Low-dose rituximab in lupus enteritis: a comparative study on its efficacy in modulating mucosal immunity and reducing inflammation

Abstract

Lupus enteritis (LE) is a serious manifestation of systemic lupus erythematosus (SLE), yet optimal treatment strategies remain unclear. This study aimed to compare the efficacy of rituximab (RTX) plus glucocorticoids versus glucocorticoids combined with conventional immunosuppressants in patients with moderate-to-severe LE. We retrospectively analyzed 36 patients with SLE-related intestinal involvement treated at our center between January 2015 and August 2024; sixteen received RTX plus glucocorticoids, and twenty received glucocorticoids with conventional immunosuppressants. Baseline characteristics, clinical features, abdominal CT findings, laboratory parameters (including serum and fecal IgA, IL-6, TNF-α, and IL-10), and disease activity scores (SLEDAI-2 K and BILAG-2004) were assessed. For fecal IgA analysis, age- and sex-matched healthy controls without relevant diseases or recent antibiotic/microbiota-modulating use were included. Treatment response and safety outcomes were compared over 6 months. Both patient groups exhibited comparable baseline characteristics. Both treatment strategies led to significant improvements in clinical symptoms and imaging abnormalities—including bowel wall thickening, mesenteric effusion, comb sign, or target sign—with no significant differences observed between the groups. After six months of treatment, the median SLEDAI-2 K score in the rituximab (RTX) group decreased from 15 to 0 (p < 0.001), and the BILAG-2004 score decreased from 31.5 to 0 (p < 0.001). IL-6 levels in the RTX group also significantly declined from 26.57 ± 7.94 pg/mL to 4.15 ± 2.10 pg/mL (p < 0.01), with a greater reduction compared to the control group. Fecal IgA levels were higher in lupus enteritis patients than in healthy controls and decreased in both groups following treatment. Baseline IL-6 correlated with SLEDAI-2 K and BILAG-2004 scores, whereas fecal IgA was elevated in patients with mesenteric effusion but not associated with overall disease activity. At 6 months, remission was achieved in 93.8% of RTX-treated patients and 85% of controls (p = 0.418), with comparable safety profiles. Both RTX plus glucocorticoids and conventional immunosuppressants plus glucocorticoids are effective in inducing clinical and radiologic remission in LE. RTX may lead to faster improvement in certain serologic and inflammatory biomarkers. Larger studies with longer follow-up and stratification by systemic involvement are warranted to optimize individualized treatment strategies.