2141 Immunohistochemical study of secondary cataracts using antibodies to cytoskeletal elements, the HNK-1 epitope and macrophages

u To study the cytoskeleral elements and the presence of macrophages and the cell-adhesion related HNK-1 epitope in secondary cataracts after extracapsular cataract extraction and IOL implantation. &&Q& Twenty-five formalin-fixed and paraffin-embedded pseudophakic human eyes obtained at autopsy were studied with 7 monoclonal antibodies (MAbs) to vunentm, cytokeratins 8 and 18, desmin, a-smooth muscle actin and to the HNK-1 epitope. Additionally, a MAb was used to detect macrophages. The specimens were immunostained using the avidin-biotinylated peroxidase complex (ABC) method and studied by light microscopy. Results MAb Vim 3B4 to vimentin immunolabeled spindle-shaped cells in the secondary cataract in 17/18 eyes. Immunoreactive spindle-shaped cells were also found with MAb CAM5.2 to cytokeratin 8 in 14/19 secondary cataracts, but with MAB CY-90 to cytokeratin I8 only in l/l9 secondary cataracts. No immunoreaction was seen with MAb D33 to desmin, whereas MAb lA4 to ol-smooth muscle actin immunolabelled spindle-shaped cells in 16119 secondary cataracts. A granular immunoreaction with MAbs HNK-1 and NC-1 to the HNK-1 epitope was present within the secondary cataract adherent to the lens capsule in all cases. This immunoreaction was attributed to the extracellular manix. MAb PG-Ml revealed few round cells representmg macrophages in 8119 secondary cataracts, and granular immunoreacdon representing disrupted macrophages was seen in additional 5 eyes. The lens capsule was not labeled with any of the MAbs used. Conclusions Immunoreactlon for vimentin, cyrokeratin 8 and ol-smooth muscle actin revealed spindle-shaped cells in the secondary cataract of the human eye. Based on their antigenic profile, these cells are myoepithelial in nature and probably represent metaplastic lens epithelial cells.