Cytological recognition of herpes simplex virus infection in bronchoscopic samples from the respiratory tract

Abstract

Case Histories Patient oneAn elderly patient was admitted directly to the intensive care unit with a diagnosis of community-acquired pneumonia (CAP) and sepsis. He was intubated and bronchial washings were obtained to investigate the underlying cause for the pneumonia. These were composed predominantly of neutrophils, macrophages and respira-tory epithelial cells with associated inflammatory debris. A population of scattered cells, some of which were multinucleated with nuclear clearing and occasional nuclear inclusions were identified, features highly suggestive of herpes simplex virus (HSV) infection (Figure 1).Of the sample, 200 µl was subjected to nucleic acid extraction via the DNA Mini Kit (Qiagen Ltd, Crawley, UK). Briefly, this method involves enzymatic digestion using proteinase K and purification through silica columns. Deoxyribonucleic acid was eluted in 200 µl of molecular grade water and stored at -20ºC pending polymerase chain reaction (PCR). A multiplex PCR was performed on the nucleic acid extracts using the method described by Aurelius et al., 1,2 which identifies the GpD and GpG gene targets for HSV 1 and 2. Positivity was discerned by a band of the correct size being visualised via agarose gel electrophoresis -HSV 1 and 2 amplicon sizes being 101 nt and 145 nt respectively. The presence of HSV 1 was confirmed (Figure 2). Cytological recognition of herpes simplex virus infection in bronchoscopic samples from the respiratory tractaBstraCt Cytological features suggesting herpes simplex virus (HSV) infection in samples obtained at bronchoscopy have been described only very rarely in routinely processed samples. We report four cases where evidence of HSV infection was identified morphologically in samples processed using thin-layer techniques, with polymerase chain reaction confirmation of the presence of virus in three cases. We suggest that the increased morphological clarity provided by this technique for processing these cytology samples may result in the morphological features of viral infection being seen more frequently. Pathologists reporting such samples need to be aware of this possibility in order to avoid potential misinterpretations. In addition, however, respiratory and intensive care physicians unused to receiving cytology reports indicating 'HSV infection' need to be aware that the significance is uncertain and in most cases it is likely to indicate the reactivation of a latent infection.

HSV-pneumonitis in a patient with lung cancer receiving check point inhibitors – a case report

“…Proof of HSV infection can be provided by histopathological or cytological examination of infected tissue showing a typical cytopathic effect [ 12 ]. As in our case cytological workup showed unequivocal confirmation of HSV-infection and immunocytochemical staining further confirmed diagnosis.…”

“…The presence of viral inclusions leads to a loss of chromatin pattern and the nuclei are observed to take on an empty homogenized or ‘ground glass’ appearance with a prominent nuclear membrane, also known as Cowdry type B nuclei [ 14 , 15 ]. Strongly eosinophilic inclusions develop in the nucleus known as Cowdry type A inclusions, which are often wedge-shaped or triangular and can appear refractile later during the infective process Cowdry bodies are characteristic but non-specific for HSV [ 12 , 16 ]. The typical findings in cytology and positive PCR confirmed HSV-1 infection in our patient with the clinical diagnoses of tracheobronchitis and pneumonitis.…”