Susceptibility of lung transplants to preformed donor-specific HLA antibodies as detected by flow cytometry

Background. Preformed anti-HLA, antibodies are known to have the potential to induce early graft damage in organ transplant recipients, However, in lu ng transplant recipients;, little information exists about the significance of preformed antibodies directed to either class I or class II HLA antigen s, Methods, A two-color flow cytometry; cross-match was performed in 92 consec utive? lung transplant recipients using serum obtained immediately before t ransplantation, The presence of preformed antibodies was correlated with th e incidence of severe graft dysfunction manifested as pulmonary infiltrates and severe hypoxemia with onset in the first few hours after transplantati on, Results. Sig patients (6.5%) had low-level anti-donor IgG: antibodies detec ted by flow cytometry, four against T and two against B lymphocytes, Three patients (50%) developed severe graft dysfunction with pulmonary infiltrate s and hypoxemia. Two patients responded to treatment, but the third, who ha d an antibody highly specific for HLA-DR11, died at 48 hr after transplant, Results of histopathologic studies in this patient are consistent with hyp eracute; rejection and support a pathogenic role of: these antibodies.. In contrast, of 86 (93.5%) cases with a negative flow cytometry cross-match, o nly 4 (5%) had severe hut reversible early graft dysfunction with pulmonary infiltrates and hypoxemia, attributed to ischemia-reperfusion injury (P<0. 005). Conclusions. Class II, and perhaps class I HLA antibodies at relatively low concentrations represent a risk factor for severe early pulmonary graft dy sfunction, with the potential to progress to hyperacute rejection and death .