Anti-adenosine deaminase antibodies in lupus erythematosus.
Adenosine deaminase (ADA) is an enzyme involved in purine metabolism and has a major role in the development and function of lymphoid cells. Congenital deficiency of ADA results in severe immunodeficiency. Patients with congenital ADA deficiency treated with polyethylene glycol-conjugated bovine ADA develop antibodies to ADA. This leads us to investigate the role of anti-ADA antibodies in patients with systemic rheumatic diseases. Commercially available ADA was used in ELISA and immunoblots for detection of anti-ADA antibodies. Four out of 100 patients examined were positive for anti-ADA antibodies. Two of them had peripheral blood lymphopenia but the antibody levels did not appear to correlate with the lymphocyte counts. Immunoblotting revealed that the antibodies recognized a 40 kDa peptide of ADA, corresponding to ADA1, the major component of ADA. Affinity-purified antibodies were used to locate the distribution of ADA on Hep-2 cells and lymphocytes by indirect immunofluorescence. Anti-ADA antibodies gave a distinct nuclear speckled pattern on acetone-fixed cells. With viable cell immunofluorescence, anti-ADA antibodies also stained the cell surface of HEp-2 cells and lymphocytes, indicating surface expression of ADA. The anti-ADA antibodies failed to gain access into the cytoplasm or nuclei when added to the cultures of HEp-2 cells. In summary, this is the first report of detection of anti-ADA1 autoantibody which is a new type of ANA with discrete, speckled nuclear staining, but which may not be associated with lymphopenia.
Lee
J Y Y
JY
Department of Dermatology, National Cheng-Kung University, Taiwan, Republic of China.
Hempel
J
J
Deng
J S
JS
D000243:Adenosine Deaminase / Q000276:immunology* / Q000378:metabolism; D000328:Adult; D001741:Black or African American; D001323:Autoantibodies / Q000097:blood / Q000276:immunology*; D002460:Cell Line; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D015151:Immunoblotting; D008180:Lupus Erythematosus, Systemic / Q000097:blood / Q000201:enzymology* / Q000276:immunology* / Q000473:pathology; D008231:Lymphopenia / Q000276:immunology; D008297:Male; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D044465:White People
D001323:Autoantibodies; D000243:Adenosine Deaminase