[Evaluation of marrow neutrophilic reserve in normal subjects and aplastic anemia patients]

The widespread use of potent marrow suppressing drugs in malignant diseases has gained increasing importance in the functional assessment of neutrophil system. A peripheral neutrophil count of 500 cells/cumm is considered to be a good indicator of risk of bacterial infection. However, despite extreme neutropenia, infection is rare in chronic benign neutropenia patients. It may be presumed that adequate marrow reserve delivers mature neutrophil during bacterial infection in these patients. Currently available methods such as determination of blood neutrophil concentration, differential counts, estimation of bone marrow cellularity provide a relatively crude estimates of the functional capacity of the neutrophil system. The use of endotoxin, etiocholanolone and steroids have been introduced to determine the marrow neutrophil reserve with greater accuracy. In this study, intravenous hydrocortisone 100 mg was used to evaluate marrow neutrophilic reserve in normal and aplastic anemia subjects. The results showed significant statistical differences (P less than 0.001) between controls and aplastic subjects in 2, 3, 4 and 5th hour groups after steroid injection. The sensitivity and specificity occurring 3 and 4 hours after steroid injection were 78.6% and 100%, respectively. The normal marrow neutrophilic reserve showed more than 1198/cumm of increment neutrophilic counts 4 hours after steroid injection. No complication was found. The present finding suggests that steroid may be useful as an accurate evaluator of marrow neutrophilic reserve.