Cerebrospinal fluid lactic dehydrogenase activity in children with acute lymphoblastic leukemia treated for cranial prophylaxis.

Total lactic dehydrogenase (TLDH) activity in cerebrospinal fluid (CSF) has been prospectively studied in order to determine whether it could be a biochemical marker for brain damage due to cranial prophylaxis in children with acute lymphoblastic leukemia (ALL). TLDH activity has been measured in 15 patients before prophylaxis, in 15 patients after the prophylaxis which consisted of cranial radiotherapy (2400 rads) and intrathecal methotrexate (0.5 mg/kg-dose, 5 doses), in 8 patients after radiotherapy alone (2400 rads) and in 9 patients after intrathecal methotrexate (0.5 mg/kg-dose, 5 doses) alone. TLDH activity in CSF of combined prophylaxis group has been found to be higher than the ones before study (p less than 0.05). There were insignificant elevations of TLDH activity in the other two groups (p greater than 0.05; p greater than 0.05). This result indicated combined cranial prophylaxis seemed to be more toxic than the other prophylaxis regimens when they were used alone.