Are suspected stroke patients identified by paramedics transported to appropriate stroke centres in Victoria, Australia?

Emergency medical services (EMS) are vital to ensuring acute stroke patients are transported to thrombolysis and/or stroke unit centres. This 6-month audit of Victorian EMS cases found the majority of suspected acute strokes are transported to appropriate stroke centres. However, there is still room for improvement, in particular, strategies to improve access to stroke services in some rural regions and to ensure patients/relatives are fully informed when requesting transport to a non-stroke service hospital.

Major histocompatibility complex class III genes and susceptibility to immunoglobulin A deficiency and common variable immunodeficiency.

We have proposed that significant subsets of individuals with IgA deficiency (IgA-D) and common variable immunodeficiency (CVID) may represent polar ends of a clinical spectrum reflecting a single underlying genetic defect. This proposal was supported by our finding that individuals with these immunodeficiencies have in common a high incidence of C4A gene deletions and C2 rare gene alleles. Here we present our analysis of the MHC haplotypes of 12 IgA-D and 19 CVID individuals from 21 families and of 79 of their immediate relatives. MHC haplotypes were defined by analyzing polymorphic markers for 11 genes or their products between the HLA-DQB1 and the HLA-A genes. Five of the families investigated contained more than one immunodeficient individual and all of these included both IgA-D and CVID members. Analysis of the data indicated that a small number of MHC haplotypes were shared by the majority of immunodeficient individuals. At least one of two of these haplotypes was present in 24 of the 31 (77%) immunodeficient individuals. No differences in the distribution of these haplotypes were observed between IgA-D and CVID individuals. Detailed analysis of these haplotypes suggests that a susceptibility gene or genes for both immunodeficiencies are located within the class III region of the MHC, possibly between the C4B and C2 genes.

Increase of HLA-DR4 in melanoma patients from Alabama.

This report describes the association of HLA-DR phenotypes in a population of 91 Caucasian melanoma patients compared with 106 Caucasian controls from the Sunbelt region of the United States. Over 75% of both patients and controls were born in Alabama or a surrounding state. There was a significant increase in the frequency of HLA-DR4 (chi 2 = 12.8; rho = 0.0003). This was present in 38.5% of the patients compared to a 16.0% frequency in the controls, producing a relative risk of 3.3. The difference in DR4 distribution remained significant after correcting for the number of antigens (rho c = 0.0018). The patients were then grouped into two categories, "low risk" and "high risk," based on their clinically assessed risk at presentation for metastatic involvement. The decrease of DR3 in the high-risk group (chi 2 = 5.2; rho = 0.02) suggested that it may represent a marker for long-term survival. Thus, it appears that susceptibility to developing melanoma may be associated with DR4 while survival may be associated with DR3.

HLA-A, -B, and -DR associations in type I diabetes mellitus with onset after age forty.

It remains to be convincingly demonstrated whether insulin-requiring, ketosis-prone, lean-at-onset, type I diabetics who develop their disease after age 40 have the same disease as the children with similar characteristics. To address this question, we examined the population HLA genetic associations of this group. One hundred forty white, insulin-using diabetics with onset of disease past age 40 yr and 268 normal white controls have thus far been analyzed for HLA type. In the group of patients who were lean-at-onset and/or ketosis-prone (N = 54), there was a significantly increased frequency of DR4 (RR = 4.63; P less than 0.01) and significantly decreased frequency of DR2 (RR = 0.18; P less than 0.05) after correction. DR4 was also significantly increased after correction (RR = 5.72; P less than 0.25) in the subgroup who were both lean and ketosis-prone (N = 23). No significant differences in HLA-DR frequencies were found between the obese and not-ketosis-prone group (N = 69) and controls. No significant associations of HLA-A or-B antigens with either group were observed after correction for the number of antigens tested. To our knowledge, this is the first such study in the United States, and the first demonstrating that late onset diabetics who are lean-at-onset and/or ketosis-prone exhibit HLA-DR antigen associations which are similar to early onset cases.

Evidence for genetic admixture as a determinant in the occurrence of insulin-dependent diabetes mellitus in U.S. blacks.

