The neural cell adhesion molecule (NCAM) present in the cerebrospinal fluid of multiple sclerosis patients is unsialylated.

The neural cell adhesion molecule (NCAM) is a glycoprotein localised in the plasma membrane of neural and glial cells, which plays a role in myelination and remyelination. It increases in the cerebrospinal fluid (CSF) of acute multiple sclerosis (MS) patients treated with corticosteroids who are improving after an attack, but it has not been shown if it appears in its sialylated (PSA) or unsialylated form. We studied the NCAM and the PSA-NCAM in serum and CSF samples of 16 acute and non-acute MS patients and in the sera of 10 non-neurological controls. The NCAM and the PSA-NCAM were dosed by two different ELISA previously set-up. The NCAM in the serum and in the CSF of the control group presented mean levels similar to those shown in previous papers: 1620 +/- 216 and 970 +/- 210 ng/ml. In the MS patient group the means were 1700 +/- 546 in the sera and 926 +/- 285 in the CSFs. All the sera were PSA-NCAM-positive: the mean PSA-NCAM concentration in the control group was 3150 +/- 950 ng/ml, while in the MS patient group it was 3570 +/- 905 ng/ml. The correlation between serum levels of NCAM and PSA-NCAM was highly significant (p < 0.001). Student's "t" test did not show any significant difference between serum levels of the two groups, both for the NCAM and for the PSA-NCAM. CSF samples did not show any positive results for the PSA-NCAM, in either controls or in MS patients. These results demonstrate that the high levels of NCAM we previously found in the CSF of improving MS patients treated with steroids did not contain a quota of PSA-NCAM, but only the unsialylated soluble form of the molecule.