J Lee1, Y Park2, B S Kim3, J G Lee1, H J Kim2, Y S Kim4, K H Huh5. 1. Department of Transplantation Surgery, Severance Hospital, Yonsei University Health System, Seoul, Korea. 2. Department of Laboratory Medicine, Severance Hospital, Yonsei University Health System, Seoul, Korea. 3. Department of Internal Medicine, Severance Hospital, Yonsei University Health System, Seoul, Korea; The Research Institute for Transplantation, Yonsei University College of Medicine, Seoul, Korea. 4. Department of Transplantation Surgery, Severance Hospital, Yonsei University Health System, Seoul, Korea; The Research Institute for Transplantation, Yonsei University College of Medicine, Seoul, Korea. 5. Department of Transplantation Surgery, Severance Hospital, Yonsei University Health System, Seoul, Korea; The Research Institute for Transplantation, Yonsei University College of Medicine, Seoul, Korea. Electronic address: khhuh@yuhs.ac.
Abstract
BACKGROUND: Solid-phase immunoassays have improved detection sensitivity for donor-specific HLA antibody (DSHA) and permitted the accurate diagnosis of antibody-mediated rejection (AMR). However, DSHA is not always sufficient to explain the cause of AMR. Consequently, a means of assessing non-HLA antibodies is required to determine the cause of AMR. The aim of the present study was to evaluate the clinical implications of antibodies (Abs) targeting angiotensin II type I receptor (AT1R) in recipients with AMR but without serum DSHA. METHODS: Non-HLA AMR cases diagnosed between January 2011 and June 2014 were included. Levels of anti-AT1R Abs (U/mL) were quantified by using AT1R assay kits (One Lambda, Calif, United States) with collected sera pretransplantation and at biopsy (cut-off value: 15 U/mL). RESULTS: Seventy-two patients were diagnosed with AMR during the above-mentioned period. Of them, 12 recipients (16.7%) had no DSHA. The sera of these 12 patients were tested (2 patients were only checked at time of biopsy). Nine patients (9/10) were presensitized for anti-AT1R Abs (median, 25.0 U/mL; range, 12.9 to 50.0 U/mL). Ten patients (10/12) were anti-AT1R- positive at time of biopsy (median, 23.2 U/mL; range, 11.4 to 50.0 U/mL). The mean time from transplantation to biopsy was 73 months. Eight patients experienced acute AMR, and 4 developed chronic AMR. Four patients showed negative C4d staining in peritubular capillaries (4/12). Patients were treated with plasmapheresis, low-dose intravenous immunoglobulin, and/or rituximab. CONCLUSIONS: AT1R Abs may play a significant role in AMR without detectable DSHA. Pretransplantation detection of AT1R Abs may be helpful for assessing the risk for non-HLA AMR.
BACKGROUND: Solid-phase immunoassays have improved detection sensitivity for donor-specific HLA antibody (DSHA) and permitted the accurate diagnosis of antibody-mediated rejection (AMR). However, DSHA is not always sufficient to explain the cause of AMR. Consequently, a means of assessing non-HLA antibodies is required to determine the cause of AMR. The aim of the present study was to evaluate the clinical implications of antibodies (Abs) targeting angiotensin II type I receptor (AT1R) in recipients with AMR but without serum DSHA. METHODS: Non-HLA AMR cases diagnosed between January 2011 and June 2014 were included. Levels of anti-AT1R Abs (U/mL) were quantified by using AT1R assay kits (One Lambda, Calif, United States) with collected sera pretransplantation and at biopsy (cut-off value: 15 U/mL). RESULTS: Seventy-two patients were diagnosed with AMR during the above-mentioned period. Of them, 12 recipients (16.7%) had no DSHA. The sera of these 12 patients were tested (2 patients were only checked at time of biopsy). Nine patients (9/10) were presensitized for anti-AT1R Abs (median, 25.0 U/mL; range, 12.9 to 50.0 U/mL). Ten patients (10/12) were anti-AT1R- positive at time of biopsy (median, 23.2 U/mL; range, 11.4 to 50.0 U/mL). The mean time from transplantation to biopsy was 73 months. Eight patients experienced acute AMR, and 4 developed chronic AMR. Four patients showed negative C4d staining in peritubular capillaries (4/12). Patients were treated with plasmapheresis, low-dose intravenous immunoglobulin, and/or rituximab. CONCLUSIONS:AT1R Abs may play a significant role in AMR without detectable DSHA. Pretransplantation detection of AT1R Abs may be helpful for assessing the risk for non-HLA AMR.