[The functional activity of the natural killers in patients with infectious mononucleosis and other viral infections].

The natural killer activity (NKA) and content of large granule-containing lymphocytes (LGL) were determined in 50 patients with infectious mononucleosis and in 36 patients with other viral infections. Results indicate that in 27 of 50 patients with infectious mononucleosis the number of LGL was less than 5% or equalled O. In 12 patients with infectious mononucleosis the number of LGL was 5% and in 11 children it was 5-20%. In children with different viral infections not related to the Epstein-Barr virus the number of LGL was below normal values. The NKA corresponded to the quantitative indices of LGL as well as the severity of the clinical condition.