Chronic urticaria is a very common allergic disease in the outpatient.It has complicated pathogenesis and there is no conclusion up to now.The activation of the mast cells and the release of the histamine are the key point of the chronic urticaria onset.In recent years,the studies have demonstrated that the autoimmunity and the chronic infection are the main cause of the disease.There are other factors including dysfunction of the coagulation,deficiency of the vitamin D,pseudoallergen,psychic factor and genetic mechanism.This article will make a review of the pathogenesis of the chronic urticaria from the aspects mentioned above.

Objective To measure the levels of plasma D-dimer,activated coagulation factor Ⅶ (FⅦa) and activated clotting factor Ⅻ (FⅫa) in patients with chronic urticaria (CU),and to investigate their relationship with the occurrence of CU.Methods Venous blood samples were collected from 50 patients with CU and 50 healthy human controls.Dry-column immune scattering chromatography was performed to detect the plasma level of D-dimer,and enzyme-linked immunosorbent assay (ELISA) to measure the levels of FⅦa and FⅫa.In addition,autologous plasma skin test (APST) was conducted in 43 patients with CU,and autologous serum skin test (ASST) in 41 patients with CU.A correlation analysis was carried out between the above three parameters and disease severity as well as between the results of APST and ASST and plasma level of D-dimer.Results The levels of plasma D-dimer and F Ⅶa were significantly higher in patients with CU than in healthy human controls (both P ＜ 0.05),while no significant difference was found in FⅫa level between the two groups (P ＞ 0.05).Moreover,the degree of increase in D-dimer plasma level was positively correlated with disease severity in the patients with CU.The plasma level of D-dimer was significantly higher in APST-positive patients than in APST-negative patients (P ＜ 0.05),but not significantly different between ASST-positive and-negative patients (P ＞ 0.05).Conclusions Coagulation mechanism,especially the extrinsic coagulation pathway,is related to the occurrence of CU.Studies on coagulation mechanism are beneficial to the evaluation of severity,and clinical treatment,of CU.

Objective To explore the in vitro culture methods for oriented differentiation of peritoneal cells and bone marrow cells into high-purity mast cells,and to identify the function of these mast cells.Methods Peritoneal cells and bone marrow cells were isolated from the peritoneal cavity lavages and femur of C57BL/6 mice,and cultured with both interleukin-3 (IL-3) and stem cell factor for 2 and 4 weeks respectively.Light microscopy was performed to observe the morphology of these cells,toluidine blue staining to identify the degree of maturity of these mast cells,and flow cytometry to measure the expression of cell surface markers C D 117 and FceR Ⅰ α.After the stimulation with compound 48/80 at different concentrations,the degranulation rate of mast cells was counted under the microscope,and β-hexosaminidase release rate was measured by spectrophotometry.Results After 2-or 4-week culture,the mouse peritoneal and bone marrow cells all manifested as refractive suspension cells of uniform size.Toluidine blue staining showed violaceous metachromatic granules in the cytoplasm of the two kinds of cells.The proportions of CD117 or FcεR Ⅰ α single-positive peritoneal and bone marrow-derived mast cells were all more than 95％,and the proportions of CD117/FcεR Ⅰ α double-positive peritoneal and bone marrow-derived mast cells were 97.68％ ± 0.80％ and 96.12％ ± 0.76％ respectively.The degranulation rates of mast cells in the 100-and 1 000-mg/L compound 48/80 groups significantly differed from those in the blank control group (all P ＜ 0.01).Compared with the blank control group,the β-hexosaminidase release rates significantly increased in bone marrow-derived mast cells in the 100-mg/L compound 48/80 group and peritoneal mast cells in the 10-and 100-mg/L compound 48/80 groups (P ＜ 0.01 or 0.05).Conclusion IL-3 and stem cell factor can co-induce the directed differentiation and proliferation of mouse bone marrow stem cells and peritoneal cells,so as to harvest highnuritv mature degranulated mast cells,and lay a foundation for subsequent cell biology research.