Cyclic oscillations of neutrophils, monocytes, and CD8-positive lymphocytes in a healthy subject.

Sir, Hematopoiesis has been suggested to show a cyclic behavior under both normal and pathologic conditions,1-3 although other studies have not confirmed such a hypothesis.4,5 We report a peculiar case characterized by cyclic oscillations of neutrophils, monocytes and CD8+ lymphocytes in an asymptomatic subject. These findings suggest the existence of periodic hematopoiesis with a clinical expression intermediate between normality and the pathologic features which characterize cyclic neutropenia (CN).6 A 21-year old male presented with asymptomatic, intermittent neutropenia, (neutrophils 1-1.2 109/L in some blood samples). During our first observation, hematologic parameters were: Hb 15.1 g/dL; Hct 44.3%; MCV 86 fL; PLT 179 109/L; WBC 3.7 109/L; neutrophils 1.47 109/L; lymphocytes 1.75 109/L; monocytes 0.27 109/L; eosinophils 0.11 109/L; basophils 0.02 109/L; LUC 0.12 109/L. May-Grünwald-Giemsa stained neutrophils showed normal morphology. The known causes of neutropenia,7 including anti-neutrophil antibodies, were excluded. Bone marrow aspiration, carried out during the first observation, revealed normal hematopoiesis and karyotype. Consent to repeat other bone marrow aspirations was not given. The subject had no brothers or sisters, and his parents did not have blood abnormalities. Blood cell counts were performed twice a week6 for 64 days; then our observation was continued for another 56 days to complete a 120-day follow-up. We found 5 episodes of neutropenia (neutrophils < 1.5 109/L), with approximately 22-day intervals (Figure 1A); nadir values ranged between 1.0-1.2 109/L. Six episodes of monocytopenia (< 0.3 109/L) were detected (Figure 1A). scientific correspondence 447