title: Cytokine generation in stored platelet concentrate: comparison of two methods of preparation.
abstract: OBJECTIVE
  Contaminating white blood cells (WBCs) in stored platelet concentrates (PC) are the main source of pro-inflammatory cytokines including interleukin-6 (IL-6), interleukin- 8 (IL-8) and tumour necrosis factor-alpha (TNF-alpha) that are implicated in transfusion reactions. We compared the levels of these cytokines in stored platelet preparations prepared by two methods. Effect of pre-storage leucofiltration on these cytokine levels was also studied.
  
  
  METHODS
  Twelve units of pooled PCs were prepared by platelet rich plasma (PRP) method and buffy-coat (BC) method each and stored for 5 days. IL-6, IL-8 and TNF-alpha levels were measured in platelet supernatants on day 0, 1, 3 and 5 of the storage using commercially available immunoassays. Pre-storage leucofiltration was done in 4-pooled units of PRP-PC and cytokine levels compared with unfiltered PCs.
  
  
  RESULTS
  Median IL-6 levels increased from day 0 to day 5 in both PRP-PC and BC-PC. In PRP-PC, IL-8 increased from <3 pg/ml on day 0 to 817 pg/ml on day 5, while in BC-PC the corresponding levels were 10 and 346.5 pg/ml, respectively. No significant increase in levels of TNF-alpha was observed in BC-PC during storage period, while levels increased significantly in PRP-PC on day 1 only. There was no significant change in the levels of all three cytokines in leucofiltered PCs over 5 days of storage.
  
  
  CONCLUSIONS
  Findings of our study showed that method of preparation and WBC content are the critical factors in determining the cytokine levels in stored PCs.
authors.affiliation: Department of Transfusion Medicine, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India. rkcchaud@sgpgi.ac.in
authors.forename: Rajendra
authors.initials: R
authors.lastname: Chaudhary
authors.forename: Amita
authors.initials: A
authors.lastname: Aggarwal
authors.forename: Dheeraj
authors.initials: D
authors.lastname: Khetan
authors.forename: Rajeshwar
authors.initials: R
authors.lastname: Dayal
mesh_terms: D001792:Blood Platelets / Q000276:immunology*; D001793:Blood Preservation; D002469:Cell Separation / Q000379:methods; D016207:Cytokines / Q000096:biosynthesis / Q000097:blood*; D006801:Humans; D066298:In Vitro Techniques; D015850:Interleukin-6 / Q000096:biosynthesis / Q000097:blood; D016209:Interleukin-8 / Q000096:biosynthesis / Q000097:blood; D047589:Leukocyte Reduction Procedures; D017713:Platelet Transfusion / Q000009:adverse effects; D011446:Prospective Studies; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000097:blood
chemical_list: D016207:Cytokines; C508600:IL6 protein, human; D015850:Interleukin-6; D016209:Interleukin-8; D014409:Tumor Necrosis Factor-alpha