| Alopecia areata (AA) is a common hair loss disease in the department of dermatology, which is now believed to be a hair follicle-specific and Thl cytokine mediated autoimmune disease. However, the mechanisms of autoimmune attacks in AA remain unclear and need further studies, since hair follicle is an organ of immune tolerant.CD200is a relatively newly-discovered immunomodulatory molecule. It was recently found to express on the membrane of keratinocytes (KCs) comprising the outer root sheath (ORS) of hair follicles of mice and humans, besides expressing on the lymphocytes, endothelial cells, nerve cells and other cells. Existing literatures suggest that CD200performs an important immune protection on the whole body and hair follicles. But there are very few researches on the function of CD200in the pathogenesis of AA till now. We then conducted some researches about that. We choose the severe AA patients as the research subjects since they are more representative and notable.Objective:To investigate the expression and significances of CD200in severe alopecia areata (AA).Methods:43patients with severe AA were chosen as the research subjects. Flow cytometry was performed to detect the expression of CD200on peripheral lymphocytes. The RT-PCR method was used to detect CD200mRNA on PBMC. The immunohistochemical method was used to detect the expression of CD200on the follicles specimen from the areas of hair loss in12patients. The serum levels of IL-10and IFN-y was detected by ELISA and then their relevance with the expression of CD200on peripheral lymphocytes was analyzed. Specimens of normal healthy people were the controls. SPSS17.0statistical software was used for statistical analysis.Results:1. The expression of CD200was significantly lower on T lymphocytes(5.73%±3.46%) and total lymphocytes (8.85%±4.8%) compared with that on T lymphocytes(12.01%±4.9%) and total lymphocytes (12.31%± 3.12%) of healthy controls (t=6.865,3.964respectively, P<0.05), while no difference was found on B lymphocytes between patients with AA (74.68%±8.12%) and the healthy controls (75.75%±9.45%, t=-0.570, P>0.05)2. The relative expression of CD200mRNA in patients with severe AA was0.209±0.145, and0.588±0.377in normal controls, the former are much lower than the latter, t=6.146, p<0.001.3. The serum concentration of IFN-γ in patients was about43.34+17.20pg/ml, which was significantly higher than that in normal control group (30.52±7.88pg/ml), t=4.443, p<0.001, while the concentration of IL-10in patients was12.31±10.14pg/ml, significantly lower than that in the normal control group (24.99±12.90pg/ml), t=-5.068, p<0.001.4. Relevance:The expression rate of CD200on CD3+T lymphocytes and total lymphocytes are negatively relevant with the serum concentration of IFN-γ, while positively relevant with the serum concentration of IL-10.5. The expression rate of CD200on hair follicles from areas of hair loss in patients with AA was about50%, which was lower than that of normal control group (P<0.05).6. During the above researches, we observed3rare cases with sever AA, whose regrowth hair was strikingly altered from the pre-AA one. None of them are healthy and good-looking. In the first case the regrowth hair was curly and slender, differing from the prior straight hair. In the second case the regrowth hair was curly and coarse, differing from the normal straight hair. The regrowth hair of the last case remained pure white. We analysed their clinical history, reviewed the related literatures and summed up the common characteristics of the altered regrowth hair, discussed the possible reasons and proposed the possible measures.Conclusions:Expression of CD200is decreased in peripheral lymphocytes and follicles of patients with severe AA, which may be associated with the pathogenesis of AA by affecting the balance of Thl/Th2cytokines and tolerance of follicles. The alterated regrowth hair in Alopecia areata has negative influence on the patients, so it needs to be paid attention to and needs further researches. |
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