CLINICAL DILEMMAS Successful lung transplantation in the presence of pre- existing donor-specific cytotoxic HLA Class II antibodies Annechien J.A. Lambeck, PhD, a Erik A. Verschuuren, MD, PhD, b Ilby Bouwman, a Theo Jongsma, a Caroline Roozendaal, PhD, a Laura B. Bungener, PhD, a Wim van der Bij, MD, PhD, b Aad P. van den Berg, MD, c Michiel E. Erasmus, MD, PhD, d Wim Timens, MD,PhD, e Simon P.M. Lems, PhD, a and Bouke G. Hepkema, PhD a From the a Department of Laboratory Medicine, Transplantation Immunology; b Department of Pulmonary Diseases; c Gastroenterology and Hepatology; d Department of Cardiothoracic Surgery; and the e Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. KEYWORDS: lung transplantation; HLA antibody; donor-specific anti- body; rejection; LSA Pre-existing HLA antibodies are a well-established causal factor for rejection and graft dysfunction after solid-organ transplantation. In lung transplant recipients, the significance of HLA antibodies has not been fully established. Although rare, several cases of hyperacute rejection of the lung allograft due to pre-existing donor-specific HLA antibodies have been described. In contrast, we describe successful lung transplantation in a patient with pre-existing donor-specific HLA antibodies. Routine screening prior to lung transplantation revealed cytotoxic HLA Class II antibodies, directed against the alpha chain of HLA-DQ, induced by a previous liver transplant. Due to clinical deterioration, it was decided to accept a lung offer without virtual crossmatching for DQ compatibility. Cytotoxic antibodies against the lung donor were confirmed retrospectively, resulting in strong positive B-cell crossmatches. Interestingly, the patient showed no clinical or histologic signs of rejection. This case demonstrates that the presence of high levels of pre-existing donor-specific HLA antibodies does not necessarily lead to rejection and graft failure. Although screening for antibodies prior to transplantation remains crucial, this study shows that we are thus far not able to predict the effect of pre-existing HLA Class II antibodies on allograft survival in individual patients. J Heart Lung Transplant ]]]]; ]: ]]]–]]] r 2012 International Society for Heart and Lung Transplantation. All rights reserved. Lung transplantation is the final treatment option for patients with end-stage lung disease. Despite a stringent immunosuppressive regimen, complications due to rejection often occur after lung transplantation, severely influencing the long-term survival of lung transplant patients. 1 Donor- specific HLA antibodies, induced by pregnancy, transfusion or transplantation, are a well-established causal factor for hyperacute, acute and chronic rejection after solid-organ transplantation, such as kidney 2,3 and heart. 4 However, in lung transplantation the significance of pre-existing HLA- specific antibodies has not been fully established, which may be partly due to the low incidence of humoral sensitization in the lung transplant population. 5,6 Several cases of severe graft failure due to hyperacute rejection caused by pre-existing donor-specific anti-HLA antibodies have been reported, 7–12 but hyperacute rejection is a rare event after lung transplantation. The degree of humoral sensitization of a patient is determined by measuring http://www.jhltonline.org 1053-2498/$ - see front matter r 2012 International Society for Heart and Lung Transplantation. All rights reserved. http://dx.doi.org/10.1016/j.healun.2012.09.015 E-mail address: a.j.a.lambeck@umcg.nl Reprint requests: Annechien J.A. Lambeck, PhD, Department of Laboratory Medicine, Transplantation Immunology, University of Gronin- gen, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30.001, 9700 RB, Groningen, The Netherlands. Telephone: 00-31-50-361-45-43. Fax: 00-31-50-361-35-91.