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Biomedical subjects

S K Hann

Publications and source records attributed to S K Hann.

At least 37 records · Page 2Linked to original sources

Hair follicle structures targeted by antibodies in patients with alopecia areata.

OBJECTIVE: To identify the structures in hair follicles (HFs) targeted by alopecia areata (AA) antibodies and the role of antigen expression in the development or localization of AA lesions. DESIGN: The identity of HF structures targeted by AA antibodies was determined by indirect immunofluorescence and the level of antigen expression from the intensity of the staining. SETTING: A university medical center. PATIENTS: Ten patients with active AA and 8 control individuals. RESULTS: Antibodies to anagen HFs were present in up to 90% of patients with AA but in less than 37% of controls. The antibodies in patients with AA reacted to antigens present only in HFs. The structures most commonly targeted were the outer root sheath and, less often, the inner root sheath, matrix, and hair shaft. The same HF structure contained several immunologically distinct antigens reactive with AA antibodies. The expression of some AA antigens was much greater in the scalp of patients with AA than in normal individuals. CONCLUSIONS: These findings indicate that the autoantibody responses to HFs in patients with AA are heterogeneous and target multiple structures in anagen HFs. The expression of some as-yet-unidentified HF antigens is increased in many patients with AA, suggesting that the initiation, localization, severity, and persistence of the disease may be related to the level of expression of some HF antigens.

Adult↗

Oral psoralen with UV-A therapy releases circulating growth factor(s) that stimulates cell proliferation.

BACKGROUND: The mechanism by which oral psoralen with UV-A (PUVA) stimulates melanocyte proliferation in vitiligo is unknown. This study was conducted to examine the hypothesis that it does so by stimulating the release of growth factors that stimulate melanocyte proliferation. DESIGN: We examined the effect of serum samples obtained from patients with vitiligo before and following 2 and 4 months of PUVA therapy, and from non-PUVA-treated patients with vitiligo and normal individuals on the growth of melanocytes in vitro. SETTING: Outpatient clinic in referral center. PATIENTS: The study was conducted on serum samples obtained from 18 patients with vitiligo, 8 of whom were treated with PUVA, and from 10 normal individuals. INTERVENTION: Treatment with PUVA. MAIN OUTCOME MEASURE: Ability of serum samples to stimulate the growth of melanocytes in culture. RESULTS: Proliferation of melanocytes in serum collected after 4 months of PUVA therapy was on the average 3-fold greater than that in serum samples collected from the same patients prior to therapy with PUVA. This circulating growth factor was absent in serum samples of non-PUVA-treated patients with vitiligo and normal individuals. The effect was nonspecific, as it also stimulated the proliferation of fibroblasts. CONCLUSIONS: These findings suggest that PUVA treatment results in the release into the circulation of growth factor(s) that can stimulate a proliferation of melanocytes and of other cells. This could account for the repigmentation of vitiligo by PUVA treatment. As the growth factor(s) also stimulated the growth of other cells, it could also explain the thickening of the epidermis that occurs following exposure to UV light.

Administration, Oral↗

Identification of autoantibody to melanocytes and characterization of vitiligo antigen in vitiligo patients.

Patients with vitiligo have circulating antibodies to melanocytes. To identify vitiligo antibodies and characterize the antigens by vitiligo antibodies, sera of 18 patients with vitiligo, 18 with Behcet's disease, 22 with syphilis and 14 normal control subjects were analyzed by indirect immunofluorescence, live cell ELISA, and immunoblotting. In indirect immunofluorescent microscopy and live cell ELISA, most vitiligo sera showed positive immunofluorescence and high optical density on the surface of melanocytes cultured from normal and vitiligo patients, indicating that autoantibodies in the vitiligo sera may react with vitiligo antigens on the surface of melanocytes. When the same experiments were performed with malignant melanoma cell lines and fibroblasts, no significant differences in the immunofluorescence and optical density were observed between normal and vitiligo sera. And the sera of patients with Behcet's disease or syphilis showed no significant difference in the reaction of live cell ELISA to fibroblasts, IGR-3 and melanocytes. The antibody titers of vitiligo patients in live cell ELISA decreased following systemic steroid treatments. Immunoblot analysis demonstrated that 44% of vitiligo sera was directed to melanocyte antigen with a molecular weight of 65 kDa. Inhibition assay using rabbit anti-melanocyte antibody showed inhibition of reaction between vitiligo sera and melanocytes in ELISA and immunoblotting. These findings support the hypothesis that the sera of vitiligo patients have autoantibodies mostly directed to the 65-kDa antigen and this antigen may originate mostly from the melanocyte surface.

