Treatment response in congenital thrombotic thrombocytopenic purpura to aid in pregnancy counseling and management: a reply

Abstract

Treatment response in congenital thrombotic thrombocytopenic purpura to aid in pregnancy counseling and management: a replyWe read with interest the letter by Drs Phelps and Kolettis and wanted to thank them for their interest in our work and our article, published in the American Journal of Obstetrics & Gynecology. 1 The management of patients with hereditary thrombotic thrombocytopenic purpura (hTTP) can be challenging, particularly because the clinical course may vary significantly even among patients sharing the same mutation in the ADAMTS13 gene. Moreover, as previously reported, the outcomes may differ in pregnancies in the same patient, often regardless of the given treatment. The lack of genotypephenotype correlation is one of the main challenges in hTTP research and can be attributed to the yet unidentified hereditary and environmental modifiers. 2 Currently, there is no reliable predictor for the clinical course and complications of hTTP. Our preliminary data suggested that the nonpregnant von Willebrand factor antigen (vWF:Ag) concentrations may be associated with disease severity and pregnancy outcomes. This is in line with previous reports on the association between vWF:Ag concentrations and the risk of stroke and cardiovascular disease. 3 However, whether the von Willebrand factor is a key player in the pathophysiology of cardiovascular disorders or just a marker of endothelial injury remains unknown. The study of the role of vWF:Ag concentrations and multimer distribution in pregnant patients with hTTP is currently under investigation by our group. Hopefully, the results of this study will assist in the identification of patients with hTTP who will not respond to standard fresh frozen plasma (FFP) treatment during pregnancy.Regular infusions of FFP are effective in preventing strokes and pregnancy complications. 4,5 However, there is no standard protocol for FFP infusions in pregnant patients with hTTP. In addition, plasma infusions may cause serious side effects and not all patients will respond well to the treatment. A potential solution may be the introduction of the recombinant ADAMTS13. 6 This treatment is currently under phase II and III clinical studies and may provide a safe and reliable therapeutic option for those high-risk patients with hTTP who are poor responders to FFP treatment.