Donor CD31 genotype and its association with acute graft-versus-host disease in HLA identical sibling stem cell transplantation.

CD31 gene polymorphisms are implicated in the pathogenesis of graft-versus-host disease (GvHD) following haematopoietic stem cell transplantation (HST). We investigated the influence of CD31 genotype on the incidence of GvHD following HST from an human leukocyte antigen (HLA)-identical sibling donor. Donor and recipient CD31 codons 125, 563 and 670 DNA polymorphisms were determined in 85 cases of HLA identical sibling HST from two transplant centres. A correlation between CD31 genotype and acute GvHD was considered significant if observed in patients from both transplant centres independently. A strong correlation was identified between donor CD31 codon 125 genotype and the incidence of acute GvHD. Acute GvHD grades II-IV occurred in 27 of 46 (59%) recipients with a CD31 codon 125 leucine / valine heterozygous donor compared to nine of 39 (23%) recipients with a CD31 codon 125 homozygous donor (P=0.0019, relative-risk 2.45, 95% confidence interval 1.3-4.5). This correlation was significant in patients from both transplant centres (P=0.015 and P=0.019). We suggest that CD31 genotype may influence the function of donor-derived leukocytes and may be informative when there is a choice of comparable donors.

Genetic factors in myasthenia gravis: a family study.

We studied forty-four patients with myasthenia gravis (MG) and their families. Thirty percent of patients had a confirmed family history of autoimmune disease; in one case this was MG. In all the families with autoimmune disease, the affected relatives were related to the patients through the maternal line. HLA-B8 and DR3 were increased in patients due to the high incidence of these antigens in female, nonthymoma patients with onset before 40 years. HLA-B5 was increased in patients with older onset. The haplotype A1-B8-DR3 was not found to be increased given the presence of B8 or DR3.

The influence of increased age and age matching on graft survival after first cadaveric renal transplantation.

We examined the influence of donor and recipient age as well as close donor and recipient age matching by analysis of the actuarial survival of 397 consecutive first cadaveric renal transplants carried out in the years 1987 to 1990. Graft failure was defined as return to dialysis, transplant nephrectomy, or death of the recipient from any cause. Overall 1-, 2-, and 3-year actuarial graft survival was 87, 84, and 79%. No effect on graft survival in adult patients was seen of advanced age of either donor or recipient. The source of the donor whether from within or outside the North Western Regional Health Authority did not influence outcome whatever the donor age. Results from patients in whom the donor was within 5 years of the recipient's age were no different from those obtained when the age difference was greater than 5 years. These data do not support the hypothesis that close age matching influences graft survival. Age matching need not be used as a recipient selection criterion. As neither recipient nor donor age influenced early graft survival, consideration should be given to increasing the average age of both donors and recipients.

Detection of HLA-specific antibodies by PRA-STAT and their association with transplant outcome.

OBJECTIVE: The aim was to investigate the correlation between renal transplant outcome and the presence of HLA-specific antibodies detected using the ELISA kit PRA-STAT as compared with complement-dependent cytotoxicity (CDC). METHOD: 295 sera from 95 renal transplant recipients (99 transplants) were investigated for the presence of HLA-specific antibodies using both PRA-STAT and CDC. The patients were divided into group I (49 transplants failed within 1 month) and group II (50 successful transplants). RESULTS: The concordance between PRA-STAT and CDC for the detection of HLA class I-specific antibodies was 87.8% (259 of 295). For 19 sera, antibodies were detected only by PRA-STAT; for 17 sera, antibodies were detected only by CDC. No donor-specific antibodies were detected by either technique for patients in group II. For four group I patients (six sera), donor-specific IgG antibodies were detected only by PRA-STAT (one before, three after transplant) and all four transplants failed. For five other group I patients (six sera), donor HLA-specific antibodies were detected only by CDC (one before, four after transplant) and all five transplants failed. The antibodies detected before transplant by CDC were shown to be IgM alloantibodies. CONCLUSION: This study showed that PRA-STAT could detect HLA-specific IgG antibodies relevant to transplant outcome that were not detected by CDC. However, it could not detect IgM alloantibodies that were also shown to be important. PRA-STAT is therefore a useful addition to a histocompatibility laboratory's screening repertoire only when used in conjunction with other techniques.

Posttransplant antidonor lymphocytotoxic antibody production in relation to graft outcome.

