|From:||Bryan Hewlett |
Sometimes, nuclear immunoreactivity is seen in sections incubated with antibodies against non-nuclear antigens.
If this anomalous nuclear staining is not present in the negative control section, such staining is often ignored or attributed to poor fixation.
Occasionally, such staining is present in the negative control. Again, this finding is often ignored.
However, if the primary antibody is directed against a nuclear antigen and staining is observed in the negative control, then difficulty in interpretation will ensue.
Oxidative damage of DNA can produce the oxidized nucleoside 8-oxodeoxyguanosine and the oxidatively modified base, 8-oxoguanine. Avidin and streptavidin have both been shown to bind with high specificity to these oxidation products1. This reaction has been proposed as an indicator of apoptotic DNA damage.
Use of a HIER pre-treatment may reveal this reaction when it is not present in untreated sections.
This reaction first came to our attention about six years ago, while staining sections of placenta for CMV. At that time we were unaware of the cause however, a fortuitous testing of a new non avidin/biotin detection system remedied the problem. We have seen this reaction a number of times since, particularly in placenta, endometrium, kidney and some tumours. When such staining is seen, we switch to a non-avidin/biotin detection system.
REFERENCE 1. Struthers
L, Patel R, Clark J, Thomas S. Direct detection of 8-oxodeoxyguanosine and
8-oxoguanine by avidin and its analogues. Analytical Biochemistry 1998; 255: 20
1. Struthers L, Patel R, Clark J, Thomas S. Direct detection of 8-oxodeoxyguanosine and 8-oxoguanine by avidin and its analogues. Analytical Biochemistry 1998; 255: 20 -31.
----- Original Message -----From: Joe NocitoTo: HistonetSent: Monday, June 02, 2003 11:27 AMSubject: CD45 nuclear stainingGreetings Histoland,I am perplexed. We have a squamous cell carcinoma case (poorly differentiated) that was CK 5/6 positive, p63 nuclear positive staining and CD45 nuclear positive staining.The background lymphocytes are staining membranous, but the tumor cells are staining positive in the nucleus. I've never seen CD45 stain nuclear in the18 + years I've been doing this. Not even at the AFIP did see this type of staining. The tonsil control stained like it should. Does anyone have an answer to this? Thanks in advance.Joe Nocito, BS, HT (ASCP) QIHC
Pathology Reference Lab
San Antonio, TX