Prospective evaluation of lymphocyte subtyping for the diagnosis of invasive candidiasis in non-neutropenic critically ill patients

Objectives: This study aimed to investigate the distinguishing ability of lymphocyte subtyping for Invasive candidiasis (IC) diagnosis and prognosis in non-neutropenic critically ill patients.

Methods: We assessed the quantitative changes in key parameters of lymphocyte subtyping at the onset of clinical signs of infection in non-neutropenic critically ill patients and their potential influence on diagnosis and outcome of IC. The primary outcome was 28-day mortality.

Results: Among the 182 consecutive critically ill patients, 22 (12.1%) were in the IC group. The CD28⁺CD8⁺ T-cell counts (AUC 0.863, 95%CI 0.804-0.909, P<0.001) had greater diagnostic value for IC than other parameters had. Adding CD28⁺CD8⁺ T to Candida score significantly improved the predictive value of Candida score (P=0.039). Multivariate logistic regression analysis identified CD28⁺CD8⁺ T-cell counts≤78 cells/mm³ (OR 24.544, 95%CI 6.461-93.236, P<0.001) as an independent predictor for IC diagnosis. CD28⁺CD8⁺ T-cell counts could also predict 28-day mortality. Kaplan-Meier survival analysis provided evidence that CD28⁺CD8⁺ T-cell count <144cells/mm³ (log-rank test; P=0.03) were associated with lower survival probabilities.

Conclusions: CD28⁺CD8⁺ T-cell counts play an important role in early diagnosis of IC. Low counts are associated with early mortality in non-neutropenic critically ill patients. These results suggest the potential usefulness of measuring CD28⁺CD8⁺ T-cell lymphocyte levels in the early recognition and diagnosis of IC.

Trial registration: ChiCTR-ROC-17010750. Registered 28 February 2017.