Cell-type specificity of anti-CD45 autoantibodies in systemic lupus erythematosus.
OBJECTIVE
To determine the specificity of anti-CD45 autoantibodies in systemic lupus erythematosus (SLE) for native CD45 and for CD45 expressed by T cells and B cells, and at different stages of cellular activation.


METHODS
CD45 purified from different types of lymphocytes was examined by immunoblotting with sera from patients with SLE. Indirect immunofluorescence experiments were performed with purified anti-CD45 autoantibodies.


RESULTS
IgM anti-CD45 autoantibodies in SLE recognize native CD45 expressed on the surface membrane of viable lymphocytes and CD45 purified from activated peripheral T cells and certain T cell lines, but not CD45 purified from B cells or resting peripheral T cells. The presence or absence of reactivity is independent of the individual isoforms expressed.


CONCLUSIONS
Recognition of CD45 by IgM antilymphocyte autoantibodies in SLE varies with the lineage and state of activation of the lymphocyte target. This pattern of reactivity is consistent with autoantibody specificities involving CD45 glycoforms, rather than CD45 isoforms.
Czyzyk
J
J
Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, 27599-7280, USA.
Fernsten
P
P
Shaw
M
M
Winfield
J B
JB
D000918:Antibody Specificity; D001323:Autoantibodies; D001402:B-Lymphocytes / Q000276:immunology; D006801:Humans; D007075:Immunoglobulin M; D017493:Leukocyte Common Antigens / Q000032:analysis*; D008180:Lupus Erythematosus, Systemic / Q000276:immunology* / Q000473:pathology; D008213:Lymphocyte Activation / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
D001323:Autoantibodies; D007075:Immunoglobulin M; D017493:Leukocyte Common Antigens