Identification Of The Pathogens In Opportunistic Infections After Allogeneic Hematopoietic Stem Cell Transplantation

Background and ObjectionViral infections and diseases remain important complications after allogeneic hematopoietic stem cell transplantation(allo-HSCT),the etiological diagnosis of viral diseases after transplantation mainly relies on laboratory examinations.Conventional methods had limited sensitivity and time consuming.Moreover,some critical patients can not accept the invasive procedures.At present,the detection of viruses in tissue biopsy specimens or/and body fluids specimens via real-time quantitative polymerase chain reaction(RQ-PCR)is considered to be the diagnostic criteria for viral diseases.However,for intestinal viral disease after allo-HSCT,the diagnostic value of viruses detected in feces via RQ-PCR remains undetermined.Metagenomics next-generation sequencing(mNGS),as a new molecular methods,has attracted more and more attention in recent years.Nowdays,it is hard to detected pathogens in cerebrospinal fluid(CSF),the clinical usefulness of mNGS remains under discussion in detection of pathogens in central nervous system(CNS)infections after allo-HSCT.Therefore,we focused on the the following questions:1.The clinical value of mNGS and conventional methods for diagnosing CNS infections after allo-HSCT;2.the efficiency of detecting viruses via RQ-PCR in feces for diagnosis of intestinal viral diseases after allo-HSCT.Methods1.The clinical value of mNGS and conventional methods for diagnosing CNS infections after allo-HSCT:A total of 53 patients undergoing allo-HSCT between July 2016 and March 2019 in Nanfang Hospital Southern Medical University were enrolled in this study.Pathogens in CSF specimens were detected by traditional methods and mNGS respectively.Then,compare the sensitivity and specificity of mNGS and conventional methods for pathogens detection in CNS infection.2.The efficiency of detecting viruses in feces via RQ-PCR for diagnosis of intestinal viral diseases after allo-HSCT:A total of 81 patients undergoing allo-HSCT in Nanfang Hospital Southern Medical University,Guangzhou First People’s Hospital,Traditional Chinese Medicine Hospital of Guangdong Province between Jan 2016 and Nov 2020 were enrolled in this study.Intestinal biopsies specimens and feces specimens were collected for pathogens detection.Then,evaluated the sensitivity and specificity of detecting viruses via RQ-PCR in feces for diagnosis of intestinal viral diseases after allo-HSCT.Statistical analysisThe SPSS statistics 19.0(SPSS,Chicago,IL)and R version 3.4.3(R Development Core Team,Vienna,Austria)were used for data analysis.All of the data received normality tests.The Pearson X2 or Fisher’s exact test was used to compare the sensitivity and specificity between mNGS and conventional testing related to the final diagnosis.The pathological diagnosis was recognized as the gold standard,the sensitivity and specificity of virus detection in feces via RQ-PCR were analyzed.The incidence of CNS infections was estimated as cumulative incidence by competing risks analysis.All P values were 2-sided with significance level at α=0.05.Results1.The clinical value of mNGS and conventional methods for diagnosing CNS infections after allo-HSCT:(1)The sensitivity of mNGS and conventional testing for diagnosing CNS infections post-transplant were 97.1%and 82.9%,respectively while the specificity of mNGS and conventional testing were 94.4%and 100%,respectively;(2)66.0%patients diagnosed with CNS infections and viruses were the most frequent pathogens.The 2-year cumulative incidence of overall CNS infections and CNS viral infections post-transplants were 6.59%and 5.29%,respectively;2.The efficiency of detecting viruses in feces via RQ-PCR for diagnosis of intestinal viral diseases after allo-HSCT:(1)In the patients with intestinal aGVHD complicated with refractory diarrhea after allo-HSCT,66.7%had intestinal viral diseases,CMV was the most common pathogen;(2)the sensitivities of RQ-PCR in feces specimens for diagnosing CMV and EBV diseases were 87.9%and 87.5%,respectively,the specificites were 95.8%and 98.2%respectively;(3)the sensitivities of RQ-PCR in blood specimens for diagnosing CMV and EBV diseases were 60.6%and 20.8%,respectively,the specificites were 20.8%and 31.6%respectively;Conclusion:1.mNGS might be a promising technology for diagnosis of CNS infections post-transplant.Viruses were the most common pathogens of CNS infections in allo-HSCT recipients;2.In the patients with intestinal GVHD complicated with refractory diarrhea after allo-HSCT,viral diseases are common complications and CMVdiseases were the most common.Viruses detected in feces via RQ-PCR may help to diagnose intestinal viral diseases,but virus detected in peripheral blood may not.