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Little is known about a possible interaction of natural killer (NK) cells with regulatory T cells (Treg) in long‐term stable kidney transplant recipients. Absolute counts of lymphocyte and Treg subsets were studied in whole blood samples of 136 long‐term stable renal transplant recipients and 52 healthy controls using eight‐colour fluorescence flow cytometry. Patients were 1946 ± 2201 days (153–10 268 days) post‐transplant and showed a serum creatinine of 1·7 ± 0·7 mg/dl. Renal transplant recipients investigated > 1·5 years post‐transplant showed higher total NK cell counts than recipients studied

FoxP3 and Vav1 are known to be involved in the development of regulatory T cells. Two polymorphic sites in the FoxP3 promoter (rs3761548 and a (GT)

Single-nucleotide polymorphisms (SNPs) within the genes of factor V (FV) (G 1691 A; exon 10), prothrombin (FII) (G20210A; 3'untranslated - region) and methylenetetrahydrofolate reductase (MTHFR) (C677T; exon 4) are associated with hypercoagulability, and systematic screening of individuals being at higher risk of thrombosis has been suggested. SNPs in the 2q33 region within the genes of CD28 (+17T/C; intron 3) and CTLA4 (-318C/T; promoter and +49A/G; exon 1) are likely to affect T-cell proliferation and antigen presentation signaling, which may lead to altered sensitivity of allograft or self-tissue recognition and affect the incidence of autoimmune diseases. We developed primers that allow specific amplification of these six SNPs at test conditions identical with those used for HLA typing with the CTS PCR-SSP reagents. One hundred ninety-six healthy German Caucasian individuals were tested for the six SNPs. The genotype frequencies for all SNPs were in Hardy-Weinberg equilibrium. There was no significant difference in the distribution of genotypes when compared to other published studies in which these SNPs were tested. The described PCR-SSP method can be used to screen large numbers of patients for these SNPs.

Anti-immunoglobulin autoantibodies (anti-Ig auto-Abs), particularly IgM-anti-IgG (classical rheumatoid factor), have been studied mainly in the context of rheumatoid arthritis. In this article we focus on other members of the anti-Ig family, including the natural IgG-anti-F(ab′)2 auto-Ab, and look for clinical and experimental findings supporting a role of these antibodies in the regulation of the immune response. We discuss the evidence for suppression of auto- and alloreactive B cells by IgG-anti-F(ab′)2 auto-Ab and the role of this Ab in the pathogenesis of certain diseases, such as autoimmune hemolytic anemia. The structure of the antibody’s antigen-binding site was clarified by isolating the VL and VH gene segments from the cDNA of B cells. Sequence analyses revealed germline gene identity of VL chains and 88% homology with the closest germline gene of VH chains. Finally, we discuss hypothetical models concerning the immunoregulatory role of natural anti-Ig auto-Abs.

Inclusion of human leukocyte antigen (HLA) matching in donor kidney allocation schemes has been based solely on its association with graft survival. Other long-term effects associated with HLA incompatibility are largely unexplored. Data from deceased donor kidney transplants reported to the Collaborative Transplant Study have been analyzed to assess the relation between HLA mismatching and clinical events to 3 years post-transplant, and an overview of these analyses is presented. A significant correlation was observed between the number of mismatches and the need for anti-rejection therapy during the first year post-transplant, which was maintained for HLA-DR and HLA-A + B mismatching separately and at years 2 and 3 post-transplant. The number of HLA-DR mismatches and the number of HLA-A + B mismatches as well as rejection treatment showed significant associations with the dose of maintenance steroids. The cumulative incidences of death with a functioning graft from infection or cardiovascular causes, but not from cancer, were also significantly associated with HLA mismatching. The number of HLA-DR mismatches showed a significant association with the incidence of non-Hodgkin lymphoma and hip fractures. These findings show that the adverse consequences of HLA mismatching on kidney transplants extend beyond an effect on graft survival, and include an increased risk of death with a functioning graft, non-Hodgkin lymphoma and hip fracture.

