Passive Smoking and Thiopurine Methyl Transferase Genotyping in 6-mercaptopurine-induced Myelosuppression in Egyptian Children with Acute Lymphoblastic Leukemia

6-mercaptopurine (6-MP) is a crucial component drug used to treat childhood acute lymphoblastic leukemia (ALL) in the maintenance phase. Thiopurine S-methyltransferase (TPMT) is an enzyme that metabolizes thiopurine drugs like 6-MP. In patients taking thiopurine medications, lack of TPMT activity is linked to an increased risk of myelosuppression. Patients with TPMT polymorphisms are more likely to develop mercaptopurine-induced myelosuppression. The goal of this study was to see how passive smoking and TPMT genetic variations affected 6-MP-induced myelosuppression in Egyptian ALL children. This study included 100 children: 50 with acute lymphoblastic leukemia in the maintenance phase of treatment who had a history of passive smoking and 50 age-matched healthy controls. 6-MP was given to patients in the maintenance phase, and myelosuppression was monitored at the end of this phase by comparing WBC counts to those obtained at the start of treatment. After six months of 6-MP administration, there was no significant association between cotinine levels and WBC count (as evidence of myelosuppression), although there was a significant correlation between TPMT genotypes and WBC count, with 75% of hetero genotype patients suffering from severe declines in WBC count and 91% of wild genotype people undergoing mild to moderate decreases in WBC count