RESUMO
Neonatal screening for hemoglobinopathies occasionally results in the detection of novel hemoglobin (Hb) variants. Two heterozygous infants were found with different beta chain mutations, neither of which produced obvious clinical or laboratory abnormalities on routine examinations. The variants were characterized by cation exchange high performance liquid chromatography (HPLC), reversed phase HPLC, and sequencing of amplified beta-globin genes. Functional studies could not be performed at this time.
Assuntos
Mutação , Globinas beta/genética , Alanina/química , Alanina/genética , Substituição de Aminoácidos , Ácido Aspártico/química , Ácido Aspártico/genética , Sequência de Bases , Pré-Escolar , Cromatografia Líquida de Alta Pressão , Humanos , Lactente , Isoleucina/química , Isoleucina/genética , Masculino , Dados de Sequência Molecular , Valina/química , Valina/genética , Globinas beta/químicaRESUMO
OBJECTIVES: This study examined the efficacy and safety of rituximab in children with chronic immune thrombocytopenic purpura. STUDY DESIGN: Twenty-four patients, 2 to 19 years of age, with platelet counts <30,000/mcL (microliter 2), received 375 mg/m 2 rituximab in 4 weekly doses. Platelet response was characterized as complete (CR) if a count >150,000/mcL was achieved; partial (PR) if 50,000 to 150,000/mcL; minimal (MR) if the count increased by >20,000/mcL to a peak count >30,000/mcL but <50,000/mcL; or no response (NR). RESULTS: Fifteen of 24 patients (63%) achieved a CR lasting 4 to 30 months, 9 of which are ongoing. Two had PRs lasting 4 and 6 months; 2 had MRs lasting 5 and 8 months, and 5 did not respond. Pruritus, urticaria, and throat tightness (but no respiratory distress) occurred with the first infusion in a small number of children. Three patients had serum sickness after the first, second, and third infusions, respectively. No increased frequency or severity of infections was seen, although immunoglobulin levels decreased to below the normal range in 6 of 14 cases. CONCLUSIONS: Rituximab may be a useful treatment for chronic immune thrombocytopenic purpura in children with a >50% CR rate lasting an average of 13 months, with 9 of 15 CRs ongoing (8 lasted 6 months or longer). There was no substantial toxicity other than transient serum sickness.
