Risk Factors Of Respiratory Infections In Patients At Early Stage Of Hematopoietic Stem Cell Transplantation

BackgroundHematopoietic stem cell transplantation (HSCT) has become one of the mostimportant treatment methods for some serious diseases, such as hematologicaldiseases, solid tumors, autoimmune diseases, genetic defects and so on. However,HSCT increases the probability of respiratory tract infections. It has been reported thatthe incidence of respiratory tract infections after HSCT is as high as64.9%. Previousliteratures focused on the risk factors of lower respiratory tract infections, especiallyabout the fungal pneumonia, few literatures focused on the risk factors of upperrespiratory tract infections after HSCT. In recent years, clinicians have noticed thatupper respiratory tract infections are likely to develop into lower respiratory tractinfections after HSCT. Upper respiratory tract infections may be harm for patientswho have received HSCT. More useful strategies to prevent and control upperrespiratory tract infections is required to developed.In recent years, the clinical application of HSCT is gradually expanding.However, there are various factors which may damage the patients’ defensive systemand lead to infections during HSCT. The respiratory tract contains a weak structurewith plenty of bloodstream, which makes it be common for location of pathogensafter transplantation. The reasons why the respiratory tract is easy to be infected afterHSCT may be explained by the following three aspects. First of all, basic diseases increase the opportunity of airway infections. Secondly, immunosuppression afterstem cell transplantation leads to high risk of airway infections. Intense chemotherapyduring pretreatment scheme completely destroys the immune and hematopoiesisfunctions. Before the bone marrow of recipients recovering normal hematopoiesisfunction, the count of peripheral blood cells is extremely low, this makes recipients tobe highly susceptible to pathogens. Even if the hematopoietic function starts toresurrect, the reconstruction of the immune function also needs a long time. Thirdly,graft versus host disease (GVHD) increases the risk of respiratory tract infectionsafter HSCT. GVHD leads to detention of immune reconstruction and immune disorder,which makes recipients to be prone to infection. GVHD damages the mucosa ofrespiratory tract. It makes pathogens easy to colonize. GVHD may also result in thatforeign donor lymphocytes attack bronchial glands of recipients. It reduces the glandsecretion, lowers airway humidity, lessens immunoglobulin secretion, decreases theresistance of respiratory tract to pathogens, and so on.In this research we collected data of168patients after HSCT in our hospital, andanalyzed risk factors of upper respiratory infections and lower respiratory infections.Our aim is to contribute to early diagnosis and treatment of respiratory infections afterHSCT. Early time is defined as1to30days after transplantation. Respiratoryinfections at early stage were defined as respiratory infections from1to30days afterHSCT.Objectives1. To summarize the rate of respiratory tract infection after HSCT;2. To discuss the relation between hematopoietic reconstruction and respiratoryinfections after HSCT;3. To analysis the risk factors of respiratory tract infections at early days afterHSCT;4. To analysis the risk factors of upper respiratory tract infections and lowerrespiratory infections further.Patients and Methods1. PatientsThere were168patients who received hematopoietic stem cell transplantation from2000to2010in our hospital. The primary disease types included32cases ofacute lymphocytic leukemia,49cases of acute non-lymphocytic leukemia,44cases ofthalassemia,12cases of aplastic anemia,3cases of chronic lymphocytic leukemia,9cases of chronic granulocytic leukemia,5cases of lymphoma,2cases of abnormalbone marrow syndrome,2cases of multiple myeloma,4cases of recurrent multiplecartilage inflammation,2cases of systemic lupus erythematosus,2cases ofpseudohypertrophic muscular dystrophy and2cases of mucopolysaccharide storagedisease. The age range was from1to63years old. There were101children (<14years) and67adults (≥14years) in total, and the ratio of adults and children was about1.51:1. There were104cases of male patients and64cases of female patients. Theratio of the male and the female was about1.63:1. According to statistical analysis,two groups were comparable in age and gender.2. Research methods2.1Collection of cases2.1.1To record the basic information of patients who received hematopoietic stemcell transplantation, such as age, gender, disease types and so on;2.1.2To analysis the information such as transplant time, conditioning regimen,hematopoietic recovery and respiratory tract infections at early time after HSCTusing retrospective case-control method.2.2Cases groupOne hundred and sisty-eight cases were divided into two groups according towhether they had respiratory infections at the early time of HSCT.122people hadrespiratory infections and46people hadn’t. Respiratory infections group were dividedinto upper respiratory infections group and lower respiratory infections group further.74peoaple had upper respiratory infections, and48people had lower respiratoryinfections.2.3Statistical analysisNumeric data in normal distribution is described by mean±standard deviation(X|-±s）. Two groups of