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.

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.

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.

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.

Benefits of quadruple immunosuppressive therapy in recipients of living related donor kidneys. A review of 855 operations.

Eight hundred fifty-five living related donor transplant recipients were analyzed according to 15 potential risk factors with regard to patient and graft survival according to immunosuppression. Group I, 1968 to 1983, (n = 440 patients) received azathioprine and prednisone; group II, 1984 to 1987, (n = 229 patients) received triple therapy--azathioprine, prednisone, and cyclosporine; and group III, 1988-1991, (n = 186 patients), quadruple therapy--azathioprine, prednisone, cyclosporine, and Minnesota antilymphocyte globulin. Three important risk factors included immunosuppression, tissue typing, and race. Groups II and III had improved allograft survival over group I (p = 0.03). Patients with two haplotype matches had similar survival in all three groups. Kidney survival in one-haplotype-matched recipients improved in group II and was equal to that of the two-haplotype-matched patients in group III. Cyclosporine improved allograft survival in both races when combined with azathioprine and prednisone. Quadruple therapy improved early survival in one-haplotype black patients, even though long-term results remained better in whites. Cyclosporine did not improve graft survival in two-haplotype recipients. The addition of cyclosporine and quadruple therapy did not increase morbidity and mortality rates.

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.

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.

Autoantibodies in black women with class A1 or class GB diabetes mellitus.

No marker except repeated fasting glucose determinations has proven useful to ascertain prospectively which women with gestational diabetes mellitus will remain euglycemic by diet modification or will require insulin therapy. We screened 183 black women with gestational diabetes mellitus to determine if the presence of islet cell, mitochondrial, nuclear, DNA, parietal cell, smooth muscle, thyroid microsomal, thyroid thyroglobulin autoantibodies, or rheumatoid factor predicted the need for insulin therapy to maintain euglycemia in women with gestational diabetes mellitus. One hundred forty-two women maintained normal fasting plasma glucose levels with dietary modifications and 41 required institution of split-dose insulin therapy. We found no significant differences in the prevalence of these autoantibodies in black women with Class GB versus Class A1 diabetes mellitus. We conclude that screening for autoantibodies in women with gestational diabetes mellitus is not useful in determining which patients will subsequently require insulin therapy during their pregnancies.

Histocompatibility antigen subtypes in black women with class A1 or class GB diabetes mellitus.

Insulin-dependent diabetes mellitus is associated with an increased frequency of certain histocompatibility antigens located on chromosome six, the most common types being B-8, B-15, DR-3, DR-4, and DR-7. We therefore theorized that screening for these subtypes may allow the identification of those women with gestational diabetes who will remain euglycemic on dietary modification (class A1) compared with those who will require insulin to achieve euglycemia (class GB). From 1982 to 1987, 228 black women with gestational diabetes were screened for the above histocompatibility antigens. As theorized, certain histocompatibility antigen subtypes were more common in women with class GB gestational diabetes mellitus; DR-2 (41.8% versus 23.7% p = 0.015), B-15 (p = 0.07), and DR-3 (p = 0.08). However, because of the low sensitivity (42%), specificity (75%), and positive predictive value (36%), this test is impractical in the clinical management of women with gestational diabetes mellitus.

Analysis of 22 years experience in living-related transplantation at the University of Alabama in Birmingham.

Over the 22 years comprising this review of living-related renal allografts, 3 distinct eras of immunosuppression protocols were used; Era I-aziathioprine and prednisone, Era II-cyclosporine, azathioprine, and prednisone; and Era III-Minnesota antilymphocyte globulin, cyclosporine, azathioprine, and prednisone. We analyzed both recipient and donor populations for graft and patient survival related to race, haplotype matching, diabetes, and immunosuppressive agents. Graft and patient survival have remained unchanged in 2-haplotype-matched recipients throughout the differing immunosuppression eras. The addition of cyclosporine, however, improved graft survival in the 1-haplotype living-related recipient. During the cyclosporine era, 1-haplotype White living-related recipient graft survival was significantly greater than 1-haplotype Black living-related recipient survivals. The reason for this disparity in graft survival does not appear to be related to noncompliance. The parametric hazard function analysis of the constant phase did not identify cyclosporine as a risk factor for late graft loss, suggesting that long-term cyclosporine usage may decrease the risk of graft loss. However, diabetes was demonstrated to be a risk factor for late graft loss. In diabetics, late graft loss is most likely secondary to death (usually cardiovascular) with a functioning graft. The organ donor pool is being expanded through the utilization of both older donors and living-unrelated donors. Graft survival in the living-unrelated group has been comparable to that of 1- and 2-haplotype-matched recipients. Results with older donors reveal donor age as a risk factor for late graft loss. The issue of living-unrelated transplantation remains controversial. In over 20 years of follow-up on our living-related donor population, we were unable to demonstrate any adverse long-term effects on renal function. Results of our analysis indicate that living-related renal donation continues to be a safe and valuable avenue for kidney transplantation.

Restriction fragment length polymorphism analysis of HLA-DR, DQ, DP and C4 alleles in Caucasians with systemic lupus erythematosus.

