Vitamin D receptor (VDR) gene polymorphism in Egyptian vitiligo patients.

BACKGROUND: Vitiligo is an autoimmune dermatological disorder, precipitated by genetic and nongenetic factors leading to destruction of epidermal melanocytes. In Egypt, it has a prevalence rate of 1.2%. Vitamin D has stimulatory and protective effects on melanocytes and acts through its nuclear vitamin D receptor (VDR) on target cells. The consequences of polymorphisms in VDR have been previously studied for mapping their link with various disorders of autoimmune etiology. AIM OF THIS WORK: To study Apa-I and Taq-I VDR single-nucleotide polymorphisms (SNPs) and the risk to develop vitiligo. METHODS: Extracted genomic DNA from the venous blood of 60 patients and controls was amplified and analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) for analysis of VDR gene polymorphisms. Serum 25-hydroxyvitamin D3 (25-OH-D3) level was measured using ELISA technique. RESULTS: The most common VDR genotypes were AA and TT among both groups with no significant difference. Analysis of the frequency of combinations of genotypes revealed AATT as the most common among patients (36.7%) while in the control group, AATt is the most common (33.3%) but no significant difference was noted on comparison of both groups. The genotype allele tt appeared to be more expressed in patients with marginal significance value (P 0.053). Serum 25-OH-D3 showed a relatively decreased level among patients and controls with no statistically significant difference. CONCLUSION: Although VDR SNPs are not correlated with vitiligo, the elevated frequency of tt genotype among vitiligo patients may suggest the risk to develop the disease.

Associations among two vitamin D receptor (VDR) gene polymorphisms (ApaI and TaqI) in acne vulgaris: A pilot susceptibility study.

BACKGROUND: Acne vulgaris (AV) pathogenesis is multifactorial. Vitamin D (VitD) plays an important role in sebocytes' differentiation and function. Most VitD functions are mediated by the nuclear VitD receptor (VDR) following binding of its biologically active form (1,25 dihydroxyvitamin D3). Genetic variations in VDR gene may cause significant receptor dysfunction and have been found to be associated with many inflammatory skin diseases. Two adjacent single nucleotide polymorphisms of VDR, ApaI (rs7975232) and TaqI (rs731236), were commonly studied. OBJECTIVE: To evaluate the association between VDR ApaI and TaqI gene polymorphism and AV. METHODS: This case control study included 30 Egyptian acne patients who attended Dermatology Outpatient Clinic of Al-Zahraa University and Misr University for Science and Technology Hospitals. Thirty age- and sex-matched healthy individuals participated as controls. VDR gene ApaI and TaqI polymorphisms were examined by polymerase chain reaction restriction fragment length polymorphism. Serum 25(OH)D was measured in all participants. RESULTS: Patients had significant decrease in ApaI A allele and AATT combined genotype (60%, 3.3%) than controls (78.3%, 20%), respectively, and significant increase in TaqI tt genotype and t allele (46.7%, 63.3%) than controls (13.3%, 41.7%), respectively. Patients showed significantly lower serum 25(OH)D3 concentration than controls. CONCLUSION: Polymorphisms of ApaI and TaqI may have a role in the pathogenesis of AV as A allele and AATT combined genotype could be considered protective against acne development and tt genotype and t allele may increase the risk of AV development. VitD deficiency can be considered as a risk factor for AV development.

ULBP3: a marker for alopecia areata incognita.

Alopecia areata incognita (AAI) is a type of diffuse hair fall with no confirmatory diagnostic test. The UL16 binding protein-3 (ULBP3) is ligands for natural-killer group 2, member D (NKG2D) receptor. It is a key regulator of both innate and adaptive immune responses. In the normal hair follicle, ULBP3 is turned off. However, different studies reported its high level in alopecia areata (AA). Therefore, this study was done to evaluate ULBP3 in AAI in comparison with telogen effluvium (TE), female pattern hair loss (FPHL), and normal hair. Biopsy specimens from 36 females suffering from AAI, 15 with FPHL, nine with TE, and ten healthy female controls were subjected to the immunogenetic detection of ULBP3 levels by real-time polymerase chain reaction (PCR). A high statistically significant increase in ULBP3 level in AAI patient group compared with FPHL, TE, and normal hair was detected. ULBP3 levels were positively correlated with the age and duration of the disease. Accordingly, ULBP3 may act as a confirmatory test for AAI. ULBP3 may be implicated in the disease pathogenesis, progression, and chronicity, and AAI may be a subtype of AA.

Effect of narrow band-ultraviolet B on CD4(+) CD25(high) FoxP3(+) T-lymphocytes in the peripheral blood of vitiligo patients.

BACKGROUND: It is widely believed that an imbalance between activated CD8(+) T cells and regulatory T cells (Tregs) exists in patients with vitiligo. Although there is evidence that narrow band ultraviolet (NB-UVB) irradiation can induce Tregs' number and activity, but up to our knowledge, none of the published studies involved the possible effect of NB-UVB on Tregs in vitiligo. OBJECTIVE: To evaluate the effect of NB-UVB on circulating CD4(+) CD25(high) FoxP3(+) regulatory T cells (FoxP3(+) Tregs) in vitiligo. METHODS: This prospective analytic study included 20 patients with active non-segmental vitiligo and 20 healthy controls. The patients were exposed to NB-UVB therapy three times per week for 30 sessions. Blood sampling before and after NB-UVB phototherapy was done to evaluate circulating CD4(+) CD25(high) Tregs and Foxp3(+) Tregs. RESULTS: The CD4(+) CD25(high) Tregs% and FoxP3(+) Tregs% were significantly higher in vitiligo patients compared with controls. NB-UVB therapy decreased both of them in patients, but they did not reach those of controls. Each of circulating CD4(+) CD25(high) Tregs% and FoxP3(+) Tregs% didn't correlate with either extent or activity of vitiligo before or after NB-UVB. CONCLUSION: Tregs functional defect is probably having an impact on NSV. NB-UVB may improve the function of Tregs. Understanding the mechanisms through which NB-UVB exert its effect on reducing the number of circulating Tregs would help open up the paths for future therapeutic options.