Assessing the immune microenvironment with multiplex immunofluorescence histochemistry demonstrates proximity of cytotoxic T-cells to plasma cells in patients with newly diagnosed multiple myeloma

Abstract

Background A dysfunctional immune tumour microenvironment (iTME) facilitates disease progression in MM. Using multiplex immunohistochemistry (mIHC) we aim to describe quantitative and qualitative changes in CD3+CD8+ T-cells (Tcytotoxic) in patients with MGUS, ND and relapsed/refractory MM (RRMM) and assess spatial proximity to PCs. Method Formalin-fixed, paraffin-embedded trephine sections from pts with MGUS (n=32), NDMM (n=65) and RRMM (n=59) were sequentially stained for CD138, CD3, CD8 and checkpoint receptors (CPs) Tim3, Lag-3 and PD-1 (Figure 1). Halo® image analysis platform was used for cell segmentation and phenotyping, facilitating enumeration of Tcytotoxic populations and analysis ..