Mannose-binding lectin (MBL) is a major component of the lectin pathway of complement activation. High and low MBL levels have been associated with susceptibility and severity of a variety of infectious and autoimmune diseases. Several single-nucleotide polymorphisms (SNPs) in the promoter region and exon 1 of the MBL2 gene are responsible for variations in serum MBL levels. We developed a sequence-based typing method for allele-specific MBL2 genotyping and measured serum MBL protein levels in 24 German blood donors. We identified the common MBL2 haplotypes including five promoter polymorphisms in linkage with the Q allele and correlated serum MBL levels with the respective genotypes. The genotyping method presented here could provide a basis for confirmatory studies in larger cohorts.

BACKGROUND: Patients with malignant tumors of the head and neck often show immune defects. Increased serum IgA levels have been reported in these groups of patients. We investigated whether IgA-anti-Fab or IgA-anti-F(ab')2 autoantibodies, which have been shown to correlate with severe dysfunction of the immune system, also appear in patients with head and neck cancer. PATIENTS: Sera of 110 patients with squamous cell carcinoma, eight patients with adenoid cystic carcinoma, and 57 healthy controls were tested with an ELISA for IgA-anti-Fab autoantibody activity. RESULTS: Patients with head and neck cancer showed a higher IgA-anti-Fab activity (OD:399, n = 118) than healthy controls (OD: 84, n = 57, p < 0.0001). An association between stage of disease and IgA-anti-Fab activity could be established in patients with SCCHN. Stage IV patients had a significantly higher IgA-anti-Fab activity (OD: 538, n = 51) than stage 1 patients (OD: 283, n = 18, p < 0.05). Patients with stage II (OD: 293, n = 13) or stage III (OD: 379, n = 28) showed intermediate activity. Also a higher IgA-anti-Fab activity than in healthy controls was demonstrated in the eight patients with ACCHN (OD: 314, n = 8, p < 0.01). The highest IgA-anti-Fab activity was observed in eight patients with SCCHN who died within six months after testing (OD: 1004, n = 8). Similar results were obtained for IgA-anti-F(ab')2 autoantibodies. Our findings suggest an association between autoimmunity and final desintegration of physiological body functions. CONCLUSIONS: The occurrence of IgA-anti-Fab/IgA-anti-F(ab')2 autoantibodies might be interpreted as an aspect of immune deficiency in patients with malignant tumors of the head and neck.

Natural anti-IgG autoantibodies are found both in healthy individuals and in patients with certain diseases. One group of these Abs recognizes epitopes located in the F(ab')2 region of the IgG molecule. The immunoregulatory role of these Abs in healthy individuals, graft rejection, and disease was previously studied, usually with a focus on the characterization of anti-idiotypic Abs. In the present study, we characterize the epitope recognized by an anti-F(ab')2gamma autoantibody of the IgA isotype, which occurs in the serum of healthy individuals and kidney transplant recipients. The autoantibody described herein reacts strongly with F(ab')2gamma but only poorly with Fab(gamma) fragments, a binding pattern pointing to an epitope located in the hinge region. Using synthetic peptides, we identified a conformational epitope that overlaps the middle and part of the lower hinge region. Structural analyses of peptide constructs showed that a defined conformation of the first three residues of the lower hinge is required for a full expression of the epitope. Binding of IgA to the hinge region of IgG1 covers part of the physiologically active Fc domain, immobilizes the Fab arms, and thereby can be expected to exert immunoregulatory functions.

The mechanism of CD4+ cell depletion in HIV-infected patients is poorly understood. In this study we investigated whether rgp120 can activate the complement system in the absence of anti-gp120 Abs. We found that the complement proteins C4, C3d, C5b-9, and properdin bind to rgp 120-coated CD4+ T cells of healthy individuals when incubated in autologous serum. Activation of the complement system occurred primarily via the classical pathway and was abolished in sera deficient in C1q and C4 as well as in the presence of EDTA. No cell lysis was observed in a lymphocytotoxicity assay using human serum, possibly because of homologous restriction of complement lysis. In contrast, addition of rabbit sera induced lysis of the rgp 120-precoated cells. Cell lysis by rabbit serum was found to be because of naturally occurring IgM anti-gp 120 Abs. The rgp 120, which was immobilized on the surface of microtiter plates activated complement in the absence of lymphocytes. Complement activation by cell-bound HIV-1 envelope glycoprotein gp120 with subsequent opsonization may be relevant for the elimination of noninfected CD4+ T cells in HIV-infected patients.

