The Role of IL-17 During Infections in the Female Reproductive Tract

Abstract

Interleukin-17 (IL-17A) is a cytokine involved in a complex array of both protective and detrimental processes. Although early biological studies focused on the pro-inflammatory function of IL-17 in the context of autoimmune and inflammatory disorders, it has become increasingly evident that the roles of IL-17 are far more nuanced. Recent work has demonstrated that the functions of IL-17 are highly context- and tissue-dependent, and there is a fine balance between the pathogenic and protective functions of IL-17. This is especially evident in mucosal tissues such as the female reproductive tract, where IL-17 has been shown to play an important role in the immune response generated during fungal, bacterial and viral infections associated with protection, but also with inflammation. In this review, we discuss the evolving landscape of IL-17 biology within the context of the vaginal mucosa, focusing on key findings that highlight the importance of this cytokine in genital mucosal immunity.

Clinical and morphopathological assay in vulvovaginal candidiasis

“…The methods of infection of the host by the Candida fungus can be multiple and are based either on its ability to evade the host's defense mechanisms or by adhering to the surface epithelium with the subsequent formation of a biofilm and invasion by the secretion of extracellular enzymes. As mentioned, adhesion of Candida to host surfaces is essential for primary colonization of human tissues, which is a prerequisite for infections [2,7,[10][11][12][13][14][15][16][17][18]. Moreover, the production of hydrolytic enzymes induced by local infection can improve host organism adhesion, invasion and elimination of host immunological components and has a role in the acquisition of nutritional factors.…”

“…Moreover, the production of hydrolytic enzymes induced by local infection can improve host organism adhesion, invasion and elimination of host immunological components and has a role in the acquisition of nutritional factors. Hydrolytic enzymes, such as secreted aspartyl proteinases (SAPs), phospholipases (PLs) and Candida species play a role in the pathogenesis of VVC [2,[8][9][10][11][12][13][14][15][16][17][18][19].…”

“…The incriminated symptomatology is quite varied, from completely asymptomatic cases or the patients may complain of modified vaginal secretion, rough white, itching, burning sensation, and dyspareunia. During the local gynecological examination, in the case of patients with acute infection, dense, white vaginal secretions with rough deposits and/or vulvar and vaginal edema and erythema, local excoriations can be observed [9,12].…”

Impact of interkingdom microbial interactions in the vaginal tract

“…L. crispatus has also been shown to increase IL-17 release by vaginal epithelial cells in response to C. albicans infection [60], yet it is unclear whether this is protective against VVC. Some studies show that a Th17 response is beneficial while others dispute this, indicating that it plays a nuanced role in this environment [71][72][73][74]. Recruited neutrophils can exacerbate VVC pathology [8,[75][76][77], yet antimicrobial peptide production involved in the Th17 response can facilitate fungal clearance [71].…”