The Role of Regulatory T and B Cells in the Etiopathogenesis of Idiopathic Granulomatous Mastitis.

BACKGROUND AND OBJECTIVES

The aim of this study was to evaluate the role of T- and B-regulatory cells (Tregs and Bregs) in the pathogenesis of idiopathic granulomatous mastitis (IGM).

METHODS

This study includes 47 patients with pathologically proven IGM (Group P) and 26 healthy subjects (Group C). The patients in Group P were divided into two groups according to whether their lesions were active (Group P, n: 21) or in remission (Group P, n: 26). By using flow-cytometry, the frequencies of CD3CD4CD45RAFoxp3 activated Tregs (aTregs), CD3CD4CD45RAFoxp3 non-suppressive Tregs, CD3CD4CD45RAFoxp3 resting Tregs (rTregs), CD3CD4CD25Foxp3 T-effector cells (Teff), total Tregs and Bregs were analyzed in all subjects.

RESULTS

The frequency of the Teff cells was statistically higher in Group P when compared with Group C ( =.004). The Foxp3 expression of Treg cells and the frequency of non-suppressive Tregs in Group P were statistically lower than Group C ( =.032 and =.02, respectively). In addition, Group P's Foxp3 expressions were statistically lower than Group C ( =.027); Group P's aTregs ratio was statistically lower than Group P ( =.021); and the non-suppressive Tregs ratio of Group P was lower than both Group P and Group C ( =.006 and <.0001). No significant differences were seen Bregs and B cell subsets.

CONCLUSION

Significant changes in Foxp3 expression and Treg subsets were seen in patients with active IGM lesion and in remission. This study shows an intrinsic defect of Tregs in patients with IGM.