| Objective(s):Pulmonary infection is an infectious diseases of the lung parenchyma and interstitium.The severity of these diseases is related to the virulence of the pathogen and the immune function of the hosts.Patelets previously were thought to be the cytoplasm shed by megakaryocytes in the bone marrow and mainly involved in hemostasis and thrombosis.In recent years,it has been discovered that the lung is also an important site of platelet production,and platelets in the pulmonary circulation play a dual role in the physiological defense and pathological damage of the lung.Previous researches on the quantitative changes of platelets and their involvements in anti-infective immunity mostly focused on animal models of pulmonary infectious diseases.However,there is rare clinical research on the changes in the parameters of platelets in patients with pulmonary infections,the relationship between platelets and other immune cells(such as the T-cell and B-cell,etc)and whether platelets and immune cells affect the development of severe pulmonary infectious diseases.Exploring the changed parameters of platelets in patients with clinical lung infections may provide useful clues for the treatment of diseases with different severity and bacteria of lung infections.Herein,this study is conducted to analyze through retrospective case comparisons of the changed parameters of peripheral platelet in the healthy controls,patients with non-severe lung infections,patients with severe lung infections,patients with different bacterial infections,and patients with lung infections combined with different underlying diseases,also exploring the correlation between the peripheral platelets and intrinsic immunity,adaptive immune cells and immune molecules in the above-mentioned group,lastly the effects of platelets,will investigated intrinsic immune indexes,and underlying diseases on the development of lung infections.Methods:1.According to the diagnostic criteria of the 2016"Guidelines for the Diagnosis and Treatment of Community-Acquired Pneumonia in Chinese Adults",367 cases of clinically diagnosed pulmonary infection were collected from January2018 to September 2022 in the Respiratory Department of the First People’s Hospital of Kunming as the lung infection group,which include 294 patients with non-severe lung infections,73 patients with severe lung infections,34 patients with Gram-positive bacterial infections,82 patients with Gram-negative bacterial infections,65 patients with lung infections combined with Cor Pulmonale,63 patients with lung infections combined with diabetes,and 59 simple lung infection,64 healthy subjects from Kunming’s First People’s Hospital were collected as controls based on the screening criteria of the healthy control group.2.Basic characteristics for all subjects,include gender,age,past medical history,body temperature on admission,heart rate,respiratory rate,blood pressure,etc were recored.Observation indicators include platelet count(PLT),plateletcrit(PCT),platelet-large cell ratio(P-LCR),mean platelet volume(MPV),platelet distribution width(PDW),total number of white blood cells(WBC),absolute value of neutrophilicgranulocyte(NEUT),absolute value of lymphocyte(LYM),absolute value of monocytes(MONO),immunoglobulin A(Ig A),immunoglobulin G(Ig G),immunoglobulin M(Ig M),and complement C3(C3),complement C4(C4),percentage of T lymphocytes(CD3~+T),percentage of helper T lymphocyte subpopulation(CD3~+CD4~+T),percentage of cytotoxic T lymphocyte subpopulation(CD3~+CD8~+T),percentage of natural killer cells(NK-CELL),percentage of B lymphocytes(B lymphocyte cell(B-CELL)percentage.The laboratory of indicators were detected in according to the instructions of test kit.3.The platelets and parameters of six group,non-severe lung-infected people,severe lung infected,lungs infected with different bacteria,and lung infections combined with different basic diseases compare with health contros.The correlation between platelets and immune cells and immune molecules in patients with different severity levels of pulmonary infection and pulmonary infection combined with different basic diseases were analyzed using the rank correlation statistical method.The influence factors for the occurrence of severe pulmonary infection were using Logistic regression to analyze.Results:1.The results of descriptive statistical analysis from the basal characteristics and the observations in 64 healthy individuals and 367 patients with lung infection showed that the data of CD3~+CD4~+T and CD3~+CD8~+T were normally distributed and the rests were skewed.There were the significantly differences of the basal characteristics except for systolic blood pressure between the healthy controls and the patients.There were the significantly differences of the observed