Background In cardiac transplantation, it is standard practice for donor hearts to be allocated to recipients without consideration of the extent of HLA matching. Because the HLA system is highly polymorphic, the likelihood that donor hearts will be well matched to their recipients by chance alone is extremely small. It has therefore not been possible in the past to analyze adequately the success rate of transplantation with HLA-matched hearts. Methods We initiated a collaborative study in 1985 to evaluate the influence of HLA compatibility on graft survival in heart transplantation. Data were collected from 104 centers in 24 countries. Results Of the 8331 patients, 128 received a graft with no HLA-A, B, or DR mismatches or only one mismatch. This frequency (1.5 percent) corresponds to the rate that would be expected from a random allocation of donor organs. The three-year rate of graft survival correlated strongly with HLA compatibility, decreasing from a mean (±SE) of 83 ±4 percent for the 128 donor hea...

IN 1987, 24 BRAZILIAN dialysis and kidney transplant centers in the state of Sao Paulo, located in 17 cities, joined efforts to participate in a single society named Sao Paulo Interior Transplant (SPIT). The main objective of SPIT is the allocation of cadaver kidneys according to HLA matching. Accordingly, all recipient candidates and cadaver donors were typed for HLA antigens in the city of Ribeirao Preto, and the allocation, scheme used the criteria proposed by The United Network for Organ Sharing (UNOS). Since its foundation, SPIT has performed over 1000 kidney transplants. The Brazilian population was formed by the contribution of genes of individuals from several ethnic backgrounds, including Caucasian immigrants from many regions of Europe, African American individuals predominantly from the Niger-Congo area of Equatorial Africa, and native Amerindian populations. DNA typing of HLA alleles for kidney transplantation has been considered to be much more accurate than serologic identification, leading to an increased allograft survival, according to the data published by several large multicenter studies. Since the Brazilian population is genetically highly diverse and since HLA molecular typing has been correlated with better allograft survival, all kidney recipients on the waiting list of SPIT were retyped for HLA-DRB1 alleles by DNA technology using sequence-specific primers (PCR-SSP) in polymerase chain reactions. In this study, we compared the results of previous HLA-DR typing using conventional serology with HLA-DRB1 typing using the PCR-SSP technique.

The allocation of cadaver kidneys for transplantation should have two objectives: a fair distribution of kidneys among the waiting recipients and a high success rate. Currently, organ exchange organizations are following mainly a policy of success oriented allocation in that the kidneys are distribu

Recipients (4076) and donors (3325) of kidney transplants performed at 110 transplant centers were typed for HLA-DRB by the DNA RFLP method. The discrepancy rate of replicate samples distributed among 8 participating laboratories was a low 2.6%. The discrepancy rate between RFLP-DRB and serological HLA-DR typings was 25.0% for organ donors and 27.6% for kidney recipients. Discrepancy rates at the different transplant centers ranged from 9.7% to 86.7%. The discrepancies consisted of antigens being incorrectly interpreted by serology (16.8%), and of serological "blanks" turning out to be definable alleles by the DNA method (10.8%). The alleles that were mainly affected by discrepancies were DR1, DR8, DR10, DR12, DR13, DR14, DR16, DR17.2, and DR18.

The outcome of simultaneous pancreas-kidney (SPK) transplantation in type 1 diabetes has dramatically improved in recent years because of optimized surgical techniques and new immunosuppressive drug regimens. Normoglycemia is followed by stabilization or even regression of diabetic lesions, i.e., of heart and kidneys. However, these effects are only visible after more than five yr of normoglycemia (achieved by a functioning allograft). This is also a likely explanation for the conflicting results of studies that investigated patient or kidney graft survival in SPK transplantation compared to kidney transplantation alone. Most studies had too short follow-up periods, i.e., less than five yr, to compare effectively different transplant strategies in patients with type 1 diabetes and therefore failed to discover a survival benefit in favor of simultaneously transplanted patients. Recent data now indicate that, with a longer follow-up, there is an increasing survival benefit for simultaneously transplanted patients compared to patients who received a single kidney transplant. This is paralleled by the comparison of simultaneously transplanted patients to patients who received a single kidney transplant from a living donor. A survival benefit for the combined procedure was here visible after 10 yr of follow-up. We give a short overview on SPK transplantation, with a focus on the effects of this procedure on diabetic complications as well as patient and kidney graft survival.

