M. m., aged 22, consults urgently due to asthenia associated with a fever of 39°C that has been going on for 72 hours. he complains of odynophagia and diffuse myalgia. On clinical examination, you find cervical lymphadenopathy and splenomegaly across a finger. A blood test was carried out in town and shows the following results: hemoglobin 13.2 g/dl, vgm 89 fl, platelets 120 g/l, leukocytes 10.6 g/l, neutrophils 1.6 g/l, basophils 0.1 g/l, eosinophils 0.4 g/l, lymphocytes 8 g /l, monocytes 0.5 g/l. blood smear: presence of numerous large lymphocytes with hyper-basophilic cytoplasm. Among the following additional examinations, which one (or which ones) do you think should be carried out as first intention in this clinical context?
Myelogram
Lymphocyte immunophenotyping
p24 antigenemia
Mni test
Cytomegalovirus (cmv) serology