Alterations in peripheral T cell and B cell subsets in patients with osteoarthritis

Our study objective was to explore whether abnormalities in the subtypes of T cells and B cells were present in peripheral blood of patients with osteoarthritis (OA) and healthy controls (HCs).

Demographic and clinical variables and blood were collected. OA severity was measured using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire. Flow cytometry was used to establish the frequencies of lineage subsets. Monoclonal antibodies against 21 surface markers were used to distinguish and evaluate T cells' and B cells' subpopulation. The proportion of each subset was compared and correlations between age, immune cells, and clinical data were analyzed.

A total of 30 OA patients (male/female = 9/21) and 45 HCs (male/female = 14/31) were included. Median WOMAC pain was 3.0 (2.0). There was no difference in the proportion of T cells, CD8+ T cells, and B cells (p > 0.05). The proportion of CD4+ T cells was higher in OA groups, together with an increased CD4 to CD8 ratio (p = 0.016). CD8+CD45RA+ T cells were reduced after adjustment for age, while CD8+CD45RA- T cells were elevated in OA (p < 0.05). CD4+CD45RA-CCR7+ T cells and CD4+CD45RA-CCR7- T cells were increased (p < 0.004). The proportion of T helper (Th) 17 and T follicular helper (Tfh) 2 cells was higher, but cytotoxic T (Tc) 17 cells were fewer in OA (p < 0.05). CD3-CD19+IgD-IgM-CD27+CD38+ B cells were decreased in OA (p ≤ 0.001). The WOMAC pain score correlated with CD3+CD4+CXCR5-PD-1+ T cells positively (B = 0.404, p = 0.027). CD3-CD19+CD27-IgD+ cells correlated negatively with erythrocyte sedimentation rate (ESR) (B = -0.550, p = 0.005).

The T cell and B cell profiles were proved to have alteration suggesting that acquired immune system may play a substantial role in the pathogenesis of OA.Key Points• The T cell and B cell profiles were proved to have alteration suggesting that acquired immune system may play a substantial role in the pathogenesis of OA.• The WOMAC pain score correlated with CD3+CD4+CXCR5-PD-1+ T cells and T helper 17 cells positively.• Memory T cells were increased in OA patients, suggesting they could play an important role in OA.