Occurrence of Antibodies Cross-reacting With Autoantigens in Primary EBV Infection

Inclusion criteria

Participants fulfilling all of the following inclusion criteria are eligible for the infectious mononucleosis (IM) group: • Informed consent as documented by signature • Confirmed primary EBV infection as confirmed by the treating clinician and defined by: • Compatible clinical (infectious mononucleosis symptoms including but not limited to malaise, headache, fever, tonsillitis, pharyngitis, cervical lymph nodes enlargement) and laboratory picture (lymphocyte count elevation, LUC cells, reactive lymphocytes in manual differential, elevated liver enzymes; of note, not all typically described features have to be fulfilled) AND • serology compatible with primary EBV infection (anti-EBNA IgG negative, anti-VCA IgG negative, anti-VCA IgM positive OR anti-EBNA IgG negative, anti-VCA IgG positive, anti- VCA IgM positive). Participants fulfilling all of the following inclusion criteria will be eligible for the control group: • Informed consent as documented by signature. • one of the following: 1. Clinical picture of upper respiratory tract infection (including but not limited to tonsillitis/pharyngitis, malaise, headache, cough, rhinitis, cervical node enlargement) 2. confirmed primary Cytomegalovirus (CMV) infection (an optimal control group; however, the number of patients with a diagnosis of primary CMV infection is limited).