Assessment of clinical activity and severity using serum ANCA and ASCA antibodies in patients with ulcerative colitis

Ulcerative colitis (UC) is a chronic, non-specific inflammatory bowel disease (IBD) with unknown etiology. The lack of specific clinical manifestations, standard diagnostic criteria, objective and accurate indicators to the severity of the disease and the efficacy of the treatment, often results in difficulties in diagnosis and timely treatment of UC. Therefore, there is a need to develop a clinically suitable serum biomarker assay with high specificity and sensitivity.

To explore the significance of anti-neutrophil cytoplasmic antibodies (ANCA) and anti-saccharomyces cerevisiae antibodies (ASCA) in the diagnosis, differential diagnosis and treatment assessment in patients with ulcerative colitis (UC). Serum levels of ANCA-IgG, ASCA-IgA and ASCA-IgG were measured by an enzyme-linked immunosorbent assay (ELISA) in 105 UC patients, 52 non-UC patients and 100 healthy controls.

(1) Both the ANCA-IgG level and its positive rate in UC patients were significantly higher than those in non-UC controls and healthy controls (p < 0.01). However, the levels of ASCA-IgA, ASCA-IgG and the positive rates in UC patients had no statistical differences when compared with those in non-UC controls or healthy controls (p > 0.05). (2) The sensitivity of ANCA⁺ and ANCA⁺/ASCA⁻ in detecting UC patients was 61.90% and 55.24%, respectively, whereas the specificity was 91.45% and 94.08%, respectively. The sensitivity of ASCA⁺ and ASCA⁺/ANCA⁻ in non-UC disease controls was 5.33% and 3.85%, respectively, and specificity was 83.9% and 88.78%, respectively. (3) When UC patients were grouped into mild, moderate or severe subtypes, the ANCA-IgG levels were correlated with the severity of UC, and the differences of the ANCA-IgG levels were statistically different among the three subtypes (p < 0.05). There was no correlation between the levels of ANCA-IgG and the disease locations of UC.

(1) Serum levels of ANCA may be useful in the diagnosis of UC. (2) Dynamic quantitation of ANCA-IgG levels may be helpful in determining the severity of UC and therefore, may guide treatment of UC.