C. Atabay et al., USE OF EYE MUSCLE ANTIBODY MEASUREMENTS TO MONITOR RESPONSE TO PLASMAPHERESIS IN PATIENTS WITH THYROID-ASSOCIATED OPHTHALMOPATHY, Journal of endocrinological investigation, 16(9), 1993, pp. 669-674
We have measured eye muscle antibodies, in immunoblotting, in the seru
m from five patients with severe ophthalmopathy associated with Graves
' hyperthyroidism who underwent plasmapheresis, correlating their leve
ls with clinical features of the eye disorder and response to treatmen
t. Blood taken before each plasma exchange was tested in SDS-polyacryl
amide gel electrophoresis and Western blotting for antibodies reactive
with pig eye muscle membrane (PEMM) antigens and in a Cr-51 release a
ssay for antibodies which are cytotoxic to human eye muscle cells in a
ntibody-dependent cell-mediated cytotoxicity (ADCC). Antibodies reacti
ve with a 64 kDa PEMM antigen were detected in three patients who had
eye disease of less than six months duration, but not in the two with
more chronic disease. Antibodies against a 95 kDa PEMM antigen were de
tected in one patient in whom anti-64 kDa antibodies were also demonst
rated. All five patients showed significant improvement in their eye d
isease following plasmapheresis exchange and titres of the anti-64 kDa
protein antibody decreased in the three patients with detectable leve
ls before treatment. TSH receptor stimulating antibodies were detected
in all five patients before treatment, failing during plasmapheresis
in four and becoming undetectable in three by the end of treatment. Th
ere was no close correlation between levels of TSH receptor antibodies
and titres of anti-64 kDa protein antibodies although both tended to
fall during and following plasmapheresis. ADCC tests were negative in
all five patients before plasmapheresis but, surprisingly, transiently
positive in three following treatment. There was no close correlation
between ADCC activity and titres of antibodies to the 64 kDa or 95 kD
a proteins before plasmapheresis, or following plasma exchange, in any
patient. While change in levels of antibodies reactive with a 64 kDa
PEMM protein during plasma exchange paralleled clinical improvement in
the small number of patients studied, this does not prove a pathogene
tic role in thyroid-associated ophthalmopathy. On the other hand, meas
urement of antibodies reactive with a 64 kDa eye muscle membrane prote
in before treatment, may, along with clinical parameters, help to iden
tify those patients with severe active ophthalmopathy likely to have a
good response to plasmapheresis.