Acute lymphocytic leukemia incidence

Thiopurine methyltransferase methylates 6-mercaptopurine, a commonly used treatment for childhood acute lymphocytic leukemia, reducing its conversion to the active form of the drug. Approximately 10% of patients have intermediate enzyme activity, and 0.3% are deficient for TPMT activity. Intermediate activity patients have a greater incidence of thiopurine toxicity, whereas TPMT-deficient patients have severe or fatal hematological toxicity from 6-mercaptopurine therapy. In one study, patients deficient for TPMT tolerated only 7% of a 2.5-yr mercaptopurine treatment regimen. Patients with intermediate TPMT activity tolerated 65% of total weeks of therapy and patients with normal TPMT activity tolerated 84% of total weeks of therapy (3). 

The incidence of nonallergic ampicillin eruptions is 40 to 100% in patients with concomitant Epstein-Barr virus (mononucleosis), cytomegalovirus, acute lymphocytic leukemia, lymphoma, or reticulosarcoma. Nonallergic penicillin-associated rashes are characteristically morbilliform (symmetrical, erythematous, confluent, maculopapular) eruptions on the extremities. The onset of typical nonallergic eruptions is more than 72 hours after (3-lactam exposure. The mechanism for the nonurticarial ampicillin rash is not known and is not related to IgE or type I hypersensitivity. Penicillin skin tests are not useful in the evaluation of nonurticarial ampicillin rashes. Patients with a history of nonurticarial ampicillin rashes may receive other (3-lactam antibiotics without greater risk of subsequent serious allergic reactions. 

L-Aspar inase L-asparaginase is an enzyme used to treat acute lymphocytic leukemia (ALL) and is associated with a high frequency of hypersensitivity responses. Route of administration plays a significant role in the incidence of hypersensitivity as IV administration causes a significant number of hypersensitive responses (6-43%) whereas IM or subcutaneous routes cause far lower incidences (6—14%). Because of the high incidence of hypersensitivity it is prudent to test a patient for hypersensitivity before the first dose or any dose that an interval of one week or more has elapsed between doses. The actual mechanism responsible for the immediate hypersensitivity response remains unclear. Studies have shown that a pegylated form of L-asparaginase is tolerated by many who have... 

---