An objective skin-type classification based on non-invasive biophysical parameters.

BACKGROUND: Despite the invention of various non-invasive bioengineering tools, skin-type analysis has largely been based on subjective assessments. However, advancements in the functional cosmetic industry and artificial intelligence-assisted dermatology are creating a greater demand for an objective skin-type classification system. OBJECTIVES: To propose an objective skin-type classification system solely based on non-invasive, bioengineering devices; provide reference values applicable to the Korean population; and compare our reference values with those of published studies. METHODS: Biophysical parameter measurements were obtained from the 2018 International Skin Characteristics Data Bank Project conducted by the Foundation of Korea Cosmetic Industry Institute. The participants were 434 healthy South Korean adults. Each participant was assessed using eight bioengineering devices (Tewameter® , pH-meter® , Corneometer® , Sebumeter® , Cutometer® , Spectrophotometer® , PRIMOS® lite, and Janus® ). The measurements were divided into tertiles to determine reference points. RESULTS: Our objective skin-type classification consists of five main categories (sensitivity, hydration, oiliness, elasticity, and skin tone) and five corresponding subcategories (erythema, roughness, pores, wrinkles, and pigmentation, respectively). Each skin type was assigned based on the reference point of the biophysical parameter, which was established as the tertile value associated with 'unfavourable' skin characteristics. Individuals were categorized as having sensitive skin when the TEWL scores were over 18.0 g/m2 /h or the pH was over 5.45; dehydrated skin when the corneometric value measured below 47.17 A.U.; oily skin when the sebumetric value exceeded 70 µg/cm2 ; and loose skin when the cutometric R2 value was below 0.68 E/mm. CONCLUSIONS: This study is the first to provide a comprehensive skin-type classification system based solely on non-invasive biophysical parameters. As measurement data accumulate, the reference points will progress to become more accurate, and they will be subdivided according to gender, age, and ethnic group. Therefore, our classification system serves as a basis for artificial intelligence-based skin-type analysis.

Effects of hydrogenated fat-spray-coated ß-carotene supplement on plasma ß-carotene concentration and conception rate after embryo transfer in Hanwoo beef cows.

We hypothesised that hydrogenated fat (HF)-spray-coated ß-carotene (ßC) supplement could be used to increase plasma ßC concentration and conception rates after embryo transfer (ET) in Hanwoo beef cows. In Experiment 1, 12 multiparous Hanwoo cows were fed one of four experimental diets in a triplicate 4 × 4 Latin square design for a 28-day period. Treatments included no ßC addition (control), HF-uncoated ßC (HFußC), HF-spray-coated ßC (HFßC), and HF-spray-coated ßC and vitamin A (HFßCA). The cows under ßC-supplemented treatments were fed 400 mg/day of ßC, and a daily intake for vitamin A of HFßCA treatment was 30 000 IU/day as retinyl acetate. Blood was collected on days 0, 26, 27, and 28 to analyse ßC and other metabolite concentrations. In Experiment 2, 199 Hanwoo cows with low fertility were randomly assigned to either control (n = 99) or HFßC treatments (n = 100) based on the results of Experiment 1. The oestrus of the cows was synchronised for ET. The HFßC group was fed from 4 weeks before to 4 weeks after ET with a daily intake of 400 mg ßC. Pregnancy for conception rates was diagnosed on day 60 after ET, and blood was collected for ßC concentrations on the day before ET. Supplementing ßC resulted in a high plasma ßC concentration (P < 0.001). Supplementing HFßC or HFßCA resulted in higher ßC concentrations than HFußC (P < 0.001); however, there was no difference between HFßC and HFßCA groups. Plasma retinol concentration was lower in the HFßCA treatment than in the control and HFßC groups (P < 0.05). Blood metabolites were unaffected by the treatments. The retinol:ßC ratio was lower in the ßC-supplemented treatments than in the controls, and was lower in HFßC and HFßCA than in HFußC groups (P < 0.001). Plasma ßC concentration was positively correlated with plasma high-density lipoprotein, low-density lipoprotein, and total cholesterol (P < 0.05). Plasma retinol concentration was negatively associated with plasma protein (P < 0.01), but positively associated with plasma creatinine (P < 0.001) and urea (P < 0.01). Supplementing HFßC to low-fertility cows resulted in higher plasma ßC concentration (P < 0.001) and conception rates (P = 0.024) than those in the controls. In conclusion, HFßC had a better bioavailability than HFußC, and an increase in conception rates by supplementing HFßC may be beneficial for producing more calves given the low pregnancy rates of bovine ET in Korea.

