Peripheral blood T-lymphocyte subsets are potential biomarkers of disease severity and clinical outcomes in patients with ulcerative colitis: a retrospective study

BACKGROUND: Ulcerative colitis (UC) is considered an immune-mediated disease. The disorder of T-lymphocyte subsets plays an important role in the pathogenesis of UC. The aim of this study was to evaluate the significance of peripheral blood T-lymphocyte subsets in assessing disease severity and predicting clinical outcomes in UC patients. METHODS: The retrospective case-control study was performed in 116 UC patients with active disease and 90 healthy controls (HC). The UC patients included were followed up for 180 days. Analyses of t-test, Spearman’s correlation coefficient, multivariable Cox regression analysis, receiver operating characteristic (ROC) curves and cumulative survival analysis were done. RESULTS: The UC patients had lower proportions of CD4(+)T cells (42.85%±9.77% vs 45.71%±7.94%, P=0.021) and higher proportion of CD8(+)T cells (27.88%±8.86% vs 25.00%±6.47%, P=0.008) than HC. The severely active UC patients had higher proportion of CD3(+)HLA-DR(+) T cells (8.83%±6.55% vs 2.80%±1.55%, P<0.001; 8.83%±6.55% vs 4.06%±5.01%, P<0.001) and CD8(+)T cells (31.35%±8.49% vs 26.98%±7.98%, P=0.029; 31.35%±8.49% vs 25.46%±9.15%, P=0.003) than mild and moderate group, whereas lower proportion of CD4(+)CD25(+)T cells (2.86%±1.35% vs 3.46%±1.07%, P=0.034) than mild group and CD4(+)T cells (40.40%±9.36% vs 44.73%±10.39%, P=0.049) than moderate group. The area under the curve (AUC) of CD3(+)HLA-DR(+) T cells for assessing severely active UC was 0.885, with the cut-off value of 5.33%. The sensitivity was 76.32% and specificity was 89.74%. The combination of CD3(+)HLA-DR(+) T cells and CRP had stronger assessment value with AUC of 0.929. The AUC of CD8(+)T cells, CD4(+)/CD8(+) ratio and CD4(+)CD25(+)T cells for assessing disease severity was 0.677, 0.669 and 0.631 respectively. Within the 180 days follow-up, 24 patients (20.69%) had UC-related readmission or surgery, with higher proportion of CD3(+)HLA-DR(+) T cells (10.66%±9.52% vs 3.88%±2.56%, P=0.003) and CD8(+)T cells (31.19%±10.59% vs 27.01%±8.20%, P=0.039) than those without readmission and surgery. The proportion of CD3(+)HLA-DR(+) T cells was the independent predictor of UC-related readmission or surgery (HR=1.109, P=0.002). The AUC of CD3(+)HLA-DR(+) T cells for predicting readmission or surgery was 0.796 with the cut-off value of 5.38%. UC patients with CD3(+)HLA-DR(+)T cells proportion>5.38% had a shorter time to readmission or surgery (log-rank test, P<0.001). CONCLUSIONS: The combination of CD3(+)HLA-DR(+)T cells and CRP may be potential biomarker of disease severity in UC patients. The high proportion of CD3(+)HLA-DR(+)T cells may be associated with an increased risk of readmission or surgery in UC patients.