Case of successful treatment with glucocorticoid for isolated anti-centromere antibody-positive acute interstitial nephritis.

Acute interstitial nephritis (AIN) is known to cause acute kidney injury and is characterized by immunocyte infiltration and interstitial fibrosis. Primary etiologies include drugs, infections, and autoimmune disorders. Herein, we presented the case of a 78-year-old woman patient with AIN with anti-centromere antibody (ACA) positivity, secondary to an idiopathic immune system disorder. Her serum creatinine (sCr) was 0.67 mg/dL 2 months prior to consulting us, which increased to 2.79 mg/dL. The renal biopsy revealed an AIN comprising interstitial infiltration with immunocytes and CD138 + cells. Furthermore, all other antibodies tested negative using immunofluorescence on both glomeruli and tubulointerstitial lesions. The ACA was elevated to a level of ≥ 500 U/mL. The ACA positive has been known to be accompanied by worsening kidney function in patients with systemic sclerosis and primary biliary cholangitis. However, any autoimmune disease were not diagnosed. Successful treatment with an initial dose of 30 mg/day of glucocorticoids tapered to 25 mg/day resulted in a decrease in the sCr to 1.53 mg/dL 4 weeks later. Nine months later, glucocorticoids was tapered, based on the threshold of a sCr of 1.03 mg/dL and the titer of ACA of 291 U/mL. In this case, glucocorticoid treatment remarkably improved renal function in AIN containing CD138 + cells accompanied by a reduction of ACA titer. The etiology of ACA-positive AIN was unknown; however, the incidence of ACA-positive AIN should always be deliberated.