The role of C3 and C4 complement components in postmenopausal vulvovaginal atrophy with a different clinical history

Introduction. Vulvovaginal atrophy (VVA) is characterized by severe hypoestrogenism, impaired microcirculation, chronic inflammation, and decreased mucosal regeneration. In women with a varying clinical history, including applied antitumor treatment, such changes may differ in severity level. Despite that the role for pro-inflammatory cytokines in VVA has been extensively investigated, systemic immuno-inflammatory changes, primarily resulting in complement activation remained understudied. Aim: to assess blood serum levels of C3 and C4 complement component levels in postmenopausal women with VVA coupled to clinical history, including various types of antitumor therapy, as well as in women without oncology history and in control group of healthy women. Materials and Methods. A cross-sectional comparative study included five groups of postmenopausal women (n = 215): VVA after radical surgery (n = 52); VVA after chemoradiotherapy (CRT) (n = 27); VVA during antiestrogen therapy (n = 48); VVA without oncology history (n = 53); control group – healthy postmenopausal women (n = 35). The blood serum C3 and C4 levels were quantitated by immunoturbidimetry. The statistical analysis included the Kruskal–Wallis criterion and pairwise intergroup comparisons using the Mann–Whitney criterion with the Bonferroni correction. Results. In all studied groups C3 and C4 levels were within the reference range, however, they differed significantly between the groups depending on the clinical history. The most prominent intergroup differences were observed in patients after CRT, who had higher C3 (1.62 g/L) and C4 (0.32 g/L) levels compared with control group (1.12 g/L for C3; 0.19 g/L for C4). In antiestrogenic therapy group (group 3) and surgical treatment group (group 1), C3 (1.48 g/L and 1.35 g/L, respectively) and C4 (0.28 g/L and 0.25 g/L, respectively) levels held an intermediate place between CRT group and control group. In women with VVA without oncology history, C3 (1.28 g/L) and C4 (0.23 g/L) levels were comparable to those in control group. Conclusion. The data obtained evidence about variability of the systemic immuno-inflammatory profile in VVA driven by patient clinical history. Within the framework of the study, changes in C3 and C4 levels reflected general intergroup differences, which, however, remained within the reference range. The results emphasize a need for further research aimed at studying activated complement system components and their clinical significance in VVA.