IL-10 and IL-17 contents in culture supernatants of γδ T lymphocytes expanded from blood of patients with reactive erythema

Reactive erythemas represent a group of dermatoses with complex immunogenesis, in which γδ T cell subpopulations may be involved, like as in development of many autoinflammatory diseases. Despite an important role of IL-17, its excessive synthesis, e.g., by γδT cells, is able of inducing autoinflammation. On the contrary, IL-10 plays a key role in the control of innate immune responses. It may suppress functions of monocytes/macrophages by reducing pro-inflammatory cytokine production. Our aim was to perform in vitro expansion of γδ T cells by culturing lymphocytes from peripheral blood of patients with erythema. Peripheral blood mononuclear cells (PBMC) were isolated from 8 patients with reactive erythema (5 patients with erythema multiforme, 1 patient with ring–shaped centrifugal erythema, 2 patients with erythema migrans, an early form of Lyme disease), and two healthy donors aged 23 to 70 years. A modified van Acker et al. method (2016) was used to culture γδ T lymphocytes. The blood cell cultures were supplied with zoledronate, IL-2 and IL-15. The contents of IL-17 and IL-10 were determined in cell culture supernatants by solid-phase ELISA using Human IL-17 ELISA Kit (RK00397, ABclonal Biotechnology Co., China) and Interleukin- 10-ELISA-BEST (JSC "Vector-Best", Russia) according to the manufacturers’ instructions. In patients with reactive erythema, 3.1% to 62.8% of cells with expression of γδ TCR were obtained by 7 days of cultivation with zoledronate, IL-2 and IL-15. The lowest percentage of these cells was observed in blood cell culture from patients with continuously recurrent erythema multiforme and ring-shaped centrifugal erythema. In the group of patients, high levels of induced IL-17 production may indicate a presence of an autoimmune component in pathogenesis of the disease and/or reflect the severity of its course. The effectiveness of therapy in the examined patients correlated with ability of cultured blood cells to synthesize and release IL-10. It has been shown that high values of spontaneous and induced IL-10 production are associated with a good response to therapy (significant clinical improvement, long-term clinical remission). Meanwhile, low values of spontaneous and induced IL-10 production were detected in patients with weak therapeutic effect (rapid development of relapses following the course of therapy). The data obtained suggest a probable prognostic significance of these substances as clinical biomarkers. The determination of these cytokines in blood cell cultures in patients with the studied pathologies may improve the assessment of therapeutic efficiency and predict the course of the disease. However, further research is needed in this area, including other types of clinical disorders.