Autoimmune response of IgE antibodies to cellular self-antigens in systemic Lupus Erythematosus.
BACKGROUND
Systemic lupus erythematosus (SLE) patients may exhibit high total IgE and antinuclear IgE antibodies (ANA-IgE). Here, we investigated the specificity of ANA-IgE in SLE patients and the involvement of cytokines in this immune response.


METHODS
Sera from 92 SLE patients and 68 healthy controls were evaluated for the presence of antinuclear IgE antibodies by immunoperoxidase with HEp-2,000(R) cells and immunoblotting with IgG-depleted sera. Total IgE, IgE specific to allergens, and serum cytokine levels were determined by ELISA.


RESULTS
Antinuclear IgE antibodies were detected only in SLE patients (29/92, 31.5%). High total IgE was associated with ANA-IgE (p < 0.0001), but was not associated with IgE antibodies to allergens. In the immunoblotting, ANA-IgE reacted with nucleosomes (23/29, 79.3%), dsDNA (14/29, 48.3%), SS-A/Ro (14/29, 48.3%), SS-B/La (2/29, 18.7%), Sm (14/29, 48.3%) and RNP (18/29, 62.1%). Patients with ANA-IgE had very low serum IL-4, less IL-5 than controls (p < 0.05), more IL-10 than seronegative patients (p < 0.05), and unaltered IFN-gamma levels. The IL-5/IL-10 ratio was lower in ANA-IgE seropositive patients in comparison with either seronegative patients (p < 0.05) or healthy controls (p = 0.001). Controls displayed higher IL-5/IFN-gamma ratios than either SLE patients with ANA-IgE (p < 0.05) or patients without these immunoglobulins (p < 0.01).


CONCLUSIONS
We conclude that IgE antibodies against cell autoantigens involved in protein expression, cellular proliferation, and cell death are present in patients with SLE. Interleukin-10 seems to down-regulate this IgE autoimmune response in SLE.
Atta
Ajax Mercês
AM
Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia, Salvador, Bahia, Brazil. ajatta@ig.com.br
Santiago
Mittermayer Barreto
MB
Guerra
Fernanda Garcia
FG
Pereira
Mariana Menezes
MM
Sousa Atta
Maria Luiza B
ML
D000293:Adolescent; D000328:Adult; D000368:Aged; D000974:Antibodies, Antinuclear / Q000276:immunology / Q000378:metabolism*; D001324:Autoantigens / Q000276:immunology / Q000378:metabolism; D015551:Autoimmunity; D001938:Brazil; D002460:Cell Line; D016207:Cytokines / Q000097:blood; D004247:DNA / Q000276:immunology / Q000378:metabolism; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology / Q000378:metabolism*; D008180:Lupus Erythematosus, Systemic / Q000097:blood / Q000175:diagnosis / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009707:Nucleosomes / Q000276:immunology / Q000378:metabolism; D012261:Ribonucleoproteins / Q000276:immunology / Q000378:metabolism; D000099207:SS-A Antigen
D000974:Antibodies, Antinuclear; D001324:Autoantigens; D016207:Cytokines; D004247:DNA; D007073:Immunoglobulin E; D009707:Nucleosomes; D012261:Ribonucleoproteins; D000099207:SS-A Antigen