Zinc transporter 8 autoantibodies in patients with type 1 diabetes from a multiethnic population and their first degree relatives.
OBJECTIVE
Zinc transporter 8 autoantibodies (ZnT8A) have been poorly studied in non-Caucasian individuals. We aimed to investigate the prevalence of ZnT8 autoantibodies in patients with T1D and their first degree relatives (FDR) from a multiethnic population, as well as its relation with the insulin (INS) or the protein tyrosine phosphatase non-receptor 22 (PTPN22) gene polymorphisms.


METHODS
ZnT8A were analyzed in sera from T1D patients (n = 72, mean age of 30.3 ± 11.4 years) of variable duration (15.7 ± 11.8 years) and their FDR (n = 78, mean age of 18.3 ± 9.1 years) by a triple mix Radioligand Binding Assay (RBA) for the ZnT8 autoantibody (ZnT8-RWQ) variants. SNP (single nucleotide polymorphism) for INS and PTPN22 were genotyped.


RESULTS
The prevalence of ZnT8A was higher in T1D patients than FDR, for ZnT8TripleA (24% vs. 4%,p = 0.001), ZnT8RA (24% vs. 4%, p < 0.001) and ZnT8QA (15% vs. 3%, p = 0.004). All FDR with ZnT8A (n = 3) had at least another positive antibody. Heterozygosis for PTPN22 was associated with a higher frequency of ZnT8TripleA (p = 0.039) and ZnT8RA (p = 0.038).


CONCLUSIONS
ZnT8A is observed in non-Caucasian patients with T1D, even years after the disease onset, as well as in their FDR. In those, there was an overlap between ZnT8A and other T1D antibodies. ZnT8A was associated with PTPN22 polymorphisms. Further longitudinal studies are necessary to elucidate the importance of these findings in the natural history of T1D patients with multiethnic background.
Department of Nutrology, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
Débora Batista
DB
Araujo
Department of Clinical Sciences, Lund University.
Hanna
H
Skärstrand
Department of Nutrology, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
Bianca
B
Barone
Department of Nutrology, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
Joana Rodrigues
JR
Dantas
Instituto Estadual de Diabetes e Endocrinologia Luiz Capriglione, Rio de Janeiro, RJ, Brazil.
Rosane
R
Kupfer
Department of Nutrology, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
Lenita
L
Zajdenverg
Department of Nutrology, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
Adolpho
A
Milech
Department of Nutrology, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
Fariba
F
Vaziri-Sani
Department of Nutrology, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
José Egídio Paulo de
JE
Oliveira
Department of Nutrology, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
Melanie
M
Rodacki
D000293:Adolescent; D000328:Adult; D001323:Autoantibodies / Q000235:genetics / Q000276:immunology*; D001938:Brazil / Q000453:epidemiology / Q000208:ethnology; D027682:Cation Transport Proteins / Q000097:blood / Q000235:genetics / Q000276:immunology*; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology / Q000208:ethnology / Q000235:genetics / Q000276:immunology*; D005190:Family / Q000208:ethnology*; D005260:Female; D005838:Genotype; D006801:Humans; D007328:Insulin / Q000235:genetics; D008297:Male; D011110:Polymorphism, Genetic / Q000235:genetics; D015995:Prevalence; D054596:Protein Tyrosine Phosphatase, Non-Receptor Type 22 / Q000235:genetics; D011869:Radioligand Assay; D055815:Young Adult; D000075703:Zinc Transporter 8
D001323:Autoantibodies; D027682:Cation Transport Proteins; D007328:Insulin; C492522:SLC30A8 protein, human; D000075703:Zinc Transporter 8; C516765:PTPN22 protein, human; D054596:Protein Tyrosine Phosphatase, Non-Receptor Type 22