Antibody-mediated rejection with detection of de novo donor-specific anti-human leukocyte antigen Class II antibodies after lung transplantation: Problems in diagnosis, treatment and monitoring on a case report basis.

Lung transplantation, like other transplants, carries a risk of graft rejection due to genetic differences between the donor and the recipient. In this paper, we focus on antibody-mediated rejection, which can cause acute and more importantly chronic graft dysfunction and subsequently shortened allograft survival. We present the case of a 46-year-old patient who, two months after lung transplantation (LTx), developed AMR manifested by the deterioration of graft function and de novo production of donor-specific antibodies (DSA): DQ3 (DQ7, DQ8, DQ9). As the patient was after left single LTx and heavily oxygen dependent a transbronchial biopsy was deemed to be high risk and it was decided to determine the clinical significance of the detected antibodies by their ability to bind complement. The test confirmed that the detected DSAs have the ability cause cytotoxicity of the transplanted organ. After treatment with methotrexate, intravenous immunoglobulin G (IVIg) and alemtuzumab, the patient's condition improved and a complete decrease in DSA was obtained. However, after a year, the production of antibodies increased sharply. Treatment with IVIg, cyclophosphamide and plasmapheresis slightly improved the patient's condition, reducing the MFI DSA values by half, but leaving them at high levels. Based on this clinical case, we discuss problems with making a diagnosis, choosing the right AMR treatment and monitoring the patient's condition during treatment. We also indicate a poor prognosis in the case of the production of DSA antibodies at the DQ locus.