Abstract:

Objective To assess the changes in bone marrow microenvironment in patients with psoriasis by determining the level of transforming growth factor β1 （TGF-β1）, stem cell factor （SCF）, keratinocyte growth factor （KGF） and tumor necrosis factor-α （TNF-α） secreted by bone marrow stromal cells（BMSCs）. Methods This study recruited 20 healthy controls with normal bone marrow picture and 20 patients with psoriasis vulgaris, including 10 at progressive stage and 10 at resting stage. The psoriasis area and severity index （PASI） score varied from 0.6 to 22.8 and averaged 10.97 in these patients. Bone marrow mononuclear cells were isolated by density-gradient centrifugation from bone marrow of these subjects, and BMSCs were cultured with adherent method. After three passages, the BMSCs were subjected to a 72-hour culture followed by the identification of cell phenotypes via flow cytometry and determination of TGF-β1, SCF, KGF and TNF-α levels in the culture supernatant via enzyme linked immunosorbent assay （ELISA）. The parameters were compared by two independent samples t test between the two groups, and the correlation of cytokines with PASI was assessed by Pearson correlation analysis. Results Inverted microscopy revealed no obvious difference in the morphology of BMSCs between the patients and controls. CD29 was expressed by more than 90% of the BMSCs, but no expression of CD45, CD34 or HLA-DR was observed in them. The BMSCs from patients showed a significantly lower level of supernatant TNF-α （（22.93 ± 10.11 ） μg/L vs. （35.73 ± 15.15） μg/L， t = 3.14，P ＜ 0.05）, a higher level of supernatant SCF （（76.80 ± 16.19） μg/L vs. （59.86 ± 22.41） μg/L, t = 2.74, P ＜ 0.05）, and a similar level of supernatant KGF and TGF-β1 （both P > 0.05） compared with those from the controls. The PASI score was uncorrelated with the levels of SCF, TNF-α, KGF or TGF-β1 secreted by BMSCs in patients with psoriasis （all P > 0.05）. Conclusions The levels of SCF and TNF-α secreted by BMSCs are aberrant in patients with psoriasis, hinting an abnormal bone marrow microenvironment in these patients.

Key words: cell factors