Infectious Mononucleosis and others acute infections (by CMV, Toxoplasma; Hepatitis, HH6, HIV1/2 viruses; others) are characterized by a proliferation of activated CD8+ cytotoxic-suppressor T lymphocytes. These lymphocytes have a peculiar morphology that can help the diagnosis. In your opinion, the quantification of these (i.e. 5%, 10%; 13% ...) can increase the quality of diagnostic information than the simple description (some, many.... activated lymphocytes)? Or it can be sufficient to report: " presence of activated lymphocytes"?
Dear Antonio,
for the diagnosis of IM is important the phyical examination to assess the presence of lymphadenopaties and splenomegaly. It is also important to rule out other diseases like HIV 1. In the CBC is important to check the number of leukocytes and platelets and the levels of Hb. If you report "presence of activated lymphocytes" I think is fine. But always make sure this are not blast cells.
For the diagnosis of IM you can do serological testing as well.
Hope it helps.
Dear Antonio,
In my lab, we routinely report the percentage of activated lymphocytes by morphology, but there is no correlation between this percentage and severity of disease or its prognosis. Therefore, in a person with clinically diagnosed IM (and/or presence of anti-EBV antibodies), it would probably be more than fine just to note that activated lymphocytes are present.
However, there are atypical EBV infections associated with several known types of primary immunodeficiency. When there is a clinically grounded suspicion this may be the case, I would say that enumeration of activated T cells (as well as other types of lymphocytes) by flow cytometry would be in order. First of all, I would go for SAP and XIAP expression, and this can be reliably determined provided that one possesses fluorochrome-labeled monoclonal antibodies against these molecules.
Thanks Ricardo and Srdja. I agree with you: when the clinical features are typical or suggestive for infectious mononucleosis, it is adequate to report the "activated lymphocytes presence". In addition, I think that in these cases, the EBV serology can be omitted.