Diagnostic utility of skin autofluorescence when patch test results are doubtful.

BACKGROUND: The standard diagnostic test for allergic contact dermatitis is the patch test, which can also be used to identify irritant contact dermatitis. Doubtful reactions (?+) can be often clinically relevant to individuals and can require additional tests. OBJECTIVES: The purpose of this study was to examine whether autofluorescence (AF) measurements in patients with doubtful reactions are helpful in diagnosing contact dermatitis. METHODS: Patients with a history of contact dermatitis were patch tested on the upper back for 48-hours of occlusion using aqueous solutions of 5% sodium lauryl sulfate. Reaction intensity was scored, and AF was measured on reactive lesions and non-lesions. Three dermatologists classified the results as positive or negative using the fluorescence photographs of patients with a doubtful reaction. RESULTS: Among doubtful reactions, the R/G% values were significantly higher in the AF- based positive group than in the negative group (P = .0086). On the other hand, the heterogeneity values of R, G, and B (HR, HG, HB) were significantly lower in the AF-based positive group (P = .0026, .0046, .0004 respectively). CONCLUSIONS: Measuring AF along with the clinical readings can help confirm doubtful patch test reactions.

Comparative analysis of the effects of CO2 fractional laser and sonophoresis on human skin penetration with 5-aminolevulinic acid.

Successful delivery of a photosensitizer into the skin is an important factor for effective photodynamic therapy (PDT). The effective method to increase drug penetration within short incubation time overcoming skin barrier have been investigated. This study was performed to analyze and compare the effectiveness of ablative fractional laser (FXL) pretreatment and/or sonophoresis for enhancing the penetration of 5-aminolevulinic acid (ALA) into human skin in vivo. Twenty-four identical 1 × 1 cm2 treatment areas were mapped on the backs of ten healthy male subjects. Each area received FXL pretreatment and/or sonophoresis with different energy settings and ALA incubation times. After treatments, porphyrin fluorescence reflecting the ALA penetration were measured. Application of ablative CO2 FXL pretreatment resulted to higher fluorescence intensities than the non-treatment group. Incubation times were positively correlated with the increments of ALA penetration. However, increasing pulse energy or combining with sonophoresis did not show additional positive effects on ALA penetration. Ablative CO2 FXL pretreatment effectively facilitated ALA penetration in human skin in vivo. Ablative CO2 FXL alone without sonophoresis setting pulse energy of 10 and 20 mJ with more than 60 min of ALA incubation time could be an ideal setting for ALA penetration.

Pilot study on the correlation between skin auto-fluorescence and serum antioxidant enzyme: skin auto-fluorescence is negatively associated with levels of malondialdehyde.

BACKGROUND/PURPOSE: Various methods have been used to objectively record skin changes. However, estimating the intrinsic and extrinsic aging of skin remains a challenge. Our objective was to study intrinsic skin aging with respect to patient age and extrinsic photo-aging of human dorsal (photo-exposed) and volar (photo-protected) forearm in vivo through skin auto-fluorescence (AF). We also examined the correlations between serum antioxidant enzyme, malondialdehyde(MDA), and skin AF. METHODS: 37 healthy volunteers were enrolled. We measured skin AF and its heterogeneity on the dorsal and volar forearms. We also examined serum concentration of catalase, superoxide dismutase, vitamin E, and MDA levels in every participant. RESULTS: In photo-protected areas, skin AF intensity in the 40 years or older group was significantly higher compared to the group less than 40 years-old. On the other hand, heterogeneity value was significantly higher in the less than 40 years-old group in photo-protected area. With respect to serum antioxidant enzyme and MDA level, only MDA level showed a negative correlation with skin AF intensity in photo-exposed area. CONCLUSION: We determined that skin AF intensity of the photo-protected area reflects intrinsic skin aging. In addition, degree of photo-aging could be indirectly inferred by skin AF of photo-exposed area and serum MDA level.

Comparative study of skin autofluorescence expression in atopic dermatitis and psoriasis: A prospective in vivo study.

