The possible role of autoimmunity in the pathogenesis of diabetes in B-thalassemia major.
OBJECTIVE
To evaluate the possible role of autoimmunity in the pathogenesis of diabetes associated with B-thalassemia, we studied a cohort of 53 B-thalassemic individuals, under long term blood transfusion, that included twelve patients with diabetes (22.6%).


METHODS
To evaluate the activation of an autoimmune response, individuals were tested for islet cell antibodies (ICA), glutamic acid decarboxylase (GAD) autoantibodies, insulin autoantibodies (IAA) and serum anti-nuclear antibodies (ANA).


RESULTS
Nine of the total B-thalassemic population (16.98%) were ICA-positive. The frequency of ICA-positive subjects among thalassemic individuals was higher than in the general population. Five (41.6%) of the ICA-positive individuals were diabetic. Of these, three were serum C-peptide-negative (<0.21 nmol/l). HLA class II typing of our thalassemic population did not reveal significantly different allelic frequencies with respect to the control population.


CONCLUSIONS
Our study demonstrates evidence of immune system activation against pancreatic B-cells in B-thalassemia and we propose that iron deposition may, through oxidative damage, act as an environmental factor that triggers the autoimmune response. Therefore, we speculate that pancreatic autoimmunity may contribute to selective B-cells damage in the pathogenesis of diabetes associated with B-thalassemia.
Monge
L
L
UOA Diabetologia, AO S. Giovanni Battista di Torino, Torino, Italy. amd-to.monge@alma.it
Pinach
S
S
Caramellino
L
L
Bertero
M T
MT
Dall'omo
A
A
Carta
Q
Q
D000328:Adult; D000974:Antibodies, Antinuclear / Q000097:blood; D001323:Autoantibodies / Q000097:blood*; D015551:Autoimmunity; D001803:Blood Transfusion; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003920:Diabetes Mellitus / Q000209:etiology / Q000276:immunology* / Q000503:physiopathology; D005260:Female; D018149:Glucose Intolerance / Q000097:blood / Q000276:immunology* / Q000503:physiopathology; D005968:Glutamate Decarboxylase / Q000276:immunology; D006683:HLA-DQ Antigens / Q000032:analysis; D059866:HLA-DQ beta-Chains; D006684:HLA-DR Antigens / Q000032:analysis; D006650:Histocompatibility Testing; D006801:Humans; D007330:Insulin Antibodies / Q000097:blood; D007515:Islets of Langerhans / Q000276:immunology; D008297:Male; D017086:beta-Thalassemia / Q000276:immunology* / Q000503:physiopathology / Q000628:therapy
D000974:Antibodies, Antinuclear; D001323:Autoantibodies; D006683:HLA-DQ Antigens; D059866:HLA-DQ beta-Chains; C069051:HLA-DQB1 antigen; D006684:HLA-DR Antigens; D007330:Insulin Antibodies; C024211:islet cell antibody; D005968:Glutamate Decarboxylase