Distribution of cell adhesion molecules (ICAM-1, VCAM-1, ELAM-1) in renal tissue during allograft rejection.

The tissue distribution of cellular adhesion molecules (CAMs) was studied in specimens from 10 normal human kidneys and in 52 biopsies from kidney allografts with cell-mediated rejection. In addition to the vascular presence of ICAM-1, a common finding in normal kidneys, expression of ICAM-1 on tubular cells was observed in 22 graft biopsies. Compared with normal kidneys, where VCAM-1 was present on Bowman's capsules and few proximal tubular cells, a markedly enhanced expression of VCAM-1 in numerous tubuli (including distal tubular segments) was observed in 51 graft biopsies. In 41 graft specimens VCAM-1 appeared also in variable numbers of peritubular capillaries. Infiltrating leukocytes carrying VCAM-1 were observed in 7 grafts. ELAM-1 could not be found in normal kidneys but was restricted to some peritubular capillaries in 29 grafts. Comparable results were obtained with cultured renal tubular cells when stimulated by TNF-alpha. That the induced appearance of adhesion molecules was in fact related to actual cellular synthesis was demonstrated by Northern blot analysis. Thus, little ICAM-1 specific mRNA of 3.4-kb length could be detected in unstimulated cultured renal tubular cells, but hybridization was markedly increased after stimulation with TNF-alpha. A substantial amount of VCAM-1 specific mRNA of 3.2-kb length was present already in unstimulated renal tubular cells. Likewise, synthesis of VCAM-1 mRNA was enhanced by stimulation with TNF-alpha. TNF-stimulated endothelial cells also showed weak synthesis of VCAM-1 mRNA. The results provide further evidence that constitutive and inducible expression of cell adhesion molecules contributes to the process of allograft rejection.

[Echocardiographic diagnosis of acute graft rejection in heart transplant patients under cyclosporin therapy]. / Echokardiographische Diagnose akuter Abstossungsreaktionen bei herztransplantierten Patienten unter Cyclosporintherapie.

Though endomyocardial biopsy has remained the gold standard for diagnosing acute cardiac rejection (AR), this invasive method does not provide adequate means for close monitoring of the rejection process. In order to assess the usefulness of M-Mode- and two-dimensional (2D) echocardiography for the noninvasive diagnosis of AR in heart transplant recipients on cyclosporin, 45 patients (mean age 40.6 +/- 8.8 years, 19.9 +/- 14.4 months postoperatively) were evaluated prospectively. Mean observation time was 9.1 +/- 4.8 months. Echocardiographic examination techniques were strictly standardized; besides measurements of left (LV) and right ventricular (RV) diastolic wall thickness and of the isovolumic relaxation time, computerized frame-by-frame-analysis was applied to LV short axis cross sections for the determination of diastolic cavity cross-sectional area and extent and mean velocity of systolic and diastolic area change. To account for technical and biological variability, 95%-confidence limits were calculated for each parameter from two rejection-free examinations, allowing identification of significant changes during AR. In this study, 36 biopsy-proven AR occurred in 19 patients. Compared to control values, mean heart rate increased from 86.2 +/- 10.2 to 94.6 +/- 15.1 b/min (p less than 0.05), diastolic septal + posterior wall thickness from 21.2 +/- 4.1 to 24.9 +/- 6.2 mm (p less than 0.001) and RV free wall thickness from 6.3 +/- 1.1 to 8.9 +/- 1.8 mm (p less than 0.001). Isovolumic relaxation time decreased from 73.2 +/- 14.4 to 54.8 +/- 16.6 ms (p less than 0.001), diastolic cross-sectional area from 12.8 +/- 2.0 to 11.1 +/- 2.2 cm2 (p less than 0.05), relative area change from 65.8 +/- 9.8 to 49.1 +/- 14.4% (p less than 0.001) and systolic and diastolic area change velocities from 28.1 +/- 7.8 and 41.8 +/- 8.5 cm2/s to 18.9 +/- 5.6 and 28.6 +/- 9.2 cm2/s, respectively (p less than 0.001). Though significant changes occurred during AR, most measurements remained within the normal range. Thus, in individual patients, AR could only be suspected in comparison to the control measurements. None of the examined parameters allowed to establish the diagnosis of AR in all instances. However, when the measurements of all parameters were considered together, 35 of the 36 AR diagnosed by biopsy could also be identified by echocardiography, including all requiring intensified immunosuppressive therapy. Mild AR was not always detected, and the differential diagnosis between LV hypertrophy and AR required an endomyocardial biopsy in some instances.(ABSTRACT TRUNCATED AT 400 WORDS)

Detection of both isotypes of complement C4, C4A and C4B, in normal human glomeruli.

Monoclonal antibodies reactive against the complement C4A and C4B isotypic components were used in an immunoperoxidase technique for the histological study of normal human renal tissue. Prominent staining with both antibodies was seen in the mesangial areas of all normal kidney sections investigated. Occasional staining of arteriolar walls of the same tissues, however, was also observed. In contrast, no mesangial staining was seen using monoclonal antibodies reactive against other 'early' complement components, such as C1q and C3. Specificity of the glomerular staining with the anti-C4 reagents was demonstrated in two patients possessing only the C4A serum component but lacking genetically the C4B locus products. As would be predicted, glomerular staining with the anti-C4A reagent, but not anti-C4B, was clearly demonstrable. It is concluded that both isotypes of complement C4 are present in normal human glomeruli and thus might be operative for normal mesangial function.

Vascular deposition of complement-split products in kidney allografts with cell-mediated rejection.

Complement activation in 73 renal transplant biopsies was investigated by indirect immunoperoxidase staining using MoAbs reactive with complement-split products. Intense deposition of complement fragments C4d and C3d in peritubular capillaries, indicating activation of the classical pathway, could be detected in the majority of transplanted kidneys with cell-mediated rejections. Abundant deposition of complement-split products was observed in 22 early biopsies from patients with high 'immunological risk' (i.e. previous, rejected transplants and/or circulating antibodies against HLA-antigens). Despite negative results in the crossmatch before transplantation and paucity of immunoglobulins in transplant biopsies, antibodies directed against endothelial cell antigens should be considered as a possible cause of classical complement activation.