In recent years, it has been proposed that genetic admixture may have played a role in the increased frequency of insulin-dependent diabetes mellitus (IDDM) in young U.S. blacks relative to African blacks. In support of this proposal, the similar associations of specific markers of the major histocompatibility complex (MHC) with IDDM in U.S. blacks with respect to U.S. whites have been cited. To determine whether racial admixture was a factor in the increased prevalence, we did three analyses of admixture. In the first we used nine genetic markers (ABO, Rh, Fy, Hp, Gc, Pl, OR, Tfr, and Gm) and determined that there was significantly greater than zero genetic contribution from whites in our sample of U.S. black IDDM patients (9.6 +/- 2.3%, P less than 0.01) when a sample of U.S. blacks without IDDM was used as one "parental" population. In the next two analyses, we estimated the amounts of genetic contribution from whites in the U.S. blacks with and without IDDM using reported gene frequencies for West African blacks for four genetic markers (ABO, Rh, Fy, and Hp). The estimate of admixture (21.4 +/- 2.8%) for the black IDDM sample was greater than that for the U.S. black controls (17.9 +/- 2.3%), although the difference was not significant. Our estimate of genetic contribution from whites, 21.4% for black IDDM patients, supports the assumptions of 20% admixture which MacDonald and Rotter and Hodge used to test their respective models for the inheritance of IDDM. These results support the hypothesis that admixture with the white population is, in part, responsible for the increase in prevalence of IDDM seen in U.S. blacks.

Risk factors for gestational diabetes in black population.

In a long-term longitudinal study of gestational diabetes mellitus in Black women, risk factors that were identified were age, obesity, a family history of diabetes, and the presence of hypertension. Poor predictors were a history of a previous large-for-date infant, parity, and age at first pregnancy. The prevalence of smooth muscle and nuclear autoantibodies was higher in gestational diabetic subjects. Gestational diabetic subjects who required insulin for glycemic control were more obese, had a lower frequency of the Bf-F phenotype and a higher frequency of the Bf-F1 phenotype, and had a lower frequency of the type 2 allele at the polymorphic locus adjacent to the insulin gene. Restriction-fragment-length polymorphisms flanking the insulin and apolipoprotein A-I and C-III genes, although not associated with gestational diabetes mellitus, may be associated with hyperlipidemia and subsequent atherosclerosis.

Molecular genetic studies of rheumatoid arthritis.

Bam HI DR-beta and DQ-beta restriction fragment length polymorphisms (RFLPs) were found with increased frequency in white persons with seropositive rheumatoid arthritis as compared with control subjects. DR-beta 4.8-, 5.2-, and 7.0-kilobase (kb) RFLPs were observed in 86.5 percent of rheumatoid arthritis patients and in 56 percent of control subjects (p = 0.001, relative risk [RR] = 5.0). The 6.0-kb RFLP was present in 79 percent of rheumatoid arthritis patients and 32 percent of control subjects (p = 0.0002, RR = 8.0). The 4.8-, 5.2-, and 7.0-kb RFLPs correlated with DR4, -7, -9, and -w53 phenotypes and the 6.0-kb RFLP correlated only with DR4. Thus, these RFLPs do not appear to be disease-specific. A DQ-beta 3.2-kb RFLP was found in 63.5 percent of rheumatoid arthritis patients and in 38.0 percent of control subjects (p = 0.01, RR = 2.8). This fragment was frequently found in persons expressing DR1 and DQw1 phenotypes. Probes consisting of the first exon of the DR-beta-I and DR-beta-IV genes, respectively, only hybridized with the 5.2- and 6.0-kb RFLPs. These data suggest that more than one gene within the major histocompatibility complex contributes to susceptibility to seropositive rheumatoid arthritis in white persons.

Restriction fragment length polymorphism analysis in ankylosing spondylitis.

