Objective:To evaluate the application of metagenomic next-generation sequencing（mNGS）in the identification of non-tuberculous mycobacteria（NTM）.Methods:A retrospective analysis was conducted on mNGS results of 358 bronchoalveolar lavage fluid（BALF）samples positive for NTM collected at the First Affiliated Hospital of Zhejiang University School of Medicine from February 2021 to January 2024. The analysis included the distribution of NTM species，the detection of mixed pathogens，and the performance of conventional mycobacterial detection methods.Results:The results showed that 362 strains of 15 NTM species were identified from 350 specimens，8 specimens were not precise to the species level. The most frequently detected species were Mycobacterium intracellulare（37.3%，135/362）， Mycobacterium abscessus（26.8%，97/362），followed by Mycobacterium avium（11.0%，40/362）， Mycobacterium kansasii（8.0%，29/362）and Mycobacterium chelonae（7.7%，28/362）. Single NTM species were detected in 339 specimens，while two or three NTM species were simultaneously detected in 11 specimens（3.1%，11/358）. Non-NTM microorganisms co-infected were detected in 53.4%（191/358）of NTM-positive BALF samples，including common pathogens such as Pseudomonas aeruginosa， Staphylococcus aureus，and Aspergillus fumigatus；and difficult-to-identify pathogens such as Legionella pneumophila and Talaromyces marneffei. In NTM-positive patients detected by mNGS，the results supported the diagnosis of NTM infection in 298 cases（298/358，83.2%）and 105 cases（105/358，29.3%）initiated anti-NTM treatment accordingly；while in 60 cases（60/358，16.8%）the positive results were considered as colonization or unrelated to clinical infection. For samples tested with acid-fast staining，mycobacterial liquid culture，and DNA microarray，the positivity rates for NTM were 31.5%（73/232），48.7%（57/117），and 43.0%（46/107），respectively. Conclusions:mNGS demonstrates advantages in identification of NTM. However，the test may detect multiple microorganisms，in that case，the interpretation with clinical and radiological results is requried to determine the main pathogens.

Objective:To evaluate the application of metagenomic next-generation sequencing（mNGS）in the identification of non-tuberculous mycobacteria（NTM）.Methods:A retrospective analysis was conducted on mNGS results of 358 bronchoalveolar lavage fluid（BALF）samples positive for NTM collected at the First Affiliated Hospital of Zhejiang University School of Medicine from February 2021 to January 2024. The analysis included the distribution of NTM species，the detection of mixed pathogens，and the performance of conventional mycobacterial detection methods.Results:The results showed that 362 strains of 15 NTM species were identified from 350 specimens，8 specimens were not precise to the species level. The most frequently detected species were Mycobacterium intracellulare（37.3%，135/362）， Mycobacterium abscessus（26.8%，97/362），followed by Mycobacterium avium（11.0%，40/362）， Mycobacterium kansasii（8.0%，29/362）and Mycobacterium chelonae（7.7%，28/362）. Single NTM species were detected in 339 specimens，while two or three NTM species were simultaneously detected in 11 specimens（3.1%，11/358）. Non-NTM microorganisms co-infected were detected in 53.4%（191/358）of NTM-positive BALF samples，including common pathogens such as Pseudomonas aeruginosa， Staphylococcus aureus，and Aspergillus fumigatus；and difficult-to-identify pathogens such as Legionella pneumophila and Talaromyces marneffei. In NTM-positive patients detected by mNGS，the results supported the diagnosis of NTM infection in 298 cases（298/358，83.2%）and 105 cases（105/358，29.3%）initiated anti-NTM treatment accordingly；while in 60 cases（60/358，16.8%）the positive results were considered as colonization or unrelated to clinical infection. For samples tested with acid-fast staining，mycobacterial liquid culture，and DNA microarray，the positivity rates for NTM were 31.5%（73/232），48.7%（57/117），and 43.0%（46/107），respectively. Conclusions:mNGS demonstrates advantages in identification of NTM. However，the test may detect multiple microorganisms，in that case，the interpretation with clinical and radiological results is requried to determine the main pathogens.

Objective:To investigate the clinical features of Epstein-Barr virus associated lymphoproliferative disease in children and to improve the understanding of this disease.Methods:This study included the children with Epstein-Barr virus associated lymphoproliferative disease admitted to the First Affiliated Hospital of College of Medicine of Zhejiang University from January 2014 to December 2018.Data of these children were collected, including age, clinical manifestations, laboratory results, treatment and outcome.The clinical features and therapeutic effects were analyzed.Results:A total of 114 cases(mean age 6 years, 0~17 years)were enrolled in this study, including 53 males and 61 females.There were 107 cases(93.86%) in the mild group (38 cases of EBV infection and 69 cases of infectious mononucleosis) and 7 cases in the severe group (6.14%). Six cases of the severe group were T cell or NK cell proliferation.Compared with the mild group, the load of EBV-DNA was higher in the severe group, but there was no significant difference( χ2=0.957, P>0.05). The IgM in severe group was significantly lower( Z=-2.041, P<0.05). But the differences in the level of immune function including IgA, IgG, CD4 + cell and CD8 + cell between the severe group and the mild group were not significant.The cases in the mild group had improved after antiviral treatments.Among the severe group, 3 cases survived after treatment, another 1 case was diagnosed as hydroa vacciniforme-like EBV-related proliferative disease (HV-like LPD). After antiviral treatment, the effect was not good, then after high-dose IVIG treatment and Bortezomib combined with methylprednisolone treatment, the EBV-DNA load decreased and the condition improved.While 1 case lost to follow-up, there were 2 cases with EBV-associated hemophagocytic syndrome and 1 case with EBV-associated lymphoma died after chemotherapy or transplantation. Conclusion:EBV-associated lymphoproliferative disease may manifest as a condition similar to infectious mononucleosis.High IgE, low IgM or high DNA load may indicate poor prognosis.Immune function after EBV infection may have different effects on prognosis.When the infected lymphocyte types are NK or T cells, it may indicate poor prognosis.The efficacy of transplantation and chemotherapy in severe cases is still uncertain.