• C2 deficiency is the most common complement component deficiency. While individuals with C2 deficiency may be completely normal, a lupus erythematosus—like disease process has developed in some. A 28-year-old woman had a chronic photodermatitis, arthralgias, and mesangial lupus nephritis. She has C2 deficiency associated with an HLA-Dw2 transplantation antigen. Her serum has shown antibodies to the macromolecule Ro (the A antigen in Sjögren's syndrome), while failing to demonstrate antinuclear antibodies in routine laboratory determinations.
(Arch Dermatol 1982;118:584-587)
Vandersteen PR, Provost TT, Jordon RE, McDuffie FC. C2 Deficient Systemic Lupus ErythematosusIts Association With Anti-Ro (SSA) Antibodies. Arch Dermatol. 1982;118(8):584-587. doi:10.1001/archderm.1982.01650200052016