Am. J. Respir. Crit. Care Med., Vol 153, No. 5, 05 1996, 1585-1590.
Immunoglobulin A levels in bronchial samples during mechanical ventilation and onset of nosocomial pneumonia in critically ill patients
D Annane, B Clair, B Mathieu, C Boucly, O Lesieur, L Donetti, M Gatey, JC Raphael and P Gajdos
Service de Reanimation Medicale, Hopital Raymond Poincare, Garches, Universite Paris V., France.
Local immunoglobulins play a key role in host defense against lung
infection. We investigated the pattern of evolution of bronchial albumin,
IgA, and IgG levels in ventilated ICU patients in relation to nosocomial
pneumonia. Immunocompetent, critically ill patients underwent serial blood
and bronchial protein determinations on Day 1 (intubation day), and on Days
3, 7, 10, and 14. The variations in proteins levels were compared with
corresponding Day 1 values in the whole population, and between patients
who developed lung infections (Group A) and the remaining population (Group
B). Forty-four patients were included into the study. In the whole
population, when compared with the baseline value, bronchial IgA/albumin
ratio increased significantly (Day 3, +58%, p = 0.04); Day 14, +171%, p
< 0.01), but serum IgA/albumin and serum and bronchial IgG/albumin
ratios did not change significantly. In Group A, the increase in the
IgA/albumin ratio was less than in Group B (Day 3, +15% versus +87%, p =
0.04; Day 14, +29% versus +210%, p < 0.01). No significant differences
were observed between the two groups for bronchial and plasma albumin and
IgG levels and for bronchial polymorphonuclear elastase levels. Bronchial
IgA production was enhanced in ventilated patients. A reduction in this
enhanced bronchial IgA production might account for the development of
nosocomial pneumonia.
