Abstract | OBJECTIVE: METHODS: Sera from 101 patients with various connective tissue diseases and 25 normal controls were investigated by enzyme-linked immunosorbent assay and immunoblotting, for their reactivity to highly purified recombinant hnRNP I. Moreover, reactivity to cellular hnRNP I protein was investigated by immunoblotting using a partially purified preparation of hnRNP proteins (including A1, A2, B, and I), and by indirect immunofluorescence. For the analysis of the fluorescence pattern, affinity-purified antibodies to hnRNP I; obtained from a selected patient, were tested on HEp-2 cells. RESULTS: By immunoblotting, antibodies reacting to recombinant hnRNP I were found in 22 of 40 patients with systemic sclerosis (SSc), 3 of 32 with RA, 0 of 23 with SLE, and 0 of 6 with MCTD. Antibodies to recombinant hnRNP I were more frequently found in patients with pre-SSc or limited SSc (15 of 24) than in those with intermediate or diffuse SSc (7 of 16). In indirect immunofluorescence studies, affinity-purified anti- hnRNP I autoantibodies gave a diffuse nucleoplasmic staining. Using an hnRNP preparation from nuclear extracts, anti- hnRNP I reactivity was detectable in SSc sera, while it was not detectable in RA, SLE, and MCTD sera reacting with hnRNP A/B proteins. CONCLUSIONS: Human autoimmune sera show distinct patterns of anti- hnRNP reactivity, i.e., anti-A/B in SLE and RA sera, and anti-I in SSc sera. This suggests that A/B proteins and the I protein may be involved in different dynamic hnRNP complexes that elicit different autoimmune responses. From a clinical perspective, anti- hnRNP I antibodies are frequently associated with pre-SSc features, suggesting an early appearance of these antibodies during the course of the disease.
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Authors | C Montecucco, R Caporali, F Cobianchi, G Biamonti |
Journal | Arthritis and rheumatism
(Arthritis Rheum)
Vol. 39
Issue 10
Pg. 1669-76
(Oct 1996)
ISSN: 0004-3591 [Print] United States |
PMID | 8843857
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Autoantibodies
- Heterogeneous Nuclear Ribonucleoprotein A1
- Heterogeneous-Nuclear Ribonucleoprotein Group A-B
- Heterogeneous-Nuclear Ribonucleoproteins
- RNA-Binding Proteins
- Recombinant Proteins
- Ribonucleoproteins
- hnRNP A2
- Polypyrimidine Tract-Binding Protein
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Topics |
- Autoantibodies
(blood, immunology)
- Cell Nucleus
(chemistry, immunology)
- Enzyme-Linked Immunosorbent Assay
- Fluorescent Antibody Technique, Indirect
- Gene Expression
(immunology)
- Heterogeneous Nuclear Ribonucleoprotein A1
- Heterogeneous-Nuclear Ribonucleoprotein Group A-B
- Heterogeneous-Nuclear Ribonucleoproteins
- Humans
- Polypyrimidine Tract-Binding Protein
- RNA-Binding Proteins
(genetics, immunology, isolation & purification)
- Recombinant Proteins
(immunology)
- Ribonucleoproteins
(genetics, immunology, isolation & purification)
- Scleroderma, Systemic
(immunology)
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