Cytological diagnosis of herpesvirus keratitis by means of in situ hybridization: report of a case

Coexistence of Pemphigus vulgaris and herpes simplex virus infection in oral mucosa diagnosed by cytology, immunohistochemistry, and polymerase chain reaction

A case of Pemphigus vulgaris concurrent with hepres simplex virus (HSV) infection in a 53-yr-old female is described, in which the diagnosis was based on oral scraping cytology. Two populations of abnormal cells were identified in the oral smear. One abnormal cell population was characterized by the presence of numerous single cells and sheets and smaller aggregates of loosely cohesive epithelial cells that appeared to have only a few points of intercellular attachment. A second population of abnormal cells showed characteristic signs of HSV infections such as ground-glass nuclear appearance and multinucleation. Subsequently, diagnosis of HSV infections based on polymerase chain reaction was applied to identify the specific DNA for HSV type 1 in the Papanicolaou specimens. To our knowledge, this is the first case in which the coexistence of Pemphigus vulgaris and HSV infection in the oral mucosa was established by cytologic diagnosis. This is discussed in view of our recent experience with this unusual oral lesion.

In situ hybridization and its diagnostic applications in pathology

In situ hybridization (ISH) is a technique by which specific nucleotide sequences are identified in cells or tissue sections. These may be endogenous, bacterial or viral, DNA or RNA. On the basis of research applications, the technique is now being translated into diagnostic practice, mainly in the areas of gene expression, infection and interphase cytogenetics. Diagnostic applications are most often based on short nucleotide sequences (oligomers) labelled with non-isotopic reporter molecules, and sites of binding may be localized by histochemical or immunohistochemical methods. The technique can be applied to routinely fixed and processed tissues; with some targets, it is even possible to obtain hybridization in autopsy material. ISH has been used to detect messenger RNA (mRNA) as a marker of gene expression, where levels of protein storage are low; for example, to confirm an endocrine tumour as the source of excess hormone production. Its application in infectious diseases has to date been mainly in viral infections, such as the typing of human papillomavirus (HPV) or the detection of Epstein-Barr virus by the presence of small nuclear RNAs (EBERs). The expression of mRNAs for histone proteins has been used to detect cells in S phase, and related methods may be applied to detect apoptotic cells. Using probes to chromosome-specific sequences, it is possible to detect aneuploidy, and to document changes in specific chromosomes, which may have prognostic significance in some tumours, such as B-cell chronic lymphatic leukaemia. Using sequence-specific probes, translocations can be identified, such as the t(11;12) of Ewing's sarcoma. This review presents an outline of the technique of in situ hybridization and discusses areas of current and potential diagnostic application.

Advances in rapid laboratory diagnosis of infectious endophthalmitis

Infectious endophthalmitis is a serious ocular condition which always requires rapid medical or surgical intervention. At present this, in a number of situations, remains empirical as a consequence of problems inherent in unequivocal identification of the causative organism, should one be present. Aqueous humor smears and culture have limited value in diagnosis. Vitreous samples can often reveal the presence of microbes, but these may not necessarily be detected in all cases, principally due to suboptimal sampling or pretreatment with antimicrobials which render microbes non-culturable on routine media. Use of electron microscopy and/or immunocytochemistry offers an alternative means of identification, but these approaches have drawbacks principally associated with interpretation. Molecular methods which identify conserved sequences from common causative microbes of endophthalmitis, or which can specify whether the organism is a bacterium or a fungus may become especially important as diagnostic tools in this clinical scenario.

Cytologic detection of herpes simplex virus DNA in nipple discharge by in situ hybridization: report of two cases

Cytologic changes in the smears from nipple discharge of two cases with herpes simplex virus (HSV) infections are described. The cytology revealed the ground-glass appearance of the nuclei with multinucleated syncytial cells. Subsequently, in situ hybridization (ISH) using a biotinylated DNA probe was applied to identify the HSV DNA in the Papanicolaou-destained specimens. Positive hybridization was found with intense staining for the HSV DNA in the nuclei of cells having a ground-glass appearance. Cytologic observation together with ISH procedure may be rapid and valuable tool for the detection and final demonstration of HSV infections. Similar investigations may be carried out in cellular samples from other body sites.

Comparison of immunocytochemistry and in situ hybridization in the cytodiagnosis of genital herpetic infection

Over a 62-month period, 53 patients were found to have cervicovaginal smears that contained cells consistent with, or equivocal cells for, a herpes simplex virus (HSV) infection. The Papanicolaou-destained smears from these cases were restrained in situ hybridization (ISH) with a biotinylated cloned DNA probe and immunocytochemistry (ICC) assay and were compared for the detection of HSV in cervicovaginal smears by two methods. Cytological findings classified the 53 slides into two groups, i.e., cytologically herpes positive (33 patients) and equivocal cases (20 patients). Each group was subdivided into two groups: group A was confirmed by ICC, and group B was confirmed by ISH technique. Of the 33 cellular samples containing cells considered to be consistent with a herpes infection, 15 (88%) of 17 were positive by means of ICC technique (group A), 6 (43%) of 14 were positive by ISH technique (group B). Of the 20 smears showing equivocal cell changes thought unlikely to be caused by an HSV infection, 6 (60%) of 10 were positive by ICC (group A), 2 (29%) of 7 were positive by ISH (group B). With the ISH technique, five smears showed dislodged cells from glass slides due to enzyme treatment and denaturation. The results revealed that the ICC technique is a rapid and reliable procedure and thus recommended for routine diagnosis of HSV infection. Moreover, ICC is easier to perform and interpret and is less expensive than ISH. Therefore, the ICC may be preferable to ISH for detecting HSV in routine Papanicolaou diagnostic work.