Sebastian syndrome with abnormal platelet response to ristocetin.

BACKGROUND: Sebastian syndrome is characterized by enlarged platelets and Döhle-like body leukocyte inclusions. This syndrome is an MYH-9-related disease, a group that also includes May-Hegglin anomaly and Fechtner syndrome. The differential diagnosis of the MYH-9 diseases requires ultrastructural studies. Certain in vitro aggregation responses may be abnormal in these conditions. OBSERVATIONS: A 6-month-old boy presented with macrothrombocytopenia but no overt bleeding tendency. Giant platelets and Döhle-like body leukocyte inclusions were present in blood smears from both the patient and his mother. Electron microscopy confirmed ultrastructural features consistent with Sebastian syndrome. Platelet aggregation studies were normal except for an impaired response to the agonist ristocetin. CONCLUSIONS: In this patient peripheral blood analyses and platelet aggregation studies revealed disease features shared with the Bernard-Soulier syndrome, but this syndrome was excluded by cellsurface glycoprotein analysis.

Unrelated cord blood transplantation in children with sickle cell disease: review of four-center experience.

UCBT was performed in seven children with SCD and stroke (HLA match 4/6 n=5; 5/6 n=2). Four received myeloablative regimens (BU, CY, ATG plus FLU in one patient). One had primary graft failure, three had sustained engraftment, two with grade III-IV GVHD (one died, one developed chronic GVHD), one with stable mixed chimerism. Three patients treated with reduced-intensity regimens (FLU, BU or CY, ATG, TLI) failed to engraft; one engrafted after second UCBT (HU, TT, RXA, ALZ, TBI). Four patients (57%) developed viral infections. Engraftment, GVHD, and infection remain challenges.

Measurement of cerebrovascular flow reserve in pediatric patients with sickle cell disease.

PURPOSE: To report a method for determining absolute percentage change in cerebral blood flow (measurement of cerebrovascular reserve) before and after acetylazolamide (Diamox) administration in children with sickle cell anemia. MATERIALS AND METHODS: Thirty-six symptomatic sickle cell disease patients (48 studies) were evaluated. After the injection of either Tc-99m bicisate ethyl cysteinate dimer (ECD) or hexamethyl propylene amine oxime (HMPAO), both whole body scans (with geometric mean correction) and single photon emission computed tomography (CT) were performed pre- and post-Diamox administration with calculation of percentage brain uptake on the whole body images for both examinations and determination of cerebrovascular reserve (percentage change in brain uptake post-Diamox). Evaluation for regional cerebral perfusion change was also performed. RESULTS: The cerebrovascular reserve measurement was 17.6% +/- 43.5% (mean +/- 1 SD). Thirty-three of 48 studies (69%) showed an abnormal cerebrovascular reserve, while only 6 of 48 studies (12.5%) showed Diamox-induced regional perfusion changes in the brain. No statistically significant relationship was found between the occurrence of a regional perfusion abnormality versus loss of cerebrovascular reserve (P = 0.75, Fisher exact test), suggesting that these are independent variables. The cerebrovascular reserve was reproducible, with an average standard deviation of +/-0.54%. CONCLUSION: A new, simple method for calculation of cerebrovascular reserve is presented; this method is reproducible and appears to be an independent variable in the evaluation of cerebrovascular status in sickle cell anemia patients. It should allow further characterization of this complex patient population, and possibly assist in detection of patients at risk for developing "silent" or overt stroke.