Comparison of cell based and solid phase assays in detecting pre transplant donor specific antibody and impact of its results on graft outcome

Abstract

Background: The clinical significance of positive results on more sensitive platforms available for antibody screening has been a matter of contention. This study explores the relationship of test results of Complement Dependent Cytotoxicity (CDC) crossmatch, ELISA anti HLA antibody test and Donor Specific Antibody (DSA) assay using donor lysate on the Luminex platform and their impact on graft outcome. Materials and Methods: Participants included patients who underwent renal transplant over four years, in whom pre transplant screening included an initial CDC cross match, followed by final CDC cross match, ELISA and DSA screening by the Luminex on the final pre transplant serum. Relevant clinical data and results of supportive laboratory investigations were taken from HLA laboratory and computerised records.Results: 126 recipients were included in the study. Pre transplant CDC positivity correlated with overall rejection episodes (P=0.03) and the historical crossmatch Ig M/G positivity with biopsy proven rejections (P=0.029). There was no significant correlation between pre-transplant DSA and ELISA results and rejection episodes.A comparison between DSA, ELISA and CDC showed a low association (Kappa value for DSA and CDC: -0.42; ELISA and CDC: - 0.63; DSA and ELISA: + 0.159).Conclusion: CDC continues to have relevance in pre transplant screening. In spite of their technical advantages and superior sensitivity, the ELISA pooled antigen assay and the Luminex crossmatch do not appear to show any significant clinical advantage when used with conventional CDC.