| To analyze the clinical features and to explore HLA-DQB1 * 0201 and HLA-DQB1 * 0602 alleles in their associations with vitiligo in Han ethnical Chinese in Jianzhe China and the cause of the disorder.Materials and Methods1. collecting samples and extracting DNA243 unrelated outpatients with vitiligo were selected between September and October 2002. Each patient was examined by a dermatologist to detect vitiligo. They were questioned about their family history, personal disease, age, and circumstances of vitiligo onset. Control group was composed of 250 healthy donors who had the same ethnic origin as our patients, originating from Jianzhe China. High molecular weight DNA was isolated by Genomic DNA miniprep bit ( Vita-gene Corp. ) from peripheral blood cells.2. PCR amplificationSequences, lengths and specificities of sequence specific primers were given in . Primers were synthesized by Sangon Co. . Other materials include dNTP, Ampli-Taq, 2% agarose gel, and electrophoretic buffer. HLA-DQB1 * 0201 and HLA-DQB1 * 0602 alleles were determined by PCR-SSP method.3. Statistical analysis of the results.Penotype frequencies were determined by direct count. The differences in allelic frequencies of patients and controls were tested for significance by the X test or Fisher's Exact Test. Strength of the correlation was estimated by relative risk according to Woolf's formula: RR = (ad)/(bc).Result1. The mean age of the first onset was 23.1 years for the males, and 23.7 years for the females. Difference between them was not statistically significant (P<0.05).2. The localized type was the major form in the initial stage. In the 198 localized vitiligo patients, 4% of them developed segmental type, 47% of them developed the other types of vulgaris ,49% of them remained localized. There is no generalized type among children, 77% of segmental type patients were children. 60.1% cases were developing.3. The sites of onset were the face, the distal of the limb, and neck in descending order of frequency, most common season of onset is spring and summer.4. HLA-DQB1 * 0201 was found significantly increased in patients, 18. 9% vs 10.4% for controls (P<0.01) , a relative risk of 2.01. Thus, vitiligo is approximately two times more frequent in individuals who have HLA-DQB1 * 0201 allele than those who don't have this allele.5. Among vitiligo vulgaris patients the frequency of HLA-DQB1 * 0201 allele significantly increased( P < 0.05 ).6. Age at onset of patients with family history was earlier than that of patients without family history. There is significant family aggregation. The incidence of those affected among relatives was first-, second-, and third degree in descending order of frequency. It also shows a higher incidence than the norm. HLA-DQB1 * 0201 allele was positively associated with vitiligo with a positive family history (P <0. 01).7. HLA-DQB1 * 0201 allele and HLA-DQB1 * 0602 allele are not significantly different between vitiligo associated with autoimmune and the norm. However, in vitiligo patients HLA-DQB1 *0602 allele is significantly higher.Conclusions1. Our results concerning the pathologesis show difference between vulgaris and segmental vitiligo; genetic and autoimmune factors play significant roles in the etiology of vulgaris.2. Most localized type vitiligo is the early stage of vulgaris vitiligo, but a small number of cases belong to the early stage of segmental vitiligo. The treatment in the localized type vitiligo stage may help the patient cope better with the disease. Segmental vitiligo is significantly more often associated with children.3. There may be difference in genetic background between vitiligo patients with or without family history.4. HLA-DQB1 * 0201 allele may be the susceptible gene or have close linkage with susceptible gene in vulgaris vitiligo. |
