Autoantibodies after LVAD: Profiling with Antigen Microarrays

Abstract

<h3>Purpose</h3> Previous studies have documented B-cell activation and increases in anti-HLA antibodies after LVAD support. We sought to determine if autoantibodies (non-HLA) antibodies as measured by antigen microarrays also increase after LVAD support. <h3>Methods and Materials</h3> We measured autoantibodies before and after LVAD support with antigen microarrays. Antigen microarrays were constructed by spotting 61 antigens onto nitrocellulose slides using a microarrayer. After blocking the slides, they were probed with diluted serum. They were then probed with fluorescently labeled secondary antibodies to differentially detect IgG and IgM reactivities. Fluorescent reactivities were detected with a scanner and significance analysis of microarrays (SAM) was used to detect significant changes in antigen reactivities. Total IgG levels were also measured by ELISA. <h3>Results</h3> We measured autoantibodies before and after implantation of continuous flow LVADs in 22 patients. Mean duration of support was 102 days. SAM analysis revealed 14 autoantibodies that were increased after LVAD. Figure 1 shows a heatmap of pre and post reactivities. Thirteen of these reactivities were IgG and one was IgM. The antibodies that increased were against heart proteins such as myosin, troponin I, and tropomyosin as well as extracellular proteins such as collagen and laminin. Although not statistically significant, there was a trend for increases in autoantibodies to correlate with increases in PRA. Total IgG levels also increased after LVAD support from 15.9 to 17.8 mg/ml. <h3>Conclusions</h3> We identified 14 autoantibodies against heart and extracellular proteins that increased after LVAD support. Increases in these reactivities and total IgG may reflect immune activation after LVAD.