AUTHOR=Ji Xingfu , Jing Guilin , Sun Haoqi , Li Xuan , Chen Xuexun 

TITLE=Case report and literature review: IgG4-related tubulointerstitial nephritis coexistent with systemic lupus erythematosus

JOURNAL=Frontiers in Medicine

VOLUME=Volume 12 - 2025

YEAR=2025

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2025.1585351

DOI=10.3389/fmed.2025.1585351

ISSN=2296-858X

ABSTRACT=We present the case of a 68-year-old man with acute kidney injury that occurred following radiofrequency cardiac ablation. Laboratory tests revealed elevated serum creatinine (SCr), positivity for antinuclear and anti-double-stranded DNA (anti-dsDNA) antibodies, elevated IgG4 levels, and hypocomplementemia. Renal biopsy identified coexisting mesangial proliferative lupus nephritis (LN) (Class II) and IgG4-related tubulointerstitial nephritis (IgG4-TIN). The patient responded well to glucocorticoid-based immunosuppressive therapy, with significant improvement in renal function. This case illustrates the rare coexistence of systemic lupus erythematosus (SLE) and IgG4-related kidney disease (IgG4-RKD), highlighting the importance of renal biopsy in distinguishing overlapping autoimmune nephropathies.