B. Carlsson

HLA-DR-DQ haplotypes defined by restriction fragment analysis: Correlation to serology

Through the analysis of RFLP (restriction fragment length polymorphism) of the HLA-DR beta, -DQ alpha, and -DQ beta genes from 70 serologically well-characterized individuals, we have established unique HLA-DR-DQ RFLP haplotypes correlating to all of the DR1-w14 specificities. The RFLP of DR beta, DQ alpha, and DQ beta genes is very high using the restriction enzyme TaqI and 21 DR-DQ RFLP haplotypes were defined with this restriction enzyme. Our analysis confirms the strong linkage disequilibrium between alleles in the DR and DQ loci. DR beta RFLP indicates a common ancestor for the DR alleles within either of the supertypic DRw52 and DRw53 specificities. The DQ beta gene shows a high degree of RFLP, and the RFLP alleles partly reflect the serologic DQw1-w3 specificities. The results presented here also demonstrate the heterogeneity of DRw6 (DRw13 and DRw14) associated haplotypes, and the DRw13 related Dw18 and Dw19 specificities were found to have distinct DR-DQ haplotypes. The DQw1 positive haplotypes DR1, 2, w10, w13, and w14 are related with regard to DQ alpha and DQ beta RFLPs and the DRw52 positive haplotypes DR3, w11, and w12, as well as the DRw53 positive haplotypes DR4, 7, and w9, are related with regard to DR beta and DQ alpha RFLPs. These findings indicate that polymorphic sequences around the DQ alpha gene are associated with DR beta and DQ beta polymorphism, which suggests a location of the DQ alpha gene between DR beta and DQ beta.

Different HLA DR-DQ associations in subgroups of idiopathic myasthenia gravis.

We have investigated theHLA-DRB and -DQB gene polymorphism in 131 myasthenia gravis (MG) patients. TheHLA genotypes in these patients were assigned by means of restriction fragment length polymorphism (RFLP)-definedDR-DQ haplotypes, correlating to serologic HLA class II typing. Using this technique we could, among randomly selected non-thymomatous (NT)-MG patients, confirm the strong association to DR3, and 70% of the patients were found to carry a specific DR3-positiveDR-DQ haplotype,T-3.1. Furthermore, an analysis of T-3.1− NT-MG patients revealed that 59 % were T-4.1÷ (DR4, DQw8). Thymic hyperplasia was found in approximately 85 % of the T-3.1+ , as well as of the T-4.1+ /3.1− patients. As previously observed, we found a clear dominance of females among the T-3.1+ NT-MG patients. However, among T-4.1+/3.1- patients, males were as common as females. Furthermore, the T-4.1+ patients were significantly older at the onset of disease than those who were T-3.1+. In female MG patients, the DRwl5-Dw2-positive haplotypeT-2.1 was strongly correlated with the presence of thymoma (T-MG). These data indicate that the HLA associations in early vs late onset of NT-MG are different, and that female patients with and without thymoma differ from each other with regard to HLA markers. Thus, at least three different HLA DR-DQ associations are found in subgroups of idiopathic MG.

Molecular probing of disease susceptibility genes in myasthenia gravis patients: an analysis of T-cell receptor and HLA class II genes using restriction fragment length polymorphism.

Two of the landmarks in myasthenia gravis research are the finding of acetylcholine receptor antibodies and the observation of an association to HLA.’ Although both observations were made more than 10 years ago, we still know very little about the initiation of autoantibody synthesis and how HLA antigens are involved in this process. Myasthenia gravis in humans can be subdivided into three major subgroups. The first group is the idiopathic form of the disease, which can be further subdivided based on age of onset, seventy of disease, and thymus pathology.’ The second major subgroup is penicillamine-induced Finally, the risk of developing myasthenia gravis

HLA Class II Polymorphism: Restriction Fragment Patterns Correlated to Ninth Workshop Serology and Function

