Pentraxin 3 as a clinical marker in children with lower respiratory tract infection

Pentraxin 3 (PTX-3) is an acute-phase protein that increases in the plasma during inflammation.

We aimed to evaluate the usefulness of PTX-3 as a clinical marker in children with lower respiratory tract infection (LRTI) and examine the correlation of PTX-3 with other biomarkers such as C-reactive protein (CRP) and procalcitonin (PCT).

We enrolled 117 consecutive patients admitted to Seoul St. Mary's Hospital with LRTI using the WHO criteria. We recorded data on fever duration and peak temperature before admission, duration of fever after admission, respiratory rate, heart rate, oxygen saturation upon admission, duration of oxygen supplementation, and duration of hospital stay. Upon admission, white blood cell (WBC) count, erythrocyte sedimentation rate, CRP level were measured. Multiplex respiratory virus polymerase chain reaction was performed using nasal swabs. PTX-3, PCT, and various cytokines were measured after the study had been completed.

We found that there was no significant difference in the level of PTX-3 according to the type of viral infection. PTX-3 levels showed a significant correlation with PCT levels, but not with levels of CRP. The level of PTX-3 showed a significant correlation with peak temperature and duration of fever before admission as well as interleukin (IL)-6 levels. PCT levels showed a significant correlation with IL-6 and granulocyte-colony stimulating factor levels, peak temperature, and duration of fever before admission, and duration of hospital stay. CRP levels showed a significant correlation with duration of fever before admission, total WBC count, and neutrophil count. PCT levels significantly predicted a hospital stay of 7 days or more. PTX-3, PCT, and CRP levels showed no correlation with any other clinical features.

PTX-3 reflected disease severity but failed to predict length of hospital stay. Further studies evaluating the use of PTX-3 as a biomarker in mild LRTI would be useful.