Blood Lymphocyte Patterns Predict Relapse Risk in Treatment-Naïve Myositis Patients

Patients with idiopathic inflammatory myopathy (IIM) show distinct patterns of circulating lymphocyte subsets before any treatment begins, and those patterns appear to carry prognostic weight, according to a retrospective study published in BMC Rheumatology. Researchers at Tianjin Medical University General Hospital analyzed 126 treatment-naïve IIM patients seen between 2018 and 2023, stratifying them by clinical subtype and by myositis-specific antibodies (MSAs), and then tracking clinical outcomes over a one-year follow-up period.

The study, which aimed to characterize peripheral blood lymphocyte subsets and assess their associations with disease subtypes and prognosis, found that lymphocyte subset profiles differed significantly across clinical subtypes. The differences were particularly evident in total lymphocyte counts, total T cell counts, absolute CD4-positive T cell counts, and natural killer (NK) cell counts. Patients with dermatomyositis showed significantly lower peripheral blood CD4-positive T cell and NK cell counts than patients with antisynthetase syndrome, one of the other major IIM subtypes examined.

When the researchers stratified patients by autoantibody profile rather than clinical subtype, they again observed distinct variations, this time in the proportion of total T cells and in both the proportion and absolute counts of NK cells. A notable contrast emerged between patients positive for Mi-2 antibodies and those positive for MDA5 antibodies: the MDA5-positive group showed markedly reduced NK cell proportions and counts, accompanied by a significantly higher proportion of total T cells compared with Mi-2-positive patients.

The prognostic findings came from longitudinal analysis over the one-year follow-up. Patients who experienced disease relapse had lower baseline levels of specific lymphocyte subsets than patients whose disease remained stable.

Multivariate Cox regression analysis strengthened this signal: the absolute CD4-positive T cell count emerged as an independent prognostic factor for relapse. In other words, even after accounting for other variables in the model, a patient’s pre-treatment CD4 T cell number retained its association with the likelihood of disease recurrence during follow-up.

Several caveats frame these results. The analysis was retrospective and conducted at a single center, and the abstract reports associations rather than demonstrating that lymphocyte changes cause relapse. The relapse predictions were generated within this cohort over a one-year window, so their performance in other populations and over longer follow-up remains to be established. The article is also being shared early as a peer-reviewed, accepted version that is citable but subject to further edits before the final Version of Record appears.

Subject of Research: Peripheral blood lymphocyte subset profiles and their association with subtypes and relapse prognosis in treatment-naïve idiopathic inflammatory myopathy

Article Title: Lymphocyte subpopulation characteristics and clinical implications in treatment-naïve idiopathic inflammatory myopathies

Article References: Su, H., Hou, H., Wang, G., Du, J., Fan, Q., Sun, W., Zhang, N., & Wei, W. (2026). Lymphocyte subpopulation characteristics and clinical implications in treatment-naïve idiopathic inflammatory myopathies. BMC Rheumatology. https://doi.org/10.1186/s41927-026-00693-1

Image Credits: AI Generated

DOI: 10.1186/s41927-026-00693-1

Keywords: idiopathic inflammatory myopathy, lymphocyte subsets, dermatomyositis, antisynthetase syndrome, MDA5, Mi-2, CD4 T cells, natural killer cells, myositis-specific antibodies, disease relapse, Cox regression, BMC Rheumatology