Diabetes Care
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Diabetes Care 30:e127 2007
DOI: 10.2337/dc07-1397
© 2007 by the American Diabetes Association
This Article
Right arrow Extract Freely available
Right arrow Full Text (PDF)
Right arrow Purchase Article
Right arrow View Shopping Cart
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Buzzetti, R.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Buzzetti, R.
Social Bookmarking
Add to CiteULike   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?

Online Letters: Comments and Responses

High Titer of Autoantibodies to GAD Identifies a Specific Phenotype of Adult-Onset Autoimmune Diabetes

Response to Kobayashi et al.

Raffaella Buzzetti, MD1, Antonio Petrone, PHD1, Marco Capizzi, MD1, Emanuele Bosi, MD2 for the Non Insulin Requiring Autoimmune Diabetes (NIRAD) Study Group

1 Department of Clinical Sciences, "La Sapienza" University, Rome, Italy
2 Department of General Medicine, Diabetes and Endocrinology, San Raffaele Vita-Salute University, Milan, Italy

Address correspondence to Raffaella Buzzetti, MD, Department of Clinical Sciences, "La Sapienza" University, Rome, Italy. E-mail: raffaella.buzzetti{at}uniroma1.it

In our article (1) on adult-onset autoimmune diabetes, titers of antibodies to GAD (GADA) are reported in arbitrary units, i.e., they are elaborated in-house; therefore, they are unsuitable for comparison with other studies. However, as anticipated by Kobayashi et al. (2), the participation in the Diabetes Antibody Standardization Program (3) allows us to convert these measurements into World Health Organization (WHO) units. The value of 32 units, which in our study indicates the threshold separating patients having low from those having high GADA titers, corresponds to 300 WHO units. With regard to thyroid autoimmunity, the finding of the preferential association of thyroid peroxidase (TPO) antibodies in patients with high GADA titers is only one of the several traits indicating that high GADA titers identify a subgroup of patients having, as a whole, more prominent characteristics of insulin deficiency (e.g., higher A1C, lower BMI, a lower prevalence of metabolic syndrome and its components) and a profile of more severe and extended autoimmunity (1). Furthermore, the corresponding genetic heterogeneity shown in our study suggests that some differences between high and low GADA titer subjects may in fact exist (not only higher prevalence of DRB1*03-DQB1*0201 but also a decreasing frequency of DQB1*0602 and DRB1*0403 from type 2 diabetes to low and high GADA titer autoimmune diabetes). The classification of patients with adult-onset autoimmune diabetes according to the presence or absence of TPO antibodies drawn from the study clearly shows and further emphasizes this difference (TPO positive, n = 51: high GADA, n = 35 [68.6%], and low GADA, n = 16 [31.4%]; and TPO negative, n = 140: high GADA, n = 59 [42.2%]; low GADA, n = 81 [57.8%]; P < 0.002). If we consider this distribution, we can see that a considerable percentage of subjects (42%), despite having high GADA titer, are TPO antibody negative, showing that in this case, the Th2-dominant state is not able to enhance the titer of GADA. On the other hand, human autoimmune diseases rarely fall into exclusive pro-Th1 or -Th2 patterns (4). Nevertheless, we agree that the pathogenetic implications of this association remain to be clarified, and further studies are requested.

References

  1. Buzzetti R, Di Pietro S, Giaccari A, Petrone A, Locatelli M, Suraci C, Capizzi M, Arpi ML, Bazzigaluppi E, Dotta F, Bosi E, the Non Insulin Requiring Autoimmune Diabetes (NIRAD) Study Group: High titer of autoantibodies to GAD identifies a specific phenotype of adult-onset autoimmune diabetes. Diabetes Care 30: 932–938, 2007[Abstract/Free Full Text]
  2. Kobayashi T, Tanaka S, Shimada A, Maruyama T: High titer of autoantibodies to GAD identifies a specific phenotype of adult-onset autoimmune diabetes: response to Buzzetti et al. (Letter). Diabetes Care 30: e126, 2007. DOI: 10.2337/dc07-1104[Free Full Text]
  3. Bingley PJ, Bonifacio E, Mueller PW: Diabetes antibody standardization program: first assay proficiency evaluation. Diabetes 52: 1128–1136, 2003[Abstract/Free Full Text]
  4. Parris Kidd: Th1/Th2 balance: the hypothesis, its limitations, and implications for health and disease. Altern Med Rev 8: 223–246, 2003[Medline]

Add to CiteULike CiteULike   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati    What's this?



This Article
Right arrow Extract Freely available
Right arrow Full Text (PDF)
Right arrow Purchase Article
Right arrow View Shopping Cart
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Buzzetti, R.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Buzzetti, R.
Social Bookmarking
Add to CiteULike   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Diabetes Diabetes Care Clinical Diabetes Diabetes Spectrum