Publication Date:
2018-11-29
Description:
Background: Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative treatment for malignant hematological diseases in adults. Due to the delayed immune reconstitution after HSCT, human cytomegalovirus (CMV) can reactivate, leading to prolonged hospitalization and increased morbidity and even mortality. Natural Killer (NK) cells have recently been described to undergo persistent reconfiguration in response to CMV-reactivation. Here we analyzed the presence and expansion of CMV-specific NK cells in patients after allogeneic HSCT. Methods: A multicolor flow cytometry panel for monitoring the CMV-specific NK cell (NKG2C+CD57+) reconstitution and expression of activating receptors was established. Reconstitution of CMV-specific NK cells was assessed in peripheral blood samples from 67 CMV-seropositive patients. The samples were collected and analyzed between day 0 and 100 post-HSCT at intervals of 7-10 days. Monitoring of CMV-reactivation by CMV-pp65 expression and reconstitution of CMV-specific T cells (CMV-CTLs) was done routinely in our laboratory, using 7 commercially available, certified CMV-tetramers, allowing for comparison of CMV-CTL and NKG2C+CD57+ NK cells. For further immunological tests, PBMCs from CMV-seropositive healthy volunteers were isolated by density gradient centrifugation. NK cells were negatively selected by magnetic bead separation. Additional purification of NKG2C+CD57+ NK cellswas achieved by cell sorting. Selected NK cells were expanded by co-culture with irradiated allogeneic PBMCs as feeder cells and the medium was supplemented with PHA and IL-2. Expanded CD57+NKG2C+ NK cells were KIR-typed. Results: Our patient cohort consisted of 67 patients after allogeneic HSCT with a median age of 59 years (range: 20-75). Forty-two patients (62.7%) were transplanted for acute leukemia, 54 (80.6%) received reduced intensity conditioning (RIC) and 62 (92.5%) received anti-thymocyte-antibodies globulin (ATG). GvHD-prophylaxis was cyclosporine A (CsA) in combination with mycophenolate motefil (MMF) for 82.1% of the patients and 77.6% were transplanted from matched donors. Thirty-three (49.2%) patients reactivated CMV (median age: 59.5 years, range 28-75; median day of reactivation: 38 days post-HSCT, range: 19-54). A significant increase in the absolute cell counts of NKG2C+CD57+ NK cells was observed after CMV reactivation, when compared to patients who did not reactivate CMV (p
Print ISSN:
0006-4971
Electronic ISSN:
1528-0020
Topics:
Biology
,
Medicine
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