The aim of this prospective study was to examine gender-related differences of cytokines in the plasma and urine of healthy individuals that might provide a clue concerning the lower rate of chronic renal diseases in females. Soluble interleukin-1 receptor antagonist (sIL-1RA), interleukin (IL)-1alpha, IL-1beta, IL-2, sIL-2R, IL-3, IL-4, IL-6, sIL-6R, IL-10, tumor necrosis factor (TNF)-alpha, transforming growth factor (TGF)-beta(2) and interferon (IFN)-gamma were determined using standard enzyme-linked immunosorbent assay (ELISA). Cytokine levels were determined in simultaneously obtained plasma and urine samples of 18 male and 28 female healthy members of our laboratory staff. Urine cytokine levels were studied three times at 1-month intervals. All individuals had a negative urine nitrite test and showed no symptoms of urinary tract infection (UTI). Plasma levels of all studied cytokines were similar in males and females (P = n.s.). However, females had significantly higher urine IL-1alpha (P0.0001; P0.0001; P0.0001) and sIL-1RA (P = 0.0001; P = 0.0003; P = 0.0002) than males at three and higher IL-1beta at one of the three investigations (P = 0.098; P = 0.003; P = 0.073). Urine levels of the other cytokines were similar in males and females. Higher urine levels of IL-1alpha, IL-1beta and sIL-1RA in females may result from stimulation of cells in the urinary tract. Increased sIL-1RA might block T lymphocyte activation. The elevated cytokines may play a role in the protection of the female urinary tract from certain renal diseases, such as pyelonephritis and other inflammatory and sclerotic kidney diseases.

Renal transplant recipients who are chronically immunosuppressed by drugs are at a higher risk of developing malignancies. Commonly observed malignancies are several forms of posttransplant lymphoproliferative disorders (PTLD), skin, lip and gynaecological cancers. The risk is associated with many risk factors including the extent of immunosuppression. Mycophenolate mofetil (MMF) is an immunosuppressant, indicated for the prophylaxis of organ rejection in patients receiving allogenic renal and heart transplants. During the European approval of MMF for renal transplantation, the question was raised as to whether the use of MMF was associated with an increased risk of PTLD in comparison with alternate immunosuppressive regimens. In response, F. Hoffman-La Roche Ltd set up a prospective observational cohort study with a companion case-control study. This paper describes the objectives and the methods of these studies along with the rationale of the methodology.

In a previous study, DNA typing revealed that 25% of serological HLA-DR typings of kidney transplants were incorrect. In the current study, we analyzed whether this error rate had improved in recent years, and whether there were differences according to geographical region. From 1988 to 1991 the error rate of serological typing improved slightly in Western Europe from 19% to 16%, and in North America, from 21% to 16%. In Eastern Europe, the error rate decreased from 49% to 33% in 1991, whereas the rate remained high in South America at 60% in 1988 and 72% in 1991. The high error rates in South America and Eastern Europe reflected a lack of good quality serological typing reagents. The 16% typing errors in Western Europe and North America demonstrated the current limit of serological techniques for cadaver donor typing and underlined the need for prospective DNA typing.

HLA-A typing by the PCR-SSP method in a male 21-year-old Caucasian individual revealed a very rare allele combination corresponding to a unique reaction pattern. Therefore, the result was examined using sequence-based typing. Sequencing of exons 2 and 3 of the HLA-A locus after allelic separation with specific primers revealed the sequence of a new allele, similar to A*0245. Sequencing of exons 1 and 4 resulted in no additional inconclusive positions. The sequence pattern of the new allele HLA-A*0256 might have been generated as a result of a double crossing over recombination of an A*0201 and either an A*03 or an A*11.

