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Whereas complement is a key mediator of hyperacute xenograft rejection, its role in acute vascular rejection (AVR) is a matter of controversy. AVR is associated with de novo synthesis of endothelial cell-derived inflammatory mediators, including the leukocyte-recruiting adhesion molecule E-selectin. Here we investigate the role and mechanism of complement in human serum-induced porcine endothelial cell activation.An in vitro xenotransplantation method was designed using porcine aortic endothelial cells stimulated with human serum in microculture wells. E-selectin expression was measured by cell-enzyme immunoassay. Complement inhibitors acting at different levels in the cascade were investigated for their effect on E-selectin expression.E-selectin was strongly induced by normal human serum but not by heat-inactivated serum. Compstatin, a synthetic C3 inhibitor, markedly reduced human serum-induced E-selectin expression. Purified C1-inhibitor suppressed E-selectin induction completely, indicating activation through the classical or lectin pathway. Furthermore, a monoclonal antibody (mAb) that inhibits cleavage of C5 or another mAb that blocks the function of C7, completely inhibited the expression of serum-induced E-selectin, consistent with the terminal C5b-9 complement complex being the mediator of the endothelial cell activation. Inhibition of the alternative pathway using a novel antifactor D mAb did not reduce E-selectin expression.Human serum-induced expression of porcine E-selectin is totally complement dependent, induced by a C1-inhibitor regulated pathway and mediated through the terminal complement complex. The data may have implications for therapeutic strategies, particularly of C1-inhibitor and anti-C5 mAb, to protect against endothelial cell activation and subsequent AVR of porcine xenografts.

1. Of 2,670 patients starting renal replacement therapy for end-stage renal disease in Norway from 1989-1997, 76% were candidates for transplantation. The annual need for transplantations increased from 47 to 64 grafts PMP as the number of elderly patients increased. The national waiting list has remained almost stable during the period from 1989-1997 at levels of 25-30 PMP, but the dialysis population has increased from 57-105 PMP. 2. A total of 1,681 transplants was performed at an annual rate varying between 38 and 46 grafts PMP. The grafts were procured from LDs in 41% and CDs in 59% of cases. Totally 69% of all patients in need were transplanted and 54% of all patients requiring replacement therapy for end-stage renal disease received a transplant. 3. Graft survival rates in recipients of first LD grafts (n = 641) were 91% and 77% at one and 5 years, respectively. One-year graft survival was 97% in HLA-identical grafts (n = 71), 92% in haploidentical grafts (n = 419), 88% in 2 haplotype-mismatched related grafts (n = 43), and 87% in spousal donor grafts (n = 108). 4. Graft survival rates in recipients of first CD grafts (n = 801) were 84% and 65% at one and 5 years, respectively. The rates were 86% and 74% in younger (n = 557) versus 78% and 46% in older (65 years) (n = 244) patients. Death with a functioning graft caused approximately 45% and 75% of all graft losses in younger and older patients, respectively. Cardiovascular disease was the major cause of death. 5. A significant beneficial effect of HLA-DR matching was observed in CD grafts performed after 1989, in particular in patients older than age 65.

A 22-year-old previously nonsensitized female patient (HLA-A2,28; B7,14; DR1,2) received a kidney from her HLA-identical brother. She irreversibly rejected the graft 2 1/2 weeks later. In vitro tests performed 6 weeks after the graft loss, using recipient responding and donor-stimulating and target cells, revealed a weak mixed lymphocyte culture (MLC) response and negative direct cell-mediated lympholysis (CML), but strong cytotoxicity against donor target cells after priming in MLC. Both MLC and CML tests using donor-responding cells and recipient-stimulating and target cells were negative. When the patient's cytotoxic cells were tested on a panel of target cells from nonrelated donors, a significant CML was only found against target cells from male donors sharing HLA-A2 and/or B7 with the patient, not with male target cells sharing A28 or B14. By using cold target inhibition tests, two separate populations of male-specific cytotoxic cells could be demonstrated. The one was restricted by HLA-A2, the other by B7. These findings indicate that a self-HLA-restricted cytotoxicity against a male-specific minor histocompatibility antigen was a major cause of the rejection in this case.

To study the role of HLA class II genes in conferring susceptibility to seronegative vs seropositive rheumatoid arthritis (RA).The distribution of DRB1 and DPB1 alleles in 33 seronegative, 20 weakly seropositive, 79 distinctly seropositive patients with RA, and in 181 healthy controls was determined by genomic typing: IgM rheumatoid factor (RF) seronegativity was ascertained in Waalers' latex, and ELISA tests.DRB1*0101/2 (encoding variants of DR1) was associated with weakly seropositive RA (and possibly seronegative RA) but not the clearly seropositive disease. In contrast DRB1*0401 and DRB1*0408 (encoding the Dw4 and Dw14.2 variants of DR4, respectively) were associated with clearly seropositive RA but were not increased among patients having weakly seropositive or seronegative RA. DRB1*0404 (encoding the Dw14.1 variant of DR4) was increased to some extent in all examined RA subsets. The distribution of DPB1 alleles in the patients was as in the controls.Seronegative and weakly seropositive RA differ from clearly seropositive RA in HLA class II associations.

Genetic factors play an important and probably necessary role, in the development of most forms for diabetes mellitus, but are not the sole cause of the disease. The disease seems to be caused by an interaction between polygenic inheritance and environmental factors. In type I diabetes, more than ten different genetic markers have been found to be associated with the disease. Genes in the HLA-region, on and near the insulin gene, are the most important ones. In the common form of type II diabetes, a series of candidate genes which are code for important steps in insulin secretion or action have been investigated. So far, none have been identified that contribute significantly to the development of the disease in the majority of cases. The most significant breakthrough in research in recent years has been in the study of maturity-onset diabetes of the young (MODY). Until now, mutations in five different genes, which are code for glucokinase and various transcription factors, have been found to be associated with this form of diabetes. Knowledge of the genetic heterogeneity of diabetes has led to a need for a more pathophysiologically correct classification of the disease.

Type 1 diabetes is a common polygenic disease. Fine mapping of polygenes by affected sibpair linkage analysis is not practical and allelic association or linkage disequilibrium mapping will have to be employed to attempt to detect founder chromosomes. Given prior evidence of linkage of the Jk-D18S64 region of chromosome 18q12-q21 to type 1 diabetes, we evaluated the 12 informative microsatellite markers in the region for linkage with disease by the transmission disequilibrium test (TDT) in a UK data set of type 1 diabetic families (n = 195). Increased transmission of allele 4 of marker D18S487 to affected children was detected ( P = 0.02). Support for this was extended in a total of 1067 families from four different countries by isolating, and evaluating by the TDT, two novel microsatellites within 70 kb of D18S487. Evidence for linkage and association was P = 5 x 10(-5) and 3 x 10(-4), respectively. There was no evidence for increased transmission of associated alleles to nonaffected siblings. Analysis of an additional 390 families by the TDT did not extend the evidence further, and reduced support in the total 1457 families to P = 0.001 for linkage and P = 0.003 for association. However, evidence for linkage by affected sibpair allele sharing was strong ( P = 3.2 x 10(-5)) in the second data set. Heterogeneity in TDT results between data sets was, in part, accounted for by the presence of more than one common disease-associated haplotype (allelic heterogeneity) which confounds the analysis of individual alleles by the TDT. Guidelines for strategies for the mapping of polygenes are suggested with the emphasis on collections of large numbers of families from multiple populations that should be as genetically homogeneous as possible.