Studies On The Etiology And Pathogenesis Of Pityriasis Rosea

Objectives: Pityriasis Rosea (PR) is a self-limited ,inflammatory skin disease of unknown etiology. Most domesticand abroad scholars believe that viruses infection and cellularimmunity mediating delayed allergy are linked to PR. And otherreasons such as autoimmunity, atopy are also considered. Someresearchers consider that clinical feature such as seasonalvariation, programmed clinical course, low recurrence rate andsome experimental findings indicate that the cause of PR isassociated with virus. Moreover, Drago has found virus-likeparticles in PR lesions and in the supernatant of coculturedmononuclear cells of PR under transmission electronmicroscope (TEM), which sustain viruses infection hypothesisfurther. Recently, many scholars have researched a mass ofviruses such as Human herpesvirus 6,7 and 8,Cytomegalovirus,Epstein-Barr virus, Parvovirus B19,Picornavirus and so on , butfor which an exact virus that results in PR has not been found.And other researchers have found that the rate of CD₄⁺ /CD₈⁺increased and the expression of HLA-DR antigen appeared inkerarinocytes in PR lesions, the level of γ-IFN raised in theblood serum of PR. So, they speculate that cellular immunitymediating delayed allergy is the reason of PR. Our studypropose to measure the level of ECHO-IgM and CV-IgMantibody in the serum of PR by Enzyme Linked ImmunosorbentAssay (ELISA), and to find virus-like particles in PR lesionespecially in Langerhans cell (LC) of PR by TEM, so as todiscuss the relationship of PR with viruses infection further.Also we propose to observe the amount, distribute,configuration, ultrastructure of LC in PR lesion by lightmicroscope and electron microscope and to observe theexpression of CD45RA and CD45RO in PR lesion byimmunohistochemical method in order to discuss the associationof PR with cellular immunity mediating delayed allergy. Thuswe can synthetically discuss the etiology and pathogenesis ofPR by these two factors of viruses infection and delayed allergy.Materials and Methods: Fifty-two PR serum samplesincluding 24 males and 28 females were selected from PRpatients diagnosed by clinic of the dermatological departmentof the Fourth Affiliated Hospital of Hebei Medical Universityduring May, 2003 to July ,2004. Age ranged from 15 to 46 years(mean 27.34±10.28 years); Course from 2 days to 2 months(mean 17.67±12.79 days ). And random select 40 out-hospitalhealthy volunteers as controls. There are no significantdifferences in sexes and ages between controls and patients. Allpatients and volunteers have no rheum, no fever, no otherinfectious diseases during 3 days before sampling. Using ELISAto detect the level of ECHO-IgM and CV-IgM antibody .Chi-square test was used for analysis of the result data.Thirty-one PR biopsies were selected from PR patientsdiagnosed by clinic and histopathology of the dermatologicaldepartment of the Fourth Affiliated Hospital of Hebei MedicalUniversity during October, 2002 to October, 2004. The patientsinclude 13 males and 18 females; age ranged from 10 years to65 years (mean 28.58±13.87 years);course from 2 days to 2years(mean 2.67±0.78 days). All patients have no other systemicdiseases and not received any immunotherapy during recent 3month. The lesion samples were investigated with routinehistopathological method ,the levels of CD_1a, CD_45RA, CD45ROexpression were detected by immunohistochemical method. Andselect 17 healthy skins from the surgery of the Fourth AffiliatedHospital of Hebei Medical University as normal controls. Therewere no significant differences in sexes, ages and locus ofbiopsy between the controls and the patients. HE staining wasused in histopathology to observe. And used histostain-SPmethod in immunohistochemistry. The results were analysed byrank sum test .Eight TEM samples were selected from PR patients of thedermatological department of the Fourth Affiliated Hospital ofHebei Medical University during August,2003 to May, 2004;including 3 males and 5 females; age ranged from 17 years to 50years;course from 2 days to 1 months .Four normal trunk skinswere used as normal contols. The samples were fixed in 4%Glutaral after obtained quickly, and then observed under TEM .Results:1 ELISA results1.1 The positive rate of ECHO-IgM in PR group and incontrol group were 17.31% and 15.00% respectively. There wasno significant difference in PR group and controlgroup(p>0.05).1.2 The positive rate of CV-IgM in PR group and incontrol group were 18.18% and 17.65% respectively. There wasno significant difference in PR group and controlgroup(p>0.05).2 The results of the observation of LC by lightmicroscope and electron microscope.2.1 Light microscope observation CD1a stains on cellplasma of LC. The amount of LC in the epidermis and dermis ofPR lesion increased markedly compared with controls (p<0.05).The amount and the length of dendrite of LC also increasedmarkedly compared with controls (p<0.01).2.2 Electron microscope observation In LC Birbeckgranules increased in PR lesion, mitochondria and roughendoplasmic reticulum decreased. Rough endoplasmic reticulumdilated. Mitochondria edema and disappearation ofmitochondria cristae can also be found. There was no virus-likeparticle in LC.4 CD45RO stains on cell membrane of lymphocyte. Theexpression of it was markedly higher than controls (p<0.01).5 CD45RA also stains on cell membrane of lymphocyte.The expression of it had no significant difference between the...