Association of Juvenile Dermatomyositis Disease Activity With the Expansion of Blood Memory B and T Cell Subsets Lacking Follicular Markers

Abstract

Objective. This study was undertaken to identify blood markers of juvenile dermatomyositis (DM) disease activity (DA), which are needed to improve disease management.Methods. The study comprised a total of 123 juvenile DM patients and 53 healthy controls. Results of laboratory tests (aldolase, creatinine kinase, lactate dehydrogenase [LDH], aspartate aminotransferase) and clinical measures of DA in patients with juvenile DM, including the Manual Muscle Testing in 8 muscles (MMT-8), Childhood Myositis Assessment Scale (CMAS), and disease activity scores (DAS) (total DAS for juvenile DM, the muscle DAS, and the skin DAS), were recorded when available. Surface phenotype of peripheral blood mononuclear cells was assessed using flow cytometry. Whole blood transcriptional profiles were studied using either RNA-sequencing or microarrays. Differential gene expression was determined using DESeq and compared by pathway and gene ontology analyses.Results. Conventional memory (CD27+IgD-) B cells expressing low CXCR5 levels (CXCR5 low/-CM B cells) were significantly increased in frequency and absolute numbers in 2 independent cohorts of juvenile DM patients compared with healthy controls. The frequency of CD4+ Th2 memory cells (CD45RA-CXCR5-CCR6-CXCR3-) was also increased in juvenile DM, especially in patients who were within <1 year from diagnosis. The frequency of CXCR5 low/-CM B cells correlated with serum aldolase levels and with a blood interferon-stimulated gene transcriptional signature. Furthermore, both the frequency and absolute numbers of CXCR5 low/-CM B cells correlated with clinical and laboratory measures of muscle DA (MMT-8, CMAS, aldolase, and LDH).Conclusion. These findings suggest that both CM B cells lacking the CXCR5 follicular marker and CXCR5-Th2 cells represent potential biomarkers of DA in juvenile DM and may contribute to its pathogenesis.

Coordinated immune dysregulation in Juvenile Dermatomyositis revealed by single-cell genomics

“…However, while ICOS expression was higher (Benjamini-Hochberg (BH) p < 0.05), no difference was found in surface expression of CXCR5 between CD45RO hi PD-1 hi CD4 + T cells and CD45RO lo PD-1 lo CD4 + T cells, and these cells were not significantly expanded in JDM (Supplemental Figure 3C-E). Taken together, these compositional and immunophenotyping observations add to the growing body of work showing that JDM in the treatment-naive state is characterized by relative imbalances of naive and mature lymphocyte states (16, 24), reduced innate immune populations (23) and distinct CD4 + T and B cell immunophenotypes (17,18).…”

“…This CD4T1 program expressed by CD4 + Teff cells contained several genes ( GATA3 , CCR4 , PRDM1 ) that indicate skewing towards a Th2 subset while expression of PRDM1 (Blimp-1) suggests participation in extra-follicular reactions. Th2 CD4 + T cells were previously found to be expanded in JDM and associated with extra-follicular B-T cell help (17, 18). We observed similar expression of Th2 genes ( GATA3 , CCR4 , PRDM1 ) in CD4T10, a Treg program ( FOXP3 , IKZF2 , IL2RA ) expressed more highly in JDM.…”

“…While these data indicate that naive B cell populations expanded are in JDM, the overall low expression of CD27 and CXCR5 across all B cells made it difficult for to conclude that this population matches the double negative B cell population associated with SLE. However, recent immunophenotyping work in a large cohort of JDM patients that found simultaneous expansion of CXCR5-central memory B cells and Th2 cells provides support for further investigation into extra-follicular B-T cell help in JDM (17).…”

Coordinated immune dysregulation in juvenile dermatomyositis revealed by single-cell genomics

“…This CD4T1 program expressed by CD4 + Teff cells contained genes (GATA3, CCR4, PRDM1) that indicate possible skewing towards a Th2 subset while expression of PRDM1 (Blimp-1) suggests participation in extra-follicular reactions (Figure 6B). Th2 CD4 + T cells were previously found to be expanded in JDM and associated with extra-follicular B-T cell help (15,16) . We observed similar expression of Th2 genes (GATA3, CCR4, PRDM1) in CD4T10, a Treg program (FOXP3, IKZF2, IL2RA) expressed more highly in JDM (Figure 6B).…”

“…The expansion of naïve B cells in JDM has been highlighted by three independent studies using flow cytometry, mass cytometry, and single-cell RNA sequencing, respectively (12)(13)(14). The adaptive arm of the immune system is further implicated in disease pathogenesis by several large immunophenotyping studies that demonstrated the expansion of extrafollicular Th2 memory cells and central memory B cells (15,16). Additionally, the innate immune system has emerged as a contributor in JDM with increased macrophages in skin and NK cell dysfunction described peripherally (13,17,18).…”