Residual Immune Response toward Decellularized Allografts may be Highly Individual

Objectives: Decellularized homograft valves (DHV) have shown promising clinical results, particularly in the treatment of congenital heart disease. However, there is a subset of young patients, who seem to elicit an immune response. As decellularization is quality controlled for each DHV, we hypothesized that there may be residual immunogenicity within the extracellular matrix of DHV.

Methods: A semiquantified Dot Blot analysis was established to screen for preformed recipient antibodies using a secondary human antibody. 15 DHV samples (seven aortic and eight pulmonary) were solubilized and exposed to serum from 20 healthy controls.

Result: Amounts of preformed antibodies bound to DHVs were higher in aortic than in pulmonary DHVs, the mean number of antibody binding (in arbitrary units) was 17.2 ± 4.5 in aortic and 14.5 ± 4.7 in pulmonary DHV (n.s.). Amounts of preformed antibodies bound to pulmonary DHVs were statistically significantly higher in sera of healthy males (n = 10) than in sera of healthy females (n = 10). The mean number of arbitrary units was 17.2 ± 4.2 in male and 11.7 ± 5.3 in female sera (p = 0.0360). Young controls (n = 10, 18–25 years) showed significantly more antibody binding than older individuals (n = 10, 48–73 years, p < 0.0315). There was a very high intraindividual variance in the mean number of antibody binding with some healthy controls showing more than 10-times higher antibody binding toward two different DHVs.

Conclusion: Residual antigenicity of decellularized homografts appears to exist despite almost complete cell removal. The established Dot Blot method allows a semiquantitative assessment of individual immune response toward extracellular DHV components and potentially preoperative homograft matching.

No conflict of interest has been declared by the author(s).