Application Value Of Bronchoalveolar Lavage Fluid Cytological Classification In Diffuse Parenchymal Lung Disease

Objective: To observe the cell classification of bronchoalveolar lavage fluid(BALF)in patients with different diffuse parenchymal lung disease(DPLD),and to study the correlation between different cell types and the severity of disease,then to explore the application value of BALF cell classifycation in DPLD.Method:125 patients who had imaging manifestations of diffuse lesions in both lungs and underwent cytological analysis of bronchoalveolar lavage fluid were enrolled in the Second Department of Respiratory Medicine of the Second Hospital of Hebei Medical University from January 2016 to October 2017.According to the 2016 adult community-acquired pneumonia diagnostic criteria and the expert consensus of ATS/ERS published in 2002 recommended ILD diagnosis and classification methods and IIP international multidisciplinery classification criteria revised in 2013,the above patients were divided into 40 cases of pneumonia group,85 cases of interstitial lung disease group.Patients with interstitial lung disease(ILD)were divided into:(1)49 cases of idiopathic interstitial pneumonia(IIP)group: 16 cases of idiopathic pulmonary fibrosis(IPF),7 cases of other IIP,5 cases of cryptogenic organizing pneumonia(COP),21 cases of interstitial pneumonia with autoimmune feature(IPAF);(2)25 cases of connective tissue disease-associated interstitial lung disease(CTD-ILD)group: 12 cases of sjogren’s syndrome-associated interstitial lung disease(SS-ILD),7 cases of rheumatoid arthritis-associated interstitial lung disease(RA-ILD),5 cases of dermatomyositis/polymyositis-associated interstitial lung disease(PM/DM-LD),1 cases of systemic sclerosis associated interstitial lungease(SSc-ILD);(3)4 cases of granulomatous ILD group: 2 cases of allergic alveolitis(HP),2 cases of sarcoidosis;(4)7 cases of rare other ILD group: 3 cases of pulmonary alveolar proteinosis(PAP),4 cases of chronic eosinophilic pneumonia(CEP);To observe the cytological classification of BALF in patients with pneumonia,ILD and each group of ILD and study the correlation between different cell types in BALF and pulmonary function test(PFT)severity,HRCT score,oxygenation index,degree of dyspnea,procalcitonin(PCT),and serum leukocyte count of each group of patients,then explore the application value of cytology classification in DPLD.Result:1 The proportion of neutrophils in BALF of patients with pneumonia was increased(21.70±13.97%)and was higher than that in the ILD group(7.92±4.56%).The difference was statistically significant(P<0.05).2 The proportion of neutrophils in BALF of patients with pneumonia was positively correlated with serum leukocyte count(r=0.418,P=0.007),and positively correlated with PCT(r=0.314,P=0.048).3 The proportion of neutrophils(8.39±4.76%)in BALF of patients with IIP was increased;the proportion of neutrophils(8.40±4.12%)in BALF of patients with CTD-ILD was increased;the proportion of BALF lymphocytes(15.75±10.72%)and neutrophil percentage(6.00±4.08%)in patients with granulomatous ILD were increased;the proportion of BALF eosinophils(33.00±32.23%)in other rare ILD patients was increased.4 The proportion of neutrophils in BALF increased in patients with IPF,other IIP,and COP(10.44±4.55%,5.86±3.76%,5.40±6.19%);the proportion of BALF neutrophils(8.38±4.38%)and eosinophils(3.43±3.75%)in patients with IPAF were increased;the proportion of neutrophils in SS-ILD,RA-ILD,PM/DM-ILD,SSc-ILD group was increased(6.25±4.37%,10.00±2.38%,9.40±2.70%,10.00%);the proportion of neutrophils(8.50±4.95%)in the sarcoidosis group was increased mainly;the proportion of lymphocytes(24.00 ±5.66%)in the HP group was increased;the proportion of macrophages(93.33 ±1.53%)in patients with PAP was increased;the percentage of eosinophils(57.2±16.07%)in patients with CEP was increased.5 The percentage of eosinophils in BALF in patients with IIP was negatively correlated with the percentage of total lung capacity(TLC%)(r=-0.323,P=0.037).6 The proportion of neutrophils in BALF of patients with IPF was positively correlated with the HRCT scores(r=0.508,P=0.045),and negatively correlated with the percentage of diffusion capacity for carbon monoxide(DLco%)(r=-0.616,P= 0.043).The proportion of eosinophils in BALF was negatively correlated with TLC% in patients with IPAF(r=-0.563,P=0.015).The proportion of BALF lymphocytes in the SS-ILD group was negatively correlated with the oxygenation index(r=-0.581,P=0.047).Conclusion:The cytological classification of bronchoalveolar lavage fluid helps make certain diagnosis and narrows the scope of differential diagnosis in diffuse parenchymal lung disease.The bronchoalveolar lavage fluid cell types vary between different interstitial lung diseases and may be related to the severity of disease.An increase in the proportion of neutrophils in bronchoalveolar lavage fluid in patients with pneumonia may suggest a pulmonary bacterial infection.