The inhibitory effect of circulating lymphocytes on granulopoiesis in human cyclic neutropenia in vitro.

The effect of peripheral mononuclear cells (MNCs), lymphocytes and sera of a patient with typical cyclic neutropenia (CN) upon the normal colony forming unit in culture (CFU-C) growth was examined. MNCs and lymphocytes obtained during the recovery phase of the cycles inhibited CFU-C growth. In contrast, these cells obtained during the neutropenic phase revealed no suppressive effect. Serum inhibitors of granulopoiesis were not detected at any time during the cycle. These findings suggest that MNCs, especially lymphocytes, may be one of the contributory factors for the development of CN in this case.