Characterization of the atypical lymphocytes in African swine fever

AIM: Atypical lymphocytes usually described as lymphocytes with altered shape, increased DNA amount, and larger size. For analysis of cause of genesis and source of atypical lymphocytes during African swine fever virus (ASFV) infection, bone marrow, peripheral blood, and in vitro model were investigated. MATERIALS AND METHODS: Atypical lymphocytes under the influence of ASFV were studied for morphologic, cytophotometric, and membrane surface marker characteristics and were used in vivo and in vitro models. RESULTS: This study indicated the increased size, high metabolic activity, and the presence of additional DNA amount in atypical lymphocytes caused by ASFV infection. Furthermore, in atypical lymphocytes, nuclear-cytoplasmic ratio usually decreased, compared to normal lymphocytes. In morphology, they looking like lymphocytes transformed into blasts by exposure to mitogens or antigens in vitro. They vary in morphologic detail, but most of them are CD2 positive. CONCLUSIONS: Our data suggest that atypical lymphocytes may represent an unusual and specific cellular response to ASFV infection.