Passenger Lymphocyte Syndrome in a Pediatric Lung Transplant Recipient with Previous Bone Marrow Transplantation

Abstract

Introduction Passenger lymphocyte syndrome (PLS) is a rare complication following solid organ transplantation (SOT). It consists of immune-mediated hemolysis due to antibodies produced by donor B-lymphocytes against recipient red blood cells [1]. Incidence across all SOT is as low as 0.5% in adults, with the highest rates being in lung and heart [2,3,4]. There have been no cases reported in children post-lung transplantation to our knowledge. Case Report A 12-year-old female received a double lung transplantation for bronchiolitis obliterans due to graft versus-host disease (GHVD). She had undergone allogeneic BMT 6 years prior for myelodysplastic syndrome (MDS). Her post-BMT course was complicated by lung, skin, and gastrointestinal GVHD. Lung transplant was uncomplicated: with donor blood group O+, recipient blood group A+, and crossmatch negative. On post-operative day 13, there was an acute drop in hemoglobin: from 131 g/L day 7, to 87 g/L day 13, to 66 g/L the same day. Septic workup was negative. Direct antiglobulin test was positive. Hemolysis markers were present with high LDH, high unconjugated bilirubin, and low haptoglobin. Eluate test was positive for anti-A1 antibody, consistent with a diagnosis of PLS. She received donor-type (O+) red cells, and was given IVIG 600 mg/kg for hypogammaglobulinemia. Hemoglobin recovered after day 21. Given her BMT history, concern around recurrent MDS was also raised. A chimerism study was sent on day 22 for this with the added benefit of examining for circulating lung-donor lymphocytes. No MDS was revealed. FISH revealed all cells were chromosomally XX (recipient had received BMT from a female donor), indicating no persistent circulating lung-donor lymphocytes since lung donor was male. Summary We report PLS following lung transplant in a 12-year-old post-BMT. Risk factors included minor ABO mismatch and organ type transplanted, with a high lymphocyte burden in lungs compared to other organs [3,4]. It is unclear whether prior allogeneic BMT and GVHD were added risk factors. Given higher PLS rates post-BMT [5], one could postulate that this may have also predisposed to PLS in this case. Albeit self-limiting, transfusion with donor blood group is necessary to prevent further hemolysis. Finally, a chimerism study for MDS has the added benefit of searching for lung-donor lymphocytes, if still present in circulation.