The influence of HLA compatibility on organ transplant survival was analyzed in more than 150,000 recipients transplanted from 1987 to 1997 at transplant centers participating in the Collaborative Transplant Study. A statistically highly significant effect of HLA matching on graft and patient survival rates was found in the analysis of kidney transplants (P0.0001). Ten years after transplantation, the graft survival rate of first cadaver kidney transplants with a complete mismatch (6 HLA-A+B+DR mismatches) was 17% lower than that of grafts with no mismatch. During the first post-transplant year, the class II HLA-DR locus had a stronger impact than the class I HLA-A and HLA-B loci. During subsequent years, however, the influence on graft survival of the three loci was found to be equivalent and additive. For optimal graft outcome, compatibility at all three HLA loci is, therefore, desirable. The excellent correlation of HLA matching observed in recipients of cadaver kidneys with very short ischemic preservation (0-6 hours) or recipients of kidneys from living unrelated donors contradicts reports that short ischemia can eliminate the influence of matching. Although HLA has a significant effect on graft outcome regardless of the state of presensitization, the matching effect is potentiated in patients with highly reactive preformed lymphocytotoxic antibodies. Among first cadaver transplant recipients with an antibody reactivity against50% of the test panel, the difference in graft survival at 5 years between patients with 0 or 6 mismatches reached 30%. A collaborative project, in which molecular DNA typing methods were employed, showed that the correction of serological HLA typing errors by more accurate DNA typing results in a significantly improved HLA matching effect. Moreover, matching for the class II locus HLA-DP, a locus that can be typed reliably only by DNA methods, showed a significant effect in cadaver kidney retransplants, especially in the presence of preformed lymphocytotoxic antibodies. The analysis of heart transplants showed a highly significant impact of HLA compatibility on graft outcome (P0.0001). This result is of particular interest because donor hearts are not allocated according to the HLA match. A biasing influence of donor organ allocation (i.e. a preferential allocation of good matches to good risk recipients) can, therefore, be excluded. In liver transplantation, neither matching for HLA class I nor HLA class II could be shown to influence transplant outcome.

There are conflicting reports in the literature concerning the efficacy of maintenance immunosuppression in renal transplantation with a regimen of azathioprine and steroids.The daily dosage (mg/kg) of azathioprine administered 1 year after transplantation was analyzed in relation to subsequent long-term graft outcome. Transplants performed from 1985 to 1996 and reported to the Collaborative Transplant Study were analyzed.In patients on maintenance immunosuppression without cyclosporine, the daily dosage of azathioprine had a highly significant influence on long-term graft outcome. Patients who received1.5 mg/kg/ day of azathioprine had a 69% graft survival rate at 7 years, compared with a 55% rate in patients receiving 1.01-1.5 mg/kg/day (P0.0001) and a 45% rate in patients receivingor = 1.00 mg/kg/day (P0.0001). This observation was valid for patients who were taken off cyclosporine during the first year as well as for patients who were treated with azathioprine and steroids (without cyclosporine) from the beginning.Maintenance immunosuppression with azathioprine and steroids results in good long-term kidney graft survival, provided azathioprine is administered at a daily dose of1.5 mg/kg.

Die Verbesserung des Langzeit-Transplantatuberlebens stellt eine der grosten Herausforderungen in der Transplantationsmedizin dar. Eine Auswertung der Datenbank der Collaborative Transplant Study identifizierte eine Reihe von Faktoren, die das Langzeituberleben beeinflussen. Drei Faktoren sollen hier herausgegriffen und untersucht werden: Spenderalter, systolischer Blutdruck des Empfangers und HLA-Kompatibilitat. Alle drei Faktoren korrelieren hoch signifikant mit dem langfristigen Uberleben von Leichennierentransplantaten. So nimmt das Organuberleben mit zunehmendem Spenderalter und Blutdruck des Empfangers ab. Und je groser die HLA-Ubereinstimmung zwischen Spender und Empfanger ist, desto besser ist der langfristige Transplantationserfolg.

