A new pattern of non-organ- and non-species-specific anti-organelle antibody detected by immunofluorescence: the mitochondrial antibody number 5.

About 0.1% of the sera in human pathology produce a peculiar, cytoplasmic, non-organ- and non-species-specific fluorescence. This may easily be differentiated from the already described anti-organelle antibodies and, more particularly, from the mitochondrial antibodies of primary biliary cirrhosis. Should rat tissues be used in the immunofluorescence test, fluorescence predominates over the first two portions of the renal proximal tubules (P1 and P2) and the mucous neck cells of the stomach. This pattern may be atrributed to mitochondria, and in particular to their inner membranes by fluorescent staining of the ellipsoid region of the rods and cones of the eyes, and by absorption with purified organelles. To distinguish this antibody from the already described mitochondrial antibodies, this one will be called mitochondrial antibody number 5 (M5). The seven carriers of this antibody suffer from systemic lupus erythematosus or autoimmune haemolytic anaemia. In these cases no diseases of the liver were observed, contrary to other classical mitochondrial antibodies.