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Fetal hemoglobin, sickling, and sickle cell disease
1Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland.
Advances in Pediatrics
|January 1, 1990
Summary
Increased fetal hemoglobin (Hb F) in sickle cell disease (SCD) patients may offer clinical benefits. Research explores Hb F induction therapies like hydroxyurea, but their precise mechanisms and efficacy require further investigation.
Area of Science:
- Hematology
- Genetics
- Pharmacology
Background:
- Sickle cell disease (SCD) is characterized by abnormal hemoglobin S (Hb S).
- Fetal hemoglobin (Hb F) can inhibit Hb S polymerization, suggesting therapeutic potential.
- Red blood cells (RBCs) in SCD patients exhibit heterogeneity in Hb F content and MCHC.
Purpose of the Study:
- To evaluate the role of increased fetal hemoglobin (Hb F) in sickle cell disease (SCD) treatment.
- To explore the mechanisms and clinical efficacy of Hb F-inducing agents.
Main Methods:
- Review of studies on hemoglobin switching in animal models and cell cultures.
- Analysis of clinical trials involving 5-azacytidine and hydroxyurea for Hb F induction in SCD patients.
- Investigation into the properties of RBCs from treated patients.
Main Results:
- 5-azacytidine successfully induced Hb F synthesis in SCD patients, though the underlying theory was flawed.
- Hydroxyurea treatment leads to significant increases in Hb F synthesis and apparent clinical benefit.
- The precise contribution of increased F cells and Hb F to observed clinical benefits remains unclear, with potential placebo effects considered.
Conclusions:
- Increased Hb F levels show promise for treating sickle cell disease variants.
- Further controlled trials and mechanistic studies are needed to fully understand hydroxyurea's effects and confirm clinical benefits.
- Current understanding of SCD biology and treatment is incomplete, necessitating continued research.