The effect of T cells from patients with infectious mononucleosis on CFU-CGM proliferation: a preliminary report

The neutropenia occurring during infection is a poorly understood phenomenon. Immunologically-stimulated T lymphocytes, acting upon normal bone marrow stem cells, have been etiologically implicated in several disorders. Fifteen patients, ages 17 to 25 years, and diagnosed with infectious mononucleosis by positive heterophile titers, were studied. Peripheral blood T lymphocytes were separated using sheep red blood cell rosetting. They were then cocultured with normal bone marrow cells, in a concentration of 2 X 10(4) cells/ml, in methylcellulose containing 10% colony-stimulating activity. Normal BM was obtained from patients with nonmalignant hematologic disorders, or leukemia in remission. Bone marrow cells were cultured at a concentration of 1 X 10(5) or 5 X 10(5) cells/ml, alone (control) or with T lymphocytes. Plates were incubated at 37 degrees C with 5% CO2. Colonies were scored at 14 days. Inhibition of normal, bone marrow growth was observed at both concentrations, after addition of T lymphocytes to the culture system. Such suppression was significant (p less than 0.05) for the lower concentration of normal bone marrow cells only. Variable and partial abrogation of effect was seen after overnight incubation of T lymphocytes, possibly due to loss of suppressor activity. There were insufficient numbers of tests with supernatant to allow computation of statistical significance. Correlation between T-cell ratios and suppressive effect has not been determined, although it is suspected that the responsible cells are within the T-suppressor fraction.