Objective To investigate the clinical characteristics,immunological features,treatment andprognosis of monoclonal gammopathy(MG)in patients with rheumatoid arthritis(RA). Methods A retrospec-tive,case-control study was conducted in 11 cases diagnosed with RA-associated MG(RA-MG)and 33 age-andsex-matched RA controls without MG from 2010 to 2017 in Peking University People′s Hospital. Comparisonsbetween groups were made using t test for normally distributed numerical data,Mann-Whitney U test for non-normally ...