ADAMTS13 phenotype in plasma from normal individuals and patients with thrombotic thrombocytopenic purpura

The activity of ADAMTS13, the von Willebrand factor cleaving protease, is deficient in patients with thrombotic thrombocytopenic purpura (TTP). In the present study, the phenotype of ADAMTS13 in TTP and in normal plasma was demonstrated by immunoblotting. Normal plasma (n = 20) revealed a single band at 190 kD under reducing conditions using a polyclonal antibody, and a single band at 150 kD under non-reducing conditions using a monoclonal antibody. ADAMTS13 was not detected in the plasma from patients with congenital TTP (n = 5) by either antibody, whereas patients with acquired TTP (n = 2) presented the normal phenotype. Following immunoadsorption of immunoglobulins, the ADAMTS13 band was removed from the plasma of the patients with acquired TTP, but not from that of normal individuals. This indicates that ADAMTS13 is complexed with immunoglobulin in these patients. The lack of ADAMTS13 expression in the plasma from patients with hereditary TTP may indicate defective synthesis, impaired cellular secretion, or enhanced degradation in the circulation. This study differentiated between normal and TTP plasma, as well as between congenital and acquired TTP. This method may, therefore, be used as a complement in the diagnosis of TTP

A hydrolysed rice-based formula is tolerated by children with cow's milk allergy: a multi-centre study

Background Children allergic to cow's milk are fed a soy- or a hydrolysed cow's milk-based substitute. Neither can rule out a sensitization risk. Previous studies have shown that hydrolysed rice is tolerated by animals and children with multiple food hypersensitivities. Objective A prospective clinical assessment of tolerance to a rice-based hydrolysed formula was carried out in children allergic to cow's milk. Patients and methods One hundred children (42 girls and 58 boys, mean age 3.17 +/- 2.93 years, median 2.20, range 0.18-14.6 years) with a history of immediate reactions to cow's milk and confirmed at double-blind, placebo-controlled food challenge (DBPCFC) when not contraindicated were assessed for clinical tolerance to cow's milk proteins. Their allergy work-up included skin prick tests with whole milk, alpha-lactalbumin (ALA), beta-lactoglobulin (BLG) and total caseins, and specific IgE determinations using CAP technology were performed against whole milk, ALA, BLG and casein. Sensitization to rice and rice-based hydrolysed formula was similarly investigated. Patients' sera were evaluated at immunoblotting for specific IgE to cow's milk proteins, rice and rice-based hydrolysed formula. DBPCFC was carried out with increasing doses of a rice-based hydrolysed formula. Results All patients were sensitized to cow's milk and/or at least one cow's milk protein fraction. Eighty-seven out of 99 were positive to cow's milk and/or a cow's milk protein fraction at skin prick test. Positive (> 0.35 kUA/L) specific IgE determinations were found for cow's milk and/or milk fractions (92/95), rice (21/91) and hydrolysed rice infant formula (4/91). At immunoblotting, sera from 96 children were positive to alpha-casein (n=54), beta-casein (n=38), ALA (n=57), BLG (n=37) and bovine serum albumin (n=61). Similarly, although patients' sera often contained specific IgE against rice proteins at CAP (21/91) and immunoblotting (70/96), only six very weakly positive responses were observed against rice-based hydrolysed formula. All DBPCFC with rice-based hydrolysed formula were negative. Conclusions Rice-based hydrolysed formula is a possible alternative not only for children with multiple allergies, but also for children with cow's milk allergy