ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 (STIII-STIVNxM1) with clinical progression after treatment and visceral metastases of tumours, harboring specific mutations. ctDNA concentration were assessed by quantitative acPCR and spectrophotometry. CTCs extraction performed from 20 ml of peripheral blood by cytopheresis in density gradient. CTCs were assessed morphologically and immunocytochemicaly. Results: Among 10(67%) of 15 patients with stage StIIIM1 after adju- vant chemotherapy (ACT), photodynamic(PDT) and target therapy(TT) mitotic activity of CTCs were detected. CTC DNA concentration was twice as higher then ctDNA concentration and number of apoptotic CTCs were 0-1. Among patients (StIII-StIVIM1) with progression after ACT and stabilization the process after PDT, in 9 (81%) cases CTC DNA concentration was lower than ctDNA concentration, and the number of apoptotic CTC cells were 2-5. Secondary mutation EGFRT780M was detected in 3 (60%) of 5 NSCLC with resistance to TT. Of these, 2 cases with double mutations. The concentration of ctDNA harboring EGFRT780M mutation is higher in cfDNA fraction than i CTC fraction. Conclusion: Mitotic activity, low percentage of apoptotic cells among CTCs, ctDNA concentration after CTCs lysis is higher than concentration of cell free ctDNA are an unfavourable prognosis (no response therapy). High percentage of apoptotic cells among CTCs and ctDNA concentration after CTCs lysis is less than the concentration of cell free ctDNA is a favourable prognosis. Sec- ondary resistance mutations analysis is more efficacy by ctDNA. The role of CTC for therapy monitoring and prognosis of cancer is more significant than сtDNA. E-PS-16 | E-Posters Nephropathology E-PS-16-001 Collapsing glomerulopathy associated with Covid-19 diag- nosed one year after SARS-CoV-2 infection: a case report of an emerging entity C. Nikolaidou, C. Gouta*, F. Iatridi, M. Stangou, I. Venizelos *Department of Histopathology, Hippokration General Hospital of Thessaloniki, Thessaloniki, Greece Background & objectives: Collapsing glomerulopathy is one of the most common glomerulopathies associated with SARS-CoV-2 infec- tion. It usually presents as rapidly progressive renal failure within a month of infection and has been associated with apolipoprotein L1 risk alleles, encountered mainly in African patients. Methods: We report the case of a 29-year-old Caucasian male with a history of kidney transplantation due to end stage renal disease/ IgA nephropathy, who presented with renal transplant dysfunction one year after SARS-CoV-2 infection. The patient was subjected to renal ultrasound and DTPA scan that showed mild to moderate glomerular disorder. Additionally, a renal biopsy was performed. Results: Light microscopy examination revealed two major features: tuft collapse with pseudocrescent formation in two of the four non globally sclerosed glomeruli and focal acute tubular injury. No signs of endarteritis were observed. Immunofluorescence staining for C1q, C3d, IgA, IgG, IgM and κ/λ light chains was negative. Immunohistochemistry for C4d was also negative on peritubular capillaries. Considering patient’s history, the diagnosis of collapsing glomerulopathy associated with COVID-19 was made. Conclusion: Kidney involvement is frequent in patients with SARS-CoV-2 infection with collapsing glomerulopathy being the most common among glomerulopathies. However, there is little information over the presentation of these entities in transplant patients. Our case report describes a biopsy-proven collapsing glo- merulopathy occurring in a kidney transplant Caucasian recipient with a low-risk apolipoprotein L1 donor background (father) and a SARS-CoV-2 infection one year earlier. Our histological findings in the kidney allograft were similar to those described in native kidneys of COVID-19 patients. E-PS-16-002 A tale of a transplant: renal allograft granulomatous intersti- tial nephritis in early post-transplant period A. Nalwa*, S. Kumar, U. Rani, N. Bajpai, M. Chaturvedy, R. Jhorawat, V. Vishwajeet, M. Rao *All India Institute of Medical Sciences, Jodhpur, India Background & objectives: Granulomatous interstitial nephritis in the early post-transplant period is an uncommon cause of kidney dysfunc- tion reported in <1% of renal allograft recipients. Accurate diagnosis and determination of aetiology are important due to consequences of altering immunosuppression in early post-transplant period. Methods: 31-year male with ESRD(unknown cause) received ABO compatible live related renal transplant and was given basiliximab induction followed by methylprednisolone, mycophenolate mofetil and tacrolimus for maintenance immunosuppression. Graft function was slow with gradual reduction in urine output,Day0 (5,500 ml) to Day3(2400ml) and rise in serum creatinine(3.0mg/dL on Day0 gradually to 4.0 mg/dL on Day3) and developed graft tenderness by Day3. Results: Urinalysis showed 2+ proteinuria and 70-80 WBCs per high-power field. A transplant kidney biopsy revealed multiple small non-necrotising epithelioid cell granulomas suggestive of granulomatous interstitial nephritis. There was no evidence of acid- fast bacilli and Gomori-Methenamine silver stain was negative for fungal profiles. There was evidence of patchy acute tubular injury in the form of epithelial simplification and reparative basophilia however, no viral cytopathic changes were seen in the tubules and immunohistochemistry for CMV and SV40 large T antigen were negative. No definitive evidence of cellular or humoral rejection was seen in the biopsy. C4d stain for humoral rejection was nega- tive. Overall a drug-induced cause was favoured. Conclusion: Drug-induced granulomatous nephritis in allografts has been reported from day8 to day720 post-transplantation. This is one of the index cases showing granulomatous interstitial nephritis post-operative Day4 with the likely culprit being sulfonamides. The graft function significantly improved after stopping all the poten- tial offending medicines. Although geographically, tuberculosis is the most common cause of granulomatous interstitial nephritis in countries like India accurate determination of the cause is of utmost importance for early recovery and long-term graft survival. E-PS-16-003 Histological findings in a prospective cohort of transplant patients with screening for development of donor-specific antibodies F. Toulza, E. Santos, K. Spensley, S. Lewis, J. Beadle, A.M. McLean, T. Cairns, M. Willicombe, C. Roufosse* *Imperial College London, United Kingdom Background & objectives: Donor specific antibodies (DSA) predis- pose kidney transplant patients to antibody mediated rejection (AMR). AMR is a leading cause of graft loss. We prospectively studied the his- tological features in biopsies taken at the time of appearance of a DSA. Methods: All patients transplanted in our centre between January 2019 and November 2021 were screened (at 1,2,3,6 and 12months post-transplantation and then every year) for the development of S310