Lactate dehydrogenase and caspase activity in nasopharyngeal secretions are predictors of bronchiolitis severity

Mehta, Reena; Scheffler, Margaret; Tapia, Lorena; Aideyan, Letisha; Patel, Kirtida D; Jewell, Alan M; Avadhanula, Vasanthi; Mei, Minghua; Garofalo, Roberto P; Piedra, Pedro A

In this study, we identify added complexity in using the promising biomarker NW-LDH for children with bronchiolitis. As an intracellular enzyme released upon cell injury, NW-LDH can be a marker of necrosis or apoptosis. Similar to our prior study, 13 RSV infection was associated with higher NW-LDH, and NW-LDH significantly correlated with NW-caspase 3/7. Unlike our prior studies where children with values in the upper quartile had a decreased risk of hospitalization, 13, 14 in this study an increasing concentration of NW-LDH was associated with an increasing likelihood of hospitalization to either the ACU or ICU. Children admitted to an ICU had significantly higher NW-LDH than children who were sent home or admitted to the ACU. These differences in predicting outcome are not readily explained; however, a higher proportion of this cohort required ICU care, (20Á6% versus 6Á1%) and none of the children had major co-morbidities compared with 25Á2% in Laham et al. study. 13 It is possible that our current cohort of children had more severe bronchiolitis, resulting in greater cellular injury to the airway epithelium. Thus, understanding the mechanisms (apoptosis versus necrosis) underlying the release of LDH might improve the prediction of outcomes, with the implication that NW-LDH from cells undergoing dysregulated inflammatory and necrotic processes results in more severe disease while NW-LDH originating from controlled apoptotic antiviral processes results in less severe disease.