We utilized the technique of restriction fragment length polymorphism (RFLP) analysis in order to examine class I major histocompatibility complex genes in 52 Alabama ankylosing spondylitis patients and 107 local control subjects. A 9.2-kilobase PvuII RFLP was identified using the class I-specific B7 cDNA probe pDP001 that was closely associated with ankylosing spondylitis, most specifically with peripheral joint (including shoulder and hip) involvement. This fragment is associated with human leukocyte antigen A3 and A9 alleles, and segregation analysis in 11 multiplex families showed the RFLP to frequently segregate independently of B27 haplotypes. Two more recent studies have not confirmed the association of the 9.2-kilobase PvuII RFLP with ankylosing spondylitis per se, believed to be due to clinical and possibly genetic differences between the patient groups studied. These data strongly suggest at least one other major histocompatibility complex class I gene to be operative in predisposition to or modification of ankylosing spondylitis.

Positive crossmatches against mandatorily shared kidneys.

From October 1987 through February 1990 approximately 8.5% (29/341) of all donor kidneys shipped under the UNOS Mandatory Sharing Policy were denied to 27 intended recipients due to a positive final crossmatch [XM(+)]. The intended recipients included 18.5% hispanics and 7.4% blacks compared to 2.4% and 1.6%, respectively, for XM(-) recipients (1-3). Further, more were highly sensitized with 81% having a current PRA greater than 10% and 56% with a peak PRA greater than 80% compared to 65% and 14%, respectively, for XM(-) recipients. More importantly, 19/27 (70%) of the recipient candidates may have had irrelevant positive XMs. The XM(+) patients were classified into five categories defined by: I) autoantibodies; II) transfusions in the 2 weeks prior to the availability of the donor; III) the XM technique; IV) highly sensitized regraft candidates with current and peak PRAs greater than 85% and V) antibody to unreported MHC antigens. Of these, 70% may have been denied a transplant due to IgM autoantibodies or the use of XM techniques lacking extensive evaluation. The authors propose that all XM(+) mandatorily-shared kidneys be examined for IgM autoantibody and that kidneys not be denied to potential recipients due to IgM autoantibody. In addition, to minimize exclusions based on positive B-cell XMs, it is proposed that mandatorily-shared kidneys be shared on the basis of the DR subtypes, insofar as is currently practical.

The effect of erythropoietin and blood transfusions on highly sensitized patients on a single cadaver renal allograft waiting list.

The effects of EPO on transfusion requirements and HLA allosensitization were studied in a group of 145 sensitized patients on a single cadaveric renal allograft waiting list. All patients included in the study had PRA levels greater than 40% and at least six months of follow-up after the general availability of EPO. A total of 108 (74%) of these patients received EPO during the study period while 37 (26%) did not. The EPO patients had a much higher incidence of prior transfusions than the non-EPO patients (64% vs. 39% P less than 0.05). During the follow-up period, there was a marked reduction in transfusion incidence in the patients who received EPO from 64% to 14% (P less than 0.05). A lesser and nonsignificant reduction in incidence of transfusions was seen in the non-EPO-EPO patients. Analysis of PRA levels in the EPO and non-EPO groups demonstrated a reduction in PRA levels over time but there was no difference between the two groups. When the patients were divided by the need for transfusions in the follow-up period, a comparison of these two groups demonstrated significant differences. At the six-month follow-up point, patients in the nontransfused group had a significantly lower mean PRA than the transfused patients (49% vs. 62%, respectively, P less than 0.05). Furthermore, a greater number of patients in the nontransfused group had PRA declines greater than or equal to 15% compared with the nontransfused group (56/46% vs. 4/15%, respectively; P = .007). Stepwise logistic regression analysis of possible risk factors for persistent high PRA levels demonstrated that continued transfusion was the only significant factor. This study suggests that the institution of EPO therapy in sensitized patients on a single cadaveric waiting list can result in substantial reduction in the need for on-going transfusions. However, the decline in PRA levels appears to be more closely tied to the avoidance of transfusion rather than to the specific institution of EPO therapy.

The effect of pretransplant stored donor-specific blood transfusion on renal allograft survival in one-haplotype living-related transplant recipients.

