Antinuclear antibodies (ANA) generally do not show organ specificity and are detectable on a wide range of tissue substrates by the indirect immunofluorescent method.

A notable exception is granulocyte-specific (GS) antibody, which reacts with nuclei of mature granulocytes (and monocytes) but not with nuclei of lymphocytes or cells of other tissues.

GS-ANA occur uncommonly in health, and their highest incidence has been found in Felty's syndrome, rheumatoid arthritis, and systemic lupus erythematosus .