[Chronic natural killer cell lymphocytosis: eight cases report and literature review].

Objective: To identify the characteristics of chronic natural killer cell lymphocytosis (CNKL).
Methods: The clinical data of eight cases defined by the World Health Organization classification was retrospectively analyzed and related literatures were reviewed.
Results: Half of the 8 patients were asymptomatic. Among them, the most common abnormalities were leukocytosis with the median of 11.8(4.5-20.0)×10⁹/L and high proportion of lymphocytes [0.78(0.51-0.89)], while anemia and thrombocytopenia only in 1 patient respectively. The absolute CD3⁻CD16⁺ NK cell count with the median of 5.7(2.4-9.6)×10⁹/L increased in peripheral blood. By the end of follow-up, except one case was lost, the other seven patients were in stable condition,including four cases without any medications and three patients receiving chlorambucil or glucocorticoid.
Conclusion: As an indolent chronic lymphoproliferative disease, CNKL was presented with mild clinical symptoms and increased number of CD3⁻CD16⁺ NK cells in peripheral blood. Patients with symptoms could be treated with immunosuppressive therapy while those asymptomatic could be followed up without intervention.