P26: Analysis of immune makers and clinical significance in thymomas with autoimmune disease in thymoma

Background: To present the clinical experience in treating thymomas and thymomas with autoimmune disease (AD). To analyze the reason of the abnormal change of T iymphocyte subset and the correlation between thymoma and AD.

Methods: The medical records of all 193 patients with thymoma in Tianjin Hospital from 2000 to 2015 were analyzed. According to that the patients with or without AD were divided into two groups, T iymphocytes subsets were detected by flow cytometry (FCM). The concentrations of serum IgG, IgM, IgA, C3, and C4 in individual patients were tested by enzyme-linked immunosorbent assay (ELISA).

Results: The most frequent initial manifestations of thymoma were fatigable weakness of extraocula, bulbar and/or limb muscles (48.2%), followed by chest symptoms (22.8%). 13.47% of the cases were accidentally found on routine chest roentgenogmphy. This group of patients had remarkable predisposition to autoimmunity, which was characterized by many kinds of autoantibodies detected among them. Thymomas are associated with a long list of autoimmune conditions (so-called paraneoplastic syndromes). The paraneoplastic syndmmes found in this group of patients included myasthenia gravis (48.2%), connective tissue diseases (4.16%), endocrinologic diseases (1.55%), hematologic disorders (2.07%), skin diseases (1.04%). The percentage of CD4+ cells and the ratio of CD4+/CD8+ T cells was significantly increased in the AD group as compared with Tm, but there was no statistically significant difference in the percentage of CD8+ T cells between the two groups, Furthermore, there was no significant difference in the levels of serum IgG, IgA, IgM, and C4 among these groups of patients (P>0.05). In contrast, the concentrations of serum C3 in the Tm group were significantly higher than that in the MG and AD groups of patients (P<0.05), while INF-r, IL-4, C3 were significantly lower (P<0.05).

Conclusions: The clinical manifestations of thymoma are variable. Patients with thymoma show significant predisposition to autoimmunity and thymomas is associated with many autoimmune disorders. There is an abnormal distribution of T cell subsets and level of cytokines and immune globulin in AD patients. Testing expression of immune makers will be helpful for predicting the clinical diagnosis and prognosis of thymoma with AD.

Keywords: Thymoma; autoimmune disease (AD); clinical significance; immune makers