| Objective:Pityriasis rosea is a self-limited, unclear, inflammatory skin disease which is first named by Gilbert in 1860. The course of the disease is about 4~6 weeks. The morbidity of PR is nearly 172.2/100,000 man year which is about 1.31% of all the dermatopathic diseases. The incidence is highest between the ages of 20 and 29, and women are affected as same as men. The recurrence rate of PR is only about 3%. The recent studies showed that the main infiltrating cells in the skin of the patients with PR were helper / inducer T lymphocyte, and Langerhans' cells were increased in epidermis and dermal papilla. It showed that cell-mediated immune response might play an important role in the pathogenesis of PR. In immune system, CD4+ helper T cell can be induced to different lineages such as Th1, Th2, Treg and Th17. It is accepted that Th0 cells differentiate to two subsets, and each subset is characterized by its own key and specific transcription factors, T-bet mRNA for Th1 and GATA-3 mRNA for Th2. T-bet (T box expressed in T cells) plays a key role in Th1 cell differentiation. It has been confirmed as a unique Th1 specific transcription factor. Its significance has been proved by knocking out the T-bet gene of mouse. Th1 cytokines were deficient in the mouse whose T-bet genes were knocking out even the CD4+ T cells were induced with IL-12. GATA-3 (GATA-binding protein-3) is a member of the zinc-finger family of transcription factors. It has been confirmed as a unique Th2 specific transcription factor. It is necessary for the expression of Th2 cytokines. Conversely,GATA-3 can redirect Th1 cells into Th2 cells. We planed to compare the level of T-bet mRNA and GATA-3 mRNA in the peripheral blood mononuclear cells between the patients with PR and the normal persons, in order to elaborate the function of Th1 cell and Th2 cell in the pathogenesis of PR from the transcription level.RT-PCR is a new technology which is based on conventional PCR technique. In the experiment, PCR technique collects the fluorescence signal while the target sequences copy, and the technique can analyze the signals and get the values of samples automatically. The Ct value is deducted the background signals and fluorescence threshold is set. It effectively solves the limitation that the traditional PCR only detects quantity at end-point. The RT-PCR technology has strong specificity, high sensitivity, good duplication, accurate quantization, high automaticity and entire blocking response. Methods: The case group involved seventeen typical PR patients who were selected in outpatient clinic in the second hospital of Hebei Medical University from 2009-11 to 2010-8. Inclusion criteria: (1). All the patients are typical PR patients, and the course of the disease are from 3 days to 2 months. (1).All the cases were without other acute infection or immunological diseases before the test. All the cases involved had not taken drugs that could affect immunological function for one month such as corticosteroids and immunosuppressive agent,or antihistamines for one weeks. All the cases were without unsafe sexual behavior. Case group: Male: 9 samples. Female: 8 samples. Average age: (25.5±8.8)years. Control group: twenty healthy persons selected in the second hospital of Hebei Medical University. With respect to age and gender, there was not significant difference between the two groups by analysis of t-test. The T-bet mRNA and GATA-3 mRNA expression in 17 PR Patients and 20 healthy volunteer's Peripheral Blood Mononuclear Cells (PBMCs) were detected by SYBR Green I Real-time fluorescence quantitative reverse transcription polymerase chain reaction (RT-PCR) technology.Results:The values of Avg△Ct of T-bet mRNA expression in PR group and control group were 3.33±0.94 and 4.31±1.11, t=2.85,P=0.007(P<0.05). The expression of T-bet mRNA in PR patients'PBMCs was higher than that in the control group. The values of Avg△Ct of GATA-3 mRNA expression inPR group and control group were 5.22±0.69 and 4.36±1.02,t=-2.92, P=0.006 (P<0.05). The expression of GATA-3 mRNA in PR patients'PBMCs was lower than that in the control group.Conclusion:The expression of T-bet mRNA in PR patients'PBMCs was higher than that in the control group, but the expression of GATA-3 mRNA was lower than that in the control group. The ratio of T-bet mRNA/ GATA-3 mRNA in PR patients group was higher than that in the control group. It suggests that Th1 subsets posses a highest potential of predominance in PR patients. Th1 cell subsets may play an important role in the pathogenesis of PR. |
