immunogenicity after TIV. These preliminary data may inform future vaccination-adjuvants aiming at modulating PIK3C2B in order to improve vaccination outcomes in PHIV.