The association between fractalkine/CX3CR1 axis with IgA vasculitis and nephritis

BackgroundThe study investigated whether the fractalkine/CX3CR1 axis is associated with the presence and severity of IgA vasculitis (IgAV) and IgA vasculitis nephritis (IgAVN) in children.MethodsWe included 59 children with IgAV, 42 children with IgAVN (including 18 children with kidney biopsy), 26 plasma controls and 8 kidney controls. Clinical pathological data were collected, and the fractalkine/CX3CR1 axis and macrophage expression in the circulation and kidneys were detected.ResultsCirculating fractalkine/CX3CR1 axis expression was significantly upregulated in children with IgAV and IgAVN compared to healthy controls. Plasma fractalkine levels and the proportion of CX3CR1+ monocytes were significantly higher in children with IgAVN than in those with IgAV, and the kidney expression of fractalkine/CX3CR1 axis and CD68 were significantly increased in the IgAVN group relative to normal controls, especially in children with IgAVN with more severe ISKDC pathological grading. Additionally, kidney levels of fractalkine, CX3CR1, and CD68 exhibited significant positive correlations with tubulointerstitial grading and serum creatinine levels.ConclusionThe expression of fractalkine/CX3CR1 axis is associated with the presence and severity of IgAV and IgAVN. Our findings support further investigation of fractalkine/CX3CR1 as a target for future therapies in IgAV and IgAN.ImpactThe expression of plasma fractalkine/CX3CR1 axis is associated with the presence and severity of IgAV and IgAVN.The expression of kidney fractalkine/CX3CR1 axis and macrophage are upregulated in IgAVN, which is closely associated with poorer kidney function and more severe kidney pathology.Our findings support further investigation of fractalkine/CX3CR1 as a target for future therapies in IgAV and IgAVN.