Respiratory syncytial virus may be a pathogen in allergic conjunctivitis.
OBJECTIVE
The host response to allergens appears to be regulated by T helper type 2 cell patterns of local cytokine production. We hypothesized that respiratory syncytial virus (RSV) infects the normal conjunctival epithelium and produces interleukin (IL)-4, causing a local allergic reaction.


METHODS
Giemsa staining, immunocytochemical study, flow cytometric analysis, and reverse-transcriptase polymerase chain reaction (RT-PCR) were performed on tear and cytology samples from individuals with allergic and postoperative conjunctivitis. Histamine was assayed by radioimmunoassay, and IL-4 by enzyme-linked immunosorbent assay.


RESULTS
The total number of cells collected by brush cytology did not differ between allergic and postoperative conjunctivitis. The levels of IL-4 and histamine in the specimens and mean IL-4 tear level were significantly increased in patients with allergic conjunctivitis. Cytocentrifuge preparations contained conjunctival epithelial cells with lymphocytes (a few CD3- and CD4-bearing cells), mast cells, eosinophils, and higher human leukocyte antigen (HLA)-DR expression in allergic patients. RT-PCR analysis showed that samples from allergic conjunctivitis expressed increased transcripts of IL-4 and IL-13. A higher percentage of RSV sequences were detected in allergic patient samples. Immunocytochemical study and RT-PCR showed that epithelial cells were infected with RSV. Average concentrations of IL-4 in culture supernatants were higher than levels in uninfected cells.


CONCLUSIONS
These results suggest that the clinical features of human allergic conjunctivitis are associated with T helper type 2 cytokine expression. RSV in conjunctival epithelial cells may be an environmental pathogen in allergic conjunctivitis.
Fujishima
Hiroshi
H
Department of Ophthalmology, Tokyo Dental College, Sugano, Ichikawa, Japan. fujishim@tdc.ac.jp
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D003233:Conjunctivitis, Allergic / Q000378:metabolism / Q000821:virology*; D004797:Enzyme-Linked Immunosorbent Assay; D004847:Epithelial Cells / Q000378:metabolism / Q000821:virology; D015828:Eye Infections, Viral / Q000378:metabolism / Q000821:virology*; D005260:Female; D005434:Flow Cytometry; D006684:HLA-DR Antigens / Q000378:metabolism; D006632:Histamine / Q000378:metabolism; D006801:Humans; D015847:Interleukin-4 / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000378:metabolism; D012367:RNA, Viral / Q000032:analysis / Q000302:isolation & purification; D011863:Radioimmunoassay; D018357:Respiratory Syncytial Virus Infections / Q000378:metabolism / Q000821:virology*; D018113:Respiratory Syncytial Virus, Human / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013666:Tears / Q000378:metabolism
D006684:HLA-DR Antigens; D012333:RNA, Messenger; D012367:RNA, Viral; D015847:Interleukin-4; D006632:Histamine