BACKGROUND/PURPOSE: Treatment of atopic dermatitis (AD) and psoriasis requires their differentiation from other eczematoid dermatitis and a determination of disease severity. However, both can be clinically difficult and the findings subjectively interpreted. We investigated the utility of in vivo autofluorescence (AF) measurements for diagnosis of both diseases, and determination of severity. MATERIALS AND METHODS: Thirty patients with AD and 30 with psoriasis were recruited, together with sex- and age-matched patients with healthy skin. AF intensity was measured using the EcoSkin® fluorescence video dermatoscope. In AD and psoriasis patients, AF in non-sun-exposed lesional and non-lesional skin was measured. To identify the locations that reflect characteristics of AD, AF was also measured at the other sites in the patients with AD. RESULTS: AD was associated with lower AF and psoriasis with higher AF intensity peaking around 620 nm. In addition, skin AF intensity of each disease was associated with severity of lesion. CONCLUSIONS: Non-invasive measurement of skin AF in vivo can aid in diagnosis of AD and psoriasis as well as in treatment monitoring.

Impact of chemical peeling combined with negative pressure on human skin.

OBJECTIVE: In vivo changes in skin barrier function after chemical peeling with alpha hydroxyacids (AHAs) have been previously reported. However, the additional effects of physical treatment with chemical agents on skin barrier function have not been adequately studied. This study measured the degree of acute skin damage and the time required for skin barrier repair using non-invasive bioengineering methods in vivo with human skin to investigate the additional effect of a 4% AHA chemical jet accelerated at supersonic velocities. METHODS: Thirteen female subjects (average age: 29.54 ± 4.86 years) participated in this study. The faces of the subjects were divided into half according to the block randomization design and were then assigned to receive AHA peeling alone or AHA peeling combined with pneumatic pressure on each side of the face. Transepidermal water loss (TEWL), skin colour and skin blood flow were evaluated at baseline and at 30 min, 2, 5 and 7 days after treatment. RESULTS: The TEWL and skin blood flow were significantly increased after 30 min in chemodermabrasion compared with chemical peeling alone (P < 0.05). The TEWL and skin blood flow recovered to baseline after 2 days, and TEWL was significantly decreased at 7 days compared with chemical peeling alone (P < 0.05). CONCLUSIONS: Chemodermabrasion can temporarily impair skin barriers, but it is estimated that it can enhance the skin barrier function after 7 days compared to the use of a chemical agent alone. In addition, chemodermabrasion has a more effective impact in the dermis and relatively preserves the skin barrier.

Twelve-point scale grading system of scanning electron microscopic examination to investigate subtle changes in damaged hair surface.

BACKGROUND: To assess the hair surface condition, scanning electron microscope (SEM) is commonly used and it remains an indispensable hair morphology characterization technique. Yet, the technique is criticized for having subjective viewpoints and limitations in distinguishing the appearance of cuticle layers. OBJECTIVES: The aim of this study is to establish an objective classification system and also to subdivide by detailed description of damaged cuticle layers. METHODS: Hair samples were collected from female subjects (n = 500) who participated in hair efficacy study and Asian hair bunches (n = 180) that were previously collected. Damage to hair was initiated by chemical, heat stress and ultraviolet irradiation. We suggested the grading criterion on a 12-point scale and compared with a wide range grading system on a 5-point scale. We evaluated other hair surface-related parameters such as hair luster-ring and combing load to verify the validity and efficacy of our new grading system. RESULTS: The grading criterion on our 12-point scale revealed an improved discrimination compared to the wide range grading system. Hair surface-related parameters were significantly improved after hair care product, and these tendencies were likely to be determined to be similarly improved using the 12-point scale grading system. CONCLUSION: The 12-point scale classification system was demonstrated to be a more precise standardization and appropriate evaluation method to investigate the subtle distinction of the hair shaft after hair care product application.

Analysis of comedone, sebum and porphyrin on the face and body for comedogenicity assay.