numeric data in normal distribution are compared with eachother by independent T-test. Numeric data in unnormal distribution is described byMedian and standard deviation. Counting data is described by ratio. Two and more groups of counting material are compared with each other by ANOVA. The sampleswhich are too limited to are compared with each other by spearman correlationcoefficient analysis. SPSS16.0software is applied to statistics analysis. Theunivatiate analysis is used to screen out the possibly significant risk factors. TheForward Logistic Regression analysis is applied to identify the independent riskfactors. P<0.05is considered statistically significant.Results1. The rate of early respiratory infectionsThere were168patients who accepeted HSCT in our hospital from2000to2010.122patients had early respiratory infections after HSCT, and the rate of respiratoryinfections was72.6%.74cases had upper respiratory infections, accounting for44.0%.48cases had lower respiratory infections, accounting for28.6%.From2000to2005, there were59patients who received HSCT in our hospital intotal.52patients of them had early respiratory infections after HSCT, and the rate ofrespiratory infections was88.1%. From2006to2010, there were109patients whoaccepted HSCT in our hospital in total.70patients of them had early respiratoryinfections after HSCT, and the rate of respiratory infections was64.2%. We comparedthe rate of early respiratory infections2000-2005and2006-2010by chi-square test,P<0.05. The difference had statistical significance. The rate of early respiratoryinfections from2006to2010was lower than the rate from2000to2005.2. Time of hematopoietic reconstruction and respiratory infectionsThe mean time of hematopoietic reconstruction of patients was14.5±5.4days.The median time of early respiratory infections of patients was7days.122patientshad respiratory infections in our hospital in total.99patients had respiratory infectionsbefore hematopoietic reconstruction, accounting for81.1%.23patients hadrespiratory infections after hematopoietic reconstruction, accounting for18.9%.3. Risk factors of respiratory infectionsAccording to single factor analysis, age, stem cell sources, type of conditioning regimen, unrelated doner transplantation, HLA unmatched transplantation, long timeof hematopoietic recovery were risk factors of early respiratory infections after HSCT(P<0.05). According to logistic regression analysis, age and unrelated donertransplantation were independent risk factors of early respiratory infections afterHSCT (P<0.05).4. Risk factors of upper respiratory tract infectionsAccording to single factor analysis, age, stem cell sources, unrelated donertransplantation, HLA unmatched transplantation, long time of hematopoietic recoverywere risk factors of upper respiratory tract infection at early time after HSCT (P<0.05).According to logistic regression analysis, age and unrelated doner transplantationwere independent risk factors of upper respiratory tract infection at early time afterHSCT (P<0.05).5. Risk factors of lower respiratory tract infectionsAccording to single factor analysis, stem cell sources, unrelated donertransplantation, HLA unmatched transplantation, aGVHD, previous fungal pneumoniawere risk factors of lower respiratory tract infection at early time after HSCT (P<0.05).According to logistic regression analysis, HLA unmatched transplantation andprevious fungal pneumonia were independent risk factors of lower respiratory tractinfection at early time after HSCT (P<0.05).6. Other relevant factors of lower respiratory tract infectionsAccording to Spearman correlation analysis, oral ulcers，Sepsis had positivecorrelation with lower respiratory tract infections, but we did not classified them intothe risk factors in case of limited cases.Conclusions1. The rate of respiratory infections was81.5%from2000to2010. The rate of earlyrespiratory infections from2006to2010was lower than rate from2000to2005.2. The mean time of hematopoietic reconstruction of patients was14.5±5.4days. The median time of early respiratory infections of patients was7days. Most ofthe respiratory infections occurred before hematopoietic reconstruction.3. According to single factor analysis, risk factors of respiratory infection were age,stem cell sources, type of conditioning regimen, unrelated doner transplantation,HLA unmatched transplantation, long time of hematopoietic recovery. Accordingto multiple factors analysis, the independent risk factors of respiratory infectionswere age and unrelated doner transplantation.4. According to single factor analysis, risk factors of upper respiratory tractinfection were age, stem cell source, unrelated doner transplantation, HLAunmatched transplantation, long time of hematopoietic recovery. According tomultiple factors analysis, the independent risk factors of upper respiratoryinfections were age and unrelated doner transplantation.5. According to single factor analysis, risk factors of lower respiratory tractinfection were stem cell sources, unrelated doner transplantation, HLAunmatched transplantation, aGVHD, previous fungal pneumonia. According tomultiple factors analysis, the independent risk factors of lower respiratoryinfections were HLA unmatched transplantation and previous fungal pneumonia.6. Sepsis and oral ulcer had positive correlation with lower respiratory tractinfection at early time after HSCT.