Preliminary studies showed an excellent success rate of kidney grafts in patients with high pretransplantation serum levels of IgA autoantibodies directed against the Fab region of the human IgG molecule.With the collaboration of 30 centers from around the world, we attempted to verify the role of IgA-anti-Fab autoantibodies in kidney transplantation in an entirely new series of 4316 cadaveric kidney transplants, with special consideration of presensitized and poorly HLA-matched recipients.In agreement with previously published preliminary findings, 147 recipients with a high pretransplantation IgA-anti-Fab of1000 had a 2-year kidney graft survival rate of 88+/-3% (+/- SE), compared with an 80+/-1% rate in 851 recipients with a low IgA-anti-Fab of60 (P = 0.02). Even in patients at an increased risk of graft rejection, high pretransplantation IgA-anti-Fab autoantibody activity was associated with superior graft survival. Among 815 presensitized patients, 31 had a high pretransplantation IgA-anti-Fab activity of1000 and their 2-year graft survival rate was 94+/-4%, in contrast to a 71+/-4% rate in 165 presensitized recipients with a low IgA-anti-Fab of60 (P = 0.02). Of 2294 recipients who received a kidney withor =3 HLA-A+B+DR mismatches, 79 recipients had a high pretransplantation IgA-anti-Fab of1000 and a 2-year graft survival rate of 90+/-4%, as compared with a 79+/-2% rate in 459 patients with a low IgA-anti-Fab of60 (P = 0.04).The present study confirms that kidney graft recipients with high pretransplantation IgA-anti-Fab activity have excellent graft survival, and it extends this observation to presensitized recipients and poor HLA matches.

The success rate of kidney transplants in Asian recipients was reported in the literature to be exceptionally high. This raises the question whether HLA incompatibilities do not elicit allograft rejection in Asians. Asian recipients, 3,721, of kidney transplants from unrelated living or cadaveric donors were analyzed. The transplants were part of the Collaborative Transplant Study database. HLA typing data and clinical follow-up information were provided by the participating centers. The survival rate of cadaver kidney transplants was associated statistically significantly with the number of HLA-DR mismatches (p0.01) as well as with the number of HLA-A + B + DR mismatches (p0.01). A significant association of HLA mismatches with graft outcome was also found in a subanalysis of cadaver transplants from Asian donors into Asian recipients (p = 0.03). Among transplants from unrelated living donors, both HLA-DR mismatches and HLA-A + B + DR mismatches were associated with graft outcome (p0.01). The success rate of 123 grafts with 2 HLA-DR mismatches was a poor 69 +/- 4% at 3 years, suggesting that such transplants should be avoided if possible. Kidney transplants from unrelated donors into Asians benefit from improved HLA compatibility. The results, therefore, suggest that prospective HLA matching strategies for Asian patients should be pursued.

The clinical value of serological HLA matching for cadaver kidney transplantation remains uncertain because the success rate for HLA-matched cadaver transplants is lower than that of HLA-matched sibling grafts. Up to 25% of serological HLA-DR typings may be incorrect when compared with a more accurate DNA-RFLP method, and we have now examined whether incorrect HLA-DR typings account for the lower than expected success rates of HLA-matched cadaver transplants. 58 transplant centres took part in this study and DNA was extracted from over 4000 samples of frozen tissue at the study centre. 8 laboratories then completed blind RFLP typing for HLA-DR. Serological typing data were reported by individual transplant laboratories. 29 of 107 transplants (27%) that were reported as HLA A, B, DR compatible and 76 of 273 (28%) transplants that were reported as HLA B, DR compatible according to serological typing were found to be HLA-DR mismatched by DNA typing. The one-year transplant success rate for DNA-matched HLA, A, B, DR grafts was 87% compared with 69% for mismatched grafts (p less than 0.02); the corresponding success rate for DNA-matched HLA B, DR grafts was 85% compared with 72% for mismatched grafts (p less than 0.01). Many transplants that were previously thought to be HLA matched are mismatched, and this finding may account for previously unexplained graft failures.