Animals↗

Segmental vitiligo: clinical findings in 208 patients.

BACKGROUND: Vitiligo affects approximately 1% of the general population without racial, sexual, or regional differences. However, studies of segmental vitiligo have been few and the number of patients limited. OBJECTIVE: The aim of this study was to analyze the clinical features of patients with segmental vitiligo. METHODS: We evaluated sex, age at onset, age at initial visit, character of the initial lesion, status of progression, precipitating factors, involved sites, dermatomal distribution, family history, Koebner phenomenon, presence of poliosis, dominant hand, and associated diseases. RESULTS: Segmental vitiligo had an early onset, rapid progression, no specific precipitating factors, and linear spreading in the affected dermatomal area. The most commonly involved dermatome was the trigeminal. Only a few patients had an associated autoimmune disease. CONCLUSION: The clinical features of segmental vitiligo differ from those of nonsegmental vitiligo; pathogenesis may also differ.

Adolescent↗

Acquired Blaschko dermatitis: acquired relapsing self-healing Blaschko dermatitis.

Acquired Blaschko dermatitis is a rare disease with acquired unilateral relapsing inflammatory linear lesions along Blaschko's lines. Histopathology reveals spongiotic dermatitis. "Blaschkite de l'adulte" and "acquired relapsing self-healing Blaschko dermatitis" have been suggested as names for this condition. Our patient was a 27-year-old man with a 6 month history of repeated, unilateral, slightly pruritic, discrete and grouped erythematous papules and papulovesicles on the left side of the upper limbs and trunk along Blaschko's lines. Histologic examination showed subacute spongiotic dermatitis. The condition showed excellent improvement after treatment with systemic corticosteroid for 2 months. Only a few cases have been reported. We propose a new designation and describe a patient who represents the first reported case of acquired Blaschko dermatitis in Korea.

Adult↗

Vitiligo coexistent with nevus depigmentosus.

A 45-year-old Korean man had two distinct types of hypopigmented lesions on the forehead and back: vitiligo and nevus depigmentosus (ND). The hypopigmented macules on the forehead were incidentally discovered 15 days previously and responded well to steroid therapy. The hypopigmented macule on the back had been present since birth, was stable in size, and showed no response to steroid therapy. There were no remarkable differences between the two lesions in routine histopathology or Fontana-Masson staining. However, the lesion on the back was shown to contain melanocytes in electron microscopy (EM).

Humans↗

Detection of antibodies to melanocytes in vitiligo by western immunoblotting.

To more fully define the nature of the antibody response to melanocytes which is associated with vitiligo, a Western immunoblot assay was used to test the sera of 28 patients with vitiligo (21 with active non-segmental, and 7 with stable segmental diseases) and 26 normal individuals for antibodies to antigens in detergent extracts of melanocyte membrane fractions. Antibodies to melanocytes were found in 26 (93%) of the patients with vitiligo, and in 16 (62%) of the control individuals. Patients with vitiligo and control individuals both had antibodies to an 80 approximately 83 kD antigen. The patient with vitiligo, in addition, had antibody responses to antigens with MWs of 45, 65, and 110 kD. Antibodies to these antigens were present in 46, 25, and 31% of vitiligo patients, but in only 19%. 0%, amd 0%, respectively, of the normal individuals. The heterogeneity of the antibody responses to melanocytes in vitiligo was further confirmed by the presence of antibodies to at least 3 distinct antigens in one-third of vitiligo patients but in none of the normal individuals. There was no difference in antibody response between patients with generalized and segmental vitiligo, suggesting that the pathogenesis of diseases was similar in both cases.

Antibodies↗

Ten-year experience of phototherapy in Yonsei Medical Center.

