Objective To investigate the melanocyte lymphocyte reacion when the allogeneic lymphocytes are cultured with normal melanocytes. Methods 3H-thymidine was incorporated into the mixed culture and the transformation and proliferation rates of lymphocytes were detected by liquid scintillation counting and expressed as cpm. Electron microscopy was used to observe the ultrastructure of melanocytes after mixed culture. Results The results of lymphocyte proliferation were expressed by the stimulation indexes. The stimulation indexes in active vitiligo group was significantly different from that in stable vitiligo group and normal controls. The stimulation indexes of the melanocyte stimulated group was significantly different from that of ConA stimulated group. In the mixed melanocyte lymphocyte reaction, the allogeneic lymphocytes had little effect on the melanocytes. The ultrastructure of the melanocytes in the mixed culture showed normal morphology and normal function of synthesis of melanin. Conclusion As a specific antigen in mixed melanocyte lymphocyte reaction, melanocyte has a weak effect on the lymphocytes. The melanocytes from stable stage vitiligo patients seem more suitble to be allografted.

Objective To investigate the effect of Toll-like receptor 2(TLR2)on the proliferation of human keratinocytes.Methods Keratinocytes were isolated from the foreskin of children,and subjected to primary culture.Atier 3-5 passages.the kemtinocytes were incubated with various concentrations of peptidoglycan(PGN).a TLR2 agonist.Cell proliferation was detected by MTT colorimetric assay and the suitable concentrations of PGN were determined.The mRNA and protein expressions of Ki67.TLR2.NF-kB p65 and TGF-α were detected by real-time quantitative PCR and Western blot.respectively,in keratinocytes treated witll PGN of 0,1.25,2.5 and 5 μg/mL.Antibody blocking test was utilized to evaluate the effect of blocking TLR2 with specific anti-TLR2 neutralizing monoclonal antibody before incubation with PGN on the expressions of Ki67,TLR2,NF-KB p65 and TGF-α by keratinocytes.Results The proliferation of kemtinocytes was significantly promoted by the incubation with PGN of 1.25,2.5 and 5μg/mL for 24 hours (all P＜0.05),which also increased the expression of Ki67 protein,TLR2 mRNA and protein,and NF-KB p65 protein.Further more,the mRNA expression of Ki67 in keratinocytes was elevated bv PGN of 1.25 and 2.5μg/mL,the mRNA expression of NF-KB p65 elevated by PGN of 1.25μg/mL,and the expressions of TGF-αprotein and mRNA elevated by PGN of 1.25 and 5μg/mL (P＜0.05).The mRNA and protein expressions of Ki67,TLR2,NF-kB p65 and TGF-αwere all inhibited by the blocking of TLR2 before incubation with PGN (a11 P＜0.05).Conclusion Activation of TLR2 bv PGN could induce the over-proliferation of human keratinocytes,likely through promoting NF-rB activation and TGF-α expression.

Objective To investigate the effect ofnarrow-band ultraviolet-B(NB-UVB)(311 nm)on dendrite formation in B16 melanoma cells.Methods B16 melanoma cells were irradiated with various doses of NB-UVB(0,25,50,100,200,300 mJ/cm2).Atier additional culture of varying durations,irradiated cells were harvested and subjected to the observation of morphological changes and cell cytoskeleton F-actin microfilaments by phase contrast microscopy and laser scanning confocal microscopy(LSCM).respectively,and to the detection of cell proliferation bv MTT colorimetric assay.Pull down assay was performed to detect the activity of GTP-RhoAA and GTP-Rac1 in B16 cells before and after UVB irradiation.Results Twenty-four hours after irradiation with UVB of 100 mJ/cm2.an increase was observed in the cell body of B16 cells which appeared in sphericity,as well as in the number of dendrites(P＜0.01)which showed a branch-like appearance.compared with non-irradiated cells which had 2-3 dendrites and obscure branches.LSCM revealed that F-actin microfilaments in B16 cells were well organized with clear textures before irradiation;after irradiation wim NB-UVB of 100 mJ/cm2.stress fibers were disassembled and disrupted and the texture became unclear,which was observed as early as 30 minutes and became more and more evident,and at 6 hours the stress fibers displayed a clumping appearance with obscure textures.Following the irradiation with NB-UVB of 100 mJ/cm2,the expression level of GTP-Rac 1 protein increased at l 5 minutes,and.at 30minutes,reached 2 times of that observed in nonirradiated cells,then decreased a liale,but still remained elevated at 60 minutes and 120 minutes,compared to unirradiated cells;meanwhile.the level of GTP-RhoA dropped a little at 30 minutes,then gradually increased and,at 120 minutes.reached 1.6 times of that observed in unirradiated cells.Conclusion Narrow-band UVB(311 nm)can promote dendrite formation.likely via regulating the expression of GTP-Racl and GTP-RhoA in B16 melanoma cells.

Objective To evaluate the efficacy and tolerance of monochromatic excimer light (MEL) 308 nm in the treatment of vitiligo. Methods Seventy-seven patients were enrolled in the prospective and open clinical study. Two-hundred and one lesions were subjected to local phototherapy of MEL 308-nm once a week for 3 to 6 months. Results Of these lesions, 86.6% obtained repigmentation at different degrees. The repigmentation was more obvious in lesions on the head, face, neck and trunk than in those on the limbs or extremities. Moreover, patients with generalized and segmental vitiligo got a better improvement than patients with other types of vitiligo. Conclusion MEL 308-nm is effective in the treatment of vitiligo without obvious adverse effects.