Clinical features, treatment and follow-ups of Sj(o)gren's syndrome-associated monoclonal gammopathy / 中华风湿病学杂志

ABSTRACT

Objective To investigate the clinical characteristics,immunological features,treatment and follow-ups of Sj(o)gren's syndrome-associated monoclonal gammopathy (SS-MG).Methods A retro-spective,case-control study was conducted for 18 cases diagnosed with SS-MG and 36 age-and sex-matched non-MG-SS patients from Janurary 2010 to Janurary 2017 in Peking University People's Hospital.The clinical and laboratory features,treatment and follow-ups were recorded and compared.Comparisons between groups were made using t test for normally distributed numerical data,Mann-Whitney U test for non-normally distributed numerical data,and Pearson Chi-square,continuity correction or Fisher's exact tests for categorical data.Results SS patients,when complicated with MG,had significantly increased level of TP [(78± 11) g/L,(71±10) g/L,t=-2.382,P=0.021] and erythrocyte sedimentation rate (ESR) [52.5(45.3) mm/1 h,33.0(42.5) mm/1 h,Z=-2.179,P=0.029],higher prevalence of urine NAG positivity [75％(9/12),28％(7/25),x2=7.298,P=0.007],hypoglobulinemia [33％(6/18),3(1/36),x2=7.407,P=0.006] and thrombotic events [17％(3/18),0％(0/36),P=0.033],and less previous exposure to glucocorticoid [22％(4/18),64％(23/36),x2=8.333,P=0.004],compared to the control group.Primary SS patients complicated with MG had significantly higher ESSDAI [26.0(25.0),12.0 (9.0),Z=-2.724,P=0.006] and Clin EULAR Sj(o)gren's syndrome disease activity index (ESSDAI) [24.0(25.0),10.5 (10.0),Z=-2.523,P=0.011].Among the 18 patients,2 were diagnosed with multiple myeloma,1 was diagnosed with non-Hodgkin lymphoma,and the left were diagnosed as MG of undetermined significance (MGUS).Ten patients were followed up,among whom 2 patients with MGUS experienced increased levels of M protein,newly developed genetic abnormalities,and renal involvement.Conclusion SS patients may be complicated with MG.MGUS is the most common form.However,malignant hematologic disorders are revealed as well.In SS patients with high serum TP and ESR,hypoglobulinemia,tubulointerstitial kidney involvement and unexplained thrombotic events,especially in those with high disease activity,so MG should be an alert for further work-ups,monitoring and treatment.