Mucosa‐associated lymphoid tissue lymphoma translocation protein 1 in rheumatoid arthritis: Longitudinal change after treatment and correlation with treatment efficacy of tumor necrosis factor inhibitors

BACKGROUND: Mucosa‐associated lymphoid tissue lymphoma translocation protein 1 (MALT1) correlates with treatment outcomes in inflammatory bowel disease and rheumatoid arthritis (RA). This study aimed to further evaluate the MALT1 longitudinal change and its relationship with tumor necrosis factor inhibitors (TNFi) response in RA patients. METHODS: Seventy‐one RA patients receiving TNFi [etanercept (n = 42) or adalimumab (n = 29)] were enrolled. MALT1 was detected by RT‐qPCR in peripheral blood samples of RA patients before treatment (W0), at week (W)4, W12, and W24 after treatment. RA patients were divided into response/non‐response, remission/non‐remission patients according to their treatment outcome at W24. Meanwhile, MALT1 was also detected by RT‐qPCR in 30 osteoarthritis patients and 30 healthy controls (HCs). RESULTS: Mucosa‐associated lymphoid tissue lymphoma translocation protein 1 was elevated in RA patients compared with HCs (Z=−6.392, p < 0.001) and osteoarthritis patients (Z = −5.020, p < 0.001). In RA patients, MALT1 was positively correlated with C‐reactive protein (r(s) = 0.347, p = 0.003), but not other clinical characteristics, treatment history, or current TNFi category. Meanwhile, MALT1 decreased from W0 to W12 in total RA patients (x(2) = 86.455, p < 0.001), etanercept subgroup (x(2) = 46.636, p < 0.001), and adalimumab subgroup (x(2) = 41.291, p < 0.001). Moreover, MALT1 at W24 (p = 0.012) was decreased in response patients compared with non‐response patients; MALT1 at W12 (p = 0.027) and W24 (p = 0.010) were reduced in remission patients than non‐remission patients. In etanercept subgroup, MALT1 at W24 (p = 0.013) was decreased in response patients compared with non‐response patients. In adalimumab subgroup, MALT1 at W24 (p = 0.015) was lower in remission patients than non‐remission patients. CONCLUSION: Mucosa‐associated lymphoid tissue lymphoma translocation protein 1 reduction after treatment is associated with response and remission to TNFi in RA patients.