Effective and safe off-label use of caplacizumab treatment in a middle-aged obese male.

This study shows clinical efficacy and safety profile of an off-label use of caplacizumab for the treatment of immune-mediated thrombotic thrombocytopenic purpura in a middle-aged obese male patient manifesting aphasia, weakness and unconsciousness. Routine blood tests revealed haemolytic anaemia, severe thrombocytopenia (platelet count=20×109/L) and moderate creatinine increase. Diagnosis was based on the clinical judgement and laboratory determinations (undetectable ADAMTS13 activity and presence of anti-ADAMTS13 antibodies). The patient underwent plasma-exchange and an adjunctive treatment with prednisone (1mg/Kg/day), but the occurrence of a refractory and exacerbated form of disease suggested also using rituximab (375mg/m2 weekly for 4 weeks) and caplacizumab as salvage treatments. The caplacizumab was given at 10mg/day subcutaneously without the first intravenous bolus. Because von Willebrand factor inhibition, platelet count recovery and remission of symptoms were achieved, use of caplacizumab with this scheme appeared to be as effective as the approved one. Although this is an off-label use, this case highlights the potential of this new treatment, in terms of drug's efficacy and safety.

Structural analysis of protein Z gene variants in patients with foetal losses.

The role of protein Z (PZ) in the etiology of human disorders is unclear. A number of PZ gene variants, sporadic or polymorphic and found exclusively in the serine protease domain, have been observed. Crystal structures of PZ in complex with the PZ-dependent inhibitor (PZI) have been recently obtained. The aim of this study was a structural investigation of the serine protease PZ domain, aiming at finding common traits across disease-linked mutations. We performed 10-20 ns molecular dynamics for each of the observed PZ mutants to investigate their structure in aqueous solution. Simulation data were processed by novel tools to analyse the residue-by-residue backbone flexibility. Results showed that sporadic mutations are associated with anomalous flexibility of residues belonging to specific regions. Among them, the most important is a loop region which is in contact with the longest helix of PZI. Other regions have been identified, which hold anomalous flexibility associated with potentially protective gene variants. In conclusion, a possible interpretation of effects associated with observed gene variants is provided. The exploration of PZ/PZI interactions seems essential in explaining these effects.

The M2 haplotype in the ANXA5 gene is an independent risk factor for idiopathic small-for-gestational age newborns.

Hereditary thrombophilias can impair vascular placental functions and predispose to the birth of small-for-gestational age (SGA) babies. The placental anticoagulant protein annexin A5 (ANXA5) may contribute to this process. A functional haplotype (M2) within the ANXA5 gene is associated with fetal loss and venous thrombosis. This study investigated the prevalence of the M2 haplotype in a group of women with idiopathic SGA newborn babies. Seventy-eight women with at least one previous unexplained SGA birth and 195 controls all from Southern Italy were investigated. Hereditary thrombophilia was found in 13 (16.5%) cases and 21 (11%) controls (P < 0.05.). The M2 haplotype was found in 29% of cases (n = 23) and 15% of controls [n = 30; P = 0.001; OR = 2.3, 95% CI (1.17-4.48)]. Within the case group, 82.5% of the M2 haplotype carriers gave birth to babies with a birthweight below the 3rd percentile [P = 0.01; OR = 2.4, 95% CI (1.26-4.73)]. A logistic regression, corrected for age, parity and gravity showed that the M2 haplotype was independently associated with the delivery of an SGA new born [P = 0.029; OR = 2.6, 95% CI (1.1-6.0)]. In conclusion, the M2 haplotype of the ANXA5 gene confers a risk of delivering SGA babies.

Factor XI deficiency: two novel mutations in asymptomatic Italian patients.

SUMMARY: Factor XI (FXI) deficiency is a rare bleeding disorder, resulting in a wide range of bleeding manifestations, from asymptomatic bleeding to injury-related bleeding. To identify mutations in FXI-deficient patients and to establish a possible relationship between clinical phenotype and genotype, we studied two patients from Southern Italy with FXI deficiency. They were identified by presurgical or routine laboratory screening. None of them showed bleeding. Three different mutations were detected (Glu117Stop, Cys118Arg and Trp497Gly); two of them were novel (Cys118Arg and Trp497Gly). One patient (with severe FXI levels) showed a compound heterozygosity (Glu117Stop with Cys118Arg). Two novel missense mutations were highly conserved among different species. In our patients, bleeding tendency did not appear to be correlated with FXI levels or with a single mutation in heterozygosis. On the other hand, the compound heterozygosis might explain low FXI levels, but it is not associated with bleeding. Our data confirm that a severe FXI deficiency is not necessarily associated with bleeding.