Arginine at positions 13 or 70-71 in pocket 4 of HLA-DRB1 alleles is associated with susceptibility to tuberculoid leprosy.

Evaluation of human histocompatibility leukocyte antigen (HLA) class II genes in 54 cases of tuberculoid leprosy (TL) and 44 controls has shown a positive association with HLA-DRB1 alleles that contain Arg13 or Arg70-Arg71. Among TL patients, 87% carry specific alleles of DRB1 Arg13 or Arg70-Arg71 as compared to 43% among controls (p = 5 x 10(-6)) conferring a relative risk of 8.8. Thus, susceptibility to TL involves three critical amino acid positions of the beta chain, the side chains of which, when modeled on the DR1 crystal structure, line a pocket (pocket 4) accommodating the side chain of a bound peptide. This study suggests that disease susceptibility may be determined by the independent contribution of polymorphic residues participating in the formation of a functional arrangement (i.e., pocket) within the binding cleft of an HLA molecule.

Monoclonal rat anti-major histocompatibility complex antibodies display specificity for rat, mouse, and human target cells.

24 monoclonal rat antibodies are described that are reactive with determinants encoded by the major histocompatibility complex (MHC) of the rat. These hybridoma antibodies were derived by fusing mutant mouse myeloma cells to spleen cells from Lewis rats immunized with allogeneic Brown Norway cells. All 24 antibodies are cytotoxic for both Brown Norway target cells and target cells from the appropriate MHC congenic rats. Pattern of cytotoxicity and hemagglutination strongly suggest reactivity against class I (K or D equivalent) rat MHC determinants. Cytotoxic cross-reactivity patterns were generated for each monoclonal antibody on a panel of rat and mouse lymphoid cells and human peripheral T lymphocytes. A high degree of interspecies cross-reactivity was noted with approximately one-half of the antibodies positive on human and/or mouse target cells. 11 antibodies recognized polymorphic determinants in the mouse, and, by using target cells from MHC congenic mouse strains, it was shown that these determinants are encoded by genes within the H-2 complex. Finally, by considering the overall reactivity patterns of these monclonal antibodies on all target cells, one can show that these 24 antibodies represent a minimum of 14 antibody specificities.

Soluble HL-A7 antigen: localization in the beta-lipoprotein fraction of human serum.

The HL-A7 antigen of human leukocytes occurs as a soluble, low-density lipoprotein in the serum of HL-A7-positive individuals. Its presence in high concentration may inhibit direct leukocyte grouping, leading to erroneous results. This finding affords an easy method for the preparation of monospecific cytotoxic antiserums by absorption with serum fractions rather than leukocytes.

HLA-DR histocompatibility leukocyte antigens permit cultured human melanoma cells from early but not advanced disease to stimulate autologous lymphocytes.

HLA-DR histocompatibility antigens are commonly expressed by the melanocytes of melanoma and its precursors, but not by the melanocyte of normal skin. Further, the primary lesion of biologically early melanoma is commonly infiltrated with host T cells. Advanced disease is characterized by a paucity of such cells. To investigate the interaction of melanoma cells and autologous lymphocytes and its dependence on HLA-DR expression, we have established cell lines from biologically early (4 lines) and advanced disease (11 lines) and examined their capacity to stimulate blastogenesis of autologous T cells in vitro. Melanocytes from early disease expressed HLA-DR antigens and stimulated autologous T cells. Those from advanced disease, irrespective of DR expression, were nonstimulatory. To determine whether expression of DR was required for melanoma cells to be stimulatory, we first treated a stimulating cell line of DR3 allospecificity with anti-DR3-specific serum and demonstrated marked inhibition of its capacity to provoke blastogenesis. Next we used fluorescence-activated flow cytometry to sort a stimulating line heterogeneous for DR expression into DR-enriched and -depleted populations. When such cells were examined in the lymphocyte proliferation assay, their stimulatory capacity was proportional to their quantitative expression of HLA-DR. These studies indicate that cell lines may reflect important biological differences between early and advanced melanoma. HLA-DR expression may be an early event in neoplasia of melanocytes. These antigens are able to interact directly with autologous T cells; and their expression is necessary, but not sufficient, for melanoma cells to induce lymphocyte proliferation.

Familial autoimmune myasthenia gravis.

We describe a family with parental consanguinity and five of 10 siblings affected by late-onset autoimmune myasthenia gravis. We propose a genetic mechanism as a predisposing factor in this family. Our analysis excludes the major histocompatibility complex, the beta subunit of the acetylcholine receptor, and the T-cell receptor alpha and beta subunits as candidate genes for the disorder in this family.

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.

Mixed lymphocyte reactivity in cats.

