Diana S. Beardsley

A distinctive form of immune thrombocytopenia in a phase 2 study of alemtuzumab for the treatment of relapsing-remitting multiple sclerosis

In a phase 2 clinical trial of annual alemtuzumab for treatment of relapsing-remitting multiple sclerosis, 6 of 216 patients (2.8%) developed immune thrombocytopenia (ITP). Over mean follow-up of 4.5 years, the incidence rate of ITP was 6.2 (95% confidence interval, 2.3-13.3) per 1000 person-years. Median times from initial and last alemtuzumab exposure to ITP diagnosis were 24.5 and 10.5 months, respectively. Five patients developed severe thrombocytopenia. Four were symptomatic, including fatal intracranial hemorrhage in the index case. Four patients received standard first-line ITP therapy, all of whom responded to treatment within 1 week. All 5 surviving patients achieved complete remission and remained in complete remission without need for ongoing ITP therapy for a median duration of 34 months at last follow-up. A monitoring plan for the early detection of ITP, implemented after presentation of the index case, identified all 5 subsequent cases before serious hemorrhagic morbidity or mortality occurred. In conclusion, we describe a distinctive form of ITP associated with alemtuzumab treatment characterized by delayed presentation after drug exposure, responsiveness to conventional ITP therapies, and prolonged remission. Clinicians should maintain a high level of vigilance and consider routine monitoring for ITP in patients treated with this agent. This trial was registered at www.clinicaltrials.gov as #NCT00050778.

Safety and Efficacy of Low-Dose Intravenous Immune Globulin (IVIG) Treatment for Infants and Children with Immune Thrombocytopenic Purpura

Purpose: This report presents pooled data from two multicenter studies conducted to assess the efficacy, safety, and tolerance of lower-dose intravenous immune globulin (IVIG) regimens of 250 mg/kg/day, 400 mg/kg/day, and 500 mg/kg/day for 2 days, compared to an established higher-dose regimen of 1 g/kg/day for 2 days, in children with immune thrombocytopenic purpura (ITP). Patients and Methods: A total of 24 children received IVIG (Gammar Sr I.V.). In Study 1, 10 centers enrolled 12 children between 5 and 12 years old who received IVIG at either 400 mg/kg/day or 1 g/kg/day for 2 days. In Study 2, five centers enrolled 12 infants and children younger than 5 years old who received IVIG at 250 mg/kg/day or 500 mg/kg/day for 2 days. Both studies were prospective and randomized. Results: IVIG treatment was effective (platelets increased at least 30,000/cu mm over baseline) in 94% (16 of 17) of the evaluable patients in the low-dosage group. Platelet increases occurred rapidly: by 48 hours, total platelet counts ranged from 32,000/cu mm to 256,000/cu mm, and peak platelet counts reached 38,000/cu mm to 551,000/cu mm. Adverse events (AEs) were most often mild, lasted less than 3 hours, and were usually those typically associated with immunoglobulin administration-headache, nausea, vomiting, and fever. There were two serious AEs—an anaphylactoid reaction in one patient in the 400 mg/kg group and aseptic meningitis in one patient in the 1 g/kg high-dosage group. Both patients recovered without sequelae and were responders. Although the incidence of AEs varied by dosage groups, this difference was not significant. However, the incidence of AEs was affected by age. AEs were significantly lower in patients younger than 5 years of age. Conclusions: In this small, randomized trial, low-dose IVIG in 2-day regimens of 250, 400, or 500 mg/kg/day rapidly reversed thrombocytopenia just as effectively as 1 g/kg/day in infants and young children with ITP. Lower-dosage regimens are safe and well-tolerated; the incidence of AEs is lower in children younger than 5 years of age.

Nonoperative management of a splenic tear in a Jehovah's Witness with hemophilia

Splenic laceration, the most common visceral lesion following blunt abdominal trauma, can be treated in a nonoperative fashion in only a select group of stable patients with minimal injury. We report a unique case of life-threatening splenic trauma in a Jehovahs Witness with hemophilia that was successfully managed without surgery.

Platelet autoantigens: Identification and characterization using immunoblotting

SummaryAntiplatelet autoantibodies are important in the etiology of idiopathic (or immune) thrombocytopenic purpura (ITP). Studies using immunoblotting techniques have been helpful in identifying the antigenic target proteins for the antibodies. Antibodies against the glycoprotein (GP) IIIa portion of the GPIIb/IIIa complex were the first to be demonstrated by this approach. Similar GPIIIa autoantigens have also been found to be the most frequent targets of ITP antibodies. Not all anti-GPIIIa antibodies are directed against the same epitope on GPIIIa. A subset of anti-GPIIIa antibodies found in patients with an acquired qualitative platelet dysfunction actually interfere with fibrinogen binding to normal platelets. Antibodies directed against targets on GPV have been found in patients with acute ITP of childhood. In patients with ITP associated with lupus erythematosus, antibodies which bind to intracellular proteins of apparent molecular weights of 66 and 108 kDa have been detected. Thus, ITP antibodies can have a variety of target antigens. Study of larger series of patients will determine whether identification of platelet autoantigens correlates with clinical course of ITP.

RECOMBINANT GLYCOPROTEIN (GP)IIIa OLIGOPEPTIDES REACT WITH PLATELET AUTOANTIBODIES. ▴ 897

RECOMBINANT GLYCOPROTEIN (GP)IIIa OLIGOPEPTIDES REACT WITH PLATELET AUTOANTIBODIES. ▴ 897