Induced sputum, bronchoalveolar lavage and blood from mild asthmatics: inflammatory cells, lymphocyte subsets and soluble markers compared

Abstract

Airway inflammation in asthma can be measured directly by invasive bronchoalveolar lavage (BAL), directly and relatively noninvasively by induced sputum and indirectly from peripheral blood. We compared cellular and fluid phase indices of inflammation in induced sputum, BAL and blood from 11 adults with mild stable asthma. On one day, induced sputum selected from saliva was collected and on the next, blood and BAL. Median results of sputum compared with BAL showed a higher number of nonsquamous cells (53 versus 0.8 x 10(6) cells x mL(-1), p=0.003), more neutrophils (34.3 versus 1.0%, p<0.001), CD4+ and CD19+ T-cells (76.5 versus 54.7%, p=0.01 and 5.2 versus 1.1%, p=0.03, respectively), fewer macrophages (603 versus 95.0%, p=0.002) and markedly higher levels of eosinophil cationic protein (ECP) (264 versus 2.0 microg x L(-1), p<0.001), tryptase (17.6 versus 2.2 UI x L(-1), p<0.001) and fibrinogen (1,400 versus 150 microg x L(-1), p=0.001). Sputum and BAL neutrophils and CD4+ T-cells were strongly correlated. Sputum and BAL differed from blood by having higher proportions of T-cells (94.9 and 98.9% versus 87.7%, p=0.002) and lower proportions of CD19+ T-lymphocytes (p=0.04 and 0.006). Sputum also differed from blood by having higher proportions of CD4+ T-cells (76.5 versus 51.4%, p=0.001), lower proportions of CD8+ cells (24.0 versus 403%, p=0.04) and a higher CD4+/CD8+ ratio (3.3 versus 1.4, p=0.01). We conclude that in mild asthmatics, sputum, bronchoalveolar lavage and blood measure different compartments of inflammation. Induced selected sputum has the advantage over bronchoalveolar lavage of higher density of cell recovery and stronger signal for fluid-phase markers.

Impact of acute exposure to tobacco smoke on gelatinases in the bronchoalveolar space

“…Thus, induced sputum introduces a confounding factor already at baseline, since it may cause even more neutrophils to become exposed to the locally accumulated stimuli associated with exposure to tobacco smoke. In addition, sputum contents are likely to reflect mainly proximal and not peripheral airways, as opposed to bronchoalveolar lavage (BAL) fluid [8][9][10].…”

Update on sputum methodology

“…In both sputum and BAL a higher proportions of CD4+ T-cells and lower proportion of CD8+ cells and CD19+ T-lymphocytes were found compared to blood. Sputum also had a higher CD4+/CD8+ ratio [29]. As sputum has to be homogenized before flow cytometry, a possible effect of the DTT treatment on surface markers has to be considered.…”

Medidas de óxido nítrico no ar exalado de pacientes com história prévia de broncoespasmo no período intra-operatório

“…Para tanto, tem-se empregado técnicas invasivas como a biópsia brônquica e o lavado bronco-alveolar que são utilizados para analisar os padrões de resposta celular relacionados à gravidade clínica, expressão de células inflamatórias, produção de citocinas e de mediadores da resposta inflamatória mediada por eosinófilos e neutrófilos (Pizzichini et al,1998;Woerly et al, 2004). Contudo estes procedimentos não podem ser aplicados para monitorização rotineira do processo inflamatório.…”

“…Atualmente, dispõem-se da análise do escarro induzido e da medida do óxido nítrico no ar exalado, que são considerados métodos não invasivos, ou relativamente não invasivo (Kanazawa et al, 1997;Pizzichini et al, 1998;Hunter et al, 1999).…”

“…A primeira parte foi destinada à confecção de um esfregaço simples, onde o muco foi colocado sobre uma lâmina e distribuído por esta ("puxado") com o auxílio de outra lâmina (Saraiva-Romanholo et al, 2003). O esfregaço foi deixado para secar ao ar livre e corado com Diff Quick (Pizzichini et al, 1998 (Zar, 1984a;Zar, 1984b …”