Serial serum samples from 266 recipients of primary renal allografts were monitored posttransplant for the presence of panel reactive lymphocytotoxic antibodies (PRA). The minimum posttransplant follow-up period was 18 months. Patients were classified according to whether or not they produced PRA before and/or after transplantation. The groups were as follows: PRA negative before and after transplant, -/-, 171; PRA positive before and negative after transplant, +/-, 5; PRA positive before and positive after transplant, +/+, 27; PRA negative before and positive after transplant, -/+, 63. Actuarial graft survival at 1 year for each group was 81.3%, 100%, 70.4%, 47.6%, respectively. Fifty-five of the 63 -/+ recipients were retrospectively crossmatched with posttransplant sera against stored donor lymphocytes. Of these, 50 (91%) were posttransplant cross match positive, and 37 (67%) have lost their grafts. In 23 of the 26 cases where an anti-HLA specificity was defined, the antibody was directed against antigens present in the donor but not in the recipient. These results clearly indicate that the production of PRA in recipients of renal transplants is associated with antidonor reactivity and poor graft outcome. The fact that these PRA were often directed against donor HLA antigens emphasizes one of the hazards of mismatching for HLA at transplantation.

Successful renal transplantation of patients sensitized following deliberate unrelated blood transfusions.

One of the most powerful influences on cadaveric renal graft survival is the enhancing effect of blood transfusions from unrelated individuals (1, 2). However, the optimum number of transfusions required to achieve this effect remains controversial. Enhanced graft survival following only one or two transfusions has been observed (3), although graft survival has also been found to be better for multitransfused recipients (4). Extrapolating from their studies on mice, Wood et al. (5) suggested that only a very small volume of blood may induce the transfusion effect in humans. As the number of transfusions increases so does the risk of sensitizing the patient to produce lymphocytotoxic antibodies that may impair the chances of the patient receiving a crossmatch-negative kidney graft (6, 7). Thus the problem is to minimize the chance of sensitization while still maintaining the beneficial effect of blood transfusion.

Evidence that matching for HLA antigens significantly increases transplant survival in 1001 renal transplants performed in the northwest region of England.

In the 20-year period from March 1968 to March 1988, 860 patients received 1001 renal transplants in the Northwestern Regional Renal Transplant Unit at Manchester Royal Infirmary. Through a continuing policy of avoiding mismatches for HLA antigens and lymphocytotoxic antibody crossmatching, transplant survival rates were found to correlate with the degree of HLA-A and B antigen mismatching from 1968 to 1978 and with HLA-B and DR antigen mismatching from 1979 to 1988. Mismatching for HLA-B and DR antigens was also found to correlate with transplant survival in highly sensitized patients and in patients transplanted since 1981, the "cyclosporine era." Recipients who were HLA-DR1 positive were found to have the highest graft survival compared to recipients negative for this antigen. In contrast, HLA-DR3 positive recipients had the poorest outcome. Transplants from HLA-DRw6 positive donors showed higher transplant survival rates than donor kidneys positive for any other HLA-DR antigen. A correlation of transplant survival with HLA-B and DR mismatching was seen whether kidneys were collected within our region or received through the UK Transplant Service. We conclude that avoidance of mismatching for HLA-B and DR antigens confers high transplant survival rates (91.1% at 5 years for 0 HLA-B and DR mismatches), and in order to achieve this rate for most recipients exchange of donor kidneys between transplant centers will be essential.

Rejection in heart transplantation strongly correlates with HLA-DR antigen mismatch.

It is well established that incompatible HLA antigens presented by donor tissue readily evoke an immune response. Prospective HLA matching policies, widespread in European kidney transplant centers have reduced the level of HLA mismatching and have significantly improved graft survival. The influence of HLA incompatibility in heart transplantation remains controversial, and prospective HLA matching is seldom achieved. We examined the role of HLA antigen mismatching on transplant rejection by analyzing 2569 endomyocardial biopsies (EMB) from 157 consecutive orthotopic heart transplants performed from April 1987 to August 1993 in our own center. Biopsies were graded according to the accepted International Classification, with grade 2 and higher indicating rejection. Among 91 patients who received a 2 HLA-DR mismatch transplant 34% of 1624 biopsies analyzed were graded as > or = 2. This frequency fell to 29% of 797 biopsies for 53 patients with a one-HLA-DR mismatch and to 18% of 148 biopsies for 13 patients in the zero-HLA-DR-mismatch group (P < 0.00005). No significant effect on EMB grade frequencies was observed using the same method of analysis with transplants mismatched at the HLA-A or HLA-B loci apart from analysis of HLA-B matched transplants at 3 months posttransplant (P = 0.02). The close linkage of the HLA-B and HLA-DR loci may account for this observation. The results of this study show that heart transplants matched at the HLA-DR locus have a significantly reduced incidence of EMB grades indicative of rejection requiring augmented immunosuppressive therapy. We propose that prospective HLA-DR matching should be adopted for allocation of donor hearts for more efficient use of this precious and limited resource.

