No 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.

Typing for HLA‐D determinants, using primed lymphocyte typing (PLT), has been compared to the results obtained using conventional homozygous stimulating cell primary MLC tests. The HLA‐Dw1, ‐Dw2 and ‐Dw3 specificities were studied. Preliminary results indicate that these two methods essentially type for the HLA‐D determinants and that reproducible results can be obtained employing the PLT technique after 24 hours of incubation in the secondary cultures.

No abstract