[Neutrophil mobilization test with intravenous hydrocortisone in the study of chronic idiopathic neutropenias. Experience with 19 cases and usefulness of a new diagnostic index]. / Prueba de movilización de los neutrófilos con hidrocortisona intravenosa en el estudio de las neutropenias crónicas idiopáticas. Experiencia en 19 casos y utilidad de un nuevo índice diagnóstico.

ABSTRACT

BACKGROUND: Some patients with chronic benign neutropenia present granulocytes distribution disorders within their different physiologic pools, and this situation can be exposed by granulocyte mobilization tests. Stimulation with hydrocortisone is the best known test, but its performance and interpretation are not well standardized. Granulocyte mobilization test with hydrocortisone was performed in 19 patients with chronic peripheral idiopathic granulocytopenia, by applying homogeneous criteria. PATIENTS AND METHOD: The test included an injection of intravenous hydrocortisone 200 mg after a first basal blood neutrophil determination, and a second neutrophil count four hours after steroid administration. Following data were registered basal blood neutrophil count (BNC), final blood neutrophil count (FNC), difference between both counts or increment (INCR), and the ratio = 60% of INCR/2.0 (109/1) BNC, which we name demargination index (DI). RESULTS: Three response patterns (three patient groups) were observed pattern I, with FNC > 2.0 109/1 and DI >/= 1 (false neutropenia with hypermargination component); pattern II, with FNC > 2.0 (109/1) and DI < 1 (false neutropenia with pathogenic mechanisms others than hypermargination), and pattern III, with FNC < 2.0 (109/1) and DI < 1 (true neutropenia). There were no significant differences in BNC or INCR when groups I and II were compared, but we found differences in FNC (p = 0.026) and DI (p = 0.026). Comparison between groups I and III showed differences in all four parameters (BNC P = 0.07, FNC p < 0.001, INCR p = 0.02, and DI p < 0.001). No differences were found between groups II and III. CONCLUSIONS: Granulocyte mobilization test with intravenous hydrocortisone 200 mg and a four-hours interval between basal and final neutrophil counts, allows differentiation between false neutropenia with hypermargination component and true neutropenia.