POLYMORPHIC AMINO-ACID DOMAINS OF THE HLA-DQ MOLECULE ARE ASSOCIATED WITH DISEASE HETEROGENEITY IN MYASTHENIA-GRAVIS

The association between myasthenia gravis (MG) and polymorphic amino a cid domains in the HLA-DQ molecule was studied in 79 Swedish patients and 155 unrelated, population-based controls. A domain unique for DQB1 0201 was positively associated in MG patients with thymic hyperplasia or an early disease onset, and two domains with residues common to DQ A101 alleles or DQB1*05 and DQB1*06 alleles were negatively associate d in patients with thymic hyperplasia or an early disease onset. Our r esults suggest that MG associated with thymic hyperplasia and thymoma differ in their HLA-DQ association and thus are likely to have differe nt pathogenic mechanisms.