bjectives : Among a vatiety of nuclear antigens, extractable nuclear antigens(ENA) which
can be extracted from nuclei by homogenization in neutral saline contain ribonucleoprotin, Sm,
SS-A/Ro, SS-B/La and other antigens. Characterization of anti-ENA anti-bodies provides
information about nosology, subset definition within diseases, clinical activity, specific organ
involement and prognosis.
Methods : Authors have used double immunodiffusion test to detect antibodies to ENAs
and studied the frequencies of autoantibodies to these antigens and their correlation with
clinical and laboratory features in systemic rheumatic diseases.
Results :
1) 1,063 patients were investigated for the presence of serum antibodies to ENAs and 180
out of 1,063 patients (16.9%) had anti-ENA antibodies. 3,412 tests were performed for the
presence of antibodies to Sm, RNP, RO, La, Scl-70 and Jo-1 respectively and 230 out of 3,412
tests (6.7%) were positive.
2) The profiles of 137 patients who had anti-ENA antibodies are systemic lupus
erythematous (61), rheumatoid arthritis with secondary Sjogren's syndrome (26) and without
secondary Sjogren's syndrom (9), mixed connective tissue disease (18), scleroderma (10),
polymyosits/dermatomyositis (6), undifferentiated conective tissue disease (4), gout (1),
fibromyalgia syndrome (1) and Hashimoto's thyroiditis (1).
3) The frequencies of antibodies to ENAs were 73.5% in patiets with systemic lupus
erythemtosus, 9.6% in rheumatoid rthritis, 100% in mixed connective tissue disease, 71.4% in
scleroderma and 46.2% in polymyostis/dermatomyositis.
4) The frequencies of antibodies to Sm, RNP, Ro and La in patients with systemic lupus
erythematosus were 18.1%, 41.5% 43.9% and 4.9% respectively.
(1) Patients with anti-Sm antibodies had a higher incidence of pleuritis than those
without anti-Sm antibodies(p=0.029)
(2) Patients with anti-RNP antibodies had a higher incidence of Raynaud's phenomenon
and pleuritis and a lower incidence of renal disease than those without anti-RNP antibodies
(p=0.008, p=0.019, p=0.029).
(3) Patients with anti-Ro antibodies had a higher incidence of thrombocytopenia than
those without anti Ro antibodies.
(4) There were no clinical and laboratory differences between patients with anti-La
antibodies and without anti-La antibodies.
5) In patients with rheumatoid arthritis, anti-Ro antibody was likely to be associated with
secondary Sjogren syndrome, although statistically significant association was not found
(p=0.053).
Conclusions : Thease results showed that the detection of antibodies to ENAs by double
immunodiffusion test was expected to be a useful diagnostic marker and predict some clinical
features in systemic rheumatic diseases.
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