Autoantibodies to tubulin are specifically associated with the young age onset of the nasopharyngeal carcinoma

By far the highest incidence of the Epstein-Barr virus (EBV)-associated nasopharyngeal carcinomas in young subjects was found in North Africa, a region of intermediate risk for adults. We used the immunofluorescence analysis and ELISA to characterize the presence of IgG autoantibodies to the cytoskeleton and nuclear proteins in sera of 82 Tunisian patients with primary nasopharyngeal carcinoma and those of 82 healthy subjects. To assess the specificity of the sera autoreactivity, inhibition tests were carried out using free autoantigens. Analysis of sera autoreactivity in patients with nasopharyngeal carcinoma and in control subjects showed that 23% of the patients had serum reactivity against more than 1 autoantigen tested compared to 1.2% in the control group (p = 10(-4)). The most frequent auto reactivity in patient's sera was found with tubulin and nuclear proteins (19.5% and 22% respectively vs. 6.1% and 1.2% in controls). The IgG auto reactivity inhibition studies indicate that all autoantigens, except native DNA, showed low values of IC(50) (concentration of antigen causing 50% inhibition of the antibody binding) reflecting the high affinity of these IgG autoantibodies. When patients and controls were stratified according to their age, IgG autoantibodies to tubulin were found specifically associated with the young age onset of the nasopharyngeal carcinoma (age under 25 years). IgG auto reactivity comparison before and after cancer therapy showed that only anti-tubulin reactivity was significantly affected by treatment. Our results demonstrate that the autoantibodies to the cytoskeleton and nuclear proteins are associated with the nasopharyngeal carcinoma in Tunisians. The anti-tubulin IgG autoantibodies may represent a serologic marker for the nasopharyngeal carcinoma in children and adolescents Tunisians.