LD Antigens Associated withHL‐A8and Myasthenia Gravid¹

Abstract

The finding that the SD antigen HL-A8 is associated with myasthenia gravis has raised the question as to whether or not there is also an association between some specific LD antigen and myasthenia gravis a n d o r HL-A8.MLC technique was used to study LD antigens in 33 myasthenic patients. The cells of a myasthenic patient who was homozygous for both HL-A and LD products were used in MLC tests as stimulators with HL-A8 bearing cells from 24 myasthenics, their 17 relatives and 16 controls and to non-HL-A8 cells from nine myasthenics and 16 controls.At least three different LD genes were found to be associated with HL-A8. One of them, called LD,, was present in 17 (63 % ) of the 27 HL-A8-bearing haplotypes of myasthenics, and in nine (47 %) of the 19 HL-i\a-bearing haplotypes of controls. I n our study LD, was not found in the 84 haplotypes devoid of HL-A8. LD, is strongly associated with HL-A8 and through this also with myasthenia. Calculated from phenotype frequencies for HL-A8 and its association to LD,, the LD, frequencies are 9 % in the control population, 30 % in myasthenics and 48 70 in young females with onset of myasthenia beIow 35 years.LD, had no independent correlation with any of the clinical parameters of myasthenia gravis, even though is was found more often in HL-A8+ females with the onset of myasthenia before 35 years than in the whole myasthenic group. LD, appears to be similar to LD8a antigen.

HL‐A8 and LD‐8a in Patients with Myasthenia Gravis

“…We found that in MG the association with HL-A8 was markedly higher than with LD-8a. Kaakinen et al (1975) also found that the frequency of LD-8a was slightly higher in MG patients than in normals, they found LD-8a in 45% of 33 patients. Thus, we believe that different genes are responsible for the association with HL-A8 of diseases like myasthenia gravis on the one hand, and Addison's disease on the other, in spite of the attractive idea of special genes for autoimmune reactivity.…”

Selective IgA Deficiency in Autoimmune Diseases

“…The MHC region is reported to be associated with MG (17,141,142). Early-onset MG and patients exhibiting thymic hyperplasia are most strongly associated with the HLA-B8, DR3 haplotype, and late-onset MG is associated with B7 and DR2 alleles (143,144).…”

Hla System and Myasthenia Gravis

“…Fritze et al (1974) noticed thymic hyperplasia in HLA-BE positive MG patients. Kaakinen et al (1975) observed that HLA-Dw3 was strongly linked to HLA-BE, but only a little more (not significantly) in MG patients than in control subjects. The association between HLA-BE and MG was stronger than the association between Dw3 and MG. HLA-Dw3 had no independent correlation with any of the clinical parameters of MG. Tney concluded that they did not find a specifically MG-associated HLA-D allele.…”