C2 deficient systemic lupus erythematosus: its association with anti-Ro (SSA) antibodies

Abstract

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.

Lupus Erythematosus Associated With Genetically Determined Deficiency of the Second Component of the Complement

“…Thus, hand involvement seems to be a clinical sign suggestive of complement deficiency associated with LE. Other cutaneous findings have also been reported in C2-deficient patients with LE: diffuse maculopapular rash of SLE, 16 diffuse nonscarring alopecia, 24 buccal ulcerations, 24 cheilitis, 16 palmar petechias, 24 angioedema, 37 and LE panniculitis. 38 All tested patients but 1 had antinuclear antibodies on Hep2 cells; they also often had a high titer of antidsDNA antibodies.…”

“…Hence patients had LE with different initial complaints (eg, cutaneous LE, nephritis, and arthritis), whereas most published cases of C2 deficiency associated with LE were dermatological patients with SCLE or DLE. 16,[19][20][21][22][23][24]38,41,42 It is well known that the prognosis for patients with SCLE or DLE is better than that for patients with SLE, regardless of the association with C2 deficiency. Earlier reports therefore reflected the better prognosis in the LE cases than in the cases specifically related to C2 deficiency.…”

“…12,14,15 In contrast, the prevalence of anti-Ro (SSA) antibodies is reported to be much higher than in non-C2-deficient patients with LE. [14][15][16] Most information on C2-deficient patients with LE was reported before the identification of the molecular abnormality responsible for the type I deficiency. [17][18][19][20][21][22][23][24] The aim of this study is to assess clinical and biological characteristics as well as the prognosis of patients with LE with genetically determined deficiency of C2.…”

Dermatologic Overview of Lupus Erythematosus and Its Subsets

“…Although patients may have th~histopathologic findings of lupus erythematosus, immunoglobulin and complement are frequently absent at the .basement membrane. About 70% of these patients possess anti-Ro (SSA) antibodies (25,26).…”

Anti-Ro-Positive Lupus and Hereditary Angioneurotic Edema

“…In 5 obser vations the diagnosis of discoid lupus was not correlated with laboratory data. In the others, the anti-Ro specificity of antibodies is demonstrated as it often is in the associat ed lupus [5]. To explain the occurrence of lu pus erythematosus in the course of HAE, Donaldson et al [3] pointed out that pa- tients with impaired C4, or C2 components could not optimally clear immune ag gregates and would be susceptible to develop autoimmune diseases.…”