Immunotherapy is a milestone in the treatment of poor-prognosis pediatric acute lymphoblastic leukemia (ALL) and is expected to improve treatment outcomes and reduce doses of conventional chemotherapy without compromising the effectiveness of the therapy. However, both chemotherapy and immunotherapy cause side effects, including neurological ones.
Phase of Treatment | Drugs | Toxicity-Related Gene | Mechanism of Neurotoxicity | Neurotoxicity | References | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Induction | Vincristine | ABCC11 | 1 | , | ABCC2 | 2 | , | ABCC4 | 3 | , | ABCC5 | 4 | , | ABCB1 | 5 | , | ABCC10 | 6 | , | CEP72 | 7 | , | SLC5A7 | 8 | , | TUBB1 | 9 | , | TUBB2A | 10 | , | TUBB2B | 11 | , | TUBB3 | 12 | , | TUBB4A | 13 | , | MAP4 | 14 | , | CYP3A4 | 15 | , | CYP2C8 | 16 | , | CYP3A5 | 17 | , | CEP72 | 18 | Interferes with the assembly of microtubule structures leading to cell apoptosis. It affects the peripheral nerves but can also contribute to dysfunction of the cranial nerves and autonomic nervous system. | Peripheral neuropathy, sensory neuropathy: symmetry sensory/tactile impairment, numbness, and tingling in the hands and feet, paresthesia, decreased balance, tendon weakening, visual and hearing problems. | [8,9] | [6][7] | ||||||||||||||||||
L-asparaginase | ZBTB1 | 19 | , | GRIA1 | 20 | , | HLA-DRB1 | 21 | L-asparaginase produces three neurotoxic agents: ammonia, L-aspartic acid, and glutamic acid. These two amino acids can induce cell death in CNS neurons by excessive stimulation through NMDA (N-methyl-D-aspartate) receptor, leading to a major intracellular calcium influx and apoptosis. | Myelosuppression, encephalopathy, hepatic toxicity. | [10, | [ | 11, | 8 | 12] | ][9][10] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Consolidation | Methotrexate (intravenous infusion and intrathecally) | DHFR19bp | 22 | , | MTHFR 677C > T | 23 | , | MTHFR 677TT | 24 | , | SLC19A1 | 25 | , | TYMS | 26 | , | ADORA2A | 27 | Methotrexate is an antimetabolite that inhibits Dihydrofolate Reductase and thus tetrahydrofolate formation. This affects the synthesis of macromolecules such as myelin, and reversible leukoencephalopathy has been suggested to be secondary to impaired myelin turnover. Dihydrofolate Reductase inhibition leads to lack of folate and cobalamin, and increase in homocysteine, which is toxic to vascular endothelium may cause seizures and vascular disease. Dihydrofolate Reductase inhibition results in decreased levels of S-adenosylmethionine, which in turn plays a role in maintaining the myelin sheath, and this deficiency may lead to demyelination after intrathecal methotrexate administration. |
Transverse myelopathy-symptoms include back pain with subsequent weakness, sensory loss and bladder or bowel incontinence, blurred vision, aphasia, anarthria, seizures, aphasia, mental status disorder, stroke-like episodes, delirium, leukoencephalopathy septic meningitis characterized by headache, neck stiffness, nausea, vomiting and potential fever and encephalopathy. | [13,14,15] | [11][12][13] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
Cytarabine | DCK | 28 | , | NT5C2 | 29 | , | CDA | 30 | , | RRM1 | 31 | , | GIT1 | 32 | , | NT5C 3 | 33 | , | ENT1 | 34 | , | SCL29A1 | 25 | Cytarabine exhibits preferential toxicity for CNS | 35 | progenitor cells and oligodendrocytes, compromises cell division in vitro, and causes cell death and reduced cell division in vivo. | Myelosuppression, neurotoxicity. | [16,17,18,19] | [14][15][16][17] | |||||||||||||||||||||||||||||||||||||||||||||||
Maintenance | Methotrexate (orally) | Genes have been described above. | Mechanism has been described above. | Seizures, aphasia, mental status disorder, stroke-like episodes, delirium, leukoencephalopathy, cognitive dysfunction, personality changes. | [13,14,15,20] | [11][12][13][18] |