Ab to Zn Transporter 8 - From Len Harrison

Dear all

Thanks to Len Harrison for  informing us of an assay for measurement of antibodies to "ZnTx8 Ab is measured by IP of 35S-methionine labeled in vitro translated protein, in the Endocrine Lab at the Royal Melbourne (contact Prof. Peter Colman). " Len

Immunology forum question - Zinc transporter 8 antibody - from David Heyworth-Smith

Greetings.  Is anyone offering routine testing of zinc transporter-8 autoantibodies?  We (QML) have received a solitary request.  My brief scanning of the literature suggests measurement may have some additive predictive value to anti-GAD and anti-IA2 in relatives of type 1 diabetics and also in assessment of late onset autoimmune diabetes.  Many thanks for any information and comments.
Kind regards
David

Dr. David Heyworth-Smith
Clinical Immunologist
QML Pathology
ph 07 31214444
david.heyworthsmith@qml.com.au

GAD65 & GAD67

Dear Glenn,

 

The current literature on anti-GAD and Stiff-Person Syndrome and/or cerebellar ataxia doesn't discuss GAD67 any more. It is agreed that the antigen recognised is a different epitope on GAD65 to that recognised by diabetics without SPS (Solimena M and Carmilli PD TINS, 14(10) 452, 1991).

 

The majority of patients with SPS or cerebellar ataxia produce a "cobble-stone" immunofluorescence pattern in the granular layer on monkey cerebellum (see attached PDF). We screened around 20 diabetics with high levels of anti-GAD (RSR ELISA) with no evidence of neurological disease and none demonstrated the "cobble-stone" pattern. This suggests that the SPS sera recognize a fixation-dependent epitope on GAD65.

 

The presence of anti-amphiphysin IIF (and anti-amphiphysin blot positive) in patients with anti-GAD increases the likelihood of a tumour.

 

Regards

Bob Wilson

GAD65 & GAD67

Dear All

As you know the GAD antibody seen in Stiff-Person Syndrome is picked up on islet cell substrate (see picture below), even though this is usually used to detect the anti-GAD65 antibodies seen in DM Type I

Is anyone in our group aware of potential utility &/or availability of more specific antibody test for the GAD67 antigen which is more associated with the autoimmune condition affecting brain? Or are they so similar structurally that a cross-reactive antibody is adequate?

Any input welcomed

Regards

Glenn

Anti-GAD IIF Monkey Cerebellum:

Pancreas GAD Staining: