HLA Antibodies after Lung Transplantation: Early Results of the HALT Study

Abstract

<h3>Purpose</h3> The development of donor-specific HLA antibodies (DSA) after lung transplantation (LT) is a significant risk factor for bronchiolitis obliterans syndrome (BOS). The HALT study aimed to determine the incidence of DSA development & characterize DSA profiles early after LT. <h3>Methods and Materials</h3> We conducted a prospective observational study at 6 US LT centers that used similar induction & maintenance immunosuppression. Recipients were screened for DSA using the LABScreen® Single Antigen assay at 10, 30, 60, 90, & 120 days after LT, & if clinically indicated. DSA was defined as bead reactivity with an absolute MFI>1000, & an increase in MFI>30% & an increase in absolute MFI≥500 when compared to pre-LT reactivity. <h3>Results</h3> 115 patients were enrolled at the 6 sites between 12/2011 and 6/2012.[table1]Study follow-up will be complete in 11/2012. An interim analysis through 8/2012 showed that 40 of the 115 (35%) recipients developed DSA after LT; 6 (5%) had class I DSA only, 22 (19%) had class II DSA only, & 12 (10%) had class I & class II DSA. DSA were identified a mean 29.6±24.4 days after LT.[figure 1]The median DSA MFI was 4534 (range: 1068-18150). <h3>Conclusions</h3> DSA development is common early after LT & most DSA are directed at class II HLA. Future studies should evaluate long-term outcomes after early DSA development & the potential benefit of preemptive DSA depletion. The HALT Study is funded by the NHLBI (R34 HL105412). Recipient Demographics (n = 115)VariableAge, mean (SD)56.8 (12.4)Female, n (%)47 (41%)Diagnosis, n (%)COPD37 (32%)ILD51 (44%)CF17 (15%)PAH2 (2%)Other8 (7%)Bilateral, n (%)86 (75%)Allosensitized pre-LT, n (%)16 (14%)Number of HLA mismatches for A, B, C, DRB1, DQ, median (IQR)8 (3)