Guidelines for the Standard Monitoring of Patients With Thalassemia: Report of the Thalassemia Longitudinal Cohort.

Chronic transfusion therapy has played a central role in extending life expectancy for patients with hemoglobinopathies such as thalassemia. However, this life-saving therapy is associated with numerous complications that now comprise the bulk of management considerations for patients with thalassemia. This review reports on the experience of the Thalassemia Longitudinal Cohort and reviews available literature to establish guidelines for the management of patients with thalassemia.

Pediatric heparin-induced thrombocytopenia: prevalence, thrombotic risk, and application of the 4Ts scoring system.

OBJECTIVE: To characterize heparin-induced thrombocytopenia (HIT) at a single pediatric center including the prevalence and the accuracy of the 4Ts scoring system as a predictor of HIT. STUDY DESIGN: In this retrospective cohort study, we identified 155 consecutive patients <21 years old with sufficient data for 4Ts scoring. The 4Ts scoring system is a validated pretest tool in adults that predicts the likelihood of HIT using clinical features. Hospital-wide exposure to unfractionated and low molecular weight heparin was determined by querying the hospital pharmacy database. RESULTS: The majority of patients with suspected HIT (61.2%) were on surgical services. Prediction of HIT risk using initial 4Ts scoring found 3 (2%) had high risk 4Ts scores, 114 (73%) had intermediate risk 4Ts scores, and the remaining 38 (25%) had low risk 4Ts scores. HIT was confirmed in 0/38 patients with low risk 4Ts scores, 2/114 patients with intermediate-risk 4Ts scores, and all 3 patients with high-risk 4Ts scores presented with HIT with thrombosis. Of 12 positive HIT screening tests, results were falsely positive in 66.6% of patients with intermediate risk 4Ts scores and 100% of patients with low risk 4Ts scores. The prevalence of HIT was 0.058% and HIT with thrombosis was 0.046% in pediatric patients on unfractionated heparin. CONCLUSIONS: The prevalence of HIT appears significantly lower in pediatric patients compared with adults. Application of the 4Ts system as a pretest tool may reduce laboratory evaluation for HIT in heparin-exposed children with low risk 4Ts scores, decreasing unnecessary further testing, intervention, and cost.

Thiamine-responsive megaloblastic anemia: identification of novel compound heterozygotes and mutation update.

OBJECTIVE: To determine causative mutations and clinical status of 7 previously unreported kindreds with TRMA syndrome, (thiamine-responsive megaloblastic anemia, online Mendelian inheritance in man, no. 249270), a recessive disorder of thiamine transporter Slc19A2. STUDY DESIGN: Genomic DNA was purified from blood, and SLC19A2 mutations were characterized by sequencing polymerase chain reaction-amplified coding regions and intron-exon boundaries of all probands. Compound heterozygotes were further analyzed by sequencing parents, or cloning patient genomic DNA, to ascertain that mutations were in trans. RESULTS: We detected 9 novel SLC19A2 mutations. Of these, 5 were missense, 3 were nonsense, and 1 was insertion. Five patients from 4 kindreds were compound heterozygotes, a finding not reported previously for this disorder, which has mostly been found in consanguineous kindreds. CONCLUSION: SLC19A2 mutation sites in TRMA are heterogeneous; with no regional "hot spots." TRMA can be caused by heterozygous compound mutations; in these cases, the disorder is found in outbred populations. To the extent that heterozygous patients were ascertained at older ages, a plausible explanation is that if one or more allele(s) is not null, partial function might be preserved. Phenotypic variability may lead to underdiagnosis or diagnostic delay, as the average time between the onset of symptoms and diagnosis was 8 years in this cohort.

Validity, reliability, and responsiveness of a new measure of health-related quality of life in children with immune thrombocytopenic purpura: the Kids' ITP Tools.

OBJECTIVE: To refine the disease-specific health-related quality of life measure in immune (idiopathic) thrombocytopenic purpura (ITP) and to determine its validity, reliability, and responsiveness to change. STUDY DESIGN: The initial phase involved cognitive debriefing of 12 families, on the basis of which the measure was modified and then named Kids' ITP Tools (KIT). The measure was administered on 2 occasions with the Pediatric Quality of Life Inventory (PedsQL) to 41 patients with acute ITP and 49 patients with chronic ITP, 2 to 18 years old, and their parents (proxy-respondents) at 6 North American centers. RESULTS: Patients with acute ITP had lower scores when compared with patients with chronic ITP (child 64 versus 76, proxy 69 versus 77). The KIT moderately correlated with the PedsQL. Child versus proxy KIT scores showed moderate correlation, and the KIT was superior to the PedsQL. Test-retest reliability was substantial in the child report, but only moderate for the proxy report, similar to the PedsQL. The KIT showed a mean score change of 13 in the child and 15 in the proxy, which was greater than the PedsQL child's change of 7 and proxy change of 5. CONCLUSION: The KIT is valid, with good distinction between acute and chronic ITP and a moderate correlation with the PedsQL. The KIT demonstrated reliability comparable with that of the PedsQL, yet it was more responsive to change. Therefore the KIT can be used as an outcome measure in future clinical trials of childhood ITP.

Clinical effects and safety of rituximab for treatment of refractory pediatric autoimmune diseases.

OBJECTIVE: To evaluate the safety, tolerability, and clinical effects of rituximab, an anti-CD20 monoclonal antibody, in the treatment of severe pediatric autoimmune diseases. STUDY DESIGN: We reviewed the records of 10 patients treated with rituximab for severe, refractory autoimmune diseases at a single tertiary care children's hospital. Adverse events as well as treatment effects were recorded. RESULTS: All patients received 4 weekly doses of rituximab at 375 mg/m2 per dose. One patient died as the result of complications of her underlying systemic lupus erythematosus 7 weeks after rituximab therapy. Three patients had serious infections, all of which resolved with standard therapy. Rituximab led to transient or sustained improvement in clinical and laboratory parameters in nine subjects. At a median follow-up of 9 months, the median prednisone dose was reduced in the responders by 0.75 mg/kg per day (mean decrease of 63%), and four patients were able to discontinue corticosteroids entirely. With longer follow-up (median, 22 months), we found that 5 of 9 patients remained clinically stable after rituximab therapy, whereas 4 patients had recurrent or new features of their underlying autoimmune disorders requiring additional corticosteroids or other immunosuppressive medications. CONCLUSIONS: Rituximab had an acceptable toxicity profile in this group of patients with severe, refractory autoimmune diseases, although there were three serious infections and one patient death. Rituximab appears to be beneficial for patients with refractory autoimmune diseases and may reduce corticosteroid exposure. Although rituximab therapy provided a durable clinical benefit for some patients in this population, other patients had reemergence of their underlying autoimmune disease.

Hemoglobin Jamaica plain--a sickling hemoglobin with reduced oxygen affinity.

A baby girl presented with symptomatic sickle cell disease exacerbated by mild hypoxemia, despite a newborn-screening diagnosis of sickle cell trait. DNA sequencing of the beta globin gene revealed that her maternal beta globin allele was normal. Her paternal allele had not only the expected sickle-trait mutation, betaGlu6Val, but also a second, charge-neutral mutation, betaLeu68Phe. Analysis of the patient's hemoglobin revealed that the double-mutant protein, which we called "hemoglobin Jamaica Plain," had severely reduced oxygen affinity. Structural modeling suggested destabilization of the oxy conformation as a molecular mechanism for sickling in a heterozygote at an ambient partial pressure of oxygen.