This study describes the molecular characterization of an antigen defined by an
autoantibody from a woman with habitual abortion as GM2-activator protein. The patient
showed no disorder of renal function. Accidentally with routine serum screening for
autoantibodies, an immunoreactivity was found in kidney collecting duct intercalated cells.
Three distinct patterns of immunostaining of intercalated cells were observed: staining of the
apical pole, basolateral pole, and diffuse cytoplasmic labeling. Ultrastructurally, the …