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Collection of corneal impression cytology directly on a sterile glass slide for the detection of viral antigen: an inexpensive and simple technique for the diagnosis of HSV epithelial keratitis - a pilot study.

Athmanathan S, Bandlapally SR, Rao GN - BMC Ophthalmol (2001)

Bottom Line: All the patients with a clinical diagnosis of HSK (n = 15) were confirmed by virological investigations (viral antigen detection and/or viral cultures).Immunological techniques applied on such smears provide virological results within 2-5 hours.This technique could be modified for use in the diagnosis of other external eye diseases, which needs further evaluation.

View Article: PubMed Central - HTML - PubMed

Affiliation: Jhaveri Microbiology Center, Hyderabad Eye Research Foundation, India. sreedhar@lvpeye.stph.net

ABSTRACT

Background: Herpes simplex keratitis (HSK) is a sight threatening ocular infection and occurs worldwide. A prompt laboratory diagnosis is often very useful. Conventional virology techniques are often expensive and time consuming. We describe here a highly economical, simple, rapid and sensitive technique for the collection of impression cytology, for the laboratory diagnosis of HSK.

Methods: Fifteen patients with a clinical diagnosis of HSK (either dendritic or geographic ulcers) and five patients with other corneal infections (Mycotic keratitis, n = 3, Bacterial keratitis, n = 2) were included in the study. Corneal impression cytology specimens were collected using a sterile glass slide with polished edges instead of a membrane, by pressing the surface of one end of the slide firmly, but gently on the corneal lesion. Additionally, corneal scrapings were collected following the impression cytology procedure. Impression cytology and corneal scrapings were stained by an immunoperoxidase or immunofluorescence assay for the detection of HSV-1 antigen using a polyclonal antibody to HSV-1. Corneal scrapings were processed for viral cultures by employing a shell vial assay.

Results: This simple technique allowed the collection of adequate corneal epithelial cells for the detection of HSV-1 antigen in a majority of the patients. HSV-1 antigen was detected in 12/15 (80%) cases while virus was isolated from 5/15 (33.3%) patients with HSK. All the patients with a clinical diagnosis of HSK (n = 15) were confirmed by virological investigations (viral antigen detection and/or viral cultures). HSV-1 antigen was detected in the impression cytology smears and corneal scrapings in 11/15 (73.3%) and 12/15 (80%) of the patients, respectively (P = 1.00). None of the patients in the control group were positive for viral antigen or virus isolation. Minimal background staining was seen in impression cytology smears, while there was some background staining in corneal scrapings stained by the immunoassays.

Conclusions: Collection of impression cytology on a sterile glass slide is a simple, rapid and inexpensive technique for the diagnosis of HSK. Immunological techniques applied on such smears provide virological results within 2-5 hours. This technique could be modified for use in the diagnosis of other external eye diseases, which needs further evaluation.

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Detection of HSV-1 antigen. A smear made from corneal scraping obtained from a patient with HSK showing the presence of corneal epithelial cells positive for viral antigen (cells stained brown). Many antigen negative cells are also seen (cells stained bluish purple). Note the presence of troublesome background staining. Indirect immunoperoxidase assay, × 500.
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Figure 4: Detection of HSV-1 antigen. A smear made from corneal scraping obtained from a patient with HSK showing the presence of corneal epithelial cells positive for viral antigen (cells stained brown). Many antigen negative cells are also seen (cells stained bluish purple). Note the presence of troublesome background staining. Indirect immunoperoxidase assay, × 500.

Mentions: HSV-1 antigen was detected in the impression cytology smears (Figs. 2, 3) and corneal scrapings (Fig. 4) in 11/15 (73.3%) and 12/15 (80%) patients, respectively (P = 1.00). All the corneal scraping specimens which were found positive for the presence of viral antigen (n = 12) were also positive by impression cytology (n = 11) except in one case. Adequate cells could not be collected in this case. Minimal background staining was seen in impression cytology smears while there was a disturbing background in corneal scrapings stained by the immunological methods.


