Abstract
Hemophilia A is a rare congenital bleeding disorder caused by a deficiency of functionally active coagulation factor VIII (FVIII). Most patients with the severe form of the disease require FVIII replacement therapies, which are often associated with the development of neutralizing antibodies against FVIII. Why some patients develop neutralizing antibodies while others do not is not fully understood. Previously, we could demonstrate that the analysis of FVIII-induced gene expression signatures in peripheral blood mononuclear cells (PBMC) obtained from patients exposed to FVIII replacement therapies provides novel insights into underlying immune mechanisms regulating the development of different populations of FVIII-specific antibodies. The aim of the study described in this manuscript was the development of training and qualification test procedures to enable local operators in different European and US clinical Hemophilia Treatment Centers (HTC) to produce reliable and valid data for antigen-induced gene expression signatures in PBMC obtained from small blood volumes. For this purpose, we used the model antigen Cytomegalovirus (CMV) phosphoprotein (pp) 65. We trained and qualified 39 local HTC operators from 15 clinical sites in Europe and the US, of whom 31 operators passed the qualification at first attempt, and eight operators passed at the second attempt.