DETECTION OF AUTOANTIBODIES TO THE PANCREATIC-ISLET HEAT-SHOCK PROTEIN-60 IN INSULIN-DEPENDENT DIABETES-MELLITUS

Autoantibodies against heat shock protein (hsp) 60 have been reported to be detected in sera of non-obese diabetic mice, in an experimental model of IDDM. However, there are only a few studies which have examin ed IDDM patients for antibodies against mammalian hsp60. We produced m urine hsp60 derived from pancreatic beta cells which has high homology to human hsp60 and examined antibodies against the hsp60 in IDDM pati ents using an enzyme-linked immunosorbent assay. We extended the analy sis to patients with other immune-mediated diseases and non-insulin-de pendent diabetes mellitus (NIDDM). Positive sera for hsp60 antibody we re more frequently detected in 13 out of 84 IDDM (15.5%) and 5 out of 25 rheumatoid arthritis patients (20%), when compared to healthy subje cts (1/85; 1.2%, P < 0.001 and P < 0.01, respectively). The levels of hsp60 antibodies of IDDM (0.218 +/- 0.227) and rheumatoid arthritis pa tients (0.259 +/- 0.191) were significantly higher than those of healt hy subjects (0.076 +/- 0.131, P < 0.001, P < 0.01, respectively). Pati ents with slowly progressive IDDM (n = 26), autoimmune thyroid disease (n = 42), or NIDDM (n = 40) had levels of hsp60 antibodies similar to those in healthy subjects. We found no relationship between the level s of hsp60 antibodies and islet cell antibodies (ICA) or antibodies to glutamic acid decarboxylase (GAD65) in IDDM patients. In conclusion, hsp60 antibodies were detected in Japanese IDDM as well as in rheumato id arthritis patients. Although the positivity was low, the detection of hsp60 antibodies may be helpful for diagnosis of IDDM especially in GAD65 Ab- or ICA-negative Japanese patients. (C) 1996 Academic Press Limited