Expression of Glutathione-S-Transferase MU 1 (GSTM1) and Glutathione-S-Transferase Theta 1 (GSTT1) in Patients with Aplastic Anemia and Myelodysplastic Syndromes

Aplastic Anemia is a disorder of the hematopoietic bone marrow stem cells that is frequently associated with drug or chemical exposures. Reduced ability to detoxify drugs or chemicals may result in an increased risk of disease. Glutathione S-transferases are Phase II enzymes, which help detoxify xenobiotics. Many patients who have developed aplastic anemia and myelodysplastic syndrome have the null genotype for GSTMI and/or GSTTI. For patients with GSTMI and GSTTI positive genotypes, non-expression of these enzymes may cause an increased risk in developing aplastic anemia or myelodysplastic syndrome. To test whether genotype positive patients have GSTMI or GSTTI null phenotypes, reverse transcription polymerase chain reactions were performed on patients with aplastic anemia or myelodysplastic syndrome that were genotypically positive for GSTMI and/or GSTTI. In GSTMI genotype positive patients, 11.1% showed no detectable gene expression. In 38 patients, genotype GSTTI positive, 15.g% showed no detectable gene expression. In 15 patients whose genotype was GSTMI positive and GSTTI positive, 6.7% had no detectable gene expression for either GSTMI and GSTTI, 13.3% had no gene expression for GSTTI and 0.0% had no gene expression for GSTMI (20.0% without expression total). Patients who develop aplastic anemia and myelodysplastic syndrome may have higher levels of non-expression of the Glutathione S-transferases and may be a factor in these diseases development.