Fig 2: LTB and CXCL6 protein expression levels in IgAN with chronic renal lesions. (A) A strong LTB tubular expression has been found in the chronic lesion group compared to the other groups (n = 4 active group; n = 5 chronic; n = 4 non IgAN; n = 6 LN; n = 4 KLD). Kruskal–Wallis test p value = 0.0038. Dunn’s multiple comparison test, chronic versus active, chronic versus non-IgAN, chronic versus LN and chronic versus KLD, all p < 0.05. (B) A strong CXCL6 tubular expression has been found in the active lesion group compared to the other groups (n = 5 active group; n = 5 chronic; n = 5 non-IgAN; n = 6 LN; n = 4 KLD). Kruskal–Wallis test p = 0.0074. Dunn’s multiple comparison test, chronic versus active, chronic versus non-IgAN, chronic versus LN and chronic versus KLD, all p < 0.05. Magnification 40 × .

Fig 3: TNFAIP6, DEFA4, and CXCL6 urinary levels in IgAN. (A) Urinary TNFAIP6 levels are significantly higher in IgAN patients with active renal lesions compared to other groups (n = 34 active group, n = 17 chronic, n = 23 non-IgAN, n = 17 LN and VS and n = 14 HBD). ANOVA F(4,94) = 6.246 p = 0.0002; Tukey’s multiple comparison test, active versus all p < 0.05. (B) High urinary DEFA4 levels are present in both active and chronic renal lesion groups, and these levels are significantly higher compared to non-IgAN, LN-VS and HBD (n = 34 active group, n = 17 chronic, n = 23 non-IgAN, n = 17 LN and VS and n = 14 HBD. ANOVA F(4,94) = 5.759 p = 0.0003; Tukey’s multiple comparison test, active versus and chronic versus HBD p < 0.05. (C) Urinary CXCL6 levels are significantly higher in IgAN patients with chronic renal lesions compared to the other groups (n = 34 active group, n = 17 chronic, n = 23 non IgAN, n = 17 LN and VS and n = 14 HBD. Kruskal–Wallis test p value = 0.0002. Dunn’s multiple comparison test, chronic versus all groups p < 0.05, (D) TNFAIP6/CXCL6 ratio is able to predict patients characterized by active or chronic renal lesions using a receiver operating characteristic curve (ROC) analysis. The area under the curve (AUC) was 0.78 (n = 33 active, n = 17 chronic as controls, 95% confidence interval 0.648–0.9156, p = 0.0009), a cut-off value of 33.25 had the highest sensitivity 83.33% (95% CI 61–94) and specificity 73% (95% CI 56–85).