title: Atopy: a risk factor of refractory mycoplasma pneumoniae pneumonia?
abstract: OBJECTIVE
  To investigate the relationship of pathogen DNA copies with clinic and laboratory features among children with Mycoplasma pneumoniae (MP) pneumonia.
  
  
  METHODS
  A total of 95 enrolled children with MP pneumonia were assigned into the high-MP-load group (>106/mL) and the low-MP-load group (≤106/mL) according to MP-DNA copies in bronchoalveolar lavage fluid (BALF). Clinical characteristics and any allergy history were collected. Aeroallergens and food allergens were detected with a skin test. Serum IgE and eosinophil cationic protein (ECP) were assessed using enzyme immunoassay. BALF levels of IL-4, IFN-γ, IL-8 and TNF-α were assessed by ELISA.
  
  
  RESULTS
  Compared with the low-MP-load group, 72.7% in the high-MP-load group developed refractory MP pneumonia who failed to respond to at least 1-week treatment with macrolides (72.7% vs 41.9%, P = 0.005). More children in the high-load group than those in the low-load group presented with extrapulmonary manifestations, lung consolidation, pleural effusion and atopic conditions including any allergy history, positive findings of aeroallergen test and increased serum IgE and ECP (P < 0.05). A significant higher BALF IL-4 level was seen in the high-load group versus the low-load group (23.00 ± 11.24 vs 14.68 ± 7.12; pg/mL; P < 0.01). There were no significant differences in BALF levels of IFN-γ, IL-8 and TNF-α between the two groups (P > 0.05).
  
  
  CONCLUSIONS
  Atopy may be a risk factor for the presence and severity of refractory MP pneumonia due to the high pathogen load in airway.
authors.affiliation: Department of Pediatric Respirology & Immunology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, 1665 Kongjiang Road, Shanghai, 200092, China.
authors.forename: Yi-Xiao
authors.initials: YX
authors.lastname: Bao
authors.affiliation: Department of Pediatric Respirology & Immunology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, 1665 Kongjiang Road, Shanghai, 200092, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Pediatric Respirology & Immunology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, 1665 Kongjiang Road, Shanghai, 200092, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Tian
authors.affiliation: Department of Pediatric Respirology & Immunology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, 1665 Kongjiang Road, Shanghai, 200092, China.
authors.forename: Quang-Hua
authors.initials: QH
authors.lastname: Liu
authors.affiliation: Department of Pediatric Respirology & Immunology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, 1665 Kongjiang Road, Shanghai, 200092, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Bao
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D058491:Bacterial Load / Q000706:statistics & numerical data; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology / Q000382:microbiology; D002648:Child; D002675:Child, Preschool; D056915:DNA Copy Number Variations / Q000235:genetics; D047150:Eosinophil Cationic Protein / Q000097:blood; D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000097:blood* / Q000175:diagnosis; D007073:Immunoglobulin E / Q000097:blood; D016898:Interferon-alpha / Q000378:metabolism; D015847:Interleukin-4 / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism; D018942:Macrolides / Q000627:therapeutic use; D009177:Mycoplasma pneumoniae / Q000235:genetics* / Q000302:isolation & purification; D011019:Pneumonia, Mycoplasma / Q000175:diagnosis* / Q000188:drug therapy / Q000382:microbiology*; D012307:Risk Factors; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D016898:Interferon-alpha; D016209:Interleukin-8; D018942:Macrolides; D014409:Tumor Necrosis Factor-alpha; D015847:Interleukin-4; D007073:Immunoglobulin E; D047150:Eosinophil Cationic Protein
keywords: DNA copy numbers; atopy; bronchoalveolar lavage fluid; mycoplasma pneumoniae; refractory mycoplasma pneumoniae pneumonia