P113 High levels of angiotensin receptor type 1 antibodies in a child with FSGS who had a renal transplant

Focal Segmental Glomerulosclerosis (FSGS) can lead to ESRD requiring a renal transplant and the rate of recurrent FSGR (rFSGS) is high. The exact mechanisms of the pathogenesis of FSGS and rFSGS is unclear and both FSGS and rFSGS have similar pathological findings and clinical symptoms. To date there are no good tests that can predict FSGS or rFSGS. A very recent report indicated that antibodies against Angiotensin Receptor Type 1 (AT1R-Ab) could predict rFSGS post-transplant. Angiotensin II (AT II) acts on angiotensin 1 receptor (AT1R) and exerts hemodynamically vital actions. AT1Rs are extensively distributed across various organ systems including renal podocytes. Over-activation of AT1R via AT II or AT1R-Ab could trigger events leading to chronic renal injury. Presence of AT1R-Ab was shown to be associated with vascular rejection and malignant hypertension in the absence of detectable allograft-specific HLA antibodies and also in C4d positive AMR in a zero mismatch (ABDR) renal transplant in the absence of HLA DSAs. We present a case of a 7 year old African American male with biopsy-proven FSGS and typical features of nephrotic syndrome including proteinuria of 13 g/g based on protein to creatinine ratio. Upon initial diagnosis he was treated with steroids. Cessation of the steroids resulted in recurrence of his nephrotic syndrome. Additionally he was diagnosed with hypertension (HTN) and left ventricular hypertrophy both treated with an ACE inhibitor. He unfortunately progressed in terms of his chronic kidney disease to ESRD requiring a cadaveric renal transplant, performed in Jan 2016. His mean AT1 -Ab levels were 266.18 ± 36.06 (n = 7) and 120.72 ± 37.53 U/ML (n = 5) pre and post-transplant respectively (>17 units of AT1R-Ab is considered positive). Currently the patient is doing well on maintenance immunosuppression without recurrence of his original disease. The practice of screening for AT1R-Ab in pre and post renal transplant patients is gradually evolving. Considering the mechanisms of AT1R activation and subsequent downstream events, early monitoring for AT1R antibody levels in similar patients with HTN and idiopathic FSGS may help in appropriate management of preventing multi-organ injuries, malignant HTN, metabolic disorders and eventual ESRD. More patients with pre-transplant FSGS and r FSGS post transplant need to be evaluated for AT1R-Ab.