Soluble human leukocyte antigen: a diagnostic indicator of rheumatoid arthritis?
Early stage rheumatoid arthritis (RA) is often difficult to diagnose because initial symptoms are non-specific. To aid diagnosis, suitable serological diagnostic markers are sought. Elevated levels of soluble MHC class II (soluble human leukocyte antigen; sHLA-DR) in human serum have been associated with rheumatoid and 'rheumatoid-like' autoimmune diseases. As a result, sHLA-DR has been suggested as a specific marker of RA. However, reported levels of sHLA-DR in sera of healthy donors vary significantly and the mechanism of release of HLA-DR into serum is poorly understood. Investigations into the diagnostic potential of this molecule necessitate the development of a sensitive and specific sHLA-DR assay. We have investigated multiple ELISA setups to develop such an assay and false positive signal has been carefully removed using a combination of isotype-matched controls and immuno-depletion. sHLA-DR levels in sera of RA patients were not significantly different from those in healthy donors which suggests sHLA-DR has limited utility in the diagnosis of RA. In RA patients, we detected high levels of sHLA-DR in aspirated synovial fluid (SF), but this did not correlate with sHLA-DR levels in serum.
Hayman
M W
MW
Immunology Section, Canterbury Health Laboratories, Christchurch, New Zealand. matthew.hayman@cdhb.govt.nz
van Beijnen
M T A
MT
Stamp
L K
LK
Spellerberg
M B
MB
O'Donnell
J L
JL
D001172:Arthritis, Rheumatoid / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D015415:Biomarkers / Q000032:analysis; D016022:Case-Control Studies; D045744:Cell Line, Tumor; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D006684:HLA-DR Antigens / Q000032:analysis* / Q000097:blood; D006801:Humans; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D012995:Solubility; D013582:Synovial Fluid / Q000276:immunology / Q000378:metabolism*
D015415:Biomarkers; D006684:HLA-DR Antigens