The evaluation of neutropenia: the use of the granulocyte mobilization test

Effect of circadian variation on neutrophil mobilization to the peripheral blood in benign constitutional neutropenia

Benign constitutional neutropenia (BCN) is an asymptomatic condition characterized by mild chronic neutropenia in patients with no history of recurrent infections. Most patients are referred for further testing, increasing health care costs. We present an alternative form of assessment of individuals with BCN based on neutrophil circadian variation. The objective of this study was to evaluate whether circadian variations of neutrophil counts would result in neutrophil values higher than neutropenia threshold in individuals with BCN. Absolute neutrophil counts (ANCs) were evaluated in 102 patients with BCN (<1500 cells/μL) and 60 age- and sex-matched controls. Paired blood counts were performed in the early morning and in the early afternoon. We observed a significant difference between morning and afternoon ANC in BCN patients (879 cells/μL, 95% CI 745-1028, p < 0.001), as well as in the controls (619 cells/μL, 95% CI 443-796, p < 0.001). The ANC increase between the two evaluations was significantly greater in BCN patients compared with controls: 83% and 27%, respectively (p < 0.001). The ANC increment was higher in the groups with a lower morning ANC: 105%, 63%, and 27% in the <1000, 1000-1500, and >1500 cells/μL groups, respectively (p < 0.001). Of all BCN patients, 73% presented with >1500 cells/μL in the afternoon and 16% improved from the <1000 cells/μL to the 1000-1500 cells/μL category. In conclusion, neutrophil circadian variation measurement allows many BCN patients to be excluded from the neutropenia threshold. We identified a simple, easy, and feasible way to assess neutrophil reserve in patients with BCN with a potential reduction in costs of the assessment.

[Neutrophil mobilization test with intravenous hydrocortisone in the study of chronic idiopathic neutropenias. Experience with 19 cases and usefulness of a new diagnostic index]

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.

Two cases of autoimmune neutropenia possibly induced by beta-lactam antibiotics in infants

This report describes two infants who had neutropenia develop after treatment with beta-lactam antibiotics. The first patient, a 9-month-old girl, was administered flomoxef (FMOX); the second patient, a 14-month-old boy, was administered cefotiam (CTM). Both infants were found to have neutropenia 4 to 5 days after they were placed on respective antibiotics, and neutropenia had persisted despite antibiotics withdrawal for 1 to 3 months. Drug-induced lymphocyte stimulation test (DLST), granulocyte-bound antibodies, serum granulocyte antibodies, and immunoblotting analysis indicated that beta-lactam antibiotics possibly triggered production of granulocyte autoantibody with resultant autoimmune neutropenia.

Effect of aprotinin on neutrophil function after major vascular surgery

High-dose aprotinin reduces blood loss and blood transfusion requirements during liver transplantation and cardiac and vascular surgery. The mechanism of the haemostatic effect of aprotinin is unclear. A general effect on the anti-inflammatory response may be involved. Because leucocyte activation is part of this process, white cell function was measured in patients undergoing aortic surgery who received high-dose aprotinin therapy (n = 10) and was compared with the results from controls who did not (n = 10). The test group received an intravenous bolus (2 x 10(6) kallikrein inhibitor units) of aprotinin after induction of anaesthesia followed by continuous infusion (0.5 x 10(6) kallikrein inhibitor units/h) until the end of the operation. Blood samples were obtained before operation, immediately after surgery, and 1 and 7 days after operation. Aprotinin maintained significantly better postoperative white cell function as measured by bipolar shape formation (P less than 0.001), unstimulated nitroblue tetrazolium (NBT) reduction (P less than 0.001) and chemotaxis (P less than 0.001). Endotoxin-stimulated NBT reduction was similar in both groups, indicating that neutrophils from treated individuals retained the capacity to respond to oxidative stimuli. Aortic surgery activates neutrophils in vivo, as reflected by impaired chemotaxis and increased superoxide production. Aprotinin protects the cells against this potentially deleterious effect without affecting their ability to respond when provoked. Whether this affects leucocyte interaction with coagulation pathways and contributes to the reduction in blood loss remains to be determined.

Evaluation and comparison of neutrophil bipolar shape formation with a migration assay

The neutrophil shape change response to a chemotactic formylpeptide was assessed. Neutrophil bipolar shape formation (BSF) was also simultaneously assessed with a Boyden chamber-based neutrophil migration assay. Both assays were precise and relatively reproducible; the average coefficient of variation for the BSF assay was 9.6% and 9.2% for the migration assay. In a blind study the BSF assay showed 100% sensitivity at detecting subjects with known abnormal neutrophil migration. Unlike the migration assay, the BSF assay does not require isolated neutrophils, reducing possible cell activation and monitoring the cell response under more physiological conditions. Small blood samples--1 ml or less compared with 20-40 ml for the migration assay--are used, and the method is technically simple. Results are available within 40 minutes, and routine (EDTA) blood samples are used. It is concluded that the BSF assay is a suitable motility screening test for both the clinical and pharmacological examination of the movement of polymorphonuclear leucocytes.

Bone marrow granulocyte reserve in chronic benign idiopathic neutropenia

Fifteen patients with chronic benign idiopathic neutropenia (CBIN) with neutrophil counts less than 1.0 X 10(9)/1 have been studied. The mean age was 33 years (range 23-50) comprising 11 females and 4 males. Bone marrow cellularity was normal except in two patients who showed slight reduction and one who had a slight increase. Bone marrow differential counts were normal apart from a small increase in the percentage of promyelocytes and reduction in the myeloid/erythroid ratio in some patients. Peripheral blood counts showed no 'compensatory' monocytosis. Epinephrine stimulation tests showed no evidence of excess neutrophil margination. After endotoxin administration there was a one- to two-fold increase in neutrophil counts in three patients, a three-fold increase in three patients and a greater than four-fold increase in the remaining nine patients. The findings suggest that the benign course of CBIN is not due to excess neutrophil margination nor to compensatory monocytosis, but that at least one mechanism includes a functionally adequate release of neutrophils to the peripheral blood under conditions of stress with subnormal delivery of neutrophils under basal conditions. The variability in responses to endotoxin suggests that CBIN is not entirely homogeneous with respect to mechanism. The findings of relatively normal bone marrow cellularity and differential counts and a normal or substantial neutrophil response to endotoxin appear characteristic. They may help predict a benign clinical course in neutropenic patients and assist diagnosis of the CBIN variant of idiopathic neutropenia.