We investigated the relationship between circulating
leukotriene E4 (
LTE4) and
chronic obstructive pulmonary disease (
COPD) by measuring plasma levels of
leukotriene E4 in patients with
COPD and 10 normal controls. We also investigated the relationship between
LTE4 levels and FEV1 and PaO2.
Leukotriene E4 was measured by high performance liquid chromatography (HPLC) and radioimmunoassay. The mean
leukotriene E4 level in patients with
COPD during remission, during acute exacerbation before and after
prednisolone treatment were 16.8[4.02], 41.7[21.9], and 19.5[3.78] pg/ml (mean[SD]), respectively. In contrast, the mean
leukotriene E4 level of 10 normal controls was 11.8[4.49] pg/ml. Thus, the mean
LTE4 level during an acute exacerbation of
COPD was significantly lower in patients after
prednisolone treatment than in patients before
prednisolone treatment. The mean
LTE4 level in patients after
prednisolone treatment did not significantly differ from that in patients during remission and in normal controls (Scheffe F-test, P < 0.05) (Fig. 1). Mean FEV1 (% predict) values were 51.4[9.02] (mean[SD]), 38.0[4.82], and 44.2[4.48] on the three occasions, respectively; corresponding mean PaO2 values (mmHg) were 84.0[5.01] (mean[SD]), 61.3[1.66], and 80.6[5.30], respectively.
Leukotriene E4 levels were significantly correlated with PaO2 and relatively with FEV1 in the patients during acute exacerbation before
prednisolone treatment. Thus, we suggest that
leukotriene E4 levels in arterial blood reflect the severity of
COPD lung and oral
prednisolone reduces the plasma levels of
leukotriene E4 in patients with
COPD.