A genetic marker of high TNF-alpha production in heart transplant recipients.

The cytokine TNF-alpha has been implicated in the pathogenesis of both acute and chronic transplant rejection. Levels of the cytokine are known to vary in a normal population, leading to speculation that high responders may be at greater risk of rejection. Particular TNF region polymorphic markers have been associated with increased TNF-alpha levels and a biallelic polymorphism has been identified at position -308 of the TNF-alpha promoter that may contribute significantly to the interindividual variation in healthy persons. We describe here a new association between a polymorphic locus in the TNF gene region and increased production of TNF-alpha in heart transplant recipients. We studied two microsatellite markers that flank the TNFA gene, as well as a biallelic polymorphism at position -308 of the TNFA promoter, and found that the microsatellite allele TNFd3 was significantly associated with the capacity of leukocytes to produce TNF-alpha in vitro. No association was demonstrated for the promoter region polymorphism. Patients were receiving cyclosporine (CsA) and prednisolone (pred) at the time of sampling, which are known to interrupt 5' regulation of TNFA transcription in T cells and macrophages and may therefore negate the influence of the -308 polymorphism. Because of this we suggest that TNFd3 may be a marker for a 3' repressor region polymorphism that is of importance in immunosuppressed individuals.

Cytokine gene polymorphism and heart transplant rejection.

BACKGROUND: Allograft rejection is mediated by cytokines. As polymorphism in cytokine genes can result in interindividual differences in cytokine production, we hypothesize that some patients may have an increased risk of rejection. METHODS: We have related polymorphisms that influence cytokine production in the tumor necrosis factor (TNF)-A and interleukin (IL)-10 genes to early graft rejection in 115 heart transplant recipients. RESULTS: Certain combinations of TNF-A and IL-10 gene polymorphisms are associated with rejection. Five of 19 patients who had high levels of rejection typed as high TNF-alpha/low IL-10 producers compared with 4 of 96 patients with lower levels of rejection (P<0.005). CONCLUSIONS: We have identified a particular cytokine genotype that may confer susceptibility to increased levels of early rejection. Patients with a worse prognosis may be able to be identified pretransplant by DNA analysis of TNF-A, IL-10, and other gene polymorphisms.

Importance of minimizing HLA-DR mismatch and cold preservation time in cadaveric renal transplantation.

Univariate and multivariate analyses have been performed on donor an d recipient variables to determine possible effects on the outcome of 516 primary cadaveric renal transplants performed in our single center from 1989 until 1993. The overall actuarial patient survival at 1 year and 5 years was 94.4% and 87.4%, respectively; the 1 year and 5 year graft survival rates were 88.3% and 77.8%, respectively. A total of 95 grafts were lost; death with function (35%) and chronic rejection (22%) were the major causes. Three variables (HLA-DR mismatch, delayed graft function, and prolonged cold ischemia time) had a significant detrimental effect on both short- and long-term graft survival. Zero HLA-DR mismatched grafts showed significantly enhanced survival over those with 1 HLA-DR mismatch both at 1 year (92.8% vs. 84.5%) and at 5 years (88.3% vs. 73.9%) only if cold ischemia time was less than 26 hours (P=0.0009). Occurrence of delayed graft function significantly lowered graft survival at both 1 year and 5 years (P=0.002), and the incidence was significantly associated with prolonged cold ischemia time (P<0.0001). HLA-A or HLA-B matching, percentage panel reactive antibodies (PRA), and anastomosis time showed no independent effect on long-term survival. The small number of 2 HLA-DR mismatched grafts (n=6) precluded separate analysis of this group. Acute rejection accounted for 12% of losses but had no statistically significant effect on graft survival, even though an increased frequency of rejection episodes was significantly associated with HLA-DR mismatch (P<0.0001). These results would suggest that significant survival benefits may be achieved by prospective HLA matching if cold ischemia times are limited. The efficiency of organ sharing must he improved to make optimal use of a limited resource.

The influence of histocompatibility on graft rejection and graft survival within a single center population of heart transplant recipients.

