Hydroxychloroquine protects melanocytes from autoantibody-induced injury by reducing the binding of antigen-antibody complexes.

Vitiligo is a polygenic autoimmune disorder characterized by loss of pigmentation due to melanocyte destruction. Hydroxychloroquine (HCQ) is an effective immunosuppressant widely used in the treatment of autoimmune disorders. As generalized vitiligo (GV) is commonly considered to be a T cell and autoantibody-induced immune disorder, the present study aimed to determine whether HCQ protects melanocytes from autoantibody­induced disruption. Anti­melanocyte antibodies were obtained from the serum of patients with progressive GV and the effects of HCQ on prevent the autoantibody­induced disruption of melanocytes was observed. Cell­based ELISA, indirect immunofluorescence and western blotting were used to analyze the autoantibody content of sera samples obtained from 32 patients with progressive GV. The cytotoxicity of HCQ was detected by MTT assay, and 1 µg/ml HCQ was applied to human primary melanocytes (HMCs) to examine whether it could exert protective effects against autoantibody­induced immune injury. Flow cytometry was used to measure autoantibody binding to the surface of HMCs. Complement­dependent cytotoxicity (CDC) and antibody­dependent cell­mediated cytotoxicity (ADCC) were monitored by MTT and lactate dehydrogenase­releasing assays. The concentration of autoantibodies in sera samples taken from GV patients was significantly higher than in controls, particularly in patients who had >10% of their body surface affected by vitiligo. The majority of the autoantibodies presented in the HMCs and human keratinocytes (HKCs) and were predominantly localized to the cell surface and cytoplasm. The molecular weights of the autoantigens were identified as 30, 37­39, 42, 53, 60­75, 90, 100, 110, and 126 kDa; the 30 kDa protein was observed only in HMCs. The addition of HCQ at a concentration of 1 µg/ml produced no significant cytotoxicity in HMCs and was demonstrated to reduce the binding of GV immunoglobulin G (IgG) to the surface of HMCs. HCQ also significantly decreased the effects of ADCC and CDC that were mediated by GV IgG. The present study provides evidence that HCQ dissociates autoantibody-antigen complexes on the surface of HMCs and reverses ADCC and CDC activity in vitro. Thus, in addition to its effectiveness as an antimalarial therapeutic agent, HCQ may also be a promising potential treatment for patients with vitiligo.

Curcumin improves the paclitaxel-induced apoptosis of HPV-positive human cervical cancer cells via the NF-κB-p53-caspase-3 pathway.

Paclitaxel, isolated from Taxus brevifolia, is considered to be an efficacious agent against a wide spectrum of human cancers, including human cervical cancer. However, dose-limiting toxicity and high cost limit its clinical application. Curcumin, a nontoxic food additive, has been reported to improve paclitaxel chemotherapy in mouse models of cervical cancer. However, the underlying mechanisms remain unclear. In this study, two human cervical cancer cell lines, CaSki [human papilloma virus (HPV)16-positive] and HeLa (HPV18-positive), were selected in which to investigate the effect of curcumin on the anticancer action of paclitaxel and further clarify the mechanisms. Flow cytometry and MTT analysis demonstrated that curcumin significantly promoted paclitaxel-induced apoptosis and cytotoxicity in the two cervical cell lines compared with that observed with paclitaxel alone (P<0.05). Reverse transcription-polymerase chain reaction indicated that the decline of HPV E6 and E7 gene expression induced by paclitaxel was also assisted by curcumin. The expression levels of p53 protein and cleaved caspase-3 were increased significantly in the curcumin plus paclitaxel-treated HeLa and CaSki cells compared with those in the cells treated with paclitaxel alone (P<0.01). Significant reductions in the levels of phosphorylation of IκBα and the p65-NF-κB subunit in CaSki cells treated with curcumin and paclitaxel were observed compared with those in cells treated with paclitaxel alone (P<0.05). This suggests that the combined effect of curcumin and paclitaxel was associated with the NF-κB-p53-caspase-3 pathway. In conclusion, curcumin has the ability to improve the paclitaxel-induced apoptosis of HPV-positive human cervical cancer cell lines via the NF-κB-p53-caspase-3 pathway. Curcumin in combination with paclitaxel may provide a superior therapeutic effect on human cervical cancer.

Efficacy of quantifying melanosome transfer with flow cytometry in a human melanocyte-HaCaT keratinocyte co-culture system in vitro.

In this study, we describe a simple, specific, reproducible and quantitative assay system to assess melanosome transfer. We first established a co-culture model of normal human epidermal melanocytes and HaCaT keratinocytes. The cells were co-cultured for 72 h in a serum-free keratinocyte growth media and double labelled with Fluorescein isothiocyanate (FITC)-conjugated antibody against the melanosome-specific protein gp100, and with Phycoerythrin (PE)-conjugated antibody against the keratinocyte-specific marker cytokeratin. Then, the cells were examined using co-focal microscope and flow cytometry. The increased melanosome transfer from melanocytes to HaCaT keratinocytes was observed in a time-dependent manner. To verify the accessibility of this method, two known melanosome transfer inhibitors and two known melanosome transfer stimulators were applied. Consistent with previous investigation, soybean trypsin inhibitor (STI), niacinamide inhibited melanosome transfer, alpha-melanocyte stimulating hormone (alpha-MSH) and keratinocyte growth factor (KGF) increased melanosome transfer, respectively, in a dose-dependent manner. The model used in this study could thus represent a rapid and reliable tool to identify modulators of human melanosome transfer.

Cutaneous and systemic plasmacytosis: a Chinese case.

Cutaneous and systemic plasmacytosis (CSP) is an exceedingly rare condition arising primarily in patients of Japanese descent. Herein, we describe a patient of mainland Chinese origin suffering CSP. A 49-year-old Chinese male had asymptomatic brownish-red plaques and papules of the face and trunk for 6 years. Physical examination revealed innumerable symmetric red-brownish macules on face and trunk with fewer red-brownish papules scattered among the macules. Chemical analysis revealed hypergammaglobulinemia. Computerized tomography scan discovered some lymphadenopathy in the axillary, paratracheal and pulmonary regions. Histological examination showed focal perivascular and periadnexal infiltrate of mainly plasma cells in the superficial and deep dermis. Immunohistochemical study showed that a great number of the infiltrating cells were CD20-positive. The infiltrated polyclonal plasma cells expressed both kappa and lambda light chains. Topical therapy with tacrolimus 0.1% ointment for 2 months reduced the thickness and pigmentation of the facial skin lesions. The lesions resumed the original appearance 3 weeks after discontinuing the therapy. To the best of our knowledge, this is the first case of CSP from mainland China.

Unilateral linear capillaritis: two unusual Chinese cases.

Unilateral linear capillaritis (ULC) is a rare special variation of pigmented purpuric dermatosis (PPD), which is characterized clinically by linear or segmental distribution of pigmented purpuric macules located predominantly on the lower extremities and showing a favorable prognosis. In this case report, we describe two unusual cases of ULC, in one male and one female patient, with unilateral lesions involving the upper extremities that loosely follow the dermatome lines. Biopsy results revealed a common histopathology feature to PPD without heavy band-like infiltration in the upper dermis. On review 20 months after the onset, the eruptions of Patient 1 had spontaneously faded from parts of the affected area. Meanwhile, after a period of 18 months post onset, the eruptions of Patient 2 had became less visible after treatment with PUVA for 2 months, leaving a faded pigmentation.