In vivo and in vitro studies of fetal hemoglobin induction by hydroxyurea in beta-thalassemia/hemoglobin E patients.
OBJECTIVE
Some, but not all, beta-thalassemia/hemoglobin E (beta-thal/HbE) patients respond to hydroxyurea treatment. It would be helpful if patient responses to hydroxyurea could be screened in vitro to identify responders and nonresponders before beginning in vivo treatment.


METHODS
Thirteen beta-Thal/HbE patients were treated with hydroxyurea orally for 2 years at a starting dose of 5 mg/kg/day for 5 days/week with escalation to a maximum of 10 mg/kg/day. For comparison, erythroid cells obtained from peripheral blood of the same patients 1 year after they had stopped hydroxyurea treatment were treated with hydroxyurea in vitro. The gamma-globin mRNA was measured by real-time reverse-transcription polymerase chain reaction, fetal hemoglobin (HbF) by high-performance liquid chromatography, (G)gamma- and (A)gamma-globin chains by Triton X-100 acid urea polyacrylamide gel electrophoresis.


RESULTS
Treatment of cells in primary culture with 30 microM hydroxyurea for 96 hours significantly increased the fractional HbF content in beta-Thal/HbE patients. The (G)gamma:(A)gamma-globin mRNA was induced 0.30- to 8-fold in vitro and 0.30- to 6-fold in vivo (r(2) = 0.51, p = 0.16 by paired t-test); the fractional HbF content was induced 0.50- to 19-fold in vitro and 0.30- to 12-fold in vivo (r(2) = 0.61, p = 0.20) and the (G)gamma:(A)gamma-globin chain ratio was increased 0.80- to 1.40-fold in vitro and 1- to 1.20-fold in vivo (r(2) = 0.62, p = 0.13).


CONCLUSIONS
The correlation of in vivo and in vitro results of HbF synthesis and globin mRNA suggest that in vitro testing may predict the in vivo response.
Watanapokasin
Yuwadee
Y
Department of Biochemistry, Faculty of Medicine, Srinakharinwirot University, Bangkok, Thailand. ywwatana@yahoo.com
Chuncharunee
Suporn
S
Sanmund
Duangmanee
D
Kongnium
Wantana
W
Winichagoon
Pranee
P
Rodgers
Griffin P
GP
Fucharoen
Suthat
S
D000328:Adult; D002478:Cells, Cultured; D016903:Drug Monitoring / Q000379:methods*; D041905:Erythroid Cells / Q000187:drug effects; D005260:Female; D005319:Fetal Hemoglobin / Q000032:analysis / Q000235:genetics*; D005786:Gene Expression Regulation / Q000187:drug effects; D006446:Hemoglobin E; D006456:Hemoglobinuria / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy; D006801:Humans; D006918:Hydroxyurea / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D017086:beta-Thalassemia / Q000097:blood / Q000175:diagnosis* / Q000188:drug therapy*
D006446:Hemoglobin E; D005319:Fetal Hemoglobin; D006918:Hydroxyurea