HSPD1 and Behcet disease: Similarly, optical densities obtained from ELISAs against the recombinant human hnRNP-A2/B1, which is shown to be expressed in endothelial cells and is a target antigen of anti-endothelial cell antibodies (AECA) in BD, correlated with those against the recombinant streptococcal hsp65 [38].