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Abstract Details

Antibodies to Ha, Ks, and Zo: Frequency and Characteristics of Antibody-positive Patients in an Unselected Cohort
Neuromuscular and Clinical Neurophysiology (EMG)
P9 - Poster Session 9 (8:00 AM-9:00 AM)
Autoantibodies to Ha, Ks, and Zo are associated with diagnosis of anti-synthetase syndrome (ASyS), a subtype of myositis characterized by muscle weakness, interstitial lung disease, Raynaud’s phenomenon, arthritis and mechanic’s hands. Currently, testing for Ha, Ks, and Zo antibodies is only performed by a small number of labs, primarily on a research basis.

The aims of this study were to establish the frequency, demographic and clinical characteristics of Ha, Ks, and Zo antibody-positive patients in a referral setting, and to evaluate the performance of a line immunoblot assay (LIA) for detection of Ha, Ks, and Zo antibodies.

Consecutive samples received at ARUP Laboratories for myositis antibody testing were screened by protein immunoprecipitation (IP) of S35-labeled K562 cells. Antinuclear antibodies (ANA) were detected by indirect immunofluorescence. Samples with distinct bands corresponding to approximately 59, 65, or 60 and 70 kDa were identified as suspicious of Ha, Ks and Zo, respectively, and tested for these antibodies by LIA. As controls, samples positive for other autoantibodies associated with myositis or other autoimmune diseases and self-proclaimed healthy donors were also evaluated by LIA. Clinical and laboratory data for all Ha, Ks, and Zo antibody-positive patients were sought to confirm diagnosis.

We report on the frequency of detection of Ha, Ks and Zo antibodies in a reference laboratory setting and agreement between LIA and IP for detection of these antibodies. We also describe the clinical characteristics of patients found positive for antibodies against Ha, Ks, and Zo. 

Identification of Ha, Ks, and Zo antibodies is important for diagnosis, prognosis, and disease management in patients with ASyS. LIA confirmed the presence of Ha, Ks, or Zo antibodies in patients with corresponding bands observed in the IP assay. Combined use of both methods improves reliability for the diagnosis of ASyS in patients undergoing evaluation for inflammatory myopathies.


No disclosure on file
Tammy L. Smith, MD, PhD (Imaging and Neurosciences Center) The institution of Dr. Smith has received research support from Alexion/AstraZeneca. Dr. Smith has a non-compensated relationship as a participant with Euroimmun Academy, receiving travel support to attend, that is relevant to AAN interests or activities.
Lisa K. Peterson, PhD (ARUP Laboratories) The institution of Dr. Peterson has received research support from Kronus.