Dissection of the bone marrow microenvironment in hairy cell leukaemia identifies prognostic tumour and immune related biomarkers

Rachel M Koldej,Ashvind Prabahran,Melissa J Davis,Chin Wee Tan,David S Ritchie,Ashley P Ng

doi:10.1038/s41598-021-98536-1

Abstract

Hairy cell leukaemia (HCL) is a rare CD20+ B cell malignancy characterised by rare “hairy” B cells and extensive bone marrow (BM) infiltration. Frontline treatment with the purine analogue cladribine (CDA) results in a highly variable response duration. We hypothesised that analysis of the BM tumour microenvironment would identify prognostic biomarkers of response to CDA. HCL BM immunology pre and post CDA treatment and healthy controls were analysed using Digital Spatial Profiling to assess the expression of 57 proteins using an immunology panel. A bioinformatics pipeline was developed to accommodate the more complex experimental design of a spatially resolved study. Treatment with CDA was associated with the reduction in expression of HCL tumour markers (CD20, CD11c) and increased expression of myeloid markers (CD14, CD68, CD66b, ARG1). Expression of HLA-DR, STING, CTLA4, VISTA, OX40L were dysregulated pre- and post-CDA. Duration of response to treatment was associated with greater reduction in tumour burden and infiltration by CD8 T cells into the BM post-CDA. This is the first study to provide a high multiplex analysis of HCL BM microenvironment demonstrating significant immune dysregulation and identify biomarkers of response to CDA. With validation in future studies, prospective application of these biomarkers could allow early identification and increased monitoring in patients at increased relapse risk post CDA.

Highlights

Hairy cell leukaemia (HCL) is a rare CD20+ B cell malignancy characterised by rare “hairy” B cells and extensive bone marrow (BM) infiltration
Analysis of the immunobiology of HCL is complicated by its low incidence, the low number of circulating tumour cells and that sampling of the site of the bulk of the tumour requires sampling of the BM
We have recently shown that NanoString GeoMXTM Digital Spatial Profiling (DSP) can be used to analyse high multiplex protein expression in BM trephine s amples[14]

Summary

Introduction

Hairy cell leukaemia (HCL) is a rare CD20+ B cell malignancy characterised by rare “hairy” B cells and extensive bone marrow (BM) infiltration. Duration of response to treatment was associated with greater reduction in tumour burden and infiltration by CD8 T cells into the BM post-CDA This is the first study to provide a high multiplex analysis of HCL BM microenvironment demonstrating significant immune dysregulation and identify biomarkers of response to CDA. We have recently shown that NanoString GeoMXTM Digital Spatial Profiling (DSP) can be used to analyse high multiplex protein expression in BM trephine s amples[14] In this current study, we have utilised DSP to examine the immune microenvironment in HCL pre- and post-CDA to provide a detailed analysis of the marrow microenvironment and determine biomarkers of durable response to CDA which could be applied prospectively to identify patients that are at risk of relapse post-CDA and require further monitoring

Methods

Results

Conclusion