Characterization of S-glutathionyl hemoglobin in homozygous sickle cell disease.

S-glutathionyl hemoglobin is a proposed biomarker of oxidative stress but has not been measured in sickle cell disease patients. Unlike the S-glutathionyl adduct of normal adult hemoglobin, S-glutathionyl sickle hemoglobin (HbSSG) cannot be directly measured by capillary isoelectric focusing, because it coelutes with fetal hemoglobin (HbF). This suggests that HbF, measured in sickle cell patients with or without hydroxyurea therapy, might contain endogenous HbSSG. As S-glutathionyl hemoglobin can form during sample storage, HbSSG could falsely elevate HbF levels in stored samples. We measured HbSSG based on the quantitative difference in the heterogeneous HbF/HbSSG peak before and after hemolysates were treated with dithiothreitol. Paired t tests showed that dithiothreitol reduced HbF/HbSSG in blood from pediatric sickle cell patients (n=25, mean decrease+/-SD=1.0%+/-0.6, P<0.05) but not in normal infants (n=25). Higher HbF levels in hydroxyurea-treated patients (n=5) were not attributable to HbSSG. HbSSG increased significantly within 1 day in samples stored at -20 degrees C but was unchanged in samples stored 60 days at-70 degrees C. We conclude that blood from sickle cell patients contained up to 2.2% HbSSG, and that endogenous HbSSG is a minor interferent in the measurement of HbF in fresh blood but a major interferent in improperly stored samples.

Infant acute lymphoblastic leukemia: a 20-year children's hospital experience.

We reviewed our 20-year experience with infant acute lymphoblastic leukemia (ALL). Nine infants (4.2% of all ALL) were identified; all were < 6 months of age. White blood cell counts ranged from 42,000-1.6 million/microL, 6 of 8 had hepatosplenomegaly, and 6 of 9 (66.6%) had central nervous system disease. Of 7 with cytogenetic information, 6 (85.7%) had diploidy; the remaining child was 47, XY,+8,del(21)(q22). Four had the MLL-11q23 abnormality. All received chemotherapy. Four underwent stem cell transplantation. Survival was 67%, (15 months-21 years). Deaths occurred at 9 months, 15 months (graft vs. host), and 7 years (complications of small bowel transplantation). Only 1 undergoing stem cell transplantation died. There were no late recurrences or second malignancies. Despite extensive disease and age < 6 months at diagnosis (a poor prognostic feature), for ALL patients our 67% survival is at least as good as reported, although it is less favorable than childhood ALL.