Autoimmune hemolytic anemia and idiopathic thrombocytopenic purpura in pediatric solid organ transplant recipients, report of five cases and review of the literature.

Cytopenias are common among pediatric SOT; however, autoimmune cytopenias are infrequently reported. We report five cases of autoimmune cytopenias in pediatric LT patients: two with isolated IgG-mediated AIHA, two with ITP, and one with Evans syndrome (ITP and AIHA). All patients were maintained on tacrolimus as immunosuppression. Viral illness commonly preceded the autoimmune cytopenias. All patients responded well to medical therapy (steroids, intravenous immunoglobulin, and rituximab) and lowering tacrolimus serum level. Prognosis appears to be worse when more than one cell line (e.g., Evans syndrome) is affected, and/or there is no preceding viral illness. A critical literature review of autoimmune cytopenias in children following SOT is conducted. Autoimmune cytopenias are a rarely reported complication of pediatric SOT, but clinicians taking care of pediatric transplant recipients need to be aware of this complication.

Recurrent intrahepatic pigmented stones after liver transplantation in a patient with hemoglobin SC disease: case report and review of the literature.

Patients with hemoglobinopathies may have hepatic involvement, which if severe, can lead to chronic liver disease and a need for liver transplant. Here, we present a case of a 16-yr-old female adolescent who presented to our center with hemoglobin SC disease, obstructive jaundice because of pigmented intrahepatic biliary stones, and progressive liver disease. She underwent a successful liver transplant but a few years later, she developed recurrent cholangitis and graft dysfunction because of recurrent intrahepatic biliary stones. Recurrent formation of intrahepatic stones after liver transplant is a rare and severe complication in patients with hemoglobinopathies. We recommend hypertransfusion therapy and surveillance imaging studies after liver transplant for early detection and prevention of this complication.

The successful treatment of severe aplastic anemia with autologous cord blood transplantation.

Cord blood transplantation has been used extensively in the allogeneic setting for acquired and genetic disorders of hematopoiesis. There is less experience in the utility of autologous cord blood transplantation, and there is great controversy about the role of autologous cord blood collection and storage. We report on the successful use of autologous cord blood transplantation for the treatment of severe aplastic anemia following fulminant hepatic failure and living related liver transplantation.

Alpha Thalassemia is associated with decreased risk of abnormal transcranial Doppler ultrasonography in children with sickle cell anemia.

PURPOSE: Cerebrovascular complications of sickle cell disease (SCD) are common, but the risk factors remain unclear. The multicenter Stroke Prevention Trial in Sickle Cell Anemia (STOP) provided an opportunity to examine alpha thalassemia-2 as a modifying risk factor, using abnormal transcranial Doppler ultrasonography (TCD) as a surrogate marker for cerebrovascular disease. The authors hypothesized that children with abnormal TCD are less likely to have alpha thalassemia-2, and an increased hemoglobin level accounts for this protective effect. METHODS: A retrospective study was conducted of children with SCD who had both alpha gene and TCD data from STOP: 128 with TCD of at least 200 cm/s (abnormal TCD) and 172 with TCD less than 170 cm/s (normal TCD). RESULTS: Alpha thalassemia-2 was more frequent in the normal TCD group compared with the abnormal TCD group. The odds ratio for normal TCD and alpha thalassemia-2 was 4.1. Adjusting for either hemoglobin level or red cell size (mean corpuscular volume) reduced the odds ratio only slightly. Age, normal TCD, and alpha thalassemia-2 had significant statistical interaction, so that alpha thalassemia-2 was not related to TCD for age 10 years or older. CONCLUSIONS: The frequency of alpha thalassemia-2 was significantly higher in children with normal TCD. Speculation on mechanisms of effect includes improved erythrocyte deformability, reduced red cell adhesion, and reduced nitric oxide scavenging in alpha thalassemia-2. The association of alpha thalassemia-2 and normal TCD adds to the evidence on the protective effects of alpha thalassemia-2 in SCD and highlights the contribution of epistatic factors.

Stroke risk in siblings with sickle cell anemia.

Cerebrovascular disease is a common cause of morbidity in sickle cell anemia (HbSS): approximately 10% of patients have a clinical stroke before 20 years of age, and another 22% have silent infarction on magnetic resonance imaging. The phenotypic variation among patients with HbSS suggests a role for modifier genes and/or environmental influences. To assess the familial component of clinical stroke in HbSS, we estimated the prevalence of clinical stroke among all patients and among HbSS sibling pairs at 9 pediatric centers. The sample included 3425 patients with sickle cell disease who were younger than 21 years, including 2353 patients with HbSS. The stroke prevalence was 4.9% for all genotypes; 7.1% for patients with HbSS; 1.1% for patients with HbSbeta(o) thalassemia; 0.6% for patients with Sbeta(+) thalassemia; and 0% for patients with HbSC. In 207 sibships, more than 1 child had HbSS. There were 42 sibships in which at least 1 sibling had a stroke, and in 10 of the 42, 2 siblings had a stroke. A permutation test indicated that the number of families in which 2 children had strokes was larger than the number expected if strokes were randomly distributed among children in sibships (P =.0012). There was no difference in stroke prevalence based on sex, nor was the mean age at stroke presentation significantly different between singletons and sibships with stroke. We conclude that there is a familial predisposition to stroke in HbSS. Attempts to identify genetic modifiers should be initiated with family-based studies.

Polycythemia secondary to multiloculated renal cyst in a child.

Polycythemia has been reported in association with a variety of pediatric renal neoplasms. The authors present the case of a 10-year-old boy with polycythemia and elevated erythropoietin that resolved after resection of a multiloculated renal cyst. This case also is unusual in the small size of the lesion, 0.5 cm in greatest dimension.