Background Polyclonal immunoglobulin light chains (PLC) represent biomarkers of B cell activity in rheumatoid arthritis (RA) and are associated with increased mortality in general population. PLC levels appear to be elevated during preclinical and active periods of RA. Serum k and l light chains are important inflammatory indexes and may be used as indicators of disease activity in RA.
Objectives To explore association between serum PLC in cohorts of patients with RA depending on treatment and to determine whether PLC can be used as markers of treatment effectiveness.
Methods 150 patients with RA untreated and treated with sDMARDs were included in the study (n=52, n=98, respectively), and 31 patient with osteoarthritis. Approximately 75% of patients in all groups were elderly people. Serum levels of PLC were measured by immune nephelometry.
Results Median [lower and upper quartiles] polyclonal k and λ light chains serum concentrations in cohort of untreated RA patients were significantly higher in comparison with osteoarthritis and treated RA patients (κ: 3.1 [2.7; 3.6] vs 2.6 [2.1; 3.3] and 2.6 [2.3; 3.1] g/l, H=12.1, p<0,01; λ: 1.7 [1.3; 1.9] vs 1.4 [1.2; 1.8] and 1.3 [1.2; 1.7] g/l, p=0.014). Comparing groups treated with methotrexate, sulfasalazine and leflunomide (n=48, 15 and 16, respectively) showed no statistically significant difference of PLC levels. It appeared that treatment with methotrexate during at least 6 months reduced serum concentrations of PLC in patients with RA (κ untreated 3.0 [2.6; 3.4] vs κ methotrexate 2.6 [2.0; 2.8], p<0.01; λ untreated 1.8 [1.6; 2,05] vs λ methotrexate 1,4 [1.0; 1,7], p<0.01).
Conclusions PLC can be used as markers of treatment with sDMARDs effectiveness among elderly patients with multimorbidity.
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Disclosure of Interest None declared