Recent studies have vastly expanded our knowledge of MHC gene organization and structure [for review see 6, 7, 13]. The HLA class II gene map is presently thought to contain at least three DRβ, one DRα, two DQβ two DQα, two DPβ and two DPα genes. Serological studies indicate at least four distinct class II antigens: DR, supertypic DR (DRw52, w53), DQ and DP [12; for review see 10]. It is now possible to isolate HLA class II cDNA and genomic clones with recombinant DNA techniques. With the use of cDNA specific for DRβ, DQβ and DQα and a genomic clone corresponding to an DPβ chain first domain as probes in genomic hybridizations, we have investigated the class II gene polymorphism. The cDNA and genomic clones used as probes are described elsewhere for DRβ [1], DQβ [8], DQα [3], and DPβ (K. Gustafsson, unpublished results). As the HLA glycoproteins retain their antigenic specificities even in the absence of carbohydrate moieties [11], it can be expected that all biologically relevant polymorphism can be detected at the DNA level.

Analysis of HLA DR and DQ β‐Genes in Myasthenia Gravis Patientsa

In 1972 it was first reported that myasthenia gravis is associated with an increased frequency of certain HLA-antigens.’ The association has been further analyzed by a number of investigators, and certain patterns have emerged. Thus, the spontaneous form occurring mainly in young females (but also when it occurs in young males) is associated with the serological specificities HLA-BS/DR3*.’ as well as HLA-Dw3.’ In individuals with late onset of disease, as well as in patients with a concomitant thymoma the picture is less clear?” In peaicillamine-induced disease Bw35/DRl is increased.‘ Since the analysis of restriction fragment length polymorphism displayed by DR and DQ genes can be used for HLA-typing,’ we wanted to use this method to further analyze the association in myasthenia gravis.

Polymorphism of HLA Class II Genes in Various Diseases

Many diseases are associated with genes of the HLA region. Several disease associations were described before class I1 genes were known, such as ankylosing spondylitis to HLA-B27 and psoriasis vulgaris to HL.4-Bl3, 17, and 37. Knowledge of the B27 association is now almost complete. In our material as well as in the data of the 1980 Histocompatibility Workshop, all patients with ankylosing spondylitis or pelvospondylitis ossificans are B27 positive. B27-negative patients with pelvospondylitis seem to have a different disease as the basis for their spondylitis. In contrast, psoriasis vulgaris is now more closely associated with Cw6 and DR7, alleles that are in linkage disequilibrium with B13, 17, and 37. Similarly, insulin-dependent diabetes mellitus (IDDM) was first associated with HLA-B8 and 15 and later more closely asssociated with the cellular specificities Dw3 and w4 and the corresponding serologic specificities DR3 and 4.’ With the possibilities of also determining variation within the DQ locus using RFLP analysis and cDNA probes, the association with IDDM was found to be secondary to particular alleles of the DQ locus, referred to as DQPIV’ and DQw3.2 by Nepom et aL3 Todd et al.4 recently reported amino acid sequence analyses of DQ alleles known to be positively and negatively associated with IDDM and identified residue 57 in the DQB chain as a candidate responsible for IDDM susceptibility or resistance or both. To define the genes responsible for disease susceptibility, it is imperative to have methods of resolving the relevant level of genomic variability of genes that determine T-cell repertoire and serve as restricting elements for T-cell recognition. Genes of the HLA-D region were first detected by cellular methods and typing in MLR using homozygous typing cells. Later, when class I1 products were shown to be present only on some lymphoid cells, serologic reagents that recognized class I1 antigens were selected. Names for such specificities, such as D Related-DR, were adopted to fit reactivities of these antibodies with HLA-D typed cell panels. At this time, D was thought to represent only one locus. Some DR specificities fit well with the adopted D terminology, such as Dwl and DR1 in Caucasoids, whereas others did not. As many as five distinct D specificities were all associated with serologic specificity DR4, named Dw4, 10, 13, 14, and 15. The DR7 group comprised cellular specificities Dw7, 11, and 17, and DR2 could be subdivided into Dw2, Dwl2, MN2 (= AZH) as well as cells with unknown D type (Dwx). When the polymorphic characters of the DQ locus were defined using biochemical, serologic, and molecular approaches, it became apparent that earlier defined D specificities were the total product of class I1 antigens expressed by the DR and the DQ IOCUS.~ Therefore, the D “alleles” were not true alleles of one locus, and the means of