Application Value Of Alveolar Lavage Fluid Combined With MNGS In Immunosuppression Combined With Pulmonary Infection Etiology

Objectives:To understand the application value of alveolar lavage fluid combined with metagenomic next-generation sequencing technology(mNGS)in the diagnosis and guided treatment of pathogens in immunosuppression with pulmonary infection.Methods:We retrospectively analyzed the clinical data of 87 immunosuppressed patients and188 non-immunosuppressed patients diagnosed with lung infection from January2020 to December 2022,and the detection results of sputum culture/sputum smear,alveolar lavage solution combined with mNGS etiology were collected,and the diagnostic and treatment guidance efficacy of alveolar lavage fluid combined with mNGS in patients with immunosuppression with pulmonary infection were analyzed,and ROC curves were drawn.Results:In the non-immunosuppressive group and the immunosuppressed group,the prognosis of alveolar lavage fluid combined with mNGS-positive patients was statistically significant(P < 0.05),and the relationship between sputum culture results and prognosis was not statistically significant(P = 0.549).The positive rate of pathogen detection in alveolar lavage solution combined with mNGS in the immunosuppressive group was higher than that of conventional sputum culture,and the difference was statistically significant(P < 0.05).CRP,PCT,hospitalization cost,hospitalization days and other indexes were higher in the immunosuppressive group than in the nonimmunosuppressive group,and the absolute lymphocyte count was lower than that in the non-immunosuppressive group(P < 0.05).The immunosuppressive group was divided into four subgroups,namely 31 cases in the kidney transplant group,15 cases in the HIV group,15 cases in the malignant tumor group and 26 cases in the extrinsic hormone immunosuppressive group,among which the number of days of hospitalization and the hospitalization cost in the renal transplant group were higher than those in the extrinsic hormonal immunosuppressive group(P < 0.05).The absolute count and mean age of lymphocytes were lower than those in the extrinsic hormonal immunosuppressive group(P < 0.05).There was no significant difference in the relationship between subgroups of immunosuppressive group alveolar lavage fluid combined with mNGS,sputum culture and prognosis.ROC curve A showed that alveolar lavage fluid combined with mNGS had a treatment-guiding efficacy in all patients(AUC = 0.672;95% CI: 0.560 to 0.785);ROC curve B showed that alveolar lavage fluid plus mNGS had good therapeutic efficacy in patients with immunosuppression with pulmonary infection(AUC = 0.634;95% CI: 0.448 to0.819).Conclusions:Compared with traditional sputum culture/sputum smear,mNGS technology has significant advantages in detecting pathogens,and alveolar lavage fluid combined with mNGS can improve the positive rate of etiological diagnosis in patients with immunosuppression with pulmonary infection,which is advantageous.It has good treatment guidance effect in the rapid detection of related pathogens and further guidance of treatment.