indicators between healthy individuals and patients with lung infection except for Ig A,CD3~+T,and CD3~+CD4~+T.2.The results from comparative analysis of peripheral platelets parameters between the 3 groups:the healthy individuals,the patients with common lung infection,and the patients with severe lung infection,showed the significant differences in 5 parameters.Further stratified analysis results showed the significantly decrease in platelet count and PCT in patients with severe pulmonary infection compared to healthy patients and patients with common lung infection.The MPV,PDW and P-LCR were significantly elevated in the patients with severe lung infection compared with those with common lung infection.The MPV,PDW and P-LCR were significantly reduced in patients with common lung infection compared with healthy subjects.3.The results from the comparative analysis of peripheral platelets parameters between the 3 groups:the healthy controls,the patients with infected by bacteria in lung,and the patients infected by non-bacterial pathogens,showed significantly differences in PLT,PCT,MPV,and PDW.The further stratified analysis results showed that PLT,PCT,MPV,and PDW were significantly lower in the patients infected by bacteria in lung than in healthy controls.4.The results from the comparative analysis of peripheral platelet parameters from he healthy controls,the patients with infected by bacteria Gram-positive in lung,and the patients infected by Gram-negative bacteria in lung showed significantly differences in PLT,PCT and PDW.The further stratified analysis results showed the lower PLT and the lower PCT in the patients with infected by bacteria Gram-positive and the lower PDW in the patients infected by Gram-negative bacteria significantly.5.The results from the comparative analysis of peripheral platelet parameters from he healthy controls,the patients with simple pulmonary infection,the patients with pulmonary infection combined with pulmonary heart disease and combined diabetes mellitus showed significantly differences in five parameters among the four groups.Further stratified analysis results showed the significant lower levels of PLT and PCT in the patients with pulmonary infection combined with pulmonary heart disease and combined with diabetes mellitus.The results also showed the significant lower levels of PDW in the patients with pulmonary infection combined combined pulmonary heart disease.6.The results by the correlative analysis between peripheral platelet counts and immune index test results from the healthy individuals,the patients with common lung infection and the patients with severe lung infection showed that PLT was positively correlated with WBC,NEUT,LYM,C3,Ig G,and Ig M in the patients with common lung infections and positively correlated with MONO and LYM in the patients with severe pulmonary infections significantly.7.The results by the correlative analysis between peripheral platelet counts and immune index test results from the patients with pulmonary infection alone,the patients with pulmonary infection combined with pulmonary heart disease and combined with diabetes showed that PLT was positively correlated with WBC,NEUT and MONO in patients with combined pulmonary heart disease and PLT was positively correlated with C3 and Ig G in the patients with diabetes mellitus significantly.8.The results from logistic regression statistics of platelets,age,blood pressure and other basic conditions,intrinsic immune factors,and the presence of coexisting pulmonary heart disease or diabetes showed that coexisting pulmonary heart disease increased neutrophil count,decreased platelet and monocyte count were the influence factors for severe pulmonary infections disease.Conclusion(s):1.Peripheral platelet counts were reduced and platelet volumes changed differently in pulmonary infectious diseases,particularly in patients with severe pulmonary infections,in patients with pulmonary infections by Gram-positive bacterial,and in patients with pulmonary infections combined with pulmonary heart disease.It is worth referring to the changes of platelet parameters in the blood cell analysis reports to obseves the patients with pulmonary infections.2.Platelets may participate in the anti-infection immunity process by supplementing the immune cells and immune moleculesin in different ways in patients with lung infection and in patients with lung infection combined with different underlying diseases.Further studies are necessary.3.The combination of pulmonary heart disease,decreased absolute monocyte and platelet counts,and increased absolute neutrophil counts may be important influence factors for patients with severe pulmonary infections and deserve clinical attention. |
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