Snake-like chromatin (SLC) is a nuclear
alteration occurring under various pathological
conditions and in different tissues. The aim of this study
was the morphological and immunocytochemical
characterization of SLC-positive conjunctival epithelial
cells from keratoconjunctivitis sicca (KCS) patients.
Impression cytology specimens from the upper
bulbar conjunctiva of 10 controls and 10 KCS patients
with a high incidence of SLC cells were assessed, the
morphology of SLC nuclei evaluated by light
microscopy, and proliferation markers, nucleolar
proteins, lamins and cytokeratin filaments detected
immunocytochemically.
In KCS patients, SLC cells with a normal nuclear
shape, with nuclear membrane notching (2.3% of cells)
and with binuclear dumb-bell structures (4.4% of cells)
were observed. The most striking features of SLC cells
were the absence of an A/C lamin signal, the
redistribution of fibrillarin into two spots adjacent to
SLC structures and cytokeratin 14 positivity in the
strangulation belt of the dumb-bell structures.
The deficiency of lamin A/C is the probable reason
for the disintegration of chromatin from the nuclear
lamina in SLC cells. The occurrence of SLC-positive
cells, SLC-positive dumb-bell shaped nuclei and SLCpositive
binucleated cells, together with the absence of mitotic markers, leads to the conclusion that the SLC
phenomenon might be a form of nuclear segregation