Peripheral inflammatory T cell subsets are effective predictive factors in the development of heterotopic...

Heterotopic ossification refers to the pathological formation of extra-skeletal bone. It is a common complication of trauma or surgery that can cause disability and has no definitive cure. Furthermore, the mechanisms underlying chronic inflammation during ossification remain unclear. Therefore, this study aimed to elucidate the systemic immune microenvironment status of heterotopic ossification and identify biomarkers of therapeutic efficacy and recurrence. A combination of stereoarthrolysis with prophylactic radiotherapy and non-steroidal anti-inflammatory drugs was used to treat patients with heterotopic ossification. Changes were observed in peripheral blood lymphocyte levels after treatment. The number of IFNγ⁺CD8⁺T cells (3.753 % vs 12.90 %, P < 0.0001) and IL17⁺CD4⁺T cells (3.420 % vs 5.560 %, P = 0.0281) were was higher in the peripheral blood of relapsed patients with heterotopic ossification than in that of non-relapsed patients. Similarly, the number of these cells was elevated in patients who developed heterotopic ossification after posttraumatic elbow surgery. Peripheral CD8⁺T cells derived from patients with this pathology promoted osteogenesis through IFNγ expression in vitro. Our findings demonstrate that IFNγ⁺CD8⁺T cells and IL17⁺CD4⁺T cells are potential biomarkers of heterotopic ossification after posttraumatic elbow surgery. Furthermore, these cells can be used to predict therapeutic efficacy and relapse after combination therapy.