Comparison of the response to phytohemagglutinin, of peripheral blood mononuclear cells and cerebrospinal fluid lymphocytes in multiple sclerosis and other neurological diseases. Determination of the frequency of the precursor cells by a limiting dilution analysis.

Proliferative response to phytohemagglutinin (PHA) of cerebrospinal fluid lymphocytes (CSF-L) and peripheral blood mononuclear cells (PMBC) from patients with multiple sclerosis (MS) and other neurological diseases (OND) was tested using either bulk culture conditions or limiting dilution techniques in the presence of additional exogenous IL2. CSF-L response to PHA was found significantly lower than that of PBMC in both MS and OND patients. There was no significant difference in the response of CSF-L between the two groups. The limiting dilution analysis of the frequency of the precursors of PHA-responsive cells showed a strikingly decreased frequency of these precursors among CSF-L.