Objective: To explore the characteristics of acquired fungal infections in critically ill patients in the intensive care unit (ICU)

and the value of CD4+and CD8+T cell immune function in the clinical evaluation of acquired fungal infections. Methods: The fungus-positive patients admitted to the Department of Critical Care Medicine of The First Affiliated Hospital of Chongqing Medical University from January 2017 to December 2019 were included in the study. According to the diagnostic criteria

they were divided into fungal infection group (49 cases) and colonization group (37 cases). The acute physiology and chronic health evaluationⅡ (APACHEⅡ) scores

days of ICU

whether there was complication of sepsis

deep venous catheterization

mechanical ventilation

the use of hormones and broad-spectrum antibiotics were recorded and analyzed. The patients’vital signs such as body temperature

respiratory rate and pulse rate

and the test values of T cells such as the percentage of CD4+T cells

CD8+T cells percentage and the ratio of CD4+/CD8+were collected from specimens within 48 h. Binary logistic regression was used to analyze the risk factors of infection and establish a prediction model

mean-while the predictive probability was obtained. The receiver operating characteristic (ROC) curve was used to analyze the above indicators and evaluate the diagnostic value of fungal infections. Results: In the infection group

the APACHEⅡscore (P=0.045)

the number of cases with sepsis (P=0.049)

the number of mechanical ventilation cases (P=0.011)

and the body temperature (P=0.049) were significantly higher than those in the colonization group. It is statistically significant (P<0.05). The other indicators were not statistically significant in evaluating the comparison of fungal infection and colonization (P>0.05). According to the subgroup analysis of different strains of the first culture results

it was found that there was no statistical difference in the T cell detection value among different groups (P>0.05). Logistic regression analysis was carried out to analyze the T cell detection values in the infection group and the colonization group and to establish a prediction model 1

and its prediction probability was analyzed (P=0.013); then the prediction probability (prediction model 2) of the number of patients complicated with sepsis and the T cell detection value was analyzed (P=0.024); the predicted probability of ICU duration

APACHEⅡscores

sepsis complication

deep venous catheterization

mechanical ventilation

use of hormones

use of broad-spectrum antibiotics

and T cell detection values (prediction model 3) were analyzed (P=0.025). According to ROC curve analysis

the area under curve (AUC) of APACHEⅡscores was 0.577

body temperature (0.487)

CD4+T cells (0.515)

CD8+T cells (0.565) and CD4+/CD8+ratio (0.438). Prediction model 1 (AUC=0.611) and prediction model 2 (AUC=0.653) were of low value in evaluating the diagnosis of acquired fungal infections. Prediction model 3 (AUC=0.757) was of higher diagnostic value for evaluating acquired fungal infection. Conclusion: Severe ICU patients with sepsis or mechanical ventilation are more susceptible to fungal infection; while patients with sepsis combined with the detection of CD4+T cells and CD8+T cells

it has a suggestive effect on the diagnosis of acquired fungal infection; and when patients with sepsis are admitted to the ICU and have risk factors of fungal infection such as invasive procedures

hormones and broad-spectrum antibiotics

they are more susceptible to fungal infections.