Total inflammation in 6-month surveillance renal transplant biopsies is associated with decreased renal function and de novo class 2 donor specific antibody Z. Laszik * , S. Chandran, F. Vincenti * UCSF, Dept. of Pathology, San Francisco, USA Objective: The goal was to correlate inflammation and acute rejection (AR) with renal function and antibody status in 6-month renal transplant surveillance biopsies. Method: Relative risks of inflammation and AR in 380 6month biopsies was calculated by Multivariable Poisson regression. Results: AR was seen in 7.3 % (n=28), borderline change in 19.7 % (n=75), and C4d positivity in 2.1 % (n=8) of all biopsies. Total cortical inflammation (ti), present in 32.6 % (n=124) cases, was associated with 7 ml/min/1.73 m2 lower eGFR at 6 months (95 % CI= −10.8, −3.2). De novo HLA Class 1 was identified in 17.4 % (n=44) and Class 2 DSA in 26.1 % (n=66), with most having MFI values <1000. Increased risk of AR was seen with higher levels of de novo Class 1 (RR 1.49, 95 % CI=1.08, 2.0) or Class 2 DSA (RR 1.34, 95 % CI=1.04, 1.72). Class 2 (but not class 1) DSA was associated with a higher risk of ti (RR 1.40 for ti-score ≥1, 95 % CI=1.13, 1.72) at 6 months. Conclusion: Both ti and AR in 6-month surveillance kidney transplant biopsies are strongly associated with de novo HLA Class 2 DSA. Total inflammation at 6 months correlates with decreased kidney function. Objective: Tenofovir disoproxil fumarate has been used in the treatment of HIV patients producing occasional renal dysfunction and Fanconi Syndrome. Method: A 38-year-old patient was referred with severe acute renal failure and important metabolic acidosis and glycosuria with normoglycemia in urine analysis, altogether with urinary alkaline pH and proteinuria with a protein/ creatinine ratio of 4. He was HIV and B positive diagnosed 17 years earlier. His medication regimen consisted of lopinavir, ritonavir, tenofovir and lamivudine. The patient had a history of nausea, vomiting and some diarrhea with low fluid intake for a week. Besides slight dehydration, the physical examination was unremarkable. Renal ultrasound showed normal kidneys. With adequate fluid restoration, the renal function improved but other metabolic alterations like nephrogenic diabetes remained. Results: Renal biopsy revealed toxic acute tubular necrosis predominantly involving proximal tubules with prominent eosinophilic inclusions within proximal tubular cell cytoplasm, which represented giant, abnormal mitochondria, consistent with tenofovir toxicity. Some histochemichal studies (COX and SDH) were performed. Conclusion: Although prospective clinical trials have demonstrated a low incidence of renal toxicity with tenofovir, there are several such reports in the literature. Current recommendations suggest close monitoring of renal function after initiation of therapy with tenofovir, specially at the beginning and when used in combination with certain antiretroviral agents. Objective: Nutcracker syndrome (NS) is caused by compression of the left renal vein between the aorta and superior mesenteric artery. The main presenting symptom of this rare entity is haematuria, with various degrees of proteinuria. The diagnosis of NS syndrome is primarily by imaging and can sometimes be challenging.