The effect of pretransplant stored donor-specific blood transfusions (DSBTs) on renal allograft survival in 108 consecutive one-haplotype living-related donor (LRD) transplant recipients (group A) was compared with a similar consecutive series of 40 one-haplotype LRD recipients (group B) who did not receive DSBTs. All transplant recipients in both groups received identical immunosuppressive protocols using azathioprine and prednisone. One hundred twenty-eight patients received pretransplant stored DSBTs. Twelve of these patients (9%) developed cytotoxic antibodies to their respective donors and those transplants were not performed. Eight patients who had negative final crossmatches with their prospective donor experienced delay or cancellation of their transplants due to late donor withdrawal, or illness of the donor or recipient. Actuarial graft survival for group A and group B patients was compared at 6, 12, 18, and 24 months. Group A graft survival was 94, 90, 90, and 85% and Group B 73, 68, 63, and 63% at the comparison periods. This experience suggests that stored DSBTs are convenient, associated with a low frequency of recipient sensitization, and improved the prospects of success in one-haplotype LRD renal transplantation.

Renal retransplantation: the role of race, quadruple immunosuppression, and the flow cytometry cross-match.

To assess the impact of quadruple immunosuppression in black and white recipients of cadaver kidney retransplants, we reviewed data from 178 second or subsequent renal allografts performed at our center between 1985 and 1991. Sixty-six black and 102 white recipients were divided into 3 groups: groups 1 and 2 consisted of patients with a negative complement-dependent cytotoxicity (CDC) T cell cross-match, receiving triple drug therapy (CsA-AZA-prednisone) and quadruple immunosuppressive therapy (quad therapy; Minnesota antilymphoblast globulin-CsA-AZA-prednisone), respectively. Group 3 patients also received quad therapy, but, in addition to a negative CDC cross-match, had a negative T cell flow cytometry cross-match (FCXM). Black and white patients in groups 1 and 2 experienced similar graft survival at 1 year, ranging from 47% to 63% (P = NS). In group 3, 1-year graft survival in whites, but not blacks, improved to 82%, with fewer grafts lost to immunologic causes in the first 90 days after transplant. A parametric analysis of potential risk factors identified a significant effect of better HLA-DR matching (P = 0.0005) on improved graft survival, with previous mismatched antigens (P = 0.04), female donor (P = 0.002), and short duration of previous graft (P = 0.05) as risk factors for graft loss. Race and immunosuppressive protocol did not affect graft survival. In group 3, blacks received fewer well-matched kidneys than whites (P = 0.05), which may have contributed to poorer outcomes for black recipients. Nine of 10 patients undergoing retransplantation with a negative CDC cross-match and a positive T cell FCXM suffered graft loss at a median of 26 days after transplant. Thus, quad therapy did not enhance graft survival for either black or white patients undergoing cadaveric retransplantation. Immunologic considerations, including HLA-DR matching and the FCXM, continue to exert a strong influence on outcomes in these high-risk recipients.

Successful renal allografts in recipients with crossmatch-positive, dithioerythritol-treated negative sera. Race, transplant history, and HLA-DR1 phenotype.

Graft survival was examined in 15 renal allograft recipients from a group of 20 patients with IgM autolymphocytotoxic antibody that could be removed in a crossmatch assay using a reducing agent, dithioerythritol (DTE). The significant differences in this group of 20 patients compared with end-stage renal disease (ESRD) patients lacking autolymphocytotoxic antibodies included an increased frequency of black patients (P = 0.002), a lack of previous transplants (P = 0.003), and an increased frequency of the HLA-DR1 phenotype (P = 0.0001). Sex and the number of transfusions did not appear significant, whereas the cause of ESRD was primarily systemic lupus erythematosus. Fifteen of the 20 patients were transplanted against a positive donor crossmatch. Eleven were recipients of cadaveric kidneys, nine of which are still functioning for periods ranging from 0.5 to 40 months. Two fo the cadaveric recipients died with functional grafts. Four received living-related donor transplants, one of which was lost to acute rejection one month posttransplant, while the remaining three have survived 1.5, 9, and 21 months, respectively. Fourteen patients had immediate allograft function with no hyperacute rejection and only one case of acute tubular necrosis (ATN) was found. In summary, a negative crossmatch using DTE-treated, autologous reactive recipient sera may identify a group of patients who can be transplanted with minimal concern for hyperacute rejection or ATN. In addition to cause of ESRD, race, transplant history, and HLA-DR phenotype may further define this group of transplant candidates having IgM autolymphocytotoxic antibody. Extrapolation of these conclusions to transplant candidates lacking autolymphocytotoxic antibodies is not warranted.

