The aims of the project were:
1. To analyse the expression of the sodium iodide symporter (NIS) gene in human
thyroid cells and other tissues.
2. To develop a novel assay for NIS autoantibodies using a recombinant cell
line.
3. To use this new assay to study NIS autoantibodies in thyroid patients.
4. To study the possible relationship between NIS antibodies and other thyroid
autoantibodies, and the possible correlation with the clinical status of patients.
The work has gone very well and we have successfully carried out a study of NIS gene expression, which was published this year (Ajjan et al 1998) The study showed the expression of the NIS gene in a range of tissues including stomach, salivary gland, mammary gland, and eye muscle.
We successfully expressed the human NIS gene and produced a novel bioassay
for NIS autoantibodies. We were able to measure the level of NIS-modulated iodide
uptake and study the effects of patient antibodies on this transport. Using
the new assay we were able to assess the frequency of NIS-inhibitory antibodies
in autoimmune thyroid disease patients. The results showed that approximately
27% of Graves' patients possess NIS autoantibodies that are capable of inhibiting
iodide transport. This important study was recently published (Ajjan et al 1998).
The work currently ongoing is to look at NIS antibodies in other thyroid patients
and to attempt to isolate and study patient antibodies against this important
antigen. These studies and the work described above have placed this group in
the leading position in this area of research, and we are happy to acknowledge
the support of the British Thyroid Foundation.