In situ hybridization determination of the heterophagocytic origin of type 2B prostate epithelial lipochrome pigment granules: histochemical and ultrastructural correlates.

UNLABELLED: Morphologically, polymorphic prostatic lipochrome pigment has been classified and subclassified in the last few years. Type 2B lipochrome pigment granules (LPGs) are frequently found in prostatic epithelium in patients who had died of AIDS. Intensive apoptosis is observed in the same epithelium which lends support to the hypothesis of heterophagocytic (apoptotic) origin of type 2B pigment granules. Detection of nuclear chromatin material is necessary for the differentiation of an autophagosomal from a heterophagosomal structure in the cellular cytoplasm. OBJECT OF THE STUDY: Application of in situ hybridization (ISH) for elucidating the origin of subtype 2B LPGs in the prostate epithelial cells of patients who had died of AIDS. METHODS: ISH was used on routine necropsic prostate epithelial samples from three patients who had died of AIDS. A DNA probe raised against total human DNA was employed. RESULTS: Multiple hybridization signals were detected in type 2B LPGs which shows the presence of nuclear material in those structures. The chromatin material localized to the periphery of pigment granules. CONCLUSION: Type 2B LPGs have a heterophagocytic origin and represent phagocytosed apoptotic bodies in the phase of phagolysosomal degradation. They can be used as a morphologic tissue marker of intensive epithelial apoptosis.