HLA-DR, DQ, DP and C4 null alleles were determined by restriction fragment length polymorphism (RFLP) analysis in 60 Caucasian patients with systemic lupus erythematosus (SLE) and 66 controls. DR3 (DRw17) and DQw2.1 were increased in frequency in the patients with SLE associated with the presence of C4A null genes. HLA-DP alleles determined by RFLP analysis of genomic DNA as well as of PCR amplified DNA were not associated with SLE or any clinical or autoantibody subset thereof. No DR, DQ, or C4 null gene association was found with renal or neuropsychiatric involvement or nDNA antibodies (or levels thereof). These data suggest that the primary predisposition to SLE lies with HLA-DR or C4 null alleles, and not with HLA-DP.

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 analysis of HLA-D region genes in seropositive rheumatoid arthritis.

Analysis of HLA DRB1 and DQB1 Bam HI RFLPs revealed four DRB1 (4.8, 5.2, 6.0 and 7.0 kb) fragments and a 3.2 kb DQB1 fragment to be significantly increased in Caucasians with seropositive RA compared to healthy individuals. The 4.8, 5.2 and 7.0 kb DRB1 fragments were found in 86.5% of RA patients and in 56% of the controls (p = 10(-3), relative risk (RR) = 5.0), while the 6.0 kb fragment was found in 79% of RA patients compared to 32% of controls (p = 2 x 10(-5), RR = 8.0). The 3.2 kb DQB1 fragment was observed in 63.5% of RA patients versus 38.0% of controls (p = 10(-2), RR = 2.8). Analysis of these fragments relative to HLA phenotypes revealed that the 4.8, 5.2 and 7.0 kb DRB1 fragments were strongly correlated with DR4, -7, -9 and -w53 serotypes, the 6.0 kb RFLP with DR4 and the 3.2 kb DQB1 fragment with DR1 and DQw1. Using probes specific for the 5' or 3' regions of the DRB1 gene, the 5.2 and 6.0 kb DRB RFLPs were mapped to the 5' end and the 4.8 and 7.0 kb RFLPs to the 3' end of the DRB1 gene. A probe generated from the second exon of the DRB4 (DRw53) gene recognized only the 5.2 and the 6.0 kb RFLPs corroborating the 5' location of these RFLPs. Family studies further confirmed that these RFLP's segregated with HLA phenotypes.

DNA analysis of HLA-DR and DQ genes in American blacks with systemic lupus erythematosus.

We studied DNA polymorphisms of HLA-DR and DQ alleles in 63 American black patients with systemic lupus erythematosus (SLE). We found no HLA-DR beta, DQ alpha, or DQ beta restriction fragment length polymorphism (RFLP) or RFLP-determined DR or DQ specificity associated with SLE in either the patients or in 57 control subjects. DRw52b was positively associated with renal involvement and negatively associated with anti-nuclear RNP antibodies. Antibodies to Ro (SS-A) and La (SS-B) were associated with DR3(DRw17), DQw2.3. Early-onset SLE (less than or equal to 20 years of age) was associated with DRw8, and the frequency of neuropsychiatric involvement correlated negatively with a 3.7-kb Taq I DQ alpha RFLP. This suggests a role for DR and DQ genes in the clinical and serologic expression of SLE in American blacks.

Individuals with IgA deficiency and common variable immunodeficiency share polymorphisms of major histocompatibility complex class III genes.

IgA deficiency and common variable immunodeficiency are heritable disorders that can occur within the same family. Both immunodeficiencies are characterized by arrests in B-cell differentiation that vary in the extent of the immunoglobulin isotypes involved. A high frequency of major histocompatibility complex supratypes associated with a null allele of the gene encoding the C4A isotype of complement component C4 has been observed in IgA-deficient individuals. In search of a genetic linkage between the two immunodeficiencies, we examined the major histocompatibility complex (MHC) class III genes encoding complement components C2, C4A, and C4B and steroid 21-hydroxylase in addition to the HLA serotypes in individuals with either common variable immunodeficiency or IgA deficiency. Twelve of 19 patients with common variable immunodeficiency (63%, P less than 0.001) and 9 of 16 patients with IgA deficiency (56%, P less than 0.01) had rare C2 alleles and/or C4A and 21-hydroxylase A deletions, whereas these gene features were seen in only 5 of 34 healthy individuals (15%) in the control group. Nine of 11 patients with C4A deletion had an HLA haplotype consistent with the MHC supratype HLA-A1, Cw7, B8, C4AQ0, C4B1, BfS, DR3 previously found to be associated with IgA deficiency. The data support the hypothesis that common variable immunodeficiency and IgA deficiency are related disorders, susceptibility to which is determined by a gene(s) within or near the MHC class III gene region on chromosome 6.

Familial polyarteritis nodosa: a serologic and immunogenetic analysis.

Familial polyarteritis nodosa (PAN) is a rarely described entity. We describe a family with 2 members with PAN after a common hepatitis B infection. Many other autoimmune diseases and autoantibodies were found in other family members not corresponding to HLA phenotypes, suggesting other non-HLA-linked genetic influences may be operative in predisposition to PAN.