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AB0702 IGG and IGM anti-DSDNA isotypes in patients with systemic lupus erythematosus
  1. B. Keiserman1,
  2. O.A. Monticielo2,
  3. M.R. Ronchetti1,
  4. H.L. Staub1
  1. 1Division of Rheumatology, Hospital São Lucas, Pontifícia Universidade Catόlica do Rio Grande do Sul
  2. 2Division of Rheumatology, Department of Internal Medicine, Hospital De Clínicas De Porto Alegre, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, Brazil

Abstract

Background Systemic lupus erythematosus (SLE) is an autoimmune disease, where renal involvement is common, being a determinant for bad prognostic. Lupus nephritis is generally associated to the presence of anti-dsDNA. The IgM isotype of this autoantibody, unlike the IgG isotype, seems to be nephroprotector.

Objectives To study the influence of isotypes IgG and IgM anti-dsDNA antibodies on clinical and laboratory manifestations of SLE.

Methods We conducted a cross-sectional study with 137 patients with SLE, in which we explored the presence of isotypes IgG and IgM anti-dsDNA antibodies. The research of anti-dsDNA was performed by indirect immunofluorescence with Crithidia luciliae (CLIF).

Results Fifty-eight (42%) patients had IgG anti-dsDNA reagent and were selected for the study of the IgM isotype. The group of patients who had anti-dsDNA IgG alone (n=43) compared with the group who had concomitant isotypes IgG and IgM (n=15), showed a higher frequency of active urine sediment (34.9% versus 6.7%, p=0.046). Analysis of the median distribution of IgG/IgM anti-dsDNA ratio, according to the presence or absence of clinical and laboratory features, showed a trend of the IgG/IgM ratio be greater in the presence of arthritis and leukopenia/lymphopenia [4 (2-8)versus 1 (1-2), p=0.070 and 4 (3-8) versus 1 (1-4), p=0.066, respectively].

Conclusions Our study showed that the concomitance of the isotypes IgM and IgG anti-dsDNA inhibited the effect of the isotype IgG isolated in association with active urinary sediment. Future studies are needed to clarify the role of anti-dsDNA isotypes in SLE.

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Disclosure of Interest None Declared

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