Clinical Features And Correlative Immunologic Mechanism Of Autoimmune Urticaria

Autoimmune urticaria (AU) is a distinct subset of chronic idiopathic urticaria (CIU). The term"autoimmune urticaria"increasingly is used to reflect advances in knowledge about functional autoantibodies that activate mast cells and basophils through cross-linking the high-affinity IgE receptor (FcεRI) to secrete histamine. AU is a skin disorder characterized by the recurrence of eruptive and itchy wheals of at least 6 weeks'duration. Its etiology is not completely known, which was possible concerned closely with genetic gene, immunity and clotting mechanism, and so on. its diagnosis doesn't remain form standard ,relied principally on clinical features, ASST, functional release assays with basophils or mast cells and organspecific autoantibodies in serum. We hope to offer theoretical evidence to formulate diagnostic criteria and therapeutic principle, through analyzing the clinical manifestation, histopathological features and laboratory examination about AU patients.Much clinical evidence and experimental data suggests that AU is an autoimmune disorder with polygenic inheritance, Moreover its pathogenesis was related to four aspects, such as fanctional autoantibody against the FcεRI in the serum, functional disorder T lymphocyte, abnormalities immunologic molecular, complement dependence. For the past many years, many overseas scholars confirmed functional autoantibody against the FcεRI in the serum of patients with AU by immunoassays. IgG₁ and IgG₃ antibody have capable of activating basophils to release histamine. In addition, abnomalities cytokine in serum have been described in AU that performed an important role in its pathogenesis. Therefore, studing classification of autoantibody and diversify of IL-13 in the serum of patients with AU, which will make for illuminating their significance, Meanwhile, we are able to offer theoretical evidence to formulate diagnostic criteria and therapeutic principle.Objective: To collect clinical data about patients with autoimmune urticaria coming from out-patient clinic dermatology; to detect cytokine (IL-13), immune globulin G (IgG) and its subtype in serum, then to analyze associativity with AU.Method: Assessment was performed in a retrospective study of 170 subjects with established diagnosis of autoimmune urticaria from October 2007 to March 2009. The observations were extended to clinical features, autologous serum skin test (ASST), laboratory examination, histopathological features, and so on. Selection criteria are the recurrence of eruptive and itchy wheals of at least 6 weeks'duration and organspecific autoantibodies in the serum. We selected patients with anti-thyreoid autoantibody in the serum. In a hospital-based case-control study of 24 patients with AU and 24 patients with CU and 24 healthy donors were detected the concentration of cytokine (IL-13)in serum by using enzyme linked immunosorbent assay(ELISA) technique; the concentration of IgG and IgG₃ in serum were detected by using rate nephelometry technique.Results:1. Clinical features: 170 patiens with AU were studied including 130 females (76.5%) and 40 males (23.5%), mean age 35.79±8.49 years old. It revealed a similar clinical manifestation with the ordinary chronic urticaria. However, all subjects presented more severe clinical features with regard to the duration and itching severity. 22 (12.9%) out of 170 patients were slight pruritus, 16(9.4%) were midrange pruritus, 132(77.6%) were severe pruritus, 64(37.6%) were followed concomitant symptom such as arthralgia, gastrointestinal symptom and respiratory tract symptom. Out of 170 patients, 110 patients (64.7%) showed a positive result in the form of a wheal and flare response of more than 1.5mm than the saline control. Anti-thyreoid autoantibodies were found in 109 patients (64.1%), Anti-helicobacter pylori (HP) were found in 85 patients (50%), however, the two were found in 22 cases (12.9%).7 case were associated with connective tissue diseases (5 cases with SLE and 2 cases with Sjogren syndrome), 1 case were associated with ankylosing spondylitis (AS), 1 case was associated with vitiligo, and 45 cases were associated with Hashimoto's thyroiditis or hyperthyroidism. The histologic examination showed similar characteristics with the chronic urticaria in some cases, and urticarial vasculitis in other cases.2. Immunology research: We find the concentration of cytokine (IL-13) in serum is significant high in the cases compared with control subjects and chronic urticaria. The concentration of IgG and IgG₃ in serum is significant high in the cases compared with control subjects.Conclusion: As far as we know, this is the first study about the clinical features and serology about patients with AU. It revealed a similar clinical manifestation with the ordinary chronic urticaria. However, all subjects presented more severe clinical features with regard to the duration and itching severity. The histologic examination didn't find characteristic change, which showed similar characteristics with the chronic urticaria in some cases, and urticarial vasculitis in other cases.We detected IL-13, IgG and IgG₃ in serum by using ELISA and rate nephelometry technique. We find the concentration of cytokine (IL-13) in serum is significant high in the cases compared with control subjects and chronic urticaria, which suggest cytokine (IL-13) participate development of AU. Otherwise, we also find the concentration of IgG and IgG₃ in serum is significant high in the cases compared with control subjects. They demonstrated that functional antibody in IgG₃ is responsible for AU, which to offer guidance of biotherapy about AU. Our study offer theoretic evidence for AU diagnositic treatment and pathogenesy. It is essential to study large sample size from differently region and nation, beacause of small sample size and come from northwest of China.