Allergic tears promote upregulation of eosinophil adhesion to conjunctival epithelial cells in an ex vivo model: inhibition with olopatadine treatment.
OBJECTIVE
The mechanism by which eosinophils adhere to the ocular surface during allergic inflammation is unknown. This study examined whether the incubation of human conjunctival epithelial cells (HCEs) with tears from allergic subjects promotes eosinophil adhesion, and it examined the effect of treatment with olopatadine on this process.


METHODS
Allergic subjects (n = 6) and nonallergic subjects (n = 4) were treated in season for 1 week with olopatadine in one eye while the other eye remained untreated. Tears were collected from both eyes with the use of a microcapillary tube. HCEs were acquired by enzymatic digestion of cadaveric conjunctival tissues. Confluent cultures of HCEs were treated with diluted tears for 24 hours before incubation with peripheral blood eosinophils (purified with negative magnetic bead selection). Eosinophil adhesion was measured with an eosinophil peroxidase assay.


RESULTS
Incubation of HCEs with tears from allergic subjects significantly upregulated eosinophil adhesion compared with eosinophil adhesion to untreated HCEs or with HCEs treated with nonallergic tears and untreated HCEs (P < 0.05). Eosinophil adhesion to HCEs treated with tears from olopatadine-treated allergic subjects was inhibited (P < 0.01) compared with tear-stimulated adhesion observed from untreated eyes. Percentage of inhibition was 43.3% +/- 13.9% (mean +/- SD). Blocking antibodies demonstrated that eosinophil adhesion to HCEs in vitro involved beta2 integrins on eosinophils but not intercellular adhesion molecule-1 on human HCEs.


CONCLUSIONS
Tears collected from allergic subjects contain bioactivity capable of upregulating eosinophil adhesion to HCEs in vitro. Inhibition of this process by treatment of subjects with olopatadine suggests that some of the cellular targets of this drug may play a role in promoting eosinophil adhesion.
Cook
Ellen B
EB
Departmentsof Medicine, School of Medicine, University of Wisconsin-Madison, 53792, USA. ebc@medicine.wisc.edu
Stahl
James L
JL
Brooks
Anne M
AM
Graziano
Frank M
FM
Barney
Neal P
NP
D000328:Adult; D018926:Anti-Allergic Agents / Q000627:therapeutic use*; D019138:Antibodies, Blocking; D018821:CD18 Antigens / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology; D002469:Cell Separation; D002478:Cells, Cultured; D003228:Conjunctiva / Q000166:cytology*; D003233:Conjunctivitis, Allergic / Q000188:drug therapy / Q000276:immunology*; D003990:Dibenzoxepins / Q000627:therapeutic use*; D004804:Eosinophils / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism*; D005260:Female; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D000069605:Olopatadine Hydrochloride; D012882:Skin Tests; D013666:Tears / Q000502:physiology*; D015854:Up-Regulation
D018926:Anti-Allergic Agents; D019138:Antibodies, Blocking; D018821:CD18 Antigens; D003990:Dibenzoxepins; D018799:Intercellular Adhesion Molecule-1; D000069605:Olopatadine Hydrochloride