No evidence foran independent roleofanti-heparan sulphate reactivity apart fromanti-DNAinlupusnephritis

SUMMARY Thepresenceofanti-heparan sulphate (HS)reactivity inserum isclosely related tothe occurrence ofnephritis inpatients withsystemic lupuserythematosus (SLE). Since patients withlupus nephritis ingeneral alsohavehightitres ofanti-DNA antibodies, we wantedtoclarify the relationship between anti-HS andanti-DNA reactivity inserum. Therefore, we studied longitudinally sixpatients withlupus nephritis whoexperienced 12exacerbations oftheir disease, and five SLEpatients without nephritis experiencing 10periods ofnon-renal disease exacerbations. In addition, we tested single serum samples ofanother 24patients obtained during a renal disease exacerbation and22seraofpatients without nephritis. Theseraofall patients weretested forantiDNA (Farr assay) andanti-HS reactivity (ELISA). Weconfirmed thatSLEpatients during renal exacerbations havea significantly higher anti-HS reactivity thanpatients without nephritis (P< 0003). Inaddition, patients withnephritis alsohadhigher titres ofanti-DNAantibodies during renal exacerbations thanduring non-renal exacerbations (P<0-01). A correlation between antiDNA andanti-HS reactivity was observed (r = 040,P < 002),whichinitself explains the correlation between nephritis andanti-HS reactivity. Comparing serafromnephritis andnonnephritis patients matched foranti-DNA titre, we found no difference inanti-HS reactivity, and therefore mustconclude thattheanti-HS reactivity isa direct reflection ofanti-DNAreactivity.