Background/Purpose: Monoclonal gammopathy (MG) in patients with autoimmune diseases (AID) is pretty common, but the outcomes and predictors for hematological neoplasm (HN) progression have not been well characterized.

Methods: Patients diagnosed of AID complicated with MG in Peking Union Medical College Hospital from January 2010 to June 2017 were systematically reviewed, and followed up. Recognition of HN was set as the primary observational endpoint. Cox proportional hazard regression analysis was applied to identify possible risk predictors.

Results: Of 160 patients with AID and MG, the median time between AID diagnosis and MG diagnosis was 0.6 months (IQR: 0-42.3 months) with 87 (54.4%) patients diagnosed with AID and MG simultaneously. The most common AID was primary Sjӧgren’s syndrome (37, 23.1%), followed by rheumatoid arthritis (28, 17.5%) and systemic lupus erythematosus (25, 15.6%). About 62.5% (n=100) of AID patients in our cohort were having active disease at the detection of M protein. Thirty-nine (24.4%) patients developed HN during the follow-up (median: 3.7 years, IQR: 0.3-5.5 years) including multiple myeloma (22, 56.4%), lymphoma (9, 23.1%), macroglobulinemia (4, 10.3%), amyloidosis (3, 7.7%), and plasmacytoma (1, 2.6%) (Table 1.). The cumulative probability of HN progression was 21.8% at 1 year, 22.6% at 3 years, and 29.3% at 6 years after the finding of MG, respectively (Fig. 1A). High levels of monoclonal protein (M protein > 14.35% of total serum protein) (HR 11.71, 95%CI: 5.37-25.54, p< 0.001), significant weight loss (HR 6.24, 95%CI: 2.87-13.59, p< 0.001), and reduction of other types of immunoglobulins (HR 3.02, 95%CI: 1.40-6.48, p=0.005) were independent risk indicators. Types of M protein (Fig. 1B), disease activity, and treatment of AID (Fig. 1C) seemed unrelated to HN in our cohort.

Conclusion: Around one-fourth of MG in patients with AID develop HN, indicating that though MG mostly is a benign process in patients with AID, it can be the prelude for HN in certain group of this population. High levels of M protein, weight loss, and the reduction of other immunoglobulins are predisposing factors that warrant vigorous follow-up and monitoring.

Fig. 1 Survival analysis of patients with autoimmune diseases (AID) and monoclonal gammopathy. (A) Kaplan-Meier HN cumulative probability of monoclonal gammopathy patients with AID. (B) Kaplan-Meier hematological neoplasm (HN) cumulative probability of patients stratified with the type of M protein. (C) Kaplan-Meier HN cumulative probability of patients stratified with the use of cyclophosphamide. CTX: cyclophosphamide.

Table 1. Demographics of the autoimmune disease patients who developed hematological neoplasms during follow-up.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/monoclonal-gammopathy-in-autoimmune-diseases-analysis-and-follow-up-of-160-cases-in-a-tertiary-center-in-china/