Intrathecal IgM response in disseminated cerebrospinal metastasis from malignant melanoma.

Neurological complications are a major cause of morbidity and mortality in patients with disseminated malignant melanoma. We have studied and correlated clinical and cerebrospinal fluid (CSF) findings in 20 patients with central nervous system metastases from malignant melanoma including 8 patients with metastatic meningeal melanomatosis (MMM) and 12 patients with solid cerebral metastases (SCM). The putative CSF tumor markers, fibronectin and beta 2-microglobulin, were elevated significantly in MMM but not in SCM patients. A prominent increase in the IgM index, which reflects intrathecal B-cell stimulation, and a rise of IgG index, interleukin-6, and tumor necrosis factor-alpha in MMM patients provide preliminary evidence for a local intrathecal immune response triggered by melanoma cell invasion of the subarachnoid space.