Expression and its clinical significance of immunoglobulin G4 in inflammatory bowel disease / 中华消化杂志

ABSTRACT

Objective To explore the expression and its clinical significance of immunoglobulin G4 (IgG4) in inflammatory bowel disease (IBD) by detecting the expression of IgG4 in the serum and intestinal mucosa of patients with IBD.Methods From March 2015 to August 2016,68 patients with ulcerative colitis (UC),132 patients with Crohn's disease (CD) and 52 healthy controls were collected.The serum levels of IgG4 were detected by immunonephelometry.The expression of IgG4 in intestinal mucosa was analyzed by immunohistochemistry.Five high power fields (HPF) were randomly selected in each specimen.C-reaction protein (CRP) and erythrocyte sedimentation rate (ESR) of patients with UC,patients with CD and healthy controls were detected.The extent of disease,clinical type,disease activity scores (UC scored by Mayo score system,CD scored by Crohn's disease activity index (CDAI)) and current treatment were collected.The correlation between IgG4 expression and CRP,ESR,Mayo score and CDAI were analyzed.Independent sample t test,Chi square test and Pearson's correlation were performed for statistical analysis.Results The results of immunonephelometry indicated that the serum levels of IgG4 of patients with UC,CD and healthy controls were (0.79±-0.61),(0.69±0.59) and (0.41±0.32) g/L,respectively;all were lower than standard level 1.35 g/L.The results of immunohistochemistry revealed that the number of IgG4 positive cells in the colonic mucosa of active UC and CD patients were higher than that of healthy controls ((15.42±12.47)/HPF,(18.65±12.46)/HPF and (4.71±4.14)/HPF),and the differences were statistically significant (t=5.392 and 8.450,both P＜0.05).There was no statistically significant difference in mucosal IgG4 expression between UC,CD patients at remission phase and healthy controls ((4.72±4.23)/HPF,(5.30±4.87)/HPF and (4.71±4.14)/HPF,both P＞0.05).There was no statistically significant difference in mucosal IgG4 expression between UC and CD patients at active phase and remission phase (both P＞0.05).The case number of active patients,CRP,ESR and Mayo scores of IgG4 positive UC patients were all higher than those of IgG4 negative group(x2 =5.499,t=2.811,3.471 and 4.676;all P＜0.05).The number of active patients,CRP,ESR and CDAI of IgG4 positive CD patients were all higher than those of IgG4 negative group(x2 =4.341,t=3.842,3.892 and 2.935,all P＜ 0.05).In UC patients,the number of IgG4 positive cells was positively correlated with CRP,ESR and Mayo scores (r=0.382,0.381 and 0.470;P=0.001,0.003 and P＜0.01).The number of IgG4 positive cells was positively correlated with CRP,ESR and CDAI in CD patients (r=0.199,0.209 and 0.201;P=0.022,0.016 and 0.021).Conclusions The expression level of IgG4 significantly increased in the intestinal mucosa of IBD patients correlated with the activity of disease.The expression level of [gG4 may be one of the parameters to evaluate the activity of IBD.