Collection of corneal impression cytology directly on a sterile glass slide for the detection of viral antigen: an inexpensive and simple technique for the diagnosis of HSV epithelial keratitis - a pilot study.

Athmanathan S, Bandlapally SR, Rao GN - BMC Ophthalmol (2001)

Detection of HSV-1 antigen. A smear made from corneal scraping obtained from a patient with HSK showing the presence of corneal epithelial cells positive for viral antigen (cells stained brown). Many antigen negative cells are also seen (cells stained bluish purple). Note the presence of troublesome background staining. Indirect immunoperoxidase assay, × 500.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC57753&req=5

Figure 4: Detection of HSV-1 antigen. A smear made from corneal scraping obtained from a patient with HSK showing the presence of corneal epithelial cells positive for viral antigen (cells stained brown). Many antigen negative cells are also seen (cells stained bluish purple). Note the presence of troublesome background staining. Indirect immunoperoxidase assay, × 500.
Mentions: HSV-1 antigen was detected in the impression cytology smears (Figs. 2, 3) and corneal scrapings (Fig. 4) in 11/15 (73.3%) and 12/15 (80%) patients, respectively (P = 1.00). All the corneal scraping specimens which were found positive for the presence of viral antigen (n = 12) were also positive by impression cytology (n = 11) except in one case. Adequate cells could not be collected in this case. Minimal background staining was seen in impression cytology smears while there was a disturbing background in corneal scrapings stained by the immunological methods.

Bottom Line: All the patients with a clinical diagnosis of HSK (n = 15) were confirmed by virological investigations (viral antigen detection and/or viral cultures).Immunological techniques applied on such smears provide virological results within 2-5 hours.This technique could be modified for use in the diagnosis of other external eye diseases, which needs further evaluation.

View Article: PubMed Central - HTML - PubMed

Affiliation: Jhaveri Microbiology Center, Hyderabad Eye Research Foundation, India. sreedhar@lvpeye.stph.net

ABSTRACT

Background: Herpes simplex keratitis (HSK) is a sight threatening ocular infection and occurs worldwide. A prompt laboratory diagnosis is often very useful. Conventional virology techniques are often expensive and time consuming. We describe here a highly economical, simple, rapid and sensitive technique for the collection of impression cytology, for the laboratory diagnosis of HSK.

Methods: Fifteen patients with a clinical diagnosis of HSK (either dendritic or geographic ulcers) and five patients with other corneal infections (Mycotic keratitis, n = 3, Bacterial keratitis, n = 2) were included in the study. Corneal impression cytology specimens were collected using a sterile glass slide with polished edges instead of a membrane, by pressing the surface of one end of the slide firmly, but gently on the corneal lesion. Additionally, corneal scrapings were collected following the impression cytology procedure. Impression cytology and corneal scrapings were stained by an immunoperoxidase or immunofluorescence assay for the detection of HSV-1 antigen using a polyclonal antibody to HSV-1. Corneal scrapings were processed for viral cultures by employing a shell vial assay.

Results: This simple technique allowed the collection of adequate corneal epithelial cells for the detection of HSV-1 antigen in a majority of the patients. HSV-1 antigen was detected in 12/15 (80%) cases while virus was isolated from 5/15 (33.3%) patients with HSK. All the patients with a clinical diagnosis of HSK (n = 15) were confirmed by virological investigations (viral antigen detection and/or viral cultures). HSV-1 antigen was detected in the impression cytology smears and corneal scrapings in 11/15 (73.3%) and 12/15 (80%) of the patients, respectively (P = 1.00). None of the patients in the control group were positive for viral antigen or virus isolation. Minimal background staining was seen in impression cytology smears, while there was some background staining in corneal scrapings stained by the immunoassays.

Conclusions: Collection of impression cytology on a sterile glass slide is a simple, rapid and inexpensive technique for the diagnosis of HSK. Immunological techniques applied on such smears provide virological results within 2-5 hours. This technique could be modified for use in the diagnosis of other external eye diseases, which needs further evaluation.

Show MeSH
Related in: MedlinePlus