Passenger Lymphocyte Syndrome in Pediatric Lung Transplantation: A Recipient With Previous Hematopoietic Stem Cell Transplantation

Background Passenger lymphocyte syndrome (PLS) is a rare complication following solid organ transplantation (SOT) that has not been reported in pediatric lung transplantation. It consists of hemolysis by antibodies from donor B‐lymphocytes against recipient red blood cells (RBCs). Methods We report the case of a 12‐year‐old girl who received bilateral lung transplantation for bronchiolitis obliterans secondary to graft‐versus‐host disease. She had undergone allogeneic matched unrelated hematopoietic stem cell transplantation (HSCT) 6 years prior for myelodysplastic syndrome (MDS). Details around the PLS event are reported, with emphasis on novel considerations. Results Lung transplant was uneventful with minor ABO mismatch between donor (O+) and recipient (A+), with a negative crossmatch. There was an abrupt drop in hemoglobin from 10.8 g/dL on post‐operative day 11 to 6.6 g/dL on day 13. Direct antiglobulin test and markers for hemolysis were positive. Eluate test returned positive for anti‐A1 antibody, confirming PLS. Transfusion with donor‐type (O+) RBCs and IVIG were beneficial. A chimerism study revealed no recurrent MDS with fluorescence in situ hybridization revealing no circulating lung donor lymphocytes. The process was self‐limiting and hemoglobin recovered. Conclusions This case is the first to highlight PLS following lung transplantation in a child, and informs around post‐HSCT considerations. The novel use of chimerism studies and FISH can help elucidate the PLS course. It remains unclear if HSCT predisposes to PLS after subsequent SOT, although this may be due to sensitization to past RBC antigens.