The fine specificity of human T cell lines towards myelin basic protein peptides in southern Italian multiple sclerosis patients.

We studied the relationship between the HLA specificities associated with multiple sclerosis (MS) susceptibility in southern Italy and the reactivity of the human myelin basic protein (hMBP) immunogenic peptides 84-98 and 143-168, using short-term T-cell lines established from 9 MS patients and from 8 healthy individuals. In our population, DR15 was significantly associated with MS (34.9% in MS versus 13.7% in healthy controls, P < 0.05). This result is in agreement with the association found in northern Europe, but not with data obtained in a population from the island of Sardinia (Italy). In MS patients the frequency of reactive T-cell lines (TCL), tested for fine specificity against the immunodominant hMBP peptides 84-98 and 143-168, was increased for the hMBP 143-168 peptide (P < 0.05) but not for the 84-98 peptide. Although this reactivity was higher in DR15+ MS patients than in DR 15- MS patients, it seemed not to be associated with DR15 specificity in the MS population. Furthermore, there were no significant differences in frequency of reactive TCL to hMBP peptide 84-98 in DR15-positive or DR15-negative MS patients. Consequently, it appears that peptide 84-98, considered as a relevant autoantigen, is not implicated in the pathogenesis of MS in our population from southern Italy.