Selective adsorption of antiphospholipid and anti-dsDNA autoantibodies on histidine based pseudobioaffinity adsorbent from sera of patients with systemic lupus erythematosus (SLE)

Systemic lupus erythematosus (SLE) is an autoimmune diseases characterized by the presence of antiphospholipid and anti-dsDNA autoantibodies in the sera of patients. These autoantibodies and their subclasses have received increasing attention by medical community due to their association with recurrent venous thrombosis, fetal loss and thrombocytopenia. In particular, attention has been paid to IgG subclasses in SLE. The biological and functional properties together with the subclass distribution might therefore influence the course of SLE. The separation and elimination of these autoantibodies from sera of patients can be effective in clinical therapy. In the present study, histidine based pseudobioaffinity adsorbents have been used for the selective adsorption and separation of anti-double stranded DNA (anti-dsDNA), anticardiolipin (aCL) and anti-β2-glycoprotein-I (anti-β2-GPI) antibodies from sera of patients with SLE. For this purpose histidine acting as a pseudobiospecific ligand has been coupled to bisoxirane activated sepharose CL-6B for the adsorption and separation of these autoantibodies. The removal of autoantibodies was carried out under gentle adsorption and elution chromatographic conditions at pH values 7.0 and 8.0. Autoantibodies isotypes and subclasses distribution in the separated fractions were studied by enzyme-linked immune-sorbent assay. The obtained results showed that the separated anticardiolipin and anti-β2-glycoprotein-I autoantibodies belong to IgG1, IgG2 and IgG3subclasses, while those of anti-dsDNA belong to IgM isotype and were shown to have a DNA hydrolyzing activity that hydrolyzes plasmid DNA. The results also indicate a total IgM and IgG recovery superior to 90% of the fraction loaded at pH 7.4 and pH 8.0 respectively.