Systemic sclerosis-rheumatoid arthritis overlap syndrome: a unique combination of features suggests a distinct genetic, serological and clinical entity.
OBJECTIVE
To determine the genetic, clinical and serological characteristics of systemic sclerosis (SSc)-rheumatoid arthritis (RA) overlap syndrome.


METHODS
Clinical manifestations and immunolaboratory features of 22 SSc-RA patients were assessed. The HLA-DR genotype of the 22 SSc-RA patients determined by SSP-PCR was compared with that of 38 SSc patients, 100 RA patients and 50 healthy controls.


RESULTS
All overlap patients fulfilled the American College of Rheumatology (ACR) criteria for SSc and RA. Five of the 22 patients (23%) had diffuse cutaneous SSc (dcSSc) and 17 patients (77%) had limited cutaneous SSc (lcSSc). Antinuclear antibody, anti-Scl70, IgM rheumatoid factor and anti-CCP antibody positivity were detected in 22 (100%), 5 (23%), 16 (73%) and 18 patients (82%), respectively. Seventeen patients (77%) had pulmonary fibrosis, 12 (55%) had oesophageal dismotility, 11 (50%) had cardiac and five (23%) had renal involvement. Hand joint destruction was observed in 18 patients (82%). Significantly increased frequencies of HLA-DR3 (36% vs 5%), HLA-DR7 (9% vs 4%), HLA-DR11 (36% vs 7%) and HLA-DRw53 (23% vs 5%) were observed in SSc-RA compared with RA patients (P < 0.05). Allele frequencies of the 'shared epitope' (HLA-DR1 and -DR4) were significantly increased in SSc-RA (32% and 27%, respectively) and RA patients (46% and 31%, respectively) in comparison with SSc patients (10.5% and 16%, respectively) or healthy controls (16% and 14%, respectively) (P < 0.05).


CONCLUSIONS
To date this is the largest SSc-RA overlap cohort. Genetics, clinical and immunolaboratory features suggest a mixed phenotype. Our data suggest that SSc-RA overlap syndrome may be a distinct genetic, immunological and clinical entity.
Szücs
G
G
Third Department of Medicine, Rheumatology Division, University of Debrecen Medical and Health Science Center, 22 Móricz Zs str, Debrecen H-4004, Hungary. szucsg@iiibel.dote.hu
Szekanecz
Z
Z
Zilahi
E
E
Kapitány
A
A
Baráth
S
S
Szamosi
S
S
Végvári
A
A
Szabó
Z
Z
Szántó
S
S
Czirják
L
L
György Kiss
C
C
D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000235:genetics* / Q000276:immunology; D001323:Autoantibodies / Q000097:blood; D015154:Esophageal Motility Disorders / Q000235:genetics / Q000276:immunology; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006684:HLA-DR Antigens / Q000235:genetics; D015798:HLA-DR1 Antigen / Q000235:genetics; D015804:HLA-DR4 Antigen / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods; D011658:Pulmonary Fibrosis / Q000235:genetics / Q000276:immunology; D012595:Scleroderma, Systemic / Q000235:genetics* / Q000276:immunology; D013577:Syndrome
D001323:Autoantibodies; D006684:HLA-DR Antigens; D015798:HLA-DR1 Antigen; D015804:HLA-DR4 Antigen