Showing papers by "Michael Müller-Steinhardt published in 2003"

Evaluation of the decellularized pulmonary valve homograft (SynerGraft).

Abstract: BACKGROUND AND AIM OF THE STUDY Rejection is thought to contribute to the degeneration of valved homografts. A novel cryopreserved decellularized homograft valve (SynerGraft; CryoLife, Inc.) offers the unique opportunity to gain new insight into the immunology of homograft implantation and its significance for valve function. METHODS Twenty-four patients (group I; mean age 37 +/- 11 years) underwent implantation of a pulmonary SynerGraft and were examined at one and six months postoperatively; 22 patients (group II; mean age 41 +/- 17 years) with conventional homografts served as controls. Temperature, C-reactive protein (CRP) levels and white blood cell count (WBC) were studied perioperatively. Follow up included echocardiography and anti-human leukocyte antigen (HLA) class I antibody determination. RESULTS Significantly lower temperatures were measured in group I (p = 0.019). CRP level and WBC each increased postoperatively, but did not differ between groups. During follow up, none of the SynerGraft patients became positive for anti-HLA antibodies, compared with 66% of controls (p = 0.011). Homograft diameter and valve orifice area were decreased significantly at one month after surgery in groups I and II (25 +/- 1 versus 18 +/- 3 mm; 25 +/- 1 versus 19 +/- 2 mm, respectively; p <0.001 both groups). Transvalvular pressure gradients significantly increased during follow up. CONCLUSION Implantation of the SynerGraft pulmonary homograft appeared safe, and though evidence was found of a reduced immunologic response after SynerGraft implantation this (unexpectedly) did not translate into any hemodynamic advantage. Hence, factors other than rejection appear as the main contributions to the observed functional changes.

Detection of Marek's Disease Virus DNA in Chicken but Not in Human Plasma

Abstract: Marek's disease virus (MDV) causes a common lymphomatous and neuropathic disease in domestic chickens and, less commonly, turkeys and quail. It is a member of the α-herpesviruses and until now was considered to be strongly cell associated. In 1991, MDV was suggested to be the causative infectious agent of multiple sclerosis (MS) in humans. In a previous study, we investigated the leukocytes of 107 well-defined MS patients for the presence of MDV DNA but were unable to confirm a role for MDV in the pathogenesis of MS. A recent report (S. Laurent, E. Esnault, G. Dambrine, A. Goudeau, D. Choudat, and D. Rasschaert, J. Gen. Virol. 82:233-240, 2001) described the detection of MDV DNA in 20% of 202 human serum samples, regardless of whether the individuals were exposed to poultry. The detection of MDV DNA in chicken serum samples was reported as well. The aim of the present study was to investigate whether we can confirm the presence of MDV DNA in chickens and humans if we use plasma as the source for nucleic acid isolation. Leukocytes and plasma specimens from 16 chickens experimentally infected with MDV serotype 1 and plasma specimens from 300 volunteer blood donors were tested for MDV DNA by two different TaqMan PCR assays. MDV DNA was repeatedly found in the leukocytes as well as in the plasma specimens of all 16 animals. All human samples analyzed, however, tested negative by both assays. Accordingly, Marek's disease in chickens can be diagnosed by detection of MDV DNA in plasma as well as in leukocytes. Once again, we found no evidence for the spread of MDV to humans.

Individual variability in cyclosporin A sensitivity: the assessment of functional measures on CD28-mediated costimulation of human whole blood T lymphocytes.

Abstract: The quantitative analysis of cyclosporin A (CsA) effects might be helpful for optimizing immunosuppressive treatment after allogeneic organ transplantation in individual patients, as rejection can occur despite the existence of CsA blood levels within therapeutic ranges. Previous investigations found that costimulation of the CD28 pathway generally mediates CsA-resistant proliferation of T cell receptor (TCR)-activated T lymphocytes. However, here we describe considerable interindividual variation regarding the immunosuppressive effects of CsA (1000 microg/L) on anti-CD3/CD28 T cell costimulation in a human whole blood assay. In the in vitro study, we found a significant reduction of T cell proliferation, activation marker expression (CD25, CD69) on the T cell surface, and interleukin-2 (IL-2) protein expression in whole blood samples of all healthy subjects (n = 11). However, the investigation of cytokine mRNA profiles revealed variable results of in vitro CsA sensitivity. Whole blood samples of 3 of 11 healthy individuals demonstrated a marked suppression of IL-2 mRNA expression (>50%) and a partial inhibition of IL-4, interferon-gamma (IFN-gamma), and tumor necrosis factor-alpha (TNF-alpha) mRNA expression on addition of CsA. In contrast, the remaining 8 healthy individuals had cytokine mRNA expression levels that were unaffected or even increased when CsA was administered in vitro. In patients undergoing CsA monotherapy (ex vivo study, n = 9), we found a significant suppression of IL-2 mRNA levels in 4 of 9 patients ex vivo. Thus, we cannot confirm a universal CsA resistance of T cells on anti-CD3/CD28 costimulation. Instead, our results suggest an individual degree of CsA sensitivity that might be more consistent with clinical experience. Prospective studies are necessary to determine if individual degrees of CsA sensitivity correlate with clinical events and are associated with a low or high risk of transplant rejection.