title: Low adenosine triphosphate activity in CD4+ cells predicts infection in patients with lupus nephritis.
abstract: OBJECTIVE
  The ImmuKnow (Cylex) assay has been reported to predict the risk of infection in some diseases; however, it is uncertain whether ImmuKnow can predict the risk of infection in lupus nephritis (LN) patients receiving immunosuppressive therapy.
  
  
  METHODS
  The ImmuKnow Immune Cell Function Assay (Cylex, Inc., Columbia, MD, USA) was applied to measure the activity of CD4+ T cells, as a marker of global immune-competence. The correlation between changes in T cell activation and the relative risk of over-immunosuppression as well as infection was studied. The amount of adenosine triphosphate (ATP) produced by CD4+ T cells in response to phytohemagglutinin (PHA) was measured for 74 LN patients without infection, 22 LN patients with severe infection (i.e. required hospitalisation), and 28 healthy controls.
  
  
  RESULTS
  No correlation was found between the ATP level and systemic lupus erythematosus (SLE) activity. The mean ATP level was significantly lower in LN patients with infection than that in healthy controls (p<0.01) and non-infected LN patients (p<0.01). The mean ATP level in non-infected LN patients was not significantly different compared to healthy controls. A cut-off ATP value of 300 ng/mL predicted infection in LN patients with a specificity of 77% and a sensitivity of 77%. Multi-variable partial correlation coefficient between the ATP assay and severe infection was r =-0.040, p<0.001; CRP was r=0.962, p<0.001.
  
  
  CONCLUSIONS
  The ImmuKnow assay may be effective in identifying an increased risk of infection in LN patients but is not correlated with SLE activity. Combined CRP value will increase the diagnostic rate of severe infection in SLE. Larger studies are required to establish clinical advantages of this assay in SLE treatment.
authors.affiliation: Shanghai First People's Hospital, Shanghai Jiao Tong University, Shanghai, China. ljswj_2006@163.com.
authors.forename: J
authors.initials: J
authors.lastname: Liu
authors.forename: Y
authors.initials: Y
authors.lastname: Pan
authors.forename: L J
authors.initials: LJ
authors.lastname: Tang
authors.forename: J F
authors.initials: JF
authors.lastname: Bao
authors.forename: J
authors.initials: J
authors.lastname: Hao
authors.forename: Q
authors.initials: Q
authors.lastname: Yu
authors.forename: W J
authors.initials: WJ
authors.lastname: Yuan
authors.forename: H M
authors.initials: HM
authors.lastname: Jin
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000328:Adult; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D005260:Female; D006801:Humans; D007159:Immunologic Tests / Q000379:methods*; D007166:Immunosuppressive Agents / Q000009:adverse effects; D008180:Lupus Erythematosus, Systemic / Q000188:drug therapy / Q000453:epidemiology / Q000276:immunology; D008181:Lupus Nephritis / Q000188:drug therapy / Q000453:epidemiology / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009894:Opportunistic Infections / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology; D010835:Phytohemagglutinins / Q000378:metabolism; D011237:Predictive Value of Tests; D012372:ROC Curve; D012307:Risk Factors; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D007166:Immunosuppressive Agents; D010835:Phytohemagglutinins; D000255:Adenosine Triphosphate