Cellular Changes in Tears Associated with Keratoconjunctival Responses Induced by Nasal Allergy
Allergic keratoconjunctivitis occurs in a primary form, caused by an allergic reaction
localized in the conjunctiva, and in a secondary form, induced by an allergic reaction originating in the
nasal mucosa. Various hypersensitivity mechanisms involved in the keratoconjunctivitis forms result in
different keratoconjunctival response types. The Dutch author of this study investigated the cytologic changes
in tears during the secondary immediate (SIKCR), late (SLKCR), and delayed (SDYKCR) keratoconjunctival
responses. He found that the SIKCR, SLKCR, and SDYKCR, induced by nasal allergy, were associated with
different cellular profiles in the tears. In 61 patients, comprising 20 SIKCRs, 23 SLKCRs, and 18 SDYKCRs,
he repeated nasal provocation tests (NPTs) with allergens and 61 phosphate-buffered control challenges
and supplemented this with cell counting in the tears.
According to the author, the SIKCR (p<0.01), appearing 10 to 120 minutes after the NPT, was associated
with increased eosinophil and mast cell counts in tears. He also reported that the SLKCR (p<0.01),
appearing five to 12 hours after the NPT, was accompanied by increased counts of eosinophils, neutrophils, basophils,
and conjunctival epithelial and goblet cells. Finally, the SDYKCR (p<0.05), appearing 24 to 48 hours
after NPT, was associated with increased counts of lymphocytes, neutrophils, monocytes, basophils,
conjunctival epithelial, corneal epithelial and goblet cells.
In conclusion, the cells, except mast, epithelial and goblet cells, displaying no intracellular changes,
migrated probably from the conjunctival capillaries, in response to the factors released during the primary
allergic reaction in the nasal mucosa and subsequently penetrating into the conjunctiva. These results demonstrate
a causal role of nasal allergy and diagnostic value of NPT combined with recording of ocular features and
cellular profiles in tears in some keratoconjunctivitis patients.