Infectious disease requests to the IHC laboratory are on the increase for diagnosis of opportunistic infections. This is due to the increased population of immunocompromised patients, organ transplant recipients, human immunodeficiency virus (HIV) patients, and cancer patients undergoing chemotherapy.
The use of rapid and accurate IHC techniques to identify infectious entities such as viruses, bacteria, and protozoans on formalin-fixed, paraffin-embedded (FFPE) human tissue sections are a very important part of the clinical contribution and patient care provided for our patients and pathologists. The ability to set up, trouble shoot, and identify proper reactions at the microscope will aid immunohistochemists and directly impact patient care and treatment.
When performing microtomy on small tissue biopsy specimens submitted for viral and infectious disease IHC, it is very important to place multiple sections on each slide. It is not uncommon for laboratories to run two slides with multiple sections for each antibody. For example, in cytomegalovirus (CMV) and adenovirus (ADV) cases where there is only one positive cell, this method will help to positively identify the cell in subsequent sections. Both monoclonal and polyclonal antibodies can be used for detection of infectious diseases.
With the common use of heat-induced epitope retrieval (HIER) pretreatment techniques, there is the potential for non-specific avidin and biotin background staining to be present in certain tissue sections, such as liver and kidney, when using biotin containing detection methods. Non-biotin labeled polymer detection systems have become the norm and should be used whenever possible to eliminate this potential problem.