A method was developed to perform primary one-way mixed lymphocyte cultures (MLC) with cat cells. A polymorphic system of MLC reactivities was found within a cat population. In family studies, alloreactivity segregated as a single genetic locus with codominantly expressed products, designated feline lymphocyte defined (Fld)--although closely linked multigene control remains possible. The relationship of Fld to a putative feline major histocompatibility complex is discussed.

Improved T cell subset monitoring by immunogold staining following renal transplantation.

Enumeration of peripheral blood T cells, functional T cell subsets, and B cells by immunogold staining (IGS) was compared with analysis by flow cytometry in 52 renal allograft recipients. Results by the IGS method compared favorably with those obtained by flow analysis. IGS is a simple, inexpensive technique that is readily adaptable to the setting of posttransplant immune monitoring.

Renal transplantation despite a positive antiglobulin crossmatch with and without prophylactic OKT3.

The antiglobulin crossmatch (AGXM) is a sensitive technique employed by many transplant centers to enhance detection of preformed antibody to donor antigens that may cause hyperacute rejection. However, positive AGXM may detect irrelevant or very low titers of anti-HLA antibody precluding transplantation in suitable recipients. To investigate the significance of a positive AGXM, cadaveric renal transplantation was carried out despite a weakly positive AGXM (defined as cell killing above background but not greater than 20%) in 48 recipients. In an initial group (n = 10), maintained on triple therapy (cyclosporine, azathioprine, and prednisone), accelerated acute rejection occurred in 4 recipients and 3 grafts were lost. A subsequent group (n = 38) was treated with a prophylactic course of OKT3 then triple therapy. There were no episodes of accelerated acute rejection (P less than 0.01) although clinical hyperacute rejection claimed one graft and the incidence of delayed graft function was high (75%). The prophylactic OKT3 group had a reduced incidence of acute rejection (0.5 versus 1.0) per recipient and the onset of first episodes was delayed (mean onset: 13 versus 35 days after transplantation). One year actuarial primary graft survival was 88% in the prophylactic OKT3 group as compared with only 50% in the initial group. The outcome in the positive AGXM group was similar to a concurrent group (n = 32) with a negative AGXM and immediate graft function. On the other hand, the subset of positive AGXM regraft recipients treated with prophylactic OKT3 fared poorly, with a 36% (4/11) incidence of primary nonfunction. In summary, a positive AGXM, as defined in this report, is not a contraindication to primary renal transplantation--in fact, the use of the AGXM will identify recipients that would benefit from prophylactic OKT3.

Analysis of DR and DQ gene products of the DR4 haplotype in patients with IDDM: possible involvement of more than one locus.

Fifteen DR4-bearing haplotypes from twelve patients with insulin-dependent diabetes mellitus (IDDM) were analyzed serologically, cellularly, and biochemically. The HLA-Dw composition of these DR4-positive haplotypes was Dw4 (46%), Dw14 (22%), and Dw10 (33%). The biochemical analysis by two-dimensional electrophoresis (2D-PAGE) of the DR beta chains showed that each Dw specificity is characterized by a specific DR4 beta chain that appears to be identical in normal and diabetic individuals. Analysis of DQ beta chains in the DR4-bearing haplotypes revealed that certain Dw specificities such as Dw4 are characterized by the presence of either the DQw7 (formerly DQw3.1) or DQw8 (formerly DQw3.2) alleles, which generate the Dw4.1 or Dw4.2 subtypes, respectively. Others such as Dw14 and Dw10 are characterized by the presence of the DQw8 allele. In our sample of 12 patients the Dw4.2 (Dw4, DR4 beta I-4 DQw8) and Dw10 (Dw10, DR4 beta I-1, DQw8) subtypes were predominant. It is concluded that individual DR beta and DQ beta gene products from the DR4-bearing haplotype of IDDM patients are identical to those of normal control subjects and that Dw14 as well as Dw10 are involved in disease susceptibility. We suggest that disease susceptibility may be influenced by more than one locus within the HLA-D region.

Genetic polymorphism of the human tumor necrosis factor region in insulin-dependent diabetes mellitus. Linkage disequilibrium of TNFab microsatellite alleles with HLA haplotypes.

