ANTINEUTROPHIL CYTOPLASMIC ANTIBODIES (AN CA) IN THE ELDERLY

Aging in animals and human beings is frequently accompanied by a disar ray of the immune response. In subjects 70 years of age or older the f requency of some autoantibodies (anti-nuclear, RF, antithyroid anti-pa rietal cell and others) without any associated pathology is clearly in creased when compared against a younger population. ANCA (antineutroph il cytoplasmic antibodies) is considered to be a good marker for necro tizing systemic vasculitis. This auto-antibody is known to show two pa tterns when investigated by indirect immunofluorescence on alcohol fix ed normal neutrophils: c-ANCA (cytoplasmatic fluorescence) and p-ANCA (perinuclear fluorescence), each one associated with different patholo gies. The purpose of this work was to investigate how frequently was A NCA found in subjects 70 years of age or older without evidence of any associated pathology. ANCA was investigated in 447 ambulatory patient s from our hospital and the only requirement to be included was age. T he ANCA+ patients were divided into having or not clinical suspicion o f vasculitis, according to the medical charts we reviewed. The same me thodology was applied to investigate the frequency of antinuclear anti bodies (ANA+) without clinical evidence of any associated pathology. T his frequency was compared with that described in the literature as << ANA+ in healthy old subjects>>. In the 447 patients studied, 8 were po sitive for ANCA (1.8%), 3 for c-ANCA and 5 for p-ANCA. None of the 3 c -ANCA and only 1 of 5 p-ANCA belonged to patients without any associat ed pathology. A possible relationship between c-ANCA and cancer is dis cussed. As ANCA+ cases were very few no relationship with gender or ag e was investigated. The extremely low finding of ANCA+ in the absence of pathology, even considering old people's frequent immunological dis array suggests that in opposition to other autoantibodies, the presenc e of ANCA is always related to disease. The frequency of ANA+ without associated pathology was 2.9%, being this value on the lower limits of what is described in the literature. This can be due to different met hodology or to the scope of the definition of <<without associated pat hology>>.