[Diagnostic value of protein tyrosine phosphatase-2beta antibody (IA-2betaA) in type 1 diabetes].

Objective: To explore the prevalence and clinical features of protein tyrosine phosphatase-2beta antibody (IA-2betaA) in type 1 diabetes (T1DM).

Methods: Four hundred and one T1DM patients and 200 healthy controls were screened for glutamic acid carboxylase antibody (GADA), islet cell antigen-2 (IA-2A), IA-2betaA by radioligand assay. The clinical features of the patients positive in different antibodies were analyzed.

Results: Thirty-five of the 401 T1DM patients were positive in IA-2betaA with a positivity rate of 8.7%, significantly higher than that of the normal controls (1.0%, 2/100, P < 0.05). Out of the 35 cases with IA-2betaA positivity, 16 (45.7%) were positive in IA-2A. Among the 401 T1DM patients, IA-2betaA titer was not correlated with IA-2A titer (r = 0.021, P = 0.780). The IA-2betaA positive rate of the age group of 0-9 years was 62.8%, significantly higher than that of the age group > 10 years (19.7%, chi2 = 31.41, P < 0.001); and the IA-2A positive rate of the age group of 0-9 years was 20.0%, significantly higher than that of the age group > 10 years (7.6%, chi2 = 6.11, P < 0.05). GADA was not significantly correlated with age. The age and onset age of the patients positive only in IA-2betaA were 35.5 and 34.0 years respectively, both significantly higher than those of the patients positive only in IA-2A (24.2 and 21.6 years respectively, both P < 0.05).

Conclusion: Higher in child-onset T1DM, the prevalence of IA-2betaA positivity decreases with age. IA-2betaA is a practical parameter for identifying autoimmune diabetes.