Transient stress lymphocytosis during crisis of sickle cell anemia and emergency trauma and medical conditions. An immunophenotyping study.

Transient absolute lymphocytosis of peripheral blood has been described in "stress"-related emergency trauma and medical conditions. There are no reports of this phenomenon in patients with sickle cell anemia with vaso-occlusive crisis. We studied initial and follow-up immunophenotypic characteristics of 10 adult patients with sickle cell anemia in crisis and 15 adult patients with emergency conditions who presented with absolute lymphocytosis. On admission, both groups demonstrated increases in the numbers of CD20+ B cells and T cells of the CD2, CD4, CD8, and CD56 (NKH-1) phenotypes compared with control values. Findings in both groups of patients mimicked the results of parenteral epinephrine administration: a pan-B and -T lymphocytosis with marked increase in CD56 (fourfold to fivefold) and CD8 cells (threefold to fourfold) as well as moderate increases in CD20 and CD4 cells (twofold), resulting in a decrease in the CD4/CD8 ratio compared with control values. In patients with sickle cell anemia, there was an expected increase in the CD56 and CD4 populations; however, CD8 cells only doubled at the time of crisis. Therefore, the CD4/CD8 ratio was normal compared with control values. CD20+ B cell numbers exceeded those seen in the patients with medical and trauma emergencies. Elevated corticosteroid levels have been measured after injury in previous studies. Parenterally administered cortisol produces a lymphocytopenia after 4 to 6 hours that selectively decreases T cells. At 10 to 38 hours after admission, there was a marked reduction in the number of T cells in both groups of "stressed" patients, probably reflecting at least partial effects of endogenous corticosteroids. In contrast to the patients with medical and trauma emergencies, the mean lymphocyte count in the patients with sickle cell anemia remained elevated in the "high normal" range and consisted of increased numbers of B cells and CD4 cells. This finding persisted in the patients with sickle cell anemia for up to 3 months after presentation. The lymphocyte responses in both groups probably reflect interactions between adrenergic and steroidal factors.