Lupus erythematosus associated with genetically determined deficiency of the second component of the complement.
BACKGROUND
The gene deletion responsible for the type I human complement C2 deficiency was reported in 1992. The purpose of our study is to evaluate clinical and immunological characteristics of 11 patients with lupus erythematosus and type I C2 deficiency.


METHODS
We observed 5 patients with a homozygous C2 deficiency and 6 with a heterozygous C2 deficiency. Eight patients had systemic lupus erythematosus, 2 had subacute cutaneous lupus erythematosus, and 1 had chronic lupus erythematosus. Photosensitivity was present in 73% of the patients, and 64% tested positive for anti-Ro (SSA) antibodies. Renal involvement that required immunosuppressive therapy was present in 54% of the patients. Ninety percent of the patients tested positive for antinuclear antibodies, and 54% tested positive for anti-double-stranded DNA antibodies. Phenotyping of the fourth component of the complement was performed in 82% of the patients and showed a C4A4B2 phenotype, which is suggestive for the type I C2 deficiency.


CONCLUSIONS
Most patients with lupus erythematosus associated with C2 type I deficiency are photosensitive, and this is probably related to the presence of anti-Ro (SSA) autoantibodies. The prognosis for those patients is not better than that for patients with lupus erythematosus in general.
Lipsker
D M
DM
Clinique Dermatologique, 1 Place de l'Hôpital, F-67091 Strasbourg Cédex, France. dlipsker@cybercable.fr
Schreckenberg-Gilliot
C
C
Uring-Lambert
B
B
Meyer
A
A
Hartmann
D
D
Grosshans
E M
EM
Hauptmann
G
G
D000293:Adolescent; D000328:Adult; D003175:Complement C2 / Q000172:deficiency*; D017931:DNA Primers; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000097:blood / Q000235:genetics* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D016133:Polymerase Chain Reaction; D012189:Retrospective Studies
D003175:Complement C2; D017931:DNA Primers