The impact of the UNOS mandatory sharing policy on recipients of the black and white races--experience at a single renal transplant center.

The impact of the United Network for Organ Sharing mandatory sharing policy on a large transplant center procuring kidneys primarily from caucasians while serving a pool of prospective recipients composed mainly of blacks is described. This policy requires that all 6-antigen-matched and phenotypically identical donor kidneys be shipped to the appropriately matched recipients. The study consisted of 49 kidneys from 25 cadaveric donors; one kidney was unusable. In general, the 33 recipients of the mandatorily shared kidneys were caucasian (94%), unsensitized (70%), and first-time transplants (73%). Allograft survival for the 24 first-time recipients was 100% (mean graft survival = 11.3 months). Of the 9 regraft kidneys, 2 have failed (mean graft survival = 11.9 months) due to chronic rejection. In comparison, the 16 paired kidneys transplanted into non-6-antigen-matched recipients exhibited a 1-year graft survival of 80% versus 92% for the 33 recipients of mandatorily shared kidneys (P = 0.01). These 16 recipients were composed of more blacks (38%), fewer regrafts (6%), and most were unsensitized (75%). All 25 cadaveric donors were caucasians with very common HLA types. Thus, kidneys provided by the UNOS mandatory sharing policy had excellent allograft survival, and the recipients were largely unsensitized caucasians receiving their first kidney. The low number of blacks receiving allografts under this policy may be due to two factors. First, the histocompatibility differences between black recipients and the primarily caucasian cadaveric donor pool limit the number of kidneys available to blacks. Secondly, blacks do not have access to the best-matched kidneys, in part due to few black donors, their best source for well-matched kidneys. Thus, the mandatory sharing program is of clear benefit to the recipients of these well-matched kidneys; however, for a local program servicing a waiting list composed of 64% blacks the policy has been of limited value. In contrast, over 50% of local cadaveric transplants are into black recipients in a waiting time of 197 days, one third the national average for blacks. In conclusion, this study supports efforts to improve graft survival through matching but emphasizes the need to broaden our efforts in all areas of research and organ procurement to serve the entire recipient population, regardless of race.

Improved survival of primary cadaveric renal allografts in blacks with quadruple immunosuppression.

Black recipients of cadaveric kidneys have been shown to have a lower rate of allograft survival than whites. Data were reviewed from 642 primary cadaveric transplants: results in 276 patients (163 white and 113 black) (group 1) who had received triple therapy (azathioprine-CsA-prednisone, 1985-87) were compared with those in 366 patients (180 white and 186 black) (group 2) receiving quadruple immunosuppression (MALG-azathioprine-CsA-prednisone, 1987-90). Blacks in group 2 had better patient (97% vs. 91%, P = 0.03) and graft (77% vs. 55%, P = 0.0002) survival at 1 year than in group 1. There was no difference in these parameters among whites in either group. Racial differences in graft survival noted in group 1 disappeared in group 2. While HLA BDR matching improved in group 2 patients (P = 0.0001), whites received better matched kidneys than blacks in both groups (P = 0.001). HLA matching was associated with improved graft survival only in white recipients of 4 BDR-matched kidneys. In group 1, more blacks than whites had at least one episode of acute rejection (76% vs. 57%, P = 0.001); blacks also lost more grafts to acute and chronic rejection. In group 2, there were no racial differences in the number of rejection episodes or immunologic graft losses. Of 14 potential variables examined by parametric analysis, only quadruple therapy significantly reduced risk of graft loss in blacks. Quadruple immunosuppression improved primary cadaveric renal allograft survival in black recipients, abrogating previously noted racial differences.

CREG antigens differentially influence expression of extraarticular manifestations in whites and blacks with rheumatoid arthritis.