The TNF region within the MHC includes a number of immunologically important genes. Microsatellites TNFa and TNFb adjacent to TNF exhibit extensive polymorphism. Employing a PCR-based technique, we identified TNFab haplotypes and defined their distribution in 97 controls and 48 diabetics of Caucasoid origin in a search for other genes within the MHC potentially associated with IDDM. Twenty-five different TNFab haplotypes were identified. A significant difference (p < 0.0005) in frequency between patients and controls was found for TNFa1b5 (relative risk 53). However, no other TNFab microsatellites demonstrated significantly different frequencies. Among diabetics TNFa1b5 was found to be in linkage disequilibrium with HLA-DR3-B18, a haplotype known to be associated with IDDM. Thus the increased frequency of TNFa1b5 among diabetics could reflect a linkage disequilibrium with a gene within the TNF region or with other genes, including the HLAs, which characterize this haplotype. In both controls and diabetics TNFa2b3 and TNFa7b4 were in linkage disequilibrium with DR3-B8 and DR7, respectively. Among diabetics, TNFa2b1 and TNFa6b5 were in linkage disequilibrium with DR4-B62 and DR4-B44, respectively. It is intriguing that TNFab haplotypes, represented by a short piece of about 200 nucleotides in the untranslated region upstream of TNF beta gene, maintain strong linkage disequilibria with different HLA haplotypes extending over 1 million base pairs. The identification of TNFab microsatellites exhibiting a high polymorphic index in a region lacking known polymorphic markers may provide potentially important information regarding the association of HLA haplotypes with autoimmune diseases, as they are in close proximity to other genes of immunologic importance.

Segregation of HLA in families with oral clefts: evidence against linkage between isolated cleft palate and HLA.

In an earlier study of families with two or more sibs affected with a cleft of the lip with or without clefts of the palate, we found no evidence for close linkage of HLA with this malformation. In the present study, we confine our attention to isolated cleft palate, an entity that is genetically distinct from cleft palate associated with cleft lip. In 15 sibships with two or more affected sibs, cleft palate, and parental HLA haplotypes assorted independently in the affected sibs, providing evidence against close linkage of this phenotype.

Cell surface antigen identification by a modified fluorescein immunosphere method.

Fluorescein immunospheres may be used in an indirect technic to label lymphocyte cell surface antigens. Wright's counter-staining allows simultaneous identification of fine morphology and surface antigen properties. Studies designed to determine methods for separating cells with bound immunospheres from free immunospheres revealed that removal of unbound immunospheres by flotation over cold protein solution creates excessive numbers of false negatives. Glutaraldehyde cross-linking of the primary and secondary antibodies linking immunospheres to the lymphocyte stabilizes the complex. This modification of the fluorescein immunosphere method compares favorably with flow cytometry.

Transfusion reaction with pulmonary infiltration associated with HL-A-specific leukocyte antibodies.

A case of a non-hemolytic transfusion reaction with pulmonary infiltration secondary to leukocyte antibodies is described, and previously reported cases are reviewed. This type of reaction can be diagnosed at the bedside when a patient develops fever, hypotension and dyspnea within a few hours following transfusion of whole blood or a plasma product. The roentgenogram of the chest shows pulmonary infiltrates with a normal cardiac silhouette constituting non-cardiac pulmonary edema. To provide laboratory confirmation of this reaction, it is essential to search for leukocyte antibodies by both leukoagglutinin and cytotoxic technics, as well as to determine HL-A phenotypes of both donor and recipient. As the plasma products involved usually come from multiparous women, donor parity should be a routine question in the donor interview in transfusion services. To prevent this reaction, which may prove fatal, blood donated by women who have two or more children should be used for packed cells only.

Demonstration of passenger leukocytes in a case of Epstein-Barr virus posttransplant lymphoproliferative disorder using restriction fragment length polymorphism analysis.

Lymphocytic populations of the posttransplant lymphoproliferative disorder in a completely matched renal allograft and a recipient's regional lymph node were examined, using restriction fragment length polymorphism analysis with probe YNH24 to the variable number tandem repeat D2S44. The donor's DNA was found in lymphocytes extracted from both the grafted kidney and the recipient's lymph node 26 days after engraftment. In both these organs, the results of in situ hybridization with a terminally biotin-labeled oligonucleotide probe to the Not I tandem repeat region of the Epstein-Barr virus (EBV) genome, as well as those of Southern blot hybridization to the EBV nuclear antigen region of the EBV genome, were positive. These findings confirmed the presence of the donor's lymphocytes ("passenger leukocytes") in the host nodal tissue in human renal transplantation and implicated EBV as playing a role in the development of posttransplant lymphoproliferative disorder. It is speculated that the EBV proliferative stimulus contributed to the recipient and the donor lymphocyte expansions. Alternatively, the proliferation of both lymphocyte populations could result from a mutual stimulation by minor histocompatibility or other antigens.

Insulin dependent diabetes mellitus as an autoimmune disease.

In this review we have summarized several lines of evidence supporting the concept that insulin dependent diabetes (IDDM) is an autoimmune disease. Initially, we have considered the association of IDDM with other autoimmune diseases, a fact that indirectly suggests involvement of the immune system. Other evidence implicating the immune system is the presence of auto-antibodies directed against pancreatic islet cells and cellular components of the immune system associated with pancreatic insulitis. Finally, we have examined the reported association of cell-surface proteins named histocompatibility antigens (HLA) with this particular disease. Structural and functional aspects of HLA have been considered along with regulatory mechanisms concerning the expression of these antigens.