Spinal-fluid procoagulant activity: a sensitive indicator of central-nervous-system damage.

Testing the procoagulant activity (P.C.A.) of cerebrospinal fluid (C.S.F.) by measuring its effect on plasma-recalcification time is a useful indicator of central-nervous-system damage. C.S.F. from 22 normal children and adolescents aged 6 months to 17 years had a mean +/- S.D. P.C.A. of 14 +/- 6%. P.C.A. in 13 children with C.N.S. infection was significantly increased to 59 +/- 13%. In 8/13 of these children activity remained high (42 +/- 11%) after therapy. In patients with acute lymphatic leukemia (A.L.L.) 12 aged greater than 2 1/2 years and diagnosis had a normal activity (17 +/- 8%) and 4 patients aged less than 2 1/2 years at diagnosis had an activity of 21 +/- 8%; during C.N.S. prophylaxis with intrathecal methotrexate and/or cranial irradiation, mean activity in these 16 patients rose significantly to 41 +/- 11%. More than 2 years after treatment P.C.A. decreased towards normal in the older children but remained high in the younger group. 5 children with neurological sequelae (including 3 with A.L.L. and the post-irradiation syndrome) had the highest activities. Ether extraction showed that the active material had lipid properties. P.C.A. did not correlate with protein, lactic dehydrogenase, or cell count in C.S.F.