Correlation Between Soluble Adhesion Molecules in Serum and Cytokines in BALF
We measured IL-8 and IL-1β concentrations in BALF of healthy subjects and patients with DPB. The mean BALF concentration of IL-8 in DPB patients (344.7±238.0 pg/mL, n=25) was significantly higher than in healthy volunteers (4.3±3.7 pg/mL, n=ll, p<0.01). A significant correlation was observed in DPB patients between IL-8 in BALF and sL-selectin levels in serum (Fig 4A [top]) but not with other soluble molecules. The mean BALF concentration of IL-1β in DPB patients (54.2±22.7 pg/mL, n=23) was also significantly higher than in control subjects (34.3±11.6 pg/mL, n=ll, p<0.02). We also noted a significant correlation between IL-ip in BALF and sE-selectin levels in serum of DPB patients (Fig 4B [bottom]), but no such correlation was observed between IL-1β in BALF and the serum level of other adhesion molecules in the same patients.
Effect of Neutrophil Stimulation by Cytokines on Expression of L-selectin
Stimulation of neutrophils is associated with shedding of L-selectin from the cell surface. In healthy subjects, stimulation of neutrophils with FMLP or IL-8 induced a dose-dependent decrease in L-selectin expression on neutrophils (Fig 5A and B [top and center]). However, incubation of neutrophils with IL-ip did not change cell surface expression of L-selectin (Fig 5C [bottom]). In addition, incubation of neutrophils with erythromycin did not influence IL-8-induced fall in L-selectin expression (data not shown).
Effect of Treatment With Macrolides on the Level of Soluble Selectins in DPB
The serum levels of these soluble adhesion molecules were measured before and after treatment with macrolide antibiotics in 19 patients with DPB. Treatment significantly improved results of lung function tests (VC%, before, 82.4± 15.2; after, 94.2± 16.9%, p<0.01; FEV1%, before, 66.5±11.8; after, 71.1± 10.4%, p<0.05) and PaO2 (before, 70.5±9.1; after, 79.8±6.9 mm Hg, p<0.01). This was associated with a significant reduction in the total number of cells in BALF from 14.2±16.7Xl05/mL to 2.8±4.4Xl05/mL (p<0.02) and in the relative number of neutrophils in BALF from 79.4±13.3 to 28.4±32.1% (p<0.01) as reported previously. As shown in Table 2, treatment with macrolides also significantly reduced the concentration of all soluble adhesion molecules in the serum (n=19). In addition, the mean BALF concentration of IL-1β in these patients (n=13) decreased to levels similar to control values as mentioned earlier. Treatment also produced a significant fall in BALF concentration of IL-8 (n=15), but the mean posttreatment level in these patients was still higher than that in control subjects, as stated above.
Table 2—Effect of Macrolide Treatment on Serum Concentrations of Soluble Adhesion Molecules and Concentrations of Cytokines in BALF in Patients With DPB
|sL-selectin (serum, ng/mL)||944.8+239,3||753.3 ±200.5||<0.01|
|sE-selectin (serum, ng/mL)||53.2 + 17.0||42,3±16.7||<0.01|
|sP-selectin (serum, ng/mL)||205.3± 127.3||92.2± 107.9||<0.01|
|sICAM-1 (serum, ng/mL)||315.9±98.0||221.5±88.3||<0.01|
|sVCAM-1 (serum, ng/mL)||618.4 + 158.6||531.5±128.5||<0.02|
|IL-8 (BALF, pg/mL)||372.8±256.4||81.8±126.2||<0.01|
|IL-ip (BALF, pg/mL)||59.7+21.5||31.5±17.1||<0.01|
Figure 4. A, top: correlation between soluble serum L-selectin concentrations and IL-8 concentrations in BALF (n=25). B, bottom: correlation between soluble serum E-selectin concentrations and IL-ip concentrations in BALF (B, n=23) in DPB patients.
Figure 5. Effect of stimulation with FMLP (A [top]), IL-8 (B [center]), and IL-ip (C [bottom]) at 37°C for 15 min on the binding of L-selectin to peripheral blood neutrophils of five healthy people. The cells were stained by fluorescein isothiocya-nate-conjugated anti-Leu-8 and analysis was performed (using a FACScan).