BACKGROUND/PURPOSE: Many ingredients used in cosmetics evoke a comedogenic response. Rabbit ear model (REM) is a useful method that can replace human in examining materials and products in early developmental stage. However, a number of studies pointed out its disadvantage that it overreacts to comedogenic materials. The purpose of this study was to find the most appropriate region for evaluating comedogenicity in human skin. METHODS: Sixty-six female subjects (age 32.48 ± 10 years; range 20-52 years) with mild to moderate facial acne lesions were included in this study. The whole face, upper chest, and back of volunteers were photographed. Lesion (closed and open comedones) counting, instrumentation of sebum secretion level, and analysis of porphyrin number were performed. The entire study was performed under environmental conditions of specific relative temperature and humidity, controlled and maintained identically for each volunteer. RESULTS: In case of closed comedone, forehead showed a significant correlation with frontal cheek, lateral cheek, chin, and upper back. Meanwhile, significant correlations were observed between frontal cheek and chin as well as lateral cheek and chest. As for open comedone, forehead showed a significant correlation with chin site. A significant correlation was also observed between front cheek and lateral cheek as well as between upper chest and back. Analyzing the correlation between the occurrence of comedones and sebum in each region, a significant correlation between closed comedone and sebum was observed in frontal and lateral cheek. Analyzing the correlation between the occurrence of comedones and porphyrine in each region, a significant correlation between open comedone and porphyrin was observed in chin. CONCLUSION: When evaluating the comedogenicity of cosmetics ingredients or products, this study recommends using both of the methods of testing on back and directly testing on face according to the characteristics of the materials. In case of mild potent ingredients or products in particular, verification through usability test that the directly test on face will help securing reliability.

Facial skin physiology recovery kinetics during 180 min post-washing with a cleanser.

BACKGROUND/PURPOSE: Facial cleansing is important to clean and exfoliate the skin while maintaining optimal physiologic function. However, there is insufficient data on the very early stage of skin change after applying soap or cleansing foam. We investigated the recovery kinetics of facial skin physiology during 180 min after exposure to the cleanser. METHODS: For the study, 22 Korean female subjects with normal and dry to oily skin type were recruited in this study. Study subjects were required to have face washing done within the 12 hours prior to visiting the research center, with only toner, lotion, or cream applied. The next day, the subjects visited the research center without face washing. We evaluated the skin hydration (Corneometer(®) CM 825), sebum (Sebumeter(®) SM 815), transepidermal water loss (Tewameter(®) TM 300), and pH (Skin-pH-Meter(®) PH 905) to define recovery kinetics of facial skin physiology during 180 min exposure post-cleansing. RESULTS: Skin hydration, sebum, and TEWL were significantly decreased at 20 min after washing, as compared to the baseline (P < 0.05). And skin hydration returned at 40 min, and skin sebum and TEWL returned at 120 min after washing. However, skin pH did not show significant differences at all times points. CONCLUSIONS: This study indicated that each of the skin parameters was restored at defined time points post-cleansing. Our result could be a useful reference to set the resting time in the estimation of skin bioengineering parameters.

Positivity rates of antithyroid antibody, antinuclear antibody and thyroid peroxidase antibody in different types of vitiligo.

BACKGROUND: Vitiligo is associated with various autoimmune disorders, and organ-specific autoantibodies are frequently found in patients with this disorder. Vitiligo is classically divided into segmental vitiligo (SV) and nonsegmental vitiligo (NSV), and it is believed that the pathogenesis differs between these two types. As the NSV type is related to an autoimmune mechanism, autoantibody detection rates are likely to be higher in the NSV type than in the segmental type; however, no comparative studies have been performed. AIM: To analyse the rates of autoantibody positivity according to the clinical features in patients with vitiligo. METHODS: Rates of antithyroid antibody (Tg Ab), antinuclear antibody (ANA) and thyroid peroxidase antibody (TPO Ab) positivity were analysed and compared according to the sex, clinical type and age of onset of 807 patients with vitiligo. RESULTS: There were 106 patients with SV (13.1%) and 701 patients with NSV (86.9%). Tg Ab and ANA positivity did not differ between the SV and NSV types. A positive TPO Ab result was obtained in 16 patients with SV (15.1%) and 173 patients with NSV (24.7%). The TPO Ab positivity rate was significantly higher in NSV (χ² = 4.14, P < 0.05). The positivity rates of the three autoantibodies differed significantly according to age of onset (P = 0.001, P = 0.02 and P < 0.001 for Tg Ab, ANA and TPO Ab positivity, respectively). The TPO Ab positivity rate also showed a sex difference (P < 0.001). CONCLUSIONS: The positivity rates for the three autoantibodies showed differences according to age of onset and sex. The rates of Tg Ab and ANA positivity showed no significant differences according to clinical type, but the TPO Ab positivity rate was significantly different between SV and NSV. It appears likely that an autoimmune mechanism contributes to the pathogenesis of SV.

How much related to skin wrinkles between facial and body site? Age-related changes in skin wrinkle on the knee assessed by skin bioengineering techniques.

