The inflammation meter: novel technology to detect the presence of infection/inflammation in patients without leukocytosis but with increased leukocyte adhesiveness/aggregation.

OBJECTIVES: To reveal the presence of infection/inflammation in patients with relatively normal white blood cell count (WBCC) by using the leukocyte adhesiveness/aggregation test (LAAT).

METHODS: The LAAT was performed by using a simple slide test and image analysis (Inflamet), the WBCC, by an electronic cell analyzer, C-reactive protein, by Laser nephelometry and CD11b/CD18 by whole blood flow cytometry.

RESULTS: Forty out of a cohort of 121 patients with nonviral acute febrile illness had a WBCC within normal limits. The intensity of the inflammatory response in these individuals as judged by either C-reactive protein, or fibrinogen concentrations, erythrocyte sedimentation or polymorphonuclear leukocyte CD11b/CD18 expression was similar to that observed in patients with a leukocytic response. Our present finding that 63% out of the group with documented infection/inflammation and no leukocytosis had a significantly increased LAAT suggest that the lack of leukocytosis is in part a pseudoleukopenia, or is associated with some degree of uncompensated tissue leukostasis.

CONCLUSIONS: The lack of a leukocytic response in a patient with nonviral infection/inflammation is by no means a sign of a less inflammatory response. The increased state of leukocyte adhesiveness/aggregation might help to disclose the presence of inflammation in these individuals.