Beta 2-microglobulin, lysozyme and lactoferrin in cerebrospinal fluid in patients with lymphoma or leukaemia: relationship to CNS involvement and the effect of prophylactic intrathecal treatment with methotrexate.

Central nervous system (CNS) involvement in patients with leukaemia or lymphoma presents a diagnostic problem. This study was conducted to test whether combined measurements of various cellular markers such as beta 2-microglobulin (beta 2m), lactoferrin (LF) and lysozyme (LYS) in the cerebrospinal fluid (CSF) might aid in the diagnosis of CNS involvement in such patients. Forty-two patients were studied. Sixteen were considered to have CNS involvement and 26 showed no signs of such involvement. In the group with symptoms or signs of CNS involvement, nine patients out of 12 had increased total protein in CSF, 14 of 14 increased beta 2m, 14 of 16 increased LYS and five of 15 increased LF. In patients without CNS involvement total protein was increased in four of 25, beta 2m in three of 21, LYS in four of 28 and LF in one of 28 patients. The differences were statistically significant (P less than 0.01, P less than 0.001, P less than 0.001 and P less than 0.05, respectively). Prophylactic intrathecal methotrexate treatment in patients with acute lymphoblastic leukaemia caused an increase in the CSF of beta 2m, LYS and LF but not of total protein, which may reflect a drug-induced inflammatory reaction in the CNS. We conclude that combined measurements of the three cell markers add to our understanding of the cellular reaction to malignant cells in the CNS in leukaemia and lymphoma and may be valuable supplements in the diagnosis of this CNS involvement.