Clinical and cytokine response to immunopure apheresis in patients with refractory ulcerative colitis: results from a single-center study

Abstract Background Ulcerative colitis (UC) is a chronic inflammatory bowel disease marked by relapsing–remitting mucosal inflammation. Activated granulocytes, monocytes, and platelets contribute significantly to UC pathogenesis. Immunopure, a novel blood cell adsorption column, selectively removes these activated cells and may offer a promising therapeutic option for refractory UC. Methods This prospective, single-center, open-label study evaluated the efficacy, safety, and immunologic impact of Immunopure in patients with moderate-to-severe UC. Nine patients with refractory UC underwent up to ten apheresis sessions. The primary endpoint was the change in tumor necrosis factor-alpha (TNF-α) levels at the outflow side of the column during the first session. Secondary endpoints included clinical response assessed by the Lichtiger index, safety, removal rates of blood cells and cytokines, and changes in biomarkers such as C-reactive protein (CRP) and leucine-rich α2-glycoprotein (LRG). Results No significant change in TNF-α levels was observed at column outflow after the first session (1.11 ± 0.77 versus 1.08 ± 0.65 pg/mL; p = 0.82), although transient reductions up to 56.8% were noted at 15 min. Immunopure effectively removed granulocytes and monocytes (overall removal rates 28.3% and 23.8%, respectively) and modestly removed platelets (6.1%). Six of nine patients (66.7%) achieved clinical remission (Lichtiger index ≦ 4) and seven (77.8%) achieved clinical response. Adverse events were mild and transient. LRG levels tended to decrease in responders, although statistical significance was not reached. Conclusions Immunopure demonstrated a favorable safety profile and selectively removed proinflammatory leukocytes and platelets. Although the predefined primary endpoint was not met, early clinical improvement was observed in some patients. Given the small sample size and uncontrolled design, the observed clinical and immunologic changes should be interpreted cautiously as exploratory and hypothesis-generating. Trial registration Japanese Registry of Clinical Trials registration number: jRCTs032210590.