Four subjects whose plasma produced positive staining of neutrophil cytoplasm, on testing for antinuclear factor, have been found over eight years (and over 10,000 antinuclear factor studies). All four had evidence of diffuse systemic disease with polyarthralgia and lung involvement. Three of four (at least) had evidence of renal involvement and two of four skin biopsy evidence of vasculitis. Defining such a subgroup may help in defining etiology(s) and treatment regimes in diffuse vasculitic disease.