[An exploratory study on in vitro effects and mechanism of leflunomide on dendritic cells of systemic lupus erythematosus].

OBJECTIVE

To detect the effects of leflunomide to phenotype and function of dendritic cells (DCs) in systemic lupus erythematosus (SLE) patients, reveal the effective mechanism inducing remission of SLE and lay a research foundation for using 'inhibit' DCs to treat SLE in future.

METHODS

The monocytes were isolated from peripheral blood of SLE patients and cultivated into DCs with cytokines such as GM-CSF and IL-4. A771726 (active metabolite) was added in with cytokines in leflunomide group, but not in control. DCs were harvested after 9 days culture. CD(80), CD(83), CD(86) and HLA-DR surface markers on DCs were detected by flow cytometry (FACS). The ability of DCs stimulating lymphocytes proliferation was detected by MTT assay. IL-10 and IFNgamma level in the supernatant of MLR were detected by ELISA and T cell subtype after MLR was detected by FACS.

RESULTS

The DCs treated with A771726 showed a lower percentage expression of CD(83), CD(86) and HLA-DR phenotype (CD(83): 72.70 +/- 1.77 vs. 79.36 +/- 4.80, CD(86): 63.50 +/- 14.06 vs. 83.91 +/- 9.81, HLA-DR: 80.44 +/- 12.56 vs. 90.51 +/- 8.63, all P < 0.01), a weaker ability to stimulating T lymphocytes proliferation (at DC:TC = 1:10, 0.285 +/- 0.079 vs. 0.458 +/- 0.100; at DC:TC = 1:50, 0.194 +/- 0.054 vs. 0.382 +/- 0.023, all P < 0.01) and a lower secretive level of IL-10 in the MLR supernatant [(195.0 +/- 36.9) microg/L vs. (423.6 +/- 93.2) microg/L, P < 0.01], exclude those it could still increase amount of a new T cell subtype--CD(4)(+)CD(25)(+)CTLA(4)(+) T cell (12.00% & 6.23%).

CONCLUSIONS

A771726 can inhibit DCs maturation, the immature DCs can inhibit T cells proliferation and refrain T cells from dividing into Th(2) subtype, and also the immature DCs can induce a sort of regulate T cell (CD(4)(+)CD(25)(+)CTLA(4)(+) T cell) production. Through that LEF may correct part over humor immune dysfunction and get a new immune balance in SLE.