Background In patients with active rheumatoid arthritis (RA) decrease of galactosylation of IgG is observed. It has been shown that agalactosylation is correlated with disease activity (1, 3, 4).
Objectives The aim of our study was to evaluate an effect of methotrexate (MTX) therapy on glycosylation disturbances of IgG in RA patients.
Methods 40 patients with active RA was treated with MTX for 12 months in dosage 15-25 mg per week (2). All patients were in remission based on DAS 28 (≤2.6) at the end of the study. The control group was consisted of 20 healthy volunteers in the same age. IgG was isolated from patients sera and analysis of IgG galactosylation by biotinylated lectins was performed. Immunosorbent assay ELISA was used for this purpose. For galactose specifity Datura stramonium lectin (DSA), for sialic acid Sambucus nigra (SNA) and Maackia amurensis (MAA) and for fucose residue (Areulia auranta) AAA lectin was used (5).
Results Our data demonstrated that N-glycan galactosylation and sialylation of IgG in untreated (naive) RA patients was significantly lower than in control group (for DSA, MAA lectins p<0.001 and SNA p<0.05). Furthermore we showed significant increase of IgG galactosylation and sialylation in RA patients after twelve months of MTX therapy (for DSA,MAA and SNA lectin p<0.05) compared to those before treatment. Moreover the glycosylation disturbances of N-glycan IgG were strongly associated with changes of disease activity based on DAS 28 (p<0.001). For fucose residues significantly higher absorbancy of AAA lectin in RA patients before MTX treatment was observed compared to control group (p<0.05). There were no correlation between absorbancy of this lectins before and after treatment but in RA treated patients still higher level of fucosylation was observed. There were no correlation between lectins absorbancy and ACPA and RF titer.
Conclusions Defect of glycosylation of IgG in RA can be detected by simple lectin method. Assessment of disturbances of glycosylation of IgG might be a useful marker of disease activity and effectiveness of treatment.
Watson M, Rudd PM, Bland M et al. Sugar printing rheumatic diseases. Arthritis and Rheum. Vol.42, No 8, Aug 1999, pp 1682-1690
Arnett FC, Edworthy SM, Bloch DA et al. The American Rheumatism Association 1987 revised criteria for the classification of rheumatoid arthritis. Arthritis Rheum. 1998, 31: 315-324
Axford JS, Sumar N, Alavi A et al. Changes in normal glycosylation mechanisms in autoimmune rheumatic disease. J. Clin. Invest., 1992; 89: 1021-1031
Gindzienska-Sieskiewicz E, Klimiuk PA, Kisiel DG et al. The changes In monosaccharide composition of immunoglobulin G in the course of rheumatoid arthritis. Clin Rheumatol. 2007 May;26(5):685-90.
Radziejewska I, Borzym-Kluczyk M, Namiot Z et al. Glycosylation of mucins present In gastrin juice: the effect of Helicobacter pylori eradication treatment. Clin Exp Med. 2011, 11:81-88
Disclosure of Interest None declared