BACKGROUND/PURPOSE: Skin aging has been focused the wrinkle on the face than on the body, so most studies have been studied the change in Crow's feet for ages. Only little is known about the age-dependent changes of wrinkles on body sites. The aim of this study was to establish new grading criteria for severity of wrinkles on knees and to investigate the relationship of wrinkle severity with age- and site-dependent. METHODS: The skin on the knee of 38 healthy Korean female volunteers, divided into two groups young and old, were photographed. Standard photograph for body wrinkle was established (grade 0~7), and then visual assessment, skin wrinkle, and skin elasticity were evaluated on Crow's feet and the knee. We examined for any significant differences and the correlation of skin aging parameters with age and two different sites. RESULTS: Skin wrinkle severity with standard photograph and wrinkle parameters (Ra, Rmax, Rz, and Rv) had a significantly positive correlation with age-dependent on the knee (P < 0.001). Also, skin elastic parameters (R2, R5, R6, R7, and Q1) showed a significant negative correlation with age on the knee (P < 0.001). Skin wrinkle severity with standard photograph was highly correlated with all skin wrinkle parameters and skin elastic parameters (R2, R5, R7, and Q1) on the knee (P < 0.001). In addition, all the skin aging parameters on the knee were significantly correlated with Crow's feet (P < 0.01). Skin aging on the knee had the same tendency as the Crow's feet. CONCLUSIONS: This study has shown the new grading criteria of wrinkles on the knee. Skin wrinkle and elasticity on the knee are age-dependent related and aging on the knee is highly related to Crow's feet. Those parameters are using a quantitative method to evaluate body aging. Also, the knee is considered that it could be a suitable site to evaluate body aging.

Relationship between the HLA-G 14 bp insertion/deletion polymorphism and susceptibility to autoimmune disease: a meta-analysis.

Numerous studies have investigated the potential relationship between the human leukocyte antigen (HLA)-G 14-bp insertion/deletion (INS/DEL) polymorphisms and autoimmune disease (AID). However, published results are inconclusive. Our aim was to determine whether the 14-bp INS/DEL polymorphism in the HLA-G gene contributes to the risk of AID. A systemic literature search of the PubMed and EMBASE databases was conducted to identify eligible studies investigating the association of the HLA-G 14-bp INS/DEL polymorphism with AID. Our analysis included 11 publications involving a total of 6462 individuals. Overall, no significant association between the HLA-G 14-bp INS/DEL polymorphism and AID was detected in any comparison model. Further subgroup analyses based on AID types and ethnicity also revealed no significant associations. Our results suggest that the HLA-G 14-bp INS/DEL polymorphism is unrelated to the development of AID. Further studies including larger sample sizes are warranted to confirm these results.

Is the Carotid Body a Metabolic Monitor?

The carotid body is a multi-modal sensor and it has been debated if it senses low glucose. We have hypothesized that the carotid body is modified by some metabolic factors other than glucose and contributes to whole body glucose metabolism. This study examined the roles of insulin, leptin and transient receptor potential (TRP) channels on carotid sinus nerve (CSN) chemoreceptor discharge. In agreement with other studies, CSN activity was not modified by low glucose. Insulin did not affect the CSN hypoxic response. Leptin significantly augmented the CSN response to hypoxia and nonspecific Trp channel blockers (SKF96365, 2-APB) reversed the effect of leptin. Gene expression analysis showed high expression of Trpm3, 6, and 7 channels in the carotid body and petrosal ganglion. The results suggest that the adult mouse carotid body does not sense glucose levels directly. The carotid body may contribute to neural control of glucose metabolism via leptin receptor-mediated TRP channel activation.

The effect of physically applied alpha hydroxyl acids on the skin pore and comedone.

