Combined measurement of diabetes mellitus immunological markers: an assessment of its benefits in adult-onset patients.
The convenience of combining the measurement of antibodies to glutamic acid decarboxylase (GADA), protein tyrosine phosphatase (IA-2A), and autoantibodies to insulin (IAA) in diabetic patients was assessed. We analysed 71 type 1 and 115 adult-onset diabetic patients. The latter were grouped into three categories according to the time of evolution to insulin dependence. The main findings were as follows: (i) in type 1 diabetes, the combined analysis of GADA and IA-2A showed a sensitivity of 87.4% and was not appreciably improved by adding IAA; (ii) out of 31 adults who required insulin immediately or within the first two years of diagnosis, 41.9, 29.0, and 6.5% were positive for at least one, two or all three, and all three markers, respectively; GADA was the most prevalent (35.5%) and IA-2A the least represented (16.1%); (iii) 34 adult patients with slow evolution to insulin dependence showed a completely different profile: 5.9% were GADA positive and 23.5% were IAA positive and no double or triple positivity was observed as all patients were IA-2A negative; and (iv) 50 type 2 patients who had not required insulin treatment showed a low incidence of GADA (4%) as the only marker present. We conclude that a combined double-antigen test for GADA and IA-2A is a useful strategy for prospective screening of type 1 diabetes. However, in adults, the profile of individual markers discloses the course to insulin dependence. Therefore, it seems advisable to measure the markers separately, to allow a better classification of these patients, and help define their treatment.
Valdez
S N
SN
Chair of Immunology, School of Pharmacy and Biochemistry, University of Buenos Aires, Argentina.
Sica
M P
MP
Labovsky
V
V
Iacono
R F
RF
Cardoso
A L
AL
Krochik
A G
AG
Mazza
C S
CS
Ermácora
M R
MR
Cédola
N
N
Poskus
E
E
D000293:Adolescent; D000328:Adult; D001118:Argentina; D001323:Autoantibodies / Q000097:blood*; D015415:Biomarkers; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000145:classification / Q000276:immunology; D003924:Diabetes Mellitus, Type 2 / Q000145:classification / Q000276:immunology*; D005260:Female; D005968:Glutamate Decarboxylase / Q000276:immunology*; D006801:Humans; D007328:Insulin / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases / Q000276:immunology*; D011869:Radioligand Assay
D001323:Autoantibodies; D015415:Biomarkers; D007328:Insulin; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases; D005968:Glutamate Decarboxylase