Andreas Nitsche

Treatment of BK virus-associated hemorrhagic cystitis and simultaneous CMV reactivation with cidofovir

Hemorrhagic cystitis (HC) is a common complication following high-dose chemotherapy and bone marrow transplantation, and the treatment of virus-associated HC remains to be optimized. This is the first report on the successful use of cidofovir in a patient with HC and polyoma viruria concomitant with CMV reactivation after allogeneic BMT. Treatment led to a significant decrease in viruria and to sustained suppression of CMV reactivation. Administered with probenecid and hydration, cidofovir was well tolerated, and there were no side-effects. Bone Marrow Transplantation (2000) 26, 347–350.

Human Herpesvirus 6A DNA Is Detected Frequently in Plasma but Rarely in Peripheral Blood Leukocytes of Patients after Bone Marrow Transplantation

A real-time quantitative polymerase chain reaction assay was devised to determine the load of human herpesvirus (HHV)-6A and -6B DNA in paired samples of plasma and peripheral blood leukocytes (PBL) of 25 bone marrow transplant patients. The assay detects HHV-6 DNA variants A and B in a linear range of 10(7)-10(1) genome equivalents per assay. Viral DNA was measured in 336 paired DNA PBL samples and in corresponding plasma samples. HHV-6A and/or -6B DNA was detected in PBL of 23 of 25 patients and in plasma of 24 of 25 patients. HHV-6B was the predominant variant found in PBL and also was detected in the corresponding plasma. Surprisingly, only 1 of 25 patients had detectable HHV-6A DNA in PBL, although 23 of 25 patients were positive for HHV-6A DNA in plasma. HHV-6 DNA load in plasma was significantly higher for HHV-6A than for HHV-6B (P=.0066).

Interleukin‐3 Promotes Proliferation and Differentiation of Human Hematopoietic Stem Cells but Reduces Their Repopulation Potential in NOD/SCID Mice

In the present study we explored systematically the influence of human interleukin‐3 (IL‐3) on the cord blood (CB) cell‐derived production of human hematopoietic cells in the bone marrow, blood, and spleen of chimeric nonobese/severe combined immunodeficient mice ((NOD/SCID) mice. CB mononuclear cells and MACS‐enriched CB CD34+ cells were injected into irradiated NOD/SCID mice. The mice were additionally transplanted with a stably transfected rat fibroblast cell line expressing the human IL‐3 gene (Rat‐IL‐3) constitutively, or with the nontransfected rat fibroblast cell line as a control (Rat‐1). Rat‐IL‐3 mice displayed a higher engraftment of human hematopoietic cells in bone marrow, spleen, and peripheral blood compared with mice with Rat‐1 cotransplantation. When we transplanted their total bone marrow cell population into secondary mice, surprisingly, mice transplanted with bone marrow cells from Rat‐1 mice displayed a higher proportion of human hematopoietic cells compared with Rat‐IL‐3 mice. As expected, bone marrow cultures (BMCs) from Rat‐IL‐3 mice contained a higher proportion of human cells than Rat‐1 bone marrow cells. However, when BMCs were passaged to new flasks, we observed a higher proportion of human cells in BMCs from Rat‐1 mice compared with BMCs from Rat‐IL‐3 mice. IL‐3 promotes the proliferation and differentiation of hematopoietic stem cells in chimeric bone marrow. In addition, IL‐3 may play a role in the depletion of hematopoietic stem cells in chimeric bone marrow. In the absence of IL‐3, the hematopoietic stem cells may remain in a quiescent state and proliferation can be induced by stimuli, including secondary transplantation or cell passage.

Cytomegalovirus infections in allogeneic stem cell recipients after reduced-intensity or myeloablative conditioning assessed by quantitative PCR and pp65-antigenemia

Summary:Since the incidence of cytomegalovirus (CMV) infections after hematopoietic stem cell transplantation (HSCT) may depend on the intensity of the pretreatment, we studied the incidence of CMV infections after reduced-intensity compared to myeloablative conditioning. A total of 82 patients with matched related or unrelated donors were prospectively monitored for CMV infections after HSCT by CMV-PCR techniques, CMV-antigenemia and clinical observation. A total of 45 patients received reduced-intensity conditioning consisting of fludarabine, busulfan and ATG and 37 patients received myeloablative conditioning. Leukocyte engraftment occurred after a median of 15 vs 18 days (P=0.012) and platelet engraftment after 12 days vs 20 days (P=0.001), respectively. Acute graft-versus-host disease (GVHD) grade II–IV was observed in 58 vs 54% patients (P=0.737), respectively. The onset and peak values of CMV-antigenemia and DNAemia and the incidence of CMV infections did not differ statistically significantly between the two treatment groups. Multivariate analysis confirmed CMV seropositivity of the recipient (P=0.035), acute GVHD II–IV (P=0.001) but not the type of conditioning as significant risk factors for CMV-antigenemia. In conclusion, the kinetics of CMV-antigenemia and DNAemia and the incidence of CMV infections were not statistically different in patients who received HSCT after reduced-intensity conditioning with fludarabine, busulfan and ATG compared to myeloablative conditioning.

Rapid Detection of West Nile Virus

West Nile virus (WNV) is a flavivirus endemic in Africa, the Middle East, and in South-western Asia. The virus is a member of the Japanese encephalitis serocomplex, containing a plus-strand ssRNA genome of about 11,000 bases. Natural hosts of the virus are reported to be mammals and also birds, and infections can be transmitted through mosquitoes [1]. Human infections are usually mild or sub-clinical, but during two recent epidemics in Russia and North America several mortal cases of encephalitis occurred [2]. Serological tests do not differentiate between WNV and related members of the same serocomplex, and virus isolation in cell culture followed by immunofluorescence-based identification takes about 1 week. Diagnostic assays based on reverse transcription polymerase chain reaction (RT-PCR) of the virus genome allow a quicker analysis [3–5]. Immediate pathogen identification in cases of encephalitis of unknown origin can help to prevent future epidemics.