RESUMO
There is growing evidence that Natural Killer (NK) cells exhibit in vitro activity against both Aspergillus and non-Aspergillus molds. Cytotoxic molecules such as NK cell-derived perforin seem to play an important role in the antifungal activity. In addition, NK cells release a number of cytokines upon stimulation by fungi, which modulate both innate and adaptive host immune responses. Whereas the in vitro data of the antifungal activity of NK cells are supported by animal studies, clinical data are scarce to date.
RESUMO
While the assessment of ß-D-glucan (BDG) levels in adults improves the early diagnosis of invasive fungal disease (IFD), data on BDG levels in children are limited. We therefore assessed in a prospective cohort study the value of serial BDG screening for early detection of IFD in children undergoing allogeneic hematopoietic stem cell transplantation (HSCT). IFD was defined according to the revised European Organization for Research and Treatment of Cancer/Mycosis Study Group (EORTC/MSG) criteria, with the necessary modification that BDG was not included as a microbiological criterion. For the analysis, a total of 702 serum samples were obtained in 34 pediatric HSCT recipients. Proven IFD occurred in two patients (fusariosis and Candida sepsis, respectively), and probable invasive aspergillosis was diagnosed in four patients. Analyses including different cutoff values for BDG levels and different definitions of the onset of IFD demonstrated that the BDG assay has a relatively high sensitivity and good negative predictive value, whereas the positive predictive value has major limitations (<30%). Receiver operating characteristic analyses suggested an optimal cutoff between 60 and 70 pg/ml for different definitions of the onset of IFD. Our data show that BDG screening in pediatric HSCT recipients has a low positive predictive value and is therefore of limited usefulness.
