Association between sciatica and Propionibacterium acnes.

negative control antibody. The CD40 ligand antibody completely abrogated the induction of PGE2. At 1/200 dilution, platelet concentrate supernatants still induced PGE2 production. High concentrations of bioactive CD40 ligand in platelet transfusions, perhaps in concert with other mediators, might explain the persistence of transfusion reactions even when white blood cells are removed before platelet storage. The intensity of the febrile response may depend upon the level of CD40 ligand in the platelet preparation, the sensitivity of the patients to CD40 ligand, and whether the patients are taking steroids or non-steroidal antiinflammatory drugs that would inhibit the production or activity of cyclo-oxygenase and thereby prostaglandin synthesis. If platelet soluble CD40 ligand is confirmed as the cause of these febrile responses, then we speculate that keeping the release of CD40 ligand to a minimum, or removing free CD40 ligand before transfusion, may effectively reduce adverse events after platelet transfusions. Moreover, individuals whose platelets are especially rich in CD40 ligand might prove less suitable as donors for transfusions.