OBJECTIVES: Granulomatosis with polyangiitis (GPA) is a chronic relapsing systemic autoimmune vasculitis. Current treatment of GPA is unsatisfactory as it relies on strong immunosuppressive regimens, with either cyclophosphamide or rituximab, that reduce the immunogenicity of several vaccines and are risk factors of severe form of COVID-19. This emphasizes the need to identify new drug target and to develop treatment strategies with less harmful side effects. Since CD4+ effector memory T cells (TEM) play a key role in the pathogenesis of GPA, we aimed in this study to modulate CD4+TEM cell activity via Kv1.3 blockade using the specific peptide inhibiter, ShK-186.
METHODS: Peripheral blood of 27 GPA-patients in remission and 16 age- and sex-matched healthy controls (HCs) were pre-incubated in vitro in the presence or absence of ShK-186, followed by stimulation with PMA, calcium ionophore and brefeldin-A. The effect of ShK-186 on the cytokine production (IFNγ, TNFα, IL-4, IL-17, IL-21) within total and subsets of CD4+TH cells were assessed using flow cytometry.
RESULTS: ShK-186 reduced the expression level of IFNγ, TNFα, IL-4, IL-17, and IL-21 in CD4+TH cells from GPA-patients in vitro. Further analysis performed on sorted CD4+T cell subsets, revealed that ShK-186 predominantly inhibited the cytokine production of CD4+TEM cells. ShK-186 treatment reduced the production of the pro-inflammatory cytokines to the level seen in CD4+ TH cells from HCs.
CONCLUSIONS: Modulation of cellular effector function by ShK-186 may constitute a novel treatment strategy for GPA with high specificity and less harmful side effects.