Intrapulmonary protein leakage in immunocompromised children and adults with pneumonia

Abstract

Background-Pulmonary infections are associated with an increase in capillary permeability but information regarding age related diVerences in the local inflammatory response is lacking. To quantify the degree of capillary leakage during inflammation, the concentrations of the plasma proteins albumin, 1 -antitrypsin, 2 -macroglobulin and the locally produced proteins elastase, myeloperoxidase, lactoferrin and fibronectin were studied in the bronchoalveolar lavage (BAL) fluid of immunosuppressed children and adults with pneumonia. Methods-Sixteen children aged 2-16 years and 15 adults who developed pneumonia while receiving immunosuppressive therapy for haematological malignancies were included in the study. Bronchoalveolar lavage was performed via a flexible bronchoscope with three aliquots of 1 ml/kg body weight in children and 200 ml in adults. Protein concentrations in BAL fluid were determined using highly sensitive immunoluminometric assays. Results-Despite considerable variability, the median concentrations of all proteins in BAL fluid were significantly higher in both patient populations than in previously collected age adjusted reference values. The concentrations of serum derived proteins were significantly higher in children with pneumonia than in adult patients. In contrast, no diVerences were observed between the two groups for locally produced proteins. Conclusions-These data suggest that the degree of protein exudation is more pronounced in immunosuppressed children with pneumonia than in adults in a similar clinical situation. This is in agreement with our studies in healthy individuals and may reflect a greater permeability of the alveolar-capillary membrane in children, regardless of disease status.

Relationship between antimicrobial proteins and airway inflammation and infection in cystic fibrosis

“…Our measured concentrations of antimicrobial proteins correspond with prior estimates that lysozyme and lactoferrin are the most abundant antimicrobial proteins in airway secretions, while SLPI is the third most abundant protein, with concentrations approximately tenfold less than lysozyme and lactoferrin. 3,4 As we found in our CF subjects, elevated airway concentrations of lysozyme and lactoferrin have been previously reported in CF 5,[22][23][24] and in other respiratory conditions including chronic bronchitis, 25 asthma, 26 chronic obstructive pulmonary disease, 27 pneumonia, 28 and acute respiratory distress syndrome. 29 We can only speculate whether the increase in lysozyme and lactoferrin we observed with age in our CF subjects reflects a true age-effect or whether they track with disease progression.…”

Bronchoalveolar lavage protein patterns in children with malignancies, immunosuppression, fever and pulmonary infiltrates

“…This is in agreement with previous quantitative measurements in a similar group of children [17]. We could not find any coincidence of a 1 -antitrypsin and the appearance of the chest infiltrates.…”

Accumulation of the neutrophil-derived protein YKL-40 during storage of various blood components

“…Specific substances such as MPO and elastase derived from the neutrophilic granulocytes are suspected to be involved in pneumonia [21]. However, other neutrophil derived proteins may as well participate.…”