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S J Knechtle

Publications and source records attributed to S J Knechtle.

At least 163 records · Page 9Linked to original sources
PubMed1990

Living-unrelated renal transplantation at the University of Wisconsin.

1. Use of LUrDs under a DST protocol results in a 70% actuarial graft survival at 6 years which is not statistically different from haploidentical or primary cadaver recipients transplanted over the same time period. 2. Sensitization is common, despite the use of Aza, especially in husband-to-wife donor-to-recipient relationship. 3. Rejection occurs frequently, despite the use of DST, however, it is usually reversible. The high rejection rate did not influence the quality of long-term graft survival with very few patients losing grafts to chronic rejection. 4. Expansion of the use of LUrDs could help provide additional organs for transplantation.

Adult↗
PubMed1989

Cadaveric renal transplantation in the cyclosporine and OKT3 eras: an update of the University of Wisconsin-Madison experience.

1. Quadruple immunosuppression yields excellent early renal allograft survival in primary renal transplant recipients when compared with non-primary renal transplant recipients. Although significant, the difference between primary and nonprimary recipients at 5 years has narrowed considerably (8%). 2. No beneficial effect of HLA or DR matching was noted in this study in primary transplant recipients. However, a trend toward improved graft survival was noted when patients with greater than or equal to 3 antigens matched or less than 3 antigens mismatched were compared to their counterparts. Further analysis of variables related to graft loss is required before statements regarding this trend can be made. 3. Significantly better results in nonprimary renal transplantation continues to be seen in DR matched recipients. Additionally, the use of OKT3 rather than ALG in DR matched recipients has resulted in a 92.3% 3-year allograft survival despite over half of these patients being highly sensitized. 4. Further follow-up of 2 high-risk groups of patients (diabetics and elderly patients) revealed significant decreases in patient survival at 5 years. This difference was not apparent in our earlier results (3-year follow-up) published in Clinical Transplants 1987. Despite this difference, we believe renal transplantation should continue to be offered to diabetic and elderly patients without other contraindications to transplantation. 5. The availability of the monoclonal antibody OKT3 during the CsA era has resulted in a trend toward improved patient and graft survival when compared with patients in the CsA pre-OKT3 era. This trend toward improved survival is also seen in the high-risk diabetic recipients.

Antibodies, Monoclonal↗
PubMed1987

Hepatic transplantation into sensitized recipients. Demonstration of hyperacute rejection.

Hepatic transplantation into humorally presensitized patients has occasionally been performed without reported accelerated rejection. To study survival of orthotopic hepatic transplants in sensitized recipients a series of studies in rats were performed. Lewis rats sensitized by three successive skin grafts from fully allogeneic ACI strain donors then underwent orthotopic hepatic transplantation from ACI donors. Nine of ten recipients died within 4 hr with bleeding from the liver surface. By comparison, nine unsensitized recipients survived a mean of 10.7 +/- 0.5 days before succumbing with cellular rejection. Death of the sensitized recipients was not due to coagulopathy or technical failure. Histological studies of hyperacutely rejected livers demonstrated marked hemorrhage, edema, congestion, and necrosis within the hepatic parenchyma. There was a relative lack of cellular infiltrate compared with livers rejected by unsensitized recipients. Immunofluorescent staining showed IgG bound to perivascular tissues and sinusoids, and complement bound to perivascular tissue. Serum from presensitized, but not control, recipients showed a high titer of donor-specific, complement-dependent cytotoxic activity. It is concluded that hyperacute rejection of hepatic transplants can occur in sensitized rats and is mediated by a humoral mechanism. The immunohistopathology of this process is described.

Animals↗
PubMed1987

Infiltrating cell phenotypes and patterns associated with hepatic allograft rejection or acceptance.

The association of inflammatory cell infiltration with orthotopic rat liver transplant rejection was studied by immunopathologic evaluation of allografts at different time points using high- and low-responder strain combinations. PVG(RT-1c) recipients of ACI (RT-1a) liver transplants had prolonged survival (greater than 100 days) without immunosuppression. In contrast, Lewis (RT-1l) recipients of ACI liver transplants had severe acute rejection with mean survival of 10.7 +/- 0.5 days (n = 9). Graft recipients of both strain combinations, as well as control syngeneic PVG-to-PVG and Lewis-to-Lewis graft recipients were sacrificed at various time points posttransplant. Sections of livers were evaluated in a masked fashion for histologic changes as well as the extent and phenotype of cellular infiltrates, as determined by immunoperoxidase labeling using monoclonal antibodies OX1 (pan leukocyte), W3/13 (pan T cell), W3/25 (T helper cell:Th), and OX8 (T cytotoxic-suppressor:Tc-s). The results suggest that: the intensity and relative distribution of rat hepatic allograft T cell infiltrates at a given time point do not necessarily correlate with eventual outcome; the intensities of W3/25 (Th) and OX1 (pan-leukocyte) cell infiltrates parallel each other in both high- and low-responder strain combinations; the relative ratio of T cells (W3/13) to non-T cells increases over time in low-responder strains but remains relatively constant in high-responder strains during active rejection; and the relative ratio of W3/25:OX8 (Th:Tc-s) decreases in high-responder strains but increases in low-responder strains.

Animals↗
PubMed1987

Xenograft survival in two species combinations using total-lymphoid irradiation and cyclosporine.

Total lymphoid irradiation (TLI) has profound immunosuppressive actions and has been applied successfully to allotransplantation but not xenotransplantation. Cyclosporine (CsA) has not generally permitted successful xenotransplantation of organs but has not been used in combination with TLI. TLI and CsA were given alone and in combination to rats that were recipients of hamster or rabbit cardiac xenografts. Combined TLI and CsA prolonged survival of hamster-to-rat cardiac xenografts from three days in untreated controls to greater than 100 days in most recipients. TLI alone significantly prolonged rabbit to rat xenograft survival with doubling of survival time. However, combined treatment did not significantly prolong rabbit-to-rat cardiac xenograft survival compared with TLI alone. The hamster and rat are phylogenetically closely related. Transplants from hamsters to rat are concordant xenografts since the time course of unmodified rejection is similar to first-set rejection of allografts. Although the rabbit-to-rat transplant is also between concordant species (average survival of untreated controls: 3.2 days) the rabbit and rat are more distantly related. These results suggest that TLI is an effective immunosuppressant when applied to cardiac xenotransplants in these animal models; that the choice of species critically affects xenograft survival when TLI and/or CsA are used for immunosuppression; and that the closely related species combination tested has markedly prolonged (greater than 100 days) survival using combined TLI and CsA.

Animals↗
PubMed1982

Identification of bacterial antigens in circulating immune complexes of infective endocarditis.

The presence of circulating immune complexes (IC) in patients with infective endocarditis has been well documented but the contributions of host and bacterial components to these IC have not been defined. To study this question, IC were isolated from serum of a patient with Streptococcus faecalis endocarditis by differential polyethylene glycol precipitation and competitive binding to staphylococcal protein A. A rabbit antiserum raised against the purified IC had reactivity by crossed immunoelectrophoresis primarily with an antigen derived from the cytoplasm of the infective organism. The antigen was a protein with a 12,000-dalton molecular mass. In situ radiolabeling of the IC bound to the protein A demonstrated a component of the same molecular mass as the bacterial antigen recognized by the antiserum. The patient serum had multiple antibody specificities reactive with bacterial antigens, including the antigen recognized by the rabbit anti-IC antiserum. These techniques for isolation and characterization of circulating IC may have value in the study of IC diseases in which the inciting antigens are not known.

Animals↗