Sequence-specific primed polymerase chain reaction (PCR-SSP) is widely used in HLA laboratories. The TaqMan method, which is described here for high-resolution typing of HLA-DRB1*15 and -DRB1*16, does not require elaborate and time-consuming post-PCR detection steps. In this one-tube assay, conventional PCR-SSP and fluorescence detection of the amplicon with a doubly labeled fluorescent probe are combined: a fluorogenic hybridization probe (FHP) labeled with a spectral resolvable fluorescent reporter dye (FAM or TET) at its 5' terminus and a common quencher dye (TAMRA) at its 3' terminus is cleaved by the 5' nuclease activity of Taq DNA polymerase only if the target sequence is amplified. An increase of fluorescence intensity indicates a successful amplification. For high-resolution typing of HLA-DRB1*15 and -DRB1*16 alleles we designed two FHPs and 14 specific primer mixes (7 for DR15 and 7 for DR16). Amplification of the specific sequence was detected by a FAM-labeled FHP, whereas amplification of the internal control was detected by a TET-labeled FHP. We were able to type all heterozygous DRB1*15/DRB1*16 subtype combinations. For evaluation, 60 HLA-DRB1*15-positive and 40 HLA-DRB1*16-positive individuals were typed and the results were compared with conventional PCR-SSP DR15/16 subtyping. There were no discrepancies between the two methods. The TaqMan method is an alternative to conventional PCR-SSP typing which is suitable for routine use in HLA laboratories.

It has been known for a long time that IgG-anti-F(ab')(2) antibodies (Abs) are able to suppress the B-cell response. We showed that natural IgG-anti-F(ab')(2) autoantibodies appear in the serum of patients with cold agglutination. If the anti-F(ab')2 Ab suppresses cold agglutinin (CA)-producing B cells, one would expect an inverse correlation between the titers of these two Abs. Our study confirmed this correlation. Subsequent experiments showed that some anti-F(ab')(2) Abs bind to the hinge region of IgG. It was difficult to explain how this Ab suppresses CA-producing B cells, which are of IgM isotype. Here we show that patients with cold agglutination have an IgG-anti-kappa light chain autoantibody in their serum. This is another member of the anti-F(ab')(2) Ab group. Because the vast majority of CAs are IgM-kappa Abs, the anti-kappa Ab might suppress CA-producing B cells. If this is the case, there should be an inverse association between the titer of anti-kappa Ab and CA. In a group of 302 patients, we found that high titers of the anti-kappa Ab correlate with low titers of CA and vice versa (P =.009). Interestingly, this association is found only in patients whose disease is caused by noninfectious agents, including mainly B-cell proliferations (P =.0058). Our data show that the inverse correlation is not confined to a particular CA autoantibody specificity. The results are discussed in the light of recent findings showing that anti-IgM Abs may either inactivate or kill tumoral B cells by apoptosis.

Compared to patients with a stable liver function, we found a decreased Th1 and increased Th2 response in patients presenting with ischemic type biliary lesions following liver transplantation. It remains open to speculation whether these immunological changes were induced by the damage of the bile ducts, occur as an additional damaging factor or are found as an epiphenomenon in patients with liver transplant dysfunction.

Upon the availability of a cadaveric donor kidney, a delicate allocation process precedes every transplantation. A remodeled Eurotransplant Kidney Allocation System (ETKAS)-derived from simulation studies-was installed in March 1996. The purpose was to adjust long waiting times and international exchange balances, while aiming at an optimal HLA-mismatch distribution. The new ETKAS consisted of a point-score system that was 100% patient oriented.The impact of the new ETKAS on the composition of the waiting list, and the outcome of the allocation procedures during its first year, were evaluated and compared with the results obtained in 1995.The percentage of long-waiting patients and of patients with poorly matchable HLA phenotype increased significantly, from 9% to 19% and from 19% to 29%, respectively. Zero HLA-A-, HLA-B-, HLA-DR-mismatched patients still comprised 23% of the kidney transplant activity. The kidney exchange of the different Eurotransplant countries became balanced within 4 months; this persisted during the rest of the year. Pediatric patients had a high transplantation rate due to an assignment of extra points. The composition of the waiting list showed, after 1 year, fewer long-waiting patients and fewer patients with rare HLA phenotypes.The new ETKAS was able in its first year to meet the goals set at its introduction. In comparison with the old ETKAS, there was a better trade-off between HLA matching and waiting time. The value of computer simulation studies has been demonstrated impressively in the context of organ allocation.

