The investigation of levels of IgG and IgM autoantibodies against bacterial analog of HSP60, Tyrosyl-trna synthetase, and its separated domains in sera of women with uterine leiomyoma

Abstract

Uterine leiomyomas are common gynecologic tumor in reproductive-aged women. The molecular mechanisms behind the origin of leiomyomas are still relatively unknown. Tyrosyl-tRNA synthetase (TyrRS) and Hsp60 are housekeeping proteins that could be involved into different pathologies in various ways. The aim of the study was to investigate the levels of antibodies to Hsp60 and TyrRS and its distinct domains: mini-TyrRS and C-terminal domain in sera of patients with uterine leiomyoma (UL). Materials and methods: Specific IgG and IgM autoantibodies in sera of 25 women with UL before therapy and 5 healthy subjects were measured by ELISA. The specificity of the reaction of IgG autoantibodies against the Hsp60 and mini-TyrRS proteins was checked using a western blot assay. Statistical analysis was performed using the STATISTICA 10.0 software. (StatSoft, USA). Non-parametric data were compared in the Mann-Whitney U-test. Results: The elevated levels of IgM autoantibodies against all the proteins studied occur frequently neither in control nor in experimental cohort. In the group of healthy donors, individuals with elevated levels of IgG autoantibodies against any of the proteins studied were not detected. Meanwhile 19 of 25 (76 %) and 18 of 25 (72 %) women with UL had significantly increased serum levels of autoantibodies to mini-TyrRS and Hsp60 respectively. Intriguingly, 17 of 25 samples from women with uterine fibroids (68 %) were positive against mini-TyrRS and Hsp60 analog simultaneously. The levels of autoantibodies to mini-TyrRS in sera of women with UL were 1.7 times higher than in sera of healthy donors, for Hsp60 the corresponding index was 2.1. Increasing levels of autoantibodies against each of the two proteins was statistically significant with a degree of reliability of p <0.01. The data obtained by ELISA were confirmed by western-blot analysis for Hsp60 but not for mini-TyrRS. Conclusion: We propose that elevated levels of autoantibodies to Hsp60 and mini-TyrRS in sera of persons with UL may serve as element of panel of protein markers for monitoring of pathology.