Figure 5. Analysis of Tregs in sIBM patients.

Representative flow cytometry analysis of CD25⁺CD127^low subpopulations among CD3⁺CD4⁺ T lymphocytes in a control subject (A). Tregs were defined as Foxp3+ cells among the previously gated CD3⁺CD4⁺CD25⁺CD127^low subpopulation (B). Non-specific staining (isotype control) was used to define FoxP3⁺ cells (C). Pooled data showing the percentage of Tregs among CD4⁺ T cells from sIBM patients and controls in the systemic compartment (p = 0.01). Horizontal lines indicate means (D). Percentage of inhibition (±SD; n = 4) of Tregs on the proliferation of autologous CD4⁺CD25⁻ T cells (responders). Responder+allogeneic MNCs were used as positive control. Proliferation of responder cells was measured by 3H-Tdr incorporation (counts per minute, cpm) (E). Representative flow cytometry analysis showing resting Tregs (rTregs: CD45RA⁺CD25⁺) and activated Tregs (aTregs: CD45RA⁻CD25^high) among CD4⁺ T lymphocytes in a control subject (F). Pooled data showing rTregs and aTregs from sIBM patients and controls (p = 0.0003) (G). Immunostaining of a muscle section from a sIBM patient, showing Foxp3⁺ cells (H) in the muscle infiltrate. Immunofluorescence staining showing Foxp3⁺ cells (red) within the muscle infiltrate in a sIBM patients (I). The upper left corner shows a FoxP3⁺ cell (red), the upper right corner shows CD4⁺ cells (green), the lower left corner shows nuclear staining (dapi); coexpression of CD4 and FoxP3 is shown by merged fluorescence images in the lower right corner. Horizontal lines indicate means; *p<0.05.