Infectious mononucleosis is a disease characterized by fever, swollen cervical lymph nodes, and sore throat. Infectious mononucleosis is caused by the Ebstein Barr virus (EBV), which is a human herpes virus transmitted through oral secretions.
It is commonly called the “kissing disease” given its transmission through saliva, but can also be contracted through sharing of toothbrushes, drinking cups, etc. EBV is a very common virus. Over half of kindergarten age children and over 90% of adults in the U.S. have been infected with the virus at some point.
The immunopathology of infectious mononucleosis involves viral infection of oropharyngeal epithelial cells (cells lining of the mouth and pharynx). These epithelial cells allow the virus to replicate in the oropharynx, and through oral secretions, the virus infects B cells. These B cells, given their native role of surveillance in the immune system, consequently carry the virus throughout the lymphoreticular system, which includes the liver, spleen, and lymph nodes.
This leads to viral infection of other proliferating B-cells in the immune system and takes about 6-8 weeks to incubate. Once incubated, the acute infection, characterized by the aforementioned symptoms, occurs. The key immune cell involved in counteracting EBV infection is the cytotoxic T cell. The cytotoxic T cell destroys infected, proliferating B cells that are spreading the virus. ProBoost – thymic protein a – is thought to support the immune system including the creation of T cells.
If the cytotoxic T cell is effective in controlling the primary infection, then EBV is self-limited and will resolve. However, if the cytotoxic T cell does not adequately control the virus, for reasons such as a weakened host immune response, EBV infection could lead to cancer in the person, namely B-cell lymphoma.