Adoptive antifungal immunotherapy

T. Lehrnbecher, S. Schmidt and L. Tramsen

Author address: 

Johann Wolfgang Goethe-University, Frankfurt, Germany

Abstract: 

Invasive aspergillosis (IA) remains a serious complication in patients undergoing allogeneic stem cell transplantation (alloSCT). Although prolonged neutropenia is the single most important risk factor for IA, other cells, such as CD4+ T-cells, also provide critical defense mechanisms against A. fumigatus, the most frequent cause of IA. Therefore, the reconstitution of different arms of immunity by the administration of ex vivo generated cells might help to improve the prognosis of hematopoietic transplant patients ("œadoptive immunotherapy"). For example, a preliminary study transfused Aspergillus-reactive T-cells to haploidentical hematopoietic stem cell recipients with probable IA; only 1/10 patients died versus 6/13 controls not receiving immunotherapy. We recently described a method for the clinical-scale generation of functionally active anti-Aspergillus T-cells according to good manufacturing practice (GMP) conditions. The T-cells were characterized as memory, activated TH1 cells, proliferated upon restimulation, showed reduced alloreactivity compared to unselected CD4+ cells, and significantly increased hyphal damage induced by human neutrophils. However, the adequate number and optimal timing of adoptively transferred anti- Aspergillus T-cells is unclear to date and has to be evaluated in future clinical trials. In contrast to allogeneic T-cells, the infusion of Natural Killer (NK) cells is associated with a considerably lower risk of potentially lethal graft-versus-host disease (GvHD). In order to evaluate the antifungal activity of human NK cells, we incubated purified unstimulated NK cells and IL-2 stimulated human NK cells with A. fumigatus and observed that increasing E:T ratios resulted in increasing hyphal damage at 2, 4, and 6 hours of co-incubation, respectively, which was also microscopically demonstrated in the viability staining with 5- carboxy-fluorescein diacetate (CFDA)/propidium iodide. Antifungal activity lasted longer in stimulated NK cells as compared to fresh NK cells. The extent of hyphal damage by both fresh and stimulated NK cells incubated with Aspergillus correlated with the concentration of perforin and granzyme B in the supernatant. Therefore, the application of NK cells might become an interesting option in the immunotherapeutic armamentarium in alloSCT.
2009

abstract No: 

W16.4

Full conference title: 

4th Trends in Medical Mycology
    • TIMM 4th (2012)