Relationship between SARC-F score and Peripheral Blood Lymphocytes in Juvenile Idiopathic Arthritis: An Observational Pilot Study

BackgroundGiven the relatively high prevalence of sarcopenia and immune profile abnormalities in inflammatory arthritis such as rheumatoid arthritis (RA), we investigated the relationship between exercise habits, SARC-F score and peripheral blood lymphocyte profiles in patients with Juvenile idiopathic arthritis (JIA). MethodsAll participants with JIA completed the SARC-F survey and self-reported exercise habits through online questionnaires. We defined two groups based on SARC-F scores as musculoskeletal function impaired (SARC-Fhi+) and musculoskeletal function not impaired (SARC-Fhi-). We used flow cytometry of peripheral blood mononuclear cells to define immune cell subpopulations. Statistical analyses were performed using GraphPad Prism software version10. ResultsOf the 18 participants with a median age of 24 years - five belonged to the SARC-Fhi+ group and 13 to the SARC-Fhi-group, of whom 80% and 38% were female, respectively. The SARC-Fhi + group had fewer CD45RA+CD27+ naive CD4+ T cells (26.60% vs. 45.30%, p=0.0264) and greater CD45RA-CD27-effector memory CD4+ T cells (11.90% vs. 7.00%, p=0.0350). The SARC-Fhi+ group also had fewer CD56-CD16+ NK cells compared to the SARC-Fhi-group (2.60% v. 4.28%, p = 0.0194). The moderate exercise group (n = 13) had increased numbers of total CD4+ T cells (54.06% vs. 37.30%, p=0.0140) and 3-fold fewer CD45RA+CD27-EMRA CD8+ T cells (3.17% vs. 10.40%, p=0.0350). There were no other significant differences for other immune cells / subpopulations including B cells. ConclusionsOur study findings suggest notable differences in immune profile relative to SARC-F score. Furthermore, the 3-fold lower frequency of CD8+ TEMRA subpopulation of T cells, reflective of immunosenescence, suggest a potential inverse relationship between moderate exercise and peripheral immune cell profile in JIA. Key messagesO_LISARC-F score was used as a clinically relevant tool to identify musculoskeletal function in JIA C_LIO_LISARC-Fhi+ group had fewer naive CD4+ T cells and greater effector memory CD4+ T cells C_LIO_LIModerate exercise group had 3-fold lower frequency of CD8+ TEMRA T cells C_LI Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=54 SRC="FIGDIR/small/681879v1_ufig1.gif" ALT="Figure 1"> View larger version (11K): org.highwire.dtl.DTLVardef@1eb9d4org.highwire.dtl.DTLVardef@13a18a4org.highwire.dtl.DTLVardef@127d55corg.highwire.dtl.DTLVardef@28bddf_HPS_FORMAT_FIGEXP M_FIG C_FIG