Atypical mononuclear cells are one of the parameters describing a cell population. And if the basophilic mononuclear variant is characteristic of every person, then mononuclears of an atypical form are no longer characteristic of humans or animals. In other words, you are unlikely to find them in the clinical picture of common diseases. They are formed only as a result of serious deviations from the immune system. As a rule, mononucleocytes of atypical appearance are associated conditions. This means that they appear in blood tests and other tests as an additional, and not the main sign. The phenomenon of atypical mononuclear cells occurs in the presence of infections or inflammatory processes in the body in an adult or child