FOXP3+ and CD39+ regulatory T cells in subtypes of cutaneous lupus erythematosus

Abstract

Background: Lupus erythematosus (LE) is an autoimmune disease in which regulatory T cells play a pathogenetic role.

Objectives: We aimed to assess and compare the quantities of lesional Tregs in subtypes of cutaneous LE (CLE) including chronic discoid LE (CDLE), LE tumidus (LET) and subacute CLE (SCLE).

Methods: Thirty-nine patients with CLE were enrolled in the study. Immunohistochemistry was performed for CD4, CD8, FOXP3 and CD39.

Results: We studied nine CDLE patients, 21 LET patients and nine patients with SCLE. SCLE lesions [37 (0-134)] showed a significantly (P = 0.024) decreased percentage of CD4+ cells when compared with CDLE [125 (0-146)] and LET [124 (0-240)] lesions. Moreover, the CD4/CD8 ratio in SCLE lesions [0.7 (0.5-1.8)] was significantly (P = 0.027) decreased when compared with CDLE [1.9 (1.5-2.8)] and LET [1.6 (0.8-2.9)] lesions. FOXP3 immunopositivity was significantly (P = 0.017) decreased in LET [0 (0-6)] and SCLE [1 (0-2)] lesions when compared with CDLE [6 (0-38)]. Moreover, in LET [2 (0-6)] and SCLE [2 (0-2)], we observed a significantly (P = 0.0049) diminished CD39-immunoreactivity when compared with CDLE [4 (2-12)]. CD4+ cell count is a significant (P = 0.0133) negative predictor for the diagnosis of SCLE (Odds ratio 0.978, 95% CI 0.960-0.99).

Conclusions: Our data indicate that there are differences in quantities of lesional T helper cells, CD4/CD8 ratio and Tregs among subtypes of CLE. Interestingly, a more significant decrease in Tregs, which likely reflects greater loss of immune-tolerance, is observed in the more photosensitive subtypes of CLE such as SCLE and LET.