Phototherapy with PUVA or UVB has been used to treat a wide variety of diseases such as psoriasis, vitiligo, atopic dermatitis and mycosis fungoides, etc. The present study was performed to investigate the pattern of phototherapy in the phototherapy clinic of Yonsei Medical Center. One thousand six hundred ninety two patients who received PUVA or UVB phototherapy were included in this study. We analyzed the protocols for phototherapy between 1985 and 1994. The number of phototherapy per year increased sharply until 1991 and thereafter it has remained relatively constant. The most common age group at the start of phototherapy was the third decade. The most common indications for PUVA and UVB phototherapy were vitiligo and psoriasis, respectively. Most patients had received less than 50 treatments of PUVA and less than 200 J/cm2 of cumulative UVA. Most patients had received less than 50 treatments with UVB and cumulative UVB doses were variable. We had not found any malignancy in the skin. Since the maximum safe cumulative doses of UVA or UVB have not yet been established, it is difficult to decide when phototherapy should be discontinued. The data presented in this study needs to be further analyzed in correlation with photoaging and cancer development for the safe usage of phototherapy.

Academic Medical Centers↗

Detection of antibodies to human melanoma cells in vitiligo and alopecia areata by Western blot analysis.

Antibody reactivity to human melanoma cells (SK-Mel-23) was investigated in 48 patients with vitiligo, 14 with alopecia areata (AA), and 35 normal control individuals by Western blot analysis. Antibodies to SK-Mel-23 were found in 44 (92%) of the patients with vitiligo, in 7 (50%) of the patients with AA, and in 14 (40%) of the normal control individuals. Significant differences between patients with vitiligo and normal controls were found in the incidence and distribution of antibodies, but no significant differences were found between patients with AA and normal controls. The antibodies were predominantly directed to one or more antigens of approximately 110 KD, 103 KD, 88 KD, 70 KD, 56 KD, 46 DK, or 41 KD. The most common responses were to 110 KD, 88KD, and 70 KD antigens. These antibodies were present in 60%, 60%, and 73% of the patients with vitiligo; 7%, 14% and 35% of the patients with AA; and 11%, 11% and 40% of normal control individuals, respectively. There were no statistical differences in the incidence of antibodies to pigment cells between segmental and non-segmental vitiligo. These findings suggest that autoreactivity to pigment cells occurs mostly in patients with vitiligo and might be a secondary immune reaction to destroyed pigment cells.

Alopecia Areata↗

Treatment of stable vitiligo with autologous epidermal grafting and PUVA.

BACKGROUND: Previous reports have shown the benefits of epidermal grafting for vitiligo. OBJECTIVE: Our purpose was to evaluate the effectiveness and complications of epidermal grafting in combination with PUVA on stable vitiligo refractory to conventional treatments. METHODS: In 100 patients with stable refractory vitiligo we performed epidermal grafting with suction blisters followed by PUVA treatment. The grafted sites were examined for repigmentation for up to 5 years. RESULTS: Excellent repigmentation was observed at all grafted sites, especially on the face except for the lip and the alae nasae. PUVA treatment resulted in spreading of the pigmentation. Poor results were observed on the neck, axillae, and overlying bony prominences. Hyperpigmentation of the recipient and donor sites was frequently observed. Only six patients had recurrence and/or adjacent new lesions. Depigmentation developed at the donor site in only one patient with generalized vitiligo. Long-term observation in these patients indicates that repigmentation obtained by this method is permanent. CONCLUSION: Although epidermal grafting in combination with PUVA has some limitations, it is an easy, safe, inexpensive, and effective treatment for various types of stable refractory vitiligo.

Adolescent↗

Detection of antibodies to human melanoma cell in vitiligo by western blot analysis.

Vitiligo is a disease in which melanocytes are selectively destroyed. The disease is thought to be an autoimmune process being there are antibodies to pigment cells in the sera of patients and animals with vitiligo. In the present study, sera from vitiligo patients were examined for reactivity with the human melanoma cell line, SK-Mel-28, by Western blot analysis of solubilized membrane antigens of these cells to identify the pigment cell antigens defined by antibodies in the patients with vitiligo. Antibody reactivity to human melanoma cells (SK-Mel-28) was investigated in 14 patients with vitiligo, and 16 with normal control individuals. Antibodies to the 116-113, 60, 40 KD antigens were associated with vitiligo being present in 79%, 86%, and 43% respectively of the patients with vitiligo, but in only 6%, 38% and 6% of the normal controls. In contrast, antibodies to the 160-155, 78 and 64 KD antigens were equally common in vitiligo and in normal individuals. The results suggest that autoreactivity to pigment cells occurs more commonly in patients with vitiligo than in the normal control and high autoreactivity to pigment cells in the vitiligo sera might be an impertinent epiphemenon to destroyed pigment cell.

Antibodies, Neoplasm↗

An unusual form of skin tuberculosis following B.C.G. vaccination.

