The expression of IgG4 in salivary glands and the clinical analysis of 58 cases of Sj(o)gren's syndrome / 中华风湿病学杂志

ABSTRACT

Objective Mikulicz's disease (MD) was considered to be a subtype of Sj(o)gren's syndrome (SS) due to the clinical and histological similarities between them.Evidence had shown that there were differences between MD and typical SS.The purpose of this study was to investigate the correlation between MD and SS,by means of analyzing the expression of IgG4 in salivary glands and the clinical characteristics of patients who were previously considered as SS.Methods The paraffin sections of salivary glands from SS patients were stained with monoclonal antibodies to IgG4 and CD38.Patients were divided into two groups based on the pathological results.Analysis of the symptoms,the signs and the laboratory results were carried out in these patients.The difference in laboratory parameters and histopathological gradings in the two groups was analyzed.Normal and abnormal distributed data comparison was conducted using random independent samples t-test and rank sum test respectively.Two-sample rates were compared with Chi-square test.Results Based on immunohistochemistry of IgG4 distribution,the 58 patients with SS were divided into two groupsIgG4 related (9 cases) and non-IgG4 related (49 cases).Histopat-hologically,IgG4 related cases showed IgG4+ plasma cells/IgG+ plasma cells infiltration and there were more IgG4 related monoclonal antibody expressed when compared to IgG4 unrelated cases.In addition,there were also significant differences in clinical features between the two groups.IgG4 related disease was associated with male gender,higher level of plateletconnt,lymphocytes [(2.4±0.8)×109/L vs (1.4±0.7) ×109/L] count and CRP [(52±60) mg/L vs (15±17) mg/L] levels and lower titer of IgM [(1.2±0.7) g/L vs (1.8±0.8) g/L],antinuclear antibody (56％ vs 87％) and anti-SSB antibodies (13％ vs 54％) (P＜0.05),when compared with IgG4-unrelated cases.There was no significant difference in other indicators (P＞0.05).Conclusion The present study has demonstrated that some of the MD patients misdiagnosed as SS.Some of the laboratory tests such as the level of platelet and lymphocyte count,serum level of CRP,IgM,antinuclear antibody,anti-SSB antibodies,the serum levels of IgG4 and the histopathological presentations in the salivary gland are different between these two disorders.Because of good response to steroid in MD,so laboratory tests and pathological examinations for IgG4 can help to avoid misdiagnosis.