B27 and the CREG antigens (-7, -27, -40, -42, and -22) have been shown to be related to the spondyloarthropathies. We have studied the frequency distribution of these antigens in patients with RA. Two hundred ninety-six patients with either classical or definitive RA by ARA criteria were studied: 199 were whites and 97 were blacks. Appropriate local control subjects were also studied (242 whites and 283 blacks). In the white RA patients 48.7% possessed a CREG antigen (97 of 199) while in the black patients 28.9% were CREG positive (28 of 97). In the white control subjects, 45.9% had a CREG antigen and 31.4% for the black control subjects. The relationship between CREG antigens and disease expression was compared using clinical, demographic, radiologic, and therapeutic parameters. For the white group there was no difference in the age and sex, disease duration, functional capacity, anatomic grading, C/M ratio, seropositivity, frequency of extraarticular manifestations (subcutaneous nodules, vasculitis, sicca symptoms, pleuropulmonary, or pericardial disease), frequency of remittive therapy, and toxicity to chrysotherapy. For the blacks all parameters were comparable except for a decrease in the frequency of extraarticular manifestations among the CREG-positive patients (21.4 vs. 46.4%) which is significant (p less than 0.05). Our data show no significant differences in the frequency of the CREG antigens in either blacks or whites with RA as compared to normal subjects. However, a possible sparing of some of the extraarticular manifestations of the disease appears to associate with the CREG antigens.

HLA in ankylosing spondylitis: is HLA-B27 the only MHC gene involved in disease pathogenesis?

Linkage analysis of HLA haplotypes, HLA-B27 subtypes, and a 9.2-kb PvuII B7 restriction fragment length polymorphism (RFLP) (shown previously to be associated with peripheral arthritis in ankylosing spondylitis [AS]) in 115 relatives from 12 multiplex spondyloarthropathy (SNSA) and 2 B27-positive control families showed AS to be linked to HLA-B27 haplotypes. The RFLP segregated with HLA-A3- and HLA-A9-bearing haplotypes (lod score, 10.98; odds in favor of linkage, 9.2 x 10(10):1), although its linkage to AS or other SNSA per se was not seen. The association of HLA-A3/A9 with the RFLP was also seen in 52 AS patients and 92 controls, although no HLA-A, -B, -C, or -DR allele (other than HLA-B27) was significantly increased in frequency. The HLA-B27 subtype seen on all but one of the haplotypes studied was B*2705, the sole exception being HLA-B*2702. Although not ruling out a second HLA-A-linked gene influencing the clinical expression of AS, these data fail to support the role of a second MHC-associated gene in the pathogenesis of AS per se.

DR beta Taq I restriction fragment length polymorphism (RFLP) associated with insulin dependent diabetes mellitus (IDDM).

DNA from insulin-dependent diabetes mellitus patients (IDDM) and healthy control individuals was evaluated using Southern blotting to determine if a disease-associated restriction fragment length polymorphism could be found. Using a DR beta-cDNA probe hybridized to Taq I digested genomic DNA, a 3.7 kb fragment was found in all IDDM patients examined (n = 33). Although a high percentage (47 per cent) of the control population also carried the fragment, nearly one-third of those persons were serotyped as DR2. The possible role of gene regulation in the development of IDDM is discussed.

Analysis of restriction fragment length polymorphisms in rheumatic diseases.

Considerable evidence indicates that genes residing within the major histocompatibility complex (MHC) influence susceptibility to certain rheumatic diseases, such as ankylosing spondylitis (AS) and rheumatoid arthritis (RA). However, it has not yet been possible to precisely identify the gene(s) responsible for conferring enhanced susceptibility to these diseases. The availability of recombinant DNA technology should accelerate progress in obtaining this goal. A particularly promising method in this regard is restriction fragment length polymorphism (RFLP) analysis using appropriate class I and class II MHC gene probes. In preliminary studies, RFLPs have been identified for AS and RA which associate with susceptibility to the disease. Further studies using this approach should permit localization and precise identification of the disease susceptibility gene(s) for these diseases.

Associations of properdin factor B with melanoma.

We investigated 98 melanoma patients and 135 normal controls for differences in phenotype and genotype frequencies at the properdin factor B locus. A significant negative association with the Bf-F allele and melanoma was found, resulting in an estimated relative risk of 0.5. The estimated relative risk for developing melanoma among people with the Bf-FF genotype is 0.07. The Bf-S phenotype was significantly increased among the melanoma sample, with an estimated risk of 6.5. The data suggest association of the Bf locus with a melanoma protection and/or susceptibility gene(s).