5^th Global Nephrologists Annual Meeting

Biography

Biography: Agnieszka Pozdzik

Abstract

Tubulointerstitial nephritis (TIN) is a manifestation of IgG4-related diseases, which arecharacterized by infiltration of target organs by IgG4+ plasma cells and severe fibrosis. Cortico-sensitivity is one of the diagnostic criteria, but the treatment of steroid resistant and dependent forms is not well defined. We present a case of a 47-years-old patient with IgG4-related NTI followed for 72 months. He complained of fatigue and recurrent postprandial abdominal pain. With the exception of elevated levels of gamma-glutamyl transferase (GGT), transaminases and IgG4, kidney function remained normal (serum creatinine ≤ 0.9 mg/dL). After 2 cures of methylprednisolone (2010-11) azathioprine was associated in 2012. Due to the corticodependence and persistence of bilateral focal renal lesions detected by diffusion-weighted magnetic resonance imaging (DW-MRI), Rituximab (RTX) was given (2 × 376 mg/m²/15 days) in 2013. Before the first injection, positron emission tomography (PET) showed metabolic hyperactivity corresponding to axillary and abdominal aorta lymph nodes but not in the kidney. After 4 months of RTX, the patient became asymptomatic. All biological alterations disappeared. PET showed a decrease in metabolic activity at extrarenal lesions described above. A dramatic regression of bilateral renal lesions was noted by DW-MRI: the apparent diffusion coefficient had almost doubled (0.776 vs 1.111x10-3 mm²/sec) and the volume of renal lesions was reduced by 50%, which was never observed under other treatments. Our observations demonstrate: (1) the clinical, biological and radiological efficacy of rituximab in a steroid-dependent form of IgG4- related TIN and (2) the interest of DW-MRI as a non-nephrotoxic radiological and PET complementary approach not only in monitoring the effectiveness of immunosuppression but also in the early detection of renal involvement during IgG4 related disease.