Evaluation of humoral immune response to donor HLA after implantation of cellularized versus decellularized human heart valve allografts

Abstract

We have evaluated the development of antibodies in response to donor allograft valve implant in patients who received cellularized and decellularized allografts and determined possible immunogenic epitopes considered responsible for antibodies reactivity. Serum samples from all recipients who received cellularized allografts or decellularized allografts were collected before valve replacement and at 5, 10, 30 and 90 days post-operatively and frozen until required. Tests were performed using the Luminex-based single human leukocyte antigen (HLA)-A, -B, -C and HLA-DR, -DQ antigen microsphere assay. To determine possible immunogenic epitopes, we used the HLAMatchmaker (HLAMM) software if applicable. Decellularized grafts elicited lower levels of anti-HLA class I and II antibody formation after implantation than cellularized allografts. All patients from cellularized group presented donor-specific antibodies class I and II within 3 months of observation period. In HLAMM analysis, the cellularized group had significantly higher numbers of immunogenic epitopes than decellularized group for both class I and II (p: 0.002 - cl I / p: 0.009 - cl II / p: 0.004 - cl I and II). Our findings demonstrate that the anti-HLA antibodies detected in the cellularized group were against donor HLA possible immunogenic epitopes and that in the decellularized group the anti-HLA antibodies were not against donor HLA possible immunogenic epitopes. These findings lead us to suggest that choosing sodium dodecyl sulfate decellularization process is the best alternative to decrease the immunogenicity of allograft valve transplant.

Immunogenicity in xenogeneic scaffold generation: Antigen removal vs. decellularization

“…Many approaches for decellularization have been investigated [48, 49] and include osmotic [5, 47, 50–55], chemical [5, 7, 46, 51–77], enzymatic [5, 52, 55, 63, 69, 75, 78], and mechanical [55, 69, 79] methods for removal of the cellular component of a xenograft. The efficacy of various decellularization [75] strategies have been tested on relatively simple tissue types including skin [14, 46, 73], small intestine submucosa (SIS) [14, 70, 73], pericardium [5, 53, 75], heart valve [47, 50–52, 56–63, 72, 76, 78, 80, 81], blood vessel [55, 75, 79, 82], cartilage [68, 83], and bone [54] and applied to more complex organs such as liver [64, 69, 73], kidney [65, 66, 71, 77], and heart [67]. Application of decellularization methods to reduce the immunological potential of xenogeneic tissues and organs is grounded in the assumptions that (1) the cellular component of a xenograft represents the sole contributor to its antigenicity and (2) the absence of cells (by microscopic evaluation of residual nuclei, DNA quantification, and/or assessment of residual, cellular proteins of neither confirmed nor denied immunogenicity) correlates with removal of antigenic components.…”

“…[61] reported macrophage infiltration into a SynerGraft decellularized, acellular pulmonary valve allograft 5 weeks after implantation into and 5 weeks before death of a human patient. Increasing levels of donor-specific antibodies against HLA class I and II antigens were measured in adults implanted with heart valve allografts decellularized using the ionic detergent sodium dodecyl sulfate (SDS) [81]. Affonso da Costa et al .…”

Current progress in tissue engineering of heart valves: multiscale problems, multiscale solutions

“…44 Additionally, the decellularization process reduces immune response, which is largely responsible for acute rejection of xenografts. 45,46 …”

The Acquired Immune System Response to Biomaterials, Including Both Naturally Occurring and Synthetic Biomaterials

“…There is already a proof-ofprinciple that decellularized allogenic tissues fail to elicit a humoral-mediated immune response when transplanted into humans (Elliott et al, 2012;Kneib et al, 2012;Olausson et al, 2012;Macchiarini et al, 2008). The potential advantages of the decellularized scaffold approach, compared to previous approaches, lie in its similarity to native tissue, with the maintenance of tissue composition and microarchitecture, and the possibility of generating nonimmunogenic tissues.…”