Immune pathogenesis and immune therapy of a sclerosing variant of vulvar lichen sclerosus: a prospective cohort study

Abstract

Background. Today, no unified clinical classification of vulvar lichen sclerosus is registered (is yet to be registered?). Isolation of pathogenetically and clinically different variants of its course enable new approaches to the treatment to be developed. Objective. To develop a pathogenetic therapy for the sclerosing variant of vulvar lichen sclerosus, taking into account its clinical and immunological characteristics. Methods. A prospective cohort study was conducted from 2018 to 2022 on the basis of Regional Clinical Hospital No. 2, Krasonodar, Russia. 292 patients aged 20 to 70 years were histologically diagnosed with vulvar lichen sclerosus. After a clinical examination using the scale for assessing subjective and objective clinical signs of vulvar lichen sclerosus, 154 patients with a sclerosing variant of the disease course were selected for the study. The control cohort consisted of 30 women of the same age category without vulvar lichen sclerosus, taking into account the exclusion criteria. The study involved a clinical assessment (in points) of objective and subjective criteria characteristic of this variant of vulvar lichen sclerosus, as well as an assessment of the level of cytokines (interleukin-20; interleukin-23; interleukin-10; tumor necrosis factor α, interferon γ) in peripheral blood of the patients from the main and control groups. One month after the immunotherapy with sodium deoxyribonucleate, the authors evaluated its clinical efficacy (using Numerical rating scale for pain (vulvodynia) and Vulvar pruritus severity scale) and immunological efficacy (repeated assessment of the level of the studied cytokines). Analysis and statistical processing of the obtained data were performed using Graph Pad Prism version 6.0 (GraphPad Software, Inc., San Diego, CA). Results. Depigmentation of the vulvar skin against the background of vulvar sclerosis and thickening features a sclerosing variant of vulvar lichen sclerosus compared to vulvar atrophy. Stenosis of the vaginal vestibule is either absent (51.3%) or predominantly corresponds to grade I, and is less specific than depigmentation and even skin atrophy. The subjective signs include a severe vulvar pruritus without or with moderately expressed (in 68.1%) vulvodynia. An immunological study showed a statistically significant increase in the level of interleukin-20 (p < 0.0001), interleukin-23 (p < 0.0001), interferon-γ (p < 0.03), tumor necrosis factor α (p < 0.009) in patients with maximal tissue sclerosis with respect to the control group, along with a statistically significant decrease in the level of anti-inflammatory interleukin-10 (p < 0.01). The immunological efficacy of sodium deoxyribonucleate was confirmed by a statistically significant (compared to baseline) decrease in interleukin-20 (p < 0.0001), interferon-γ and tumor necrosis factor α (p < 0.002), interleukin-23 (p < 0.012) without statistical differences with the control group (except for interleukin-23, the level of which decreased after therapy but remained statistically higher (p < 0.01) than in the control group). Clinical efficacy of immunotherapy was confirmed by a statistically significant (p < 0.001) reduction in vulvodynia and vulvar pruritus after the treatment. Conclusion. The obtained data demonstrate characteristic clinical features and immunological differences in relation to the norm in women with the sclerosing variant of vulvar lichen sclerosus, thereby justifying the use of sodium deoxyribonucleate in this variant with confirmed clinical and immunological efficacy.