Clinical feature of renal impairment caused by IgG4 related disease with renal and urinary lesions

Objective To analyze the clinical features of renal and urinary lesions in IgG4 related disease (IgG4-RD). Methods Clinical data of 24 cases of IgG4-RD patients were retrospectively analyzed, including serum creatinine, hemoglobin, inflammatory factors, and serum IgG4 level before and after treatment. Results Twenty four cases of IgG4-RD with renal and urinary lesions were diagnosed in Peking Union Medical College Hospital from Aug 2010 to May 2014, including 21 males and 3 females. The average age of the patients was (63.79±12.13) years old, and the average number of organs involvement was (4.38±1.55). Elevated inflammatory factors and serum IgG4 level were detected in all patients. Elevated urine protein was detected in 19 cases and 6 cases were diagnosed as nephritic syndrome among 20 patients. Increased Scr were detected in 21 cases with an average value of (410.48±352.17) μmol/L and 3 cases had been treated with hemodialysis. Anemia was found in 14 cases and 8 cases were detected with single or bilateral kidney atrophy. Among the 21 cases with elevated Scr, 11 cases were caused by postrenal obstruction and 3 cases were pathologically proved as tubulointerstitial nephritis. Received steroid treatment, Scr level declined dramatically one week later (P<0.05) and further declined one month later (P<0.01); erythrocyte sedimentation rate declined significantly one month later (P<0.01); serum IgG4 level did not decline significantly after one month (P=0.146), but declined significantly after two months (P<0.01). Conclusions Renal insufficiency is not rare in IgG4-RD with renal and urinary lesions, and it is sensitive to steroid therapy; the decline in Scr can be seen earlier than the change in inflammatory factors and serum IgG4 level. Key words: Renal insufficiency, acute; Immunoglobulin G; Urologic disease; IgG4 related disease; Acute kidney injury