Sequence variation in promoter regions of genes for CC chemokine ligands (CCL)19 and 21 in Czech patients with myocardial infarction

Causal effects of rheumatoid arthritis or ankylosing spondylitis on membranous nephropathy: a two-sample Mendelian randomization study

Background

Membranous nephropathy (MN) is the leading cause of adult-onset nephrotic syndrome, with primary MN of unclear cause accounting for 80% of cases. Retrospective clinical research reported that MN occurring in rheumatoid arthritis (RA) and ankylosing spondylitis (AS) patients was triggered by nephrotoxic drugs or of unknown cause. However, whether RA or AS itself increases the risk of developing MN is unknown.

Methods

We conducted mendelian randomization (MR) analysis to evaluate the causal effects of RA or AS on MN using genome-wide association study (GWAS) statistics. The inverse variance weighted (IVW) method was the primary analysis, and several supplementary analyses and sensitivity analyses were performed to test the causal estimates.

Results

We obtained 30 valid instrumental variables (IVs) of RA and 16 valid IVs of AS from large-scale open-access GWASs. The genetically predicted RA significantly increased the risk of MN [IVW odds ratios (OR) = 1.327, 95% confidence interval (CI) = (1.124, 1.565), P = 8.051 × 10-4]. Three supplementary MR analyses provided the consistent positive causal effect of RA on MN (all P < 0.05). No horizontal pleiotropy was detected by MR Egger intercept analysis (P = 0.411). However, the genetically predicted AS had no causal effect on MN by IVW and supplementary analysis (all P > 0.05).

Conclusions

Genetically predicted RA could increase the risk of MN, but genetically predicted AS was not associated with MN. Screening for kidney involvement in RA patients should be noted, and active treatment of RA will reduce the public health burden of MN.

Tertiary lymphoid organs are associated with the progression of kidney damage and regulated by interleukin-17A

Background: Tertiary lymphoid organs (TLOs) occur after multiple chronic kidney injuries. interleukin-17A (IL-17A) has been reported to associate with the development of TLOs in inflammatory diseases. However, regulation of the renal TLOs and its clinical significance to the pathogenesis of chronic kidney injury are unknown.

Methods: To evaluate the clinical significance and regulation of renal TLOs, we analyzed the progression of patients with kidney damage based on the existence and absence of TLOs in a larger multicenter cohort. We also blocked the recruitment of lymphocyte cells into the kidney by FTY720 (fingolimod) in vivo. Besides, we used aged IL-17A genetic knocked out mice and IL-17A-neutralizing antibody to explore the role of IL-17A in renal TLOs formation.

Results: We demonstrated that renal TLOs of IgA nephropathy patients were associated with disease severity and were independent risk factors for renal progression after adjustment for age, sex, mean arterial pressure, proteinuria and, baseline eGFR and MEST-C score, especially in the early stage. Plasma levels of TLO-related chemokines CXCL13, CCL19, and CCL21 were higher in patients with renal TLOs. Inhibiting the formation of renal TLOs by FTY720 could reduce the intrarenal inflammation and fibrosis, and early intervention was found to be more effective. IL-17A was increased in renal TLOs models, and genetic depletion of IL-17A or treatment with anti-IL-17A antibody resulted in a marked reduction of the TLOs formation as well as alleviation of renal inflammation and fibrosis.

Conclusion: These results indicate that TLOs are associated with the progression of kidney damage and regulated by IL-17A and may be effective targets for the treatment of kidney damage.