A 25-year-old female has had brown to erythematous telangiectatic patches and grouped papules on her face, neck, arm, and trunk since childhood following B.C.G. vaccination. Histopathologically, the lesions consisted of hyperkeratosis, slight acanthosis, tuberculoid granulomas with some Langerhans type giant cells in the mid-dermis. Although various forms of cutaneous tuberculosis after B.C.G. vaccination have been reported, it was difficult for us to assign the patient's skin lesion to any specific disease entity. Remission of her cutaneous lesions occurred clinically and histopathologically after treatment with isoniazid and rifampin.

Adult↗

Biologic characteristics of cultured human vitiligo melanocytes.

BACKGROUND: Vitiligo is a pigmentary disorder of unknown cause characterized by depigmented patches due to destruction of melanocytes. Recently, the inherent cellular defect theory has been discussed. To investigate the biologic characteristics of cultured melanocytes from normal and vitiligo subjects, this study had the purpose to examine the functional and ultrastructural characteristics of these melanocytes and to observe the morphologic and functional changes of melanocytes in response to ultraviolet B irradiation. METHODS: Melanocytes were isolated and cultured from foreskin and arm skin of normal and vitiligo subjects. The DNA synthesis, tyrosinase activity assay, transmission and scanning electron microscopic examination, and the effects of ultraviolet B(UVB)-irradiation on cultured melanocytes were studied. RESULTS: Vitiligo melanocytes showed no significant differences in DNA synthesis and tyrosinase activity compared with normal melanocytes, but the vitiligo melanocytes contained dilated and/or circular rough endoplasmic reticulum (RER) on transmission electron microscopic examination. Exposure of the cultured melanocytes to UVB resulted in increased protein synthesis and tyrosinase activity. Morphologic alterations and changes in DNA synthesis were also noted. Compared with normal melanocytes, the responses of vitiligo melanocyte to UVB showed no significant difference. CONCLUSIONS: Normal and vitiligo melanocytes showed similar biologic characteristics except in the changes of RERs in the vitiligo melanocytes. The ultrastructural aberrations in vitiligo subjects do not seem to be directly related to the biologic characteristics and the responses to UVB irradiation in vitiligo melanocytes.

Cell Division↗

Immunohistochemical studies from vitiligo--comparison between active and inactive lesions.

Vitiligo is an acquired, progressive depigmenting disorder of unknown etiology. In this study, to clarify pathogenesis of vitiligo, the marginal skin of actively spreading and stable vitiligo was examined using ICAM-1, HLA-DR, CD4 and CD8 monoclonal antibodies. In immunohistochemical study, ICAM-1 was expressed in four of five epidermis in active lesions, but not in stable lesion. Dermal ICAM-1 was also expressed in all active and stable lesions. HLA-DR was also expressed in all active epidermis in active lesions, but two of five epidermis in stable lesion. Dermal HLA-DR was also expressed in all active and stable lesion. CD4 lymphocytes were expressed more strongly in active lesion, but CD8 lymphocytes were not different in both lesions. There was no significant difference of degree of positivity with CD4 and CD8 in normal control specimens. In conclusion, we think that ICAM-1 and HLA-DR expression, cytokines released from keratinocytes, melanocytes or lymphocytes and infiltration of activated T-lymphocytes play an important role in disease activity.

CD4 Antigens↗

The change of melanocyte cytotoxicity after systemic steroid treatment in vitiligo patients.

Although there is evidence of a strong association between antimelanocyte autoantibodies and vitiligo, the etiology of vitiligo is still unclear. To elucidate the biological significance of antimelanocyte autoantibodies in vitiligo, we measured the percent cytotoxicity of melanocyte mediated by autoantibody and complement in normal controls (n = 31) and in the patients with active, progressive vitiligo (n = 37). Significant differences in percent cytotoxicity of melanocyte were seen between the control and vitiligo groups (P = 0.0001). There were no significant differences in the percent cytotoxicity of melanocyte between the patients (n = 24) with more than 1 year duration and those (n = 13) with less than 1 year duration. The change of percent cytotoxicity between pre- and post-treatment groups (n = 29) with systemic steroid showed significant differences (P = 0.0243). These findings support the hypothesis that a decrease in the antibody-mediated cytotoxicity against melanocytes may play a role in the improvement of vitiliginous lesions after systemic steroid treatment.

Adolescent↗