CNS tumours: oligoclonal immunoglobulin D in cerebrospinal fluid and serum.

Oligoclonal immunoglobulin D bands were detected by isoelectric focusing in 7 out of 25 unconcentrated cerebrospinal fluid (CSF) samples obtained from patients with tumours of the central nervous system (CNS). The tumours were confirmed by clinical and histological findings. Two patients with CNS malignancy had intrathecal synthesis of oligoclonal bands both IgD and IgG. Four patients with a variety of CNS tumours had a systemic IgD immune response but no oligoclonal IgG bands. One patient with the most malignant tumour histology had a systemic IgD response as well as local synthesis of IgG. The study reveals several new aspects regarding CNS tumours: they are immunologically active and are capable of invoking oligoclonal immunoglobulin production both within the CNS and systemically. Multiple immunoglobulin activation can be found in malignant CNS tumours, and systemic IgD production may occur independently from IgG synthesis and may represent an immune response to a neoantigen produced in the CNS compartment.