title: Antibody to threonyl-transfer RNA synthetase in myositis sera.
abstract: The prevalence and clinical correlations of anti-threonyl-transfer RNA synthetase (anti-PL-7), as well as the relationship of anti-PL-7 to anti-histidyl-transfer RNA synthetase (anti-Jo-1) were studied in 109 sera from patients with myositis. Inhibition of threonine aminoacylation was used to screen for anti-PL-7. Sera from 3 patients, 2 with polymyositis and 1 with polymyositis-overlap syndrome, and a fourth serum from a patient with dermatomyositis, which was previously found to contain anti-PL-7, inhibited greater than 90% of activity (3.7% of 109 sera). All 4 sera reacted strongly in an enzyme-linked immunosorbent assay with enzyme that was either affinity purified with anti-PL-7 or was biochemically purified. There was no indication of cross-reactivity by aminoacylation inhibition or, for most sera, by enzyme-linked immunosorbent assay. Anti-PL-7 is an uncommon myositis-associated antibody that is independent of anti-Jo-1, but is directed at a functionally related enzyme.
mesh_terms: D000215:Acylation; D000328:Adult; D000604:Amino Acyl-tRNA Synthetases / Q000276:immunology*; D000974:Antibodies, Antinuclear / Q000032:analysis; D001323:Autoantibodies / Q000032:analysis* / Q000276:immunology; D003429:Cross Reactions; D003882:Dermatomyositis / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009220:Myositis / Q000276:immunology*; D013912:Threonine / Q000378:metabolism; D013914:Threonine-tRNA Ligase / Q000037:antagonists & inhibitors / Q000276:immunology*
chemical_list: D000974:Antibodies, Antinuclear; D001323:Autoantibodies; C046750:Jo-1 antibody; D013912:Threonine; D000604:Amino Acyl-tRNA Synthetases; D013914:Threonine-tRNA Ligase