The association of HLA class II alleles with multiple sclerosis (MS) has been amply documented. In the present study, the role of HLA class II (DRB1, DQA1 and DQB1) alleles and haplotypes was investigated in 43 unrelated Iranian chronic progressive multiple sclerosis (CP-MS) patients compared with 100 healthy individuals. HLA typing for DRB1, DQA1 and DQB1 was performed by restriction fragment length polymorphism (RFLP). Subtypes of DR4, DR15 and DR16 were defined using polymerase chain reaction (PCR) amplification with sequence-specific primers (PCR-SSP). The results show that, among DR2-positive MS patients and the control group, a positive association with the DRB1*1503, DQA1*0102, DQB1*0602 haplotype (21% vs. 2.7%, P = 0.057, RR = 9.8) and a negative association with the most frequent DR15 haplotype in the control group, DRB1*15021, DQA1*0103, DQB1*0601 (7% vs. 24.3%, P = 0.001), were observed. No significant association was found with the analysed HLA-DRB1, DQA1 and DQB1 alleles.

In a recent study, we observed a discrepancy rate of 8.5% between the results of molecular and serological HLA class I typing in Caucasian kidney donors and recipients. In the present study we addressed the question how often black individuals are mistyped using the serological technique. 421 Blacks whose HLA typing results were reported to the Collaborative Transplant Study (CTS) were typed retrospectively for HLA-A and -B using a PCR-SSP method. 78 of the 421 individuals (18.5%) showed a discrepancy for HLA-A and 107 individuals (25.4%) for HLA-B. 36.3% of all individuals tested showed either an HLA-A or an HLA-B discrepancy. 13.1% of the discrepancies at the HLA-A locus were due to antigen misassignments and 4.8% were due to missed antigens. HLA-B discrepancies were caused in 15.7% by antigen misassignments and in 10.5% by missed antigens. These results demonstrate an impressive advantage of the PCR-SSP method for HLA-A and HLA-B locus typing over serological typing in black individuals. The high typing discrepancy rate observed in Blacks provides a strong argument for replacing serological typing by the DNA method. It is likely that this will improve the HLA matching correlation in clinical transplantation in Blacks.

When renal amyloidosis has progressed to end-stage renal failure, most patients are severely affected by systemic amyloidosis and nephropathy. An alternative to chronic dialysis is renal transplantation. We present a patient with amyloid nephropathy who developed recurrent transplant amyloidosis. Renal transplantation was performed in 1985 with a living related donor. In 1990 the patient developed amyloidosis of the graft with membranous nephropathy and tubular acidosis due to hyporeninemic hypoaldosteronism. Secondary amyloidosis has been reported to involve glandular organs inducing hypothyroidism, hypocortisolism and hypoaldosteronism. Cyclosporine has been reported to induce hyporeninemic hypoaldosteronism and tubular acidosis, but not hypocortisolism and hypothyroidism. Progression of the amyloidosis of the graft was confirmed by a renal biopsy in 1993. Data published in the literature indicate that the survival rate of amyloidotic graft recipients is worse than those of non-amyloidotic graft recipients. This was confirmed in an analysis of the current CTS data which showed an impaired survival rate at 5-yr of 66 +/- 4% (+/- SE) for patients with amyloidosis (n = 413) as compared with 86 +/- 1% (p0.0001) for patients with glomerulonephritis and 84 +/- 1 (p0.01) for patients with polycystic kidney disease. Graft survival after 5 years was 55 +/- 4% in patients with amyloidosis as compared with 63 +/- 1% (p = 0.02) in patients with glomerulonephritis and 68 +/- 1% in patients with polycystic kidney disease. Graft survival was improved in amyloidotic patients treated with cylosporine as compared with patients on steroids and azathioprine (55 +/- 4% vs. 38 +/- 8%, p0.05). It is concluded that renal transplantation is the renal replacement therapy of choice for patients with AA-type amyloidosis although the overall patient survival is impaired in comparison with patients with other diseases.