Investigation Of Substance P In Blood Plasma, Tryptase And Dust Mite Specific IgE In Serum Of Patients With Urticaria Factitia

Objective: Urticaria factitia (also known as dermographic urticaria andsymptomatic dermographism) is characterized by whealing and itchingfollowing a minor stroking pressure, rubbing or scratching of the skin. Themajority of patients with urticaria factitia benefits from treatment withnonsedating antihistamines. Some patients, however, do not achieve adequatesymptom control even with updosing of antihistamines and may suffer fromsubstantial quality of life impairment.The causes of this disease haven't been clearly identified yet. It wasconcerned with drugs, fungus and its metabolic products, sarcoptic mite, andsystemic disease, such as thyroid disfunction, diabetes and so on. Somestudies discovered that psychological factors were important in thedevelopment of urticaria factitia. The course of urticaria factitia was long, andrecurrent attacks easily. It was troublesome for doctors to cure it in clinic.What's more, it has bad effects on patients' routine work and life.There have been a trifle of studies about the pathogenesis of symptomaticurticaria factitia in the recent decades. The records which could be searchedfor showed that psychiatric and psychologic factors seemed to be related tothis disease, and some definite allergens could be found in patients withurticaria factitia, such as dust mite, fish, crab and so on. Substance P, theearliest discovered and fully studied neuropeptide, was not only aneurotransmitter, but also a mediator of allergic response. What's more, mastcells were the main effector cell of typeⅠhypersensitivity reaction in skin,and substance P could induce mast cells degranulation, and finally resulted ina series of immune-inflammatory reaction mediated directly by mast cells.Under the direction of the network theory of nerve-immune-endocrine,we decided to reveal the roles of neuropeptide, mast cells and allergy in the pathogenesis of urticaria factitia, by investigating the level of substance P,tryptase and specific IgE in peripheral blood of24patients with urticariafactitia and16healthy subjects.Method:Test one: Twenty-four patients with urticaria factitia were involved in thestudy. They were recruited from the Dermatology Outpatient Clinics in thesecond hospital of Hebei Medical University, from August,2011to December,2011. The duration of urticaria factitia varied between5days and8years.Inclusion criteria of the patient group:①To be in line with the diagnosticcode of urticaria factitia in Dermatology and Venereology mainly edited byWu Zhi-hua. All patients were characterized by whealing and itchingfollowing a minor stroking pressure, rubbing or scratching of the skin;②Not used antihistamine drugs within1week, and glucocorticoid or other drugsthat affect the immune function of the body within1month before the test;③Non-accompanied with autoimmune diseases, allergic diseases, cancer orother serious systemic diseases;④All subjects were not in gestational periodand lactation. The control group involved16healthy persons. Radioimmunoassay (RIA) was applied to detect SP in blood plasma from24patientsand16healthy subjects with125I substance P radioimmunoassay Kit. At thesame time we detect tryptase in serum by enzyme-linked immunosorbentassay (ELISA) with Human mast cell tryptase (MCT) ELISA Kit produced byRB company of America. Each step was strictly carried out according to thedirections. The results were analysed by means of statistical methods as test ofnormality, Mann-Whitney test of rank-sum test, with SPSS13.0software. Thestatistic data was demonstrated in median or quartile.Test two: Case group was the same as test one, and20healthy personswere involved in the control group. Specific IgE in serum was detected byenzyme-linked immunosorbent assay (ELISA) with Dermatophagoidespteronyssinus and Dermatophagoides farinae specific IgE ELISA Kit whichwas produced by FOOKE company of Germany. The investigation resultswere analysed by means of statistical methods as test of X2-test. The statistic data was showed by rate and frequency number.Results:Test one:1. The results of substance P: After the test of normality, P=0.002＜0.1, sothe data disobeys Gaussian distribution. The statistic results of case group andcontrol group were expressed by median or quartile, and respectively were172.80/590.57,137.13/231.17. Statistical results of substance P in bloodplasma of patients have no statistical significance compared with the normalcontrols (P＞0.05).2. The results of tryptase: After the test of normality, P=0.000＜0.1, so thedata disobeys Gaussian distribution, too. The statistic results of case group andcontrol group were demonstrated by median or quartile, and respectively were3.69/20.92,4.62/10.22. Statistical results of tryptase in serum of patientshave no statistical significance compared with the normal controls (P＞0.05).Test two:The results of specific IgE: the positive rate of dermatophagoidespteronyssinus in patients with urticaria factitia was25.00%(six patients),dermatophagoides farinae was33.33%(eight patients), and the normalcontrols was0.00%. The positive rates of dermatophagoides pteronyssinus anddermatophagoides farinae in patients with urticaria factitia were both muchhigher than the healthy subjects, and the differences showed statisticalsignificances (the values of P were respectively0.025and0.005,<0.05).Conclusisons:1. Statistical results of substance P and tryptase of patients with urticariafactitia have no statistical significances compared with the normal controls (P＞0.05). The reasons may be as follows: First, substance P and mast cellsmight not take part in the pathogenesis of urticaria factitia; Second, the samplesize is too small; Third, no pro-stimulus which could provocate wheal byfactitious scratching was done before drawing the blood.2. The positive rates of dermatophagoides pteronyssinus and dermatopha-goides farinae in patients with urticaria factitia were both much higher than the healthy subjects, and the differences showed statistical significances (thevalues of P were respectively0.025and0.005,<0.05). Which suggested thatallergic factors were likely to be associated with the pathogenesis of thisdisease. Therapeutically, desensitization treatment aimed directly atdermatophagoides pteronyssinus and dermatophagoides farinae can be carriedout, some patients may be cured at last in this way.To sum up, the pathogenesis of urticaria factitia is complex. With theimprovement of the network theory of nerve-immune-endocrine, we believethat studies about the pathogenesis of urticaria factitia will make enormousadvancement in the near future and will greatly contribute to the clinicaltherapy of this disease.