Extended half-life rFIX in major surgery-How to improve clinical practice: An intraindividual comparison.

Practical, safe, and effective hemostatic approach to orthopedic surgery using Extended Half-Life factor IX in hemophilia B. By intraindividual comparison, we found a lower FIX consumption, number of infusions, and cost compared to plasma-derived FIX.

Identification and functional characterization of a novel splicing variant in the F8 coagulation gene causing severe hemophilia A.

BACKGROUND: We have identified a synonymous F8 variation in a severe hemophilia A (HA) patient who developed inhibitors following factor VIII (FVIII) prophylaxis. The unreported c.6273 G > A variant targets the consensus splicing site of exon 21. OBJECTIVES: To determine the impact of c.6273 G > A nucleotide substitution on F8 splicing and its translated protein. METHODS: Patient peripheral blood mononuclear cells were isolated and differentiated into monocyte-derived macrophages (MDMs). FVIII distribution in cell compartments was evaluated by immunofluorescence. The splicing of mutated exon 21 was assessed by exon trapping. Identified FVIII splicing variants were generated by site-directed mutagenesis, inserted into a lentiviral vector (LV) to transduce Chinese hamster ovary (CHO) cells, and inject into B6/129 HA-mice. FVIII activity was assessed by activated partial thromboplastin time, whereas anti-FVIII antibodies and FVIII antigen, by ELISA. RESULTS: HA-MDMs demonstrated a predominant retention of FVIII around the endoplasmic reticulum. Exon trapping revealed the production of two isoforms: one retaining part of intron 21 and the other skipping exon 21. These variants, predicted to truncate FVIII in the C1 domain, were detected in the patient. CHO cells transduced with the two FVIII transcripts confirmed protein retention and absence of the C2 domain. HA mice injected with LV carrying FVIII mutants, partially recovered FVIII activity without the appearance of anti-FVIII antibodies. CONCLUSIONS: Herein, we demonstrate the aberrant impact of a FVIII synonymous mutation on its transcription, activity, and pathological outcomes. Our data underline the importance of increasing the knowledge regarding the functional consequences of F8 mutations and their link to inhibitor development and an effective replacement therapy.

Thrombopoietin receptor agonists in patients with persistent or chronic immune thrombocytopenia.

OBJECTIVES: To assess long-term treatment patterns and outcomes in patients with persistent or chronic immune thrombocytopenia (ITP), also considering the impact of the treatment with thrombopoietin receptor agonists (TPO-RAs) prior to splenectomy. METHODS: Medical records of all patients with persistent or chronic ITP seen at our institution between January 1985 and December 2016 were reviewed. Data on demographic and clinical characteristics were analyzed using descriptive statistics. Wilcoxon rank-sum test was used to compare medians between groups of patients. RESULTS: Among 80 patients with persistent or chronic ITP, 34 underwent splenectomy and 59 were treated with TPO-RAs. Twenty patients were both splenectomized and treated with TPO-RAs; among them, 9 received TPO-RAs before splenectomy. Median time to splenectomy from diagnosis of ITP was 25 months in the group of patients pretreated with TPO-RAs vs 14.5 months in the group of splenectomized patients. These differences were not statistically significant. CONCLUSIONS: Our study provides some initial data on the potential benefits of the treatment with TPO-RAs that may allow splenectomy to be safely deferred for prolonged periods. More research is needed to evaluate the impact of the treatment with TPO-RAs prior to splenectomy.