Cytospin-enhanced direct immunofluorescence assay versus cell culture for detection of herpes simplex virus in clinical specimens

Update on oral herpes virus infections

Oral herpes virus infections (OHVIs) are among the most common mucosal disorders encountered by oral health care providers. These infections can affect individuals at any age, from infants to the elderly, and may cause significant pain and dysfunction. Immunosuppressed patients may be at increased risk for serious and potential life-threatening complications caused by OHVIs. Clinicians may have difficulty in diagnosing these infections because they can mimic other conditions of the oral mucosa. This article provides oral health care providers with clinically relevant information regarding etiopathogenesis, diagnosis, and management of OHVIs.

Continual collection and re-separation of circulating tumor cells from blood using multi-stage multi-orifice flow fractionation

Circulating tumor cells (CTCs) are highly correlated with the invasive behavior of cancer; as such, the ability to isolate and quantify CTCs is of great biomedical importance. This research presents a multi-stage multi-orifice flow fractionation (MS-MOFF) device formed by combining three single-stage multi-orifice segments designed for separating breast cancer cells from blood. The structure and dimensions of the MS-MOFF were determined by hydrodynamic principles to have consistent Reynolds numbers (Re) at each multi-orifice segment. From this device, we achieved improved separation efficiency by collecting and re-separating non-selected target cells in comparison with the single-stage multi-orifice flow fractionation (SS-MOFF). The recovery of breast cancer cells increased from 88.8% to greater than 98.9% through the multi-stage multi-orifice segments. This device can be utilized to isolate rare cells from human blood, such as CTCs, in a label-free manner solely through the use of hydrodynamic forces.

Continuous separation of breast cancer cells from blood samples using multi-orifice flow fractionation (MOFF) and dielectrophoresis (DEP)

Circulating tumor cells (CTCs) are highly correlated with the invasive behavior of cancer, so their isolations and quantifications are important for biomedical applications such as cancer prognosis and measuring the responses to drug treatments. In this paper, we present the development of a microfluidic device for the separation of CTCs from blood cells based on the physical properties of cells. For use as a CTC model, we successfully separated human breast cancer cells (MCF-7) from a spiked blood cell sample by combining multi-orifice flow fractionation (MOFF) and dielectrophoretic (DEP) cell separation technique. Hydrodynamic separation takes advantage of the massive and high-throughput filtration of blood cells as it can accommodate a very high flow rate. DEP separation plays a role in precise post-processing to enhance the efficiency of the separation. The serial combination of these two different sorting techniques enabled high-speed continuous flow-through separation without labeling. We observed up to a 162-fold increase in MCF-7 cells at a 126 µL min(-1) flow rate. Red and white blood cells were efficiently removed with separation efficiencies of 99.24% and 94.23% respectively. Therefore, we suggest that our system could be used for separation and detection of CTCs from blood cells for biomedical applications.

Oral herpetic infections (HSV 1-8)

Oral herpes virus infections are commonly seen by the dental practitioner. Saliva is a reservoir for the herpes virus, and a variety of infections, both localized and systemic, may be induced by the virus. Patients who are immunocompromised may be at risk for serious and potentially life-threatening complications of herpes virus infections. This article highlights the basic virology and clinical manifestations of herpetic infections and the differential diagnosis and management of oral herpes virus infections.

Detection and differentiation of herpes simplex virus types 1 and 2 by a duplex LightCycler PCR that incorporates an internal control PCR reaction

BACKGROUND

In recent years polymerase chain reaction (PCR) has proven to be a highly sensitive and specific method for the diagnosis of herpes simplex virus (HSV) infections. The advent of real-time HSV PCR protocols now enables rapid result turnaround times with minimal hands-on time.

OBJECTIVES

In this study, we developed a real-time duplex PCR assay (HSVgD-dPCR) comprising of HSV and internal control PCR reactions.

STUDY DESIGN

Using the LightCycler, the HSVgD-dPCR targeted the HSV glycoprotein D gene and HSV typing was performed by melting curve analysis. The internal control PCR reaction targeted sequences of the DNA of the human endogenous retrovirus (ERV-3). In total, 300 swab specimens, from patients with suspected HSV infection, were tested by the HSVgD-dPCR assay. The results were then compared to the results obtained by another HSV LightCycler assay, which utilized published primer and probe sequences targeting the HSV DNA polymerase gene (Dpol-HSV-LCPCR).

RESULTS

Overall, 91 (30.3%) specimens were positive and 204 (68.0%) specimens were negative for HSV by both LightCycler assays. In addition, four (1.3%) specimens were positive by Dpol-HSV-LCPCR and negative by HSVgD-dPCR, whereas one (0.3%) specimen was positive by HSVgD-dPCR and negative by Dpol-HSV-LCPCR. The presence of HSV in these five specimens was confirmed by conventional PCR. Melting curve analysis by the HSVgD-dPCR assay enabled all HSV positive specimens to be typed, whereas sequence variation prevented three HSV positive specimens from being typed by the Dpol-HSV-LCPCR. Using the ERV-3 PCR, 5% specimens were found to contain inhibitory substances.

CONCLUSIONS

By developing the HSVgD-dPCR we have enhanced the diagnostic utility of real-time detection of HSV by incorporating an internal control reaction and by accurately typing a greater proportion of HSV positive specimens.

Update on herpesvirus infections

Herpesviruses are responsible for many illnesses that affect the oral and maxillofacial region. The most common of these are primary or recurrent HSV infection, but knowledge of the manifestations of the eight herpesviruses that cause infections in humans will provide clinicians with a better understanding and basis for diagnosing and managing patients with these diseases. Immunocompromised patients are at greater risk for serious illness: therefore, clinicians treating transplant patients, patients receiving cancer chemotherapy, or HIV-infected individuals should be aware of the various clinical manifestations of infection with herpesviruses.

Detection of cutaneous herpes simplex virus infections by immunofluorescence vs. PCR

BACKGROUND

Detection of cutaneous infections with herpes simplex virus (HSV) has proven difficult, as serum antibody tests sometimes are not sensitive and specific enough for that purpose.

OBJECTIVE

This study was conducted to compare the sensitivity for detection of HSV of an immunofluorescence method (Syva Microtrak) and an internally controlled PCR.

METHODS

Cutaneous swabs from skin lesions were analysed by immunofluorescence separately for HSV types 1 and 2 and by competitive PCR. Detection of PCR products was done by ELISA, if positive additionally by agarose gel electrophoresis.

RESULTS

Of 79 samples 34 were PCR-positive by ELISA (34 = 100%), of which 23 (68%) were also positive on the agarose gel. Eleven samples (32%) were positive by immunofluorescence. No sample was positive by immunofluorescence and negative by PCR.

CONCLUSIONS

These results demonstrate that immunofluorescence using Syva Microtrak is not suitable for exclusion of herpes simplex virus infection as sensitivity was only 32%. However, as immunofluorescence is cheaper and faster than PCR, first screening can be done with immunofluorescence, and negative samples can be investigated by PCR to finally prove or exclude the presence of HSV DNA.