BACKGROUND: We report a consecutive single center series of 261 patients who received first orthotopic heart transplants from 1986 to 1997. The 1- and 5-year graft survivals were 78 and 68%. The influence of histocompatibility was investigated by comparing graft survival and numbers of treated rejection episodes with HLA-A, -B, and -DR mismatches over different time periods. FINDINGS: Recipients with six mismatches for HLA-A+-B+-DR combined (13.4%) had reduced survival at 7 years (47%) when compared with other recipients (64%). In the first year of transplant, recipients with four HLA-A+-B mismatches had significantly reduced actuarial graft survival (P=0.03) with the greatest influence apparent at 6 months [0-3 mismatches (n=193) 85% versus 4 mismatches (n=68) 69%; P=0.005, OR=2.1]. For 182 recipients with functioning hearts at 1 year, the number of rejection episodes treated within this time was strongly influenced by HLA-DR mismatch [0 DR mismatch (n=15) mean 1.2 rejection episodes versus 1 DR mismatch (n=76) mean 2.7 rejection episodes versus 2 DR mismatches (n=91) mean 3.8 rejection episodes: P=0.0002]. Of these 182 transplants, recipients who had more than four treated rejection episodes during the first year had a significantly reduced 7- year survival [<5 rejection episodes (n=133) 85% versus more than four rejection episodes (n=49) 66%; P=0.02, OR=3.4], as did those with two HLA-DR mismatches [0+1 mismatch (n=91) 87% versus 2 mismatches (n=91) 70%; P<0.05, OR=2.4]. INTERPRETATION: We show that graft loss in the first 6 months of transplant is significantly influenced by four HLA-A+-B mismatches. HLA-DR mismatch significantly increases the number of rejection episodes within the first year, without influencing graft survival. After 12 months both >4 rejection episodes in the first year and two HLA-DR mismatches are markers for late graft loss. We postulate that immunological graft loss in the first 6 months is dominated by the direct allorecognition pathway driven by HLA-DR mismatch. This mechanism is later lost or suppressed. Our data highlight HLA-DR mismatch as a marker for late graft loss and we show an advantage to avoiding transplanting hearts with six HLA-A+-B+-DR mismatches and to minimizing HLA-DR mismatches whenever possible.

Matching for properdin factor B (Bf) in renal transplantation.

Forty-five donor and recipient primary cadaveric kidney transplant pairs were phenotyped for the properdin factor B (Bf) polymorphism. Graft survival was analyzed on the basis of Bf matching between donor and recipient. Patients receiving a Bf-identical kidney had significantly better graft survival than those receiving a Bf-incompatible kidney (P = 0.045). It is postulated that Bf, which maps in the major histocompatibility system, is a marker for genes of importance in kidney transplant survival.

Techniques used to define human MHC antigens: serology.

The classical, routine test employed for definition of HLA antigens expressed in humans (tissue typing) is the complement-mediated cytotoxicity assay developed by Terasaki and McClelland in the early 1960s. In both healthy persons and patients, the assay target cells are usually lymphocytes obtained from peripheral blood, but when typing cadaver donors, splenic or lymph node lymphocytes can be used. HLA-A, B, Cw (class I) antigens are expressed on all nucleated cells while HLA-DR, DQ (class II) are restricted to B lymphocytes and immune activated cells. Tissue typing has been achieved using culture cells from amniocentesis and typing of cell lines is possible with small modifications to the standardised cytotoxicity assay. Usually, target cells are incubated under oil with typing antisera at 22 degrees C in a 60- or 72-well Terasaki tray. After 30 min rabbit serum is added as a source of complement. After a further 60 min incubation the test is stained. A positive reaction results in target cell death. There are local variations to this test. Automation of the assay is now commonplace, from reagent dispensing to automated reading of finished assay. The use of antibody-coated magnetisable microspheres has enabled separation of pure B lymphocyte samples for class II typing and has reduced incubation times through antigen modulation. It is possible to define antibodies to HLA antigens in the same assay using target cells with known HLA phenotypes.

Comparison of serologic and biochemical definitions of HLA class I polymorphisms in cadaver renal transplantation.

The role of biochemical variants in matching renal donors with recipients was investigated in a population of 26 donor recipient pairs from the period 1979-85. Serologic typing was compared with a biochemical analysis of HLA-A and -B antigens in a group in which there had been no mismatches for HLA-A and -B antigens by serology. HLA-A and -B serology was updated using stored material for 92.2% of the renal recipients and donors (n = 51), and HLA-A, -B, and -DR serology was updated for 84.3%. No inconsistencies were found with the HLA-A and -B antigens assigned at the time of transplant. HLA-A and -B antigens of 70% of the renal recipients and donors were analyzed by immunoprecipitation from lymphocytes and serum and analyzed after isoelectric focusing by autoradiography and Western blotting. No biochemical differences between recipient and donor were found for any one pair when HLA-A and -B antigens were serologically the same. This biochemical analysis was useful in providing results where there was doubt over the presence or absence of an antigen serologically. In a well-matched situation, HLA-A and -B serologic types were concordant with results obtained biochemically. However, in a poorly matched situation this could be different.

