A direct immunofluorescence study in elastosis perforans serpiginosa.

Two cases of elastosis perforans serpiginosa were studied by direct immunofluorescence. In one case, homogeneous deposits of IgM, C3 and C4 on the abnormal elastic fibres in the papillary dermis were demonstrated. In addition, in both cases, along the basement membrane zone, coarse linear deposits of fibrinogen and properdin were observed inside and near the transepidermal channels. Groups of cytoid bodies stained for IgM and occasional weak linear deposits of IgG, IgA, IgM and C3 were also observed. The immune deposits on the abnormal elastic fibres might indicate antigenic alteration and activation of humoral immunological mechanisms in the process of their elimination. The other findings may reflect a non-specific binding by damaged tissue structures.