Immature granulocytes as an early clinical predictor in children with respiratory syncytial virus bronchiolitis.

Background: Immature granulocytes can be measured easily in a complete blood count by new automated hemolytic analyzers and have recently been studied as bio-markers in many infectious/inflammatory diseases. This study aims to investigate whether immature granulocyte percentage (IG%) would enable greater discrimination than conventionally utilized laboratory values in terms of early clinical prediction in instances with respiratory syncytial virus (RSV) bronchiolitis.

Methods: A prospective observational cohort study involved 149 individuals with RSV bronchiolitis. Complete blood count (including IG%), C-reactive protein, and procalcitonin (PCT) assays were performed.

Results: Sixty-two (42%) RSV bronchiolitis patients responded well to outpatient therapy; 60 (40%) were admitted to the hospital, and 27 (18%) required pediatric intensive care unit (PICU) follow up. Inpatients had a higher platelet count than outpatients, and PICU patients had a higher platelet lymphocyte ratio (PLR). Pediatric intensive care unit patients had greater PCT levels than outpatients, and their IG% was higher than that of both inpatient and outpatient groups. In the receiver operating characteristic analysis examining the usefulness of parameters in predicting PICU hospitalization, PLR, PCT, and IG% produced statistically significant findings, with IG% having the highest area under the curve (0.730).

Conclusions: Immature granulocyte percentage was the biomarker that best differentiated PICU patients from other patient groups when compared with traditional acute phase reactants. Immature granulocytes may help to determine the severity of infection/inflammation at an early stage of the disease.