Insight into inflammatory cell and cytokine profiles in adult IgA vasculitis.

Immunoglobulin A vasculitis (IgAV) is an immune complex, small vessel vasculitis with dominant IgA deposits in vessel walls, predominantly affecting the pediatric population. However, adults frequently have more severe gastrointestinal tract (GIT) and renal involvements as compared to children. Our aim was to study serological and cellular biomarkers to support clinicians in their diagnosis and the course of IgAV in adult patients. This cross-sectional study included 62 adult IgAV patients and 53 healthy blood donors (HBDs). Demographic and clinical data, as well as routine laboratory tests, were meticulously analyzed. Serum levels of IL-1β, IL-2, IL-6, IL-8, IL-9, IL-10, IL-17A, IL-23, TNF-α and serum amyloid A (SAA) were measured. Percentages of neutrophils, lymphocytes, and monocytes with neutrophil expression of L-selectin and integrin αM were determined by flow cytometry. SAA (12-fold), IL-6 (3-fold), IL-8 (2-fold), and TNF-α (2-fold) were significantly elevated in sera of adult IgAV patients compared to HBDs. There was a 16% elevation in neutrophils in IgAV patients, with IgAV neutrophils showing significantly higher CD62L surface expression. IgAV patients with GIT involvement exhibited elevated numbers of leukocytes, neutrophils, and neutrophil/lymphocyte (NLR), but lower neutrophil CD11b expression, as compared to IgAV patients without GIT. IgAV patients exhibit a low-medium grade inflammatory, neutrophil-driven response. Patients with GIT can be distinguished by their elevated NLR.