OBJECTIVE: Alpha hydroxy acids (AHA) have been recognized as commonly used therapy for acne. Our studies examined whether an additional effect of physical treatment using chemical peeling combined with negative pressure and compared with AHA treatment only occurs in acne-prone subjects. METHODS: The chemical peeling agent used 4% of an AHA solution (mixture of 1000 mL of carbonated water, 20 mL of glycolic acid and 20 mL of lactic acid). All subjects' faces were randomly divided into test and control groups. The test group was treated with chemical peeling combined with a physical effect, and the control group applied chemical peeling alone. For the 23 healthy females (average age: 30.17 ± 5.06 year), we measured sebum output level by light transmission, pore area and number by optical image analyser, and comedone counting before treatment and at 1, 2 and 4 weeks after a single treatment. RESULTS: Compared to the before treatment, whiteheads and blackheads were significantly decreased at 1, 2 and 4 weeks in the test group (P < 0.05), but for the control group, whiteheads and blackheads showed a tendency to decrease at 1, 2 and 4 weeks. Also at 1 week, whiteheads and blackheads of the test group significantly decreased compared to the control group (P < 0.05). Pore area and number significantly decreased at 1 week (P < 0.05), and the sebum output level was significantly decreased at 4 weeks (P < 0.05) only in the test group, which did not show any significant group difference for individual parameters. CONCLUSION: 4% AHA solution combined with a physical effect had rapidly improving effects on whiteheads and blackheads synergistically. Combined physical therapy may have more impact on pore size and seborrhoea.

Dermal matrix affects translucency of incident light on the skin.

BACKGROUND/AIMS: The age-dependent changes in the optical reflection characteristics have been studied about skin hydration, melanin index, or skin color. However, the age-dependent changes in the optical reflection have little attention on inner skin structures. To control the factors affecting the optical reflection except for dermal matrix, subjects were selected as our guideline and we evaluated the optical reflection of subsurface on skin layers of two age groups. METHOD: Young and old healthy volunteers were recruited after signing a written informed consent form. Facial skin was measured by means of noninvasive measurements: skin hydration, color, epidermis and dermis thickness, dermal density, subsurface reflectance, and transmittance. RESULT: Compared to young group, old group showed that dermal density and thickness was decreased significantly although epidermis thickness was not changed. CONCLUSION: In conclusion, dermal density is one of the major factors which affects the subsurface reflectance in skin.

Autofluorescence analysis of dermatitis and squamous cell carcinoma in paraffin wax-embedded skin samples.

BACKGROUND: Recent research has investigated the use of autofluorescence (AF) for distinguishing between normal and cancerous tissues according to different fluorescence characteristics. AIM: To analyze if AF can help differentiate cancerous lesions from other nonneoplastic lesions, such as dermatitis, in each layer of the skin ex vivo. METHODS: Paraffin wax-embedded tissue samples were obtained from patients who were histopathologically diagnosed with squamous cell carcinoma (SCC), psoriasis, chronic dermatitis (lichen simplex chronicus, prurigo nodularis) or acute dermatitis (atopic dermatitis). AF intensity was measured in four layers of the epidermis (corneal, granular, spinous and basal) and two layers of the dermis (papillary and reticular). RESULTS: AF was highest in all layers of psoriasis samples compared with all layers of all other groups. Higher AF values were seen in SCC compared with all skin layers of acute and chronic dermatitis; this finding was especially true in the corneal layer, papillary dermis and reticular dermis. CONCLUSIONS: This ex vivo AF study provides basic data for future in vivo studies of AF as a noninvasive diagnostic tool.

Association between an HLA-G 14 bp insertion/deletion polymorphism and non-segmental vitiligo in the Korean population.

Vitiligo is a pigmentary skin disorder characterized by the chronic and progressive loss of melanocytes. Although the etiology of vitiligo is still unknown, several theories have been proposed to explain the pathogenesis of vitiligo including autoimmune, neural, self-destruction, oxidative stress, and genetic theories. Human leukocyte antigen (HLA)-G is a nonclassic, major histocompatibility complex class I molecule that plays an important role in suppression of the immune response. Several recent studies have provided evidence that a 14 bp insertion (INS)/deletion (DEL) polymorphism in the HLA-G gene might be associated with autoimmune disease. Our aim in this study was to determine whether the 14 bp INS/DEL polymorphism in the HLA-G gene contributes to the risk of developing non-segmental vitiligo (NSV) in the Korean population. We conducted a case-control association study of 192 NSV patients and 491 matched, unaffected controls. The HLA-G 14bp INS/DEL polymorphism was analyzed by gene scan after amplification using the polymerase chain reaction. Genotype frequencies for the 14bpINS/DEL were different between the vitiligo group and Korean control group. The proportion of subjects with a homozygote 14bpINS/14bpINS genotype was significantly higher in the vitiligo group compared with the control group (7.1 vs. 3.5 %, OR 2.25, 95 % CI 1.06-4.76, p = 0.039 in the recessive model). Our results suggest that the HLA-G 14bpINS/DEL polymorphism is associated with the development of NSV in the Korean population.