#1511 The immune cell ‘signature’ of incident hypertension

Abstract

Abstract Background and Aims Hypertension results from complex genetic and environmental interactions, mediated by cardiac, vascular, endocrine, and renal systems. The immune system may modulate all of these, though the exact mechanisms linking immune activation with hypertension and organ damage remain poorly defined. We aimed to identify the immune cell ‘signature’ in patients with newly diagnosed, untreated hypertension (HTN; n=76) compared to normotensive controls (NTN; n=67), as well as in relation to nocturnal dipping status. Method Flow cytometry of peripheral blood mononuclear cells (Attune, Thermo Fisher) characterising B cell, T cell, monocyte and dendritic cells (DC) subsets, including activation signature with intracellular staining, in an exploratory comparative analysis. Results The proportion of CD4+ naïve T cells (CD45RA+CCR7+) was lower in hypertension, with CD45RO+CD62L+ cells attaining nominal statistical significance between NTN and HTN groups (1.3 ± 1.1 vs 1.2 ± 1.0, p=0.039). CD4+ T central memory cells were expanded (TCM, 23.1 ± 7.2 vs 27.7 ± 10.0, p=0.002, Figure) in HTN along with T effector memory (TEM) cells lacking CD62 in an adjusted model, (TEM, CD4+CD45RA-CCR7-CD62l-; 31.4 ± 7.5 vs 33.7 ± 10.3, p0.035; CD8+CD45RA-CCR7-CD45RO+CD62l− 48.9 ± 10.5 vs 52.2 ± 13.3, p=0.011). Hypertensive group had proportionally fewer CD4+CD28+ cells (95.1 ± 9.8 vs 92.0 ± 13.5, p=0.034) and CD8+CD28+ (68.0 ± 19.7 vs 62.0 ± 21.0, p=0.011), as well as CD8+ TEMRA cells (Figure). In a fully adjusted model, the CCR7-CD45RO-CD62L+ (52.2 ± 14.5 vs 50.2 ± 16.1, p=0.036), and CD8+CD28+CD45RA+CCR7- significantly differed between groups (23.1 ± 14.7 vs 25.0 ± 17.8, p=0.008). On the molecular level, T cells were polarised in HTN towards a Th1/Tc1 and Th17.1/Tc17.1 pro-inflammatory milieu (Figure). No differences were detected in B cell subsets. The innate immune ‘signature’ was characterised by intermediate monocytes with a differing pattern of CCR2 and CCR5 chemokine receptor expression (Table 1), and alterations in STAT1 and STAT6 phosphorylation cascades. NK cell CD56+Dim expression and fewer CD122-expressing NKT (0.13 ± 0.0 vs 0.08 ± 0.1, p=0.046) and CD122+ T lymphocytes (1.3 ± 3.4 vs 0.6 ± 0.4, p=0.019) further supported pro-inflammatory milieu in hypertension. Finally, in an exploratory nominal statistical analysis, nocturnal non-dipping was associated with particular changes in immune cell signature, including expanded CD4+TCM (CD4+CD45RO+CD62L-, 9.4 ± 4.3 vs 8.0 ± 3.3, p=0.04) and reduced CD4+TEM and TEMRA compartments; polarisation towards Th17 and Tc1; and altered Monocyte CCR2 and CCR5 expression. Additionally, non-dipping was linked to dendritic cell mannose receptor downregulation e.g. mDC non-dipper 10.9 ± 5.8 vs dipper 13.6 ± 9.7, p=0.03. Conclusion These exploratory data support alterations of circulating innate (monocytes) and adaptive (T cells) immune compartments in newly diagnosed untreated, and uncomplicated hypertension.