C4A and C4B null alleles are genetic markers of different types of systemic sclerosis in Japanese patients.
OBJECTIVE
The contribution of the polymorphism of complement C4A and C4B alleles to the pathogenesis of systemic sclerosis (SSc) was studied in Japanese patients.


METHODS
C4A and C4B typing was carried out in 44 SSc patients and in 83 normal subjects using electrophoresis followed by immunofixation and immunoblotting. HLA-DR typing and HLA DRB1*15 and *08 genotyping were carried out by the PCR method and the PCR-SSCP method, respectively.


RESULTS
In SSc with diffuse scleroderma, the frequency of C4BQ0 was significantly increased (44.4%, p < 0.001, pc < 0.01). In SSc with antitopoisomerase I antibody (a-Scl-70) C4BQ0 was also increased (50.0%, p < 0.001, pc < 0.01). Association analysis indicated that the increase in C4BQ0 was not primary but reflected an increase in HLA-DRB1*1502. In contrast, C4A/Q0 was significantly increased in limited scleroderma (53.8%, p < 0.005, pc < 0.05) and SSc without a-SCL-70 (53.8%, p < 0.005, pc < 0.05).


CONCLUSIONS
Diffuse scleroderma with SSC with a-Scl-70 have different genetical backgrounds from limited scleroderma and SSc without a-Scl-70, respectively, in Japanese patients. C4AQ0 were independent genetic markers for each clinical subgroup and for a a-Scl-70 positivity.
Takeuchi
F
F
Dept. of Medicine and Physical Therapy, Faculty of Medicine, University of Tokyo, Japan.
Nabeta
H
H
Hong
G H
GH
Matsuta
K
K
Tokunaga
K
K
Tanimoto
K
K
Nakano
K
K
D000328:Adult; D000368:Aged; D000483:Alleles; D015934:Complement C4a / Q000235:genetics*; D015935:Complement C4b / Q000235:genetics*; D005260:Female; D005819:Genetic Markers; D006684:HLA-DR Antigens / Q000235:genetics; D059810:HLA-DR Serological Subtypes; D059811:HLA-DRB1 Chains; D006650:Histocompatibility Testing; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D011110:Polymorphism, Genetic; D012595:Scleroderma, Systemic / Q000235:genetics* / Q000276:immunology*
D005819:Genetic Markers; D006684:HLA-DR Antigens; D059810:HLA-DR Serological Subtypes; C106559:HLA-DR15 antigen; C067266:HLA-DR16 antigen; C041559:HLA-DR8 antigen; D059811:HLA-DRB1 Chains; D015934:Complement C4a; D015935:Complement C4b