# RNAseq of INOCA patients identifies innate, invariant, and acquired immune changes: potential autoimmune microvascular dysfunction

## TL;DR

RNA sequencing of blood from INOCA patients reveals immune-related gene changes linked to autoimmune dysfunction and microvascular issues.

## Contribution

Identifies novel immune mechanisms involving MAIT cells, B cells, and dendritic cells in INOCA pathophysiology.

## Key findings

- INOCA is associated with elevated transcripts of MAIT cells, memory B cells, and plasmacytoid dendritic cells.
- Reduced neutrophil transcripts suggest chronic activation and degradation in INOCA patients.
- Transcriptome changes in INOCA differ from classical CAD, pointing to autoimmune microvascular dysfunction.

## Abstract

Ischemia with non-obstructive coronary arteries (INOCA) is a major clinical entity that involves potentially 20%–30% of patients with chest pain. INOCA is typically attributed either to coronary microvascular disease and/or vasospasm, but is likely distinct from classical coronary artery disease (CAD).

To gain insights into the etiology of INOCA and CAD, RNA sequencing of whole blood from patients undergoing both stress testing and elective invasive coronary angiography (ICA) was conducted.

Stress testing and ICA of 177 patients identified 40 patients (23%) with INOCA compared to 39 controls (stress-, ICA-). ICA+ patients divided into 38 stress- and 60 stress+. RNAseq was performed by Illumina with ribosomal RNA depletion. Transcriptome changes were analyzed by DeSeq2 and curated by manual and automated methods.

Differentially expressed genes for INOCA were associated with elevated levels of transcripts related to mucosal-associated invariant T (MAIT) cells, plasmacytoid dendritic cells (pcDC), and memory B cells, and were associated with autoimmune diseases such as rheumatoid arthritis. Decreased transcripts were associated with neutrophils, but neutrophil transcripts, per se, were not less abundant in INOCA. CAD transcripts were more related to T cell functions.

Elevated transcripts related to pcDC, MAIT, and memory B cells suggest an autoimmune component to INOCA. Reduced neutrophil transcripts are likely attributed to chronic activation leading to increased translation and degradation. Thus, INOCA could result from stimulation of B cell, pcDC, invariant T cell, and neutrophil activation that compromises cardiac microvascular function.