Lack of association of HLA polymorphisms with human papillomavirus-related cervical cancer.

An association of HLA-DQ3 with SCC of the cervix has been reported by researchers in Germany and Norway. This article documents a similar-sized study with patients and controls from northwest England. We report in detail on serologically determined HLA polymorphism in SCC patients with respect to HPV 16 infection, MHC class II expression within the tumor, serologic response to HPV, and other relevant clinical variables. We have also extended our studies to include DNA-based analysis using PCR and SSO probes for HLA-DQ. No significant association of any HLA-A, -B, -C, -DR, or -DQ antigen with SCC patients was found. While a possible explanation of the differences among studies could be a reflection of disease heterogeneity, the several tumor and clinical factors examined do not account for the observed differences from previous reports. Further studies are needed for a greater understanding of the interaction of HPV and HLA type in the development of cervical neoplasia.

HLA-DQ alleles associate with cutaneous features of onchocerciasis. The Kaduna-London-Manchester Collaboration for Research on Onchocerciasis.

Onchocerciasis is associated with a spectrum of cutaneous changes, ranging from clinically normal skin to acute and chronic pathology. An important aspect of disease expression may be the level of immune response to parasite antigens, which is likely to be regulated by MHC-encoded molecules. We therefore investigated HLA class I and class II phenotypes in Nigerian residents of an area endemic for onchocerciasis. All study subjects were carefully characterized for parasite load and skin pathology. Individuals with depigmentation had increased frequencies of DQA1*0501 and DQB1*0301 compared with persons with normal skin and high microfilarial load (NSHMF) (Odds Ratios 3.6 (95% CI 1.0 to 13.2) and 3.8 (1.0 to 15.2), respectively). Conversely, individuals with depigmentation had a decreased frequency of DQA1*0101 and Cw6 compared with NSHMF (Odds Ratios 0.2 (0.1 to 0.9) and 0.1 (0.02 to 0.8), respectively). When NSHMF subjects were examined by age, a further decrease in DQA1*0501 frequency and increase in DQA1*0101 frequency were observed in older NSHMF individuals. These results strongly suggest that there is an immunogenetic basis for the spectrum of cutaneous presentations in onchocerciasis and that HLA-DQ molecules are associated with the level of immune response to parasite antigens.

Are major histocompatibility system class III products independent markers for susceptibility to rheumatoid arthritis?

Three components of the complement pathway C2, Factor B, and C4 are coded for by four genes C2, Bf, C4A, and C4B in the class III region of the major histocompatibility system in man. Studies of the polymorphism of these plasma proteins have shown associations of BfS, C2C, and C4B3 (2.9) with RA. Family studies have shown that these markers occur together, usually on DR4 positive haplotypes and in particular on the A2-Cw3-Bw62-C4B3-C4A3-BfS-C2C-DR4 haplotype. It is argued that Class III gene products are unlikely to be independent markers of susceptibility to RA.

Rheumatoid arthritis: inheritance and association with other autoimmune diseases.

This paper reviews the significance of the associations between rheumatoid arthritis (RA) and both diabetes mellitus and autoimmune thyroid disorders (ATD). All three disorders are thought to result from an interaction between genetic susceptibility and environmental factors. There is a probable real but not dramatic aggregation of insulin-dependent diabetes mellitus (IDDM) in the families of RA probands and a significant aggregation of ATD in both first- and second-degree relatives of RA probands. HLA-linked genes predispose to all three disorders while genes linked to Gm have been implicated in predisposition to RA and ATD. Within the HLA region two or more genes may predispose independently to RA; one of these genes is in linkage disequilibrium with HLA-DR4 and a second is in linkage disequilibrium with DR1 and 3. The familial aggregation of RA and IDDM is at least partially attributable to a single gene linked to HLA-DR4 predisposing to both disorders. By contrast, although 'DR4 negative RA' seems more frequent in sibships containing members with ATD, the familial aggregation of RA and ATD cannot be accounted for by a single gene linked to HLA predisposing to both disorders. Neither can this familial aggregation be accounted for by a single gene linked to Gm predisposing to RA and ATD so that any genetic predisposition common to both disorders is likely to involve at least a third locus which is still to be defined. A simple model with an interaction between at least three independent genetic loci and genetic heterogeneity is proposed to account for the known facts concerning the genetic susceptibility to RA.