Anti-tubulin antibodies in recent onset type 1 (insulin-dependent) diabetes mellitus: comparison with islet cell antibodies.

Antibodies to tubulin, the fundamental protein of microtubules, were studied by radioimmunoassay in patients with Type 1 (insulin-dependent) diabetes of varying duration and in healthy control subjects. Elevated levels of anti-tubulin antibodies were found in 46% of 28 patients with Type 1 diabetes of recent onset (less than or equal to 6 months) and in only 6.2% of 64 patients with long-standing Type 1 diabetes (duration 6-43 years). None of 34 DR3-positive normal subjects and none of 20 Type 2 (non-insulin-dependent) diabetic patients were positive for anti-tubulin antibodies. Anti-tubulin antibody levels were elevated in two out of 26 first-degree relatives of Type 1 diabetic patients. The specificity of the detection of anti-tubulin antibodies was demonstrated by dilution of the sera, competitive binding experiments between labelled and unlabelled tubulin, immunoblotting. Antibodies to tubulin were elevated in 60% of patients with islet cell surface antibodies and there was a significant association between anti-tubulin antibodies and islet-cell surface antibodies. These antibodies, however, recognize different specificities, since adsorption of islet cell surface antibody by rat islets did not alter the anti-tubulin antibody activity. Elevated anti-actin antibody responses were found in two out of 17 and one out of 26 patients with recent onset and long-standing Type 1 diabetes, respectively. In conclusion, anti-tubulin antibodies are detected in a high proportion of patients with diabetes of recent onset, are associated with islet cell surface antibodies and like islet cell surface antibodies decrease or disappear during the course of the disease.(ABSTRACT TRUNCATED AT 250 WORDS)