PLASMA-LEVELS OF LEUKOTRIENE E4 DURING CLINICAL COURSE OF CHRONIC OBSTRUCTIVE PULMONARY-DISEASE

We investigated the relationship between circulating leukotriene E4 (L TE4) and chronic obstructive pulmonary disease (COPD) by measuring pla sma levels of leukotriene E4 in patients with COPD and 10 normal contr ols. We also investigated the relationship between LTE4 levels and FEV 1 and PaO2. Leukotriene E4 was measured by high performance liquid chr omatography (HPLC) and radioimmunoassay. The mean leukotriene E4 level in patients with COPD during remission, during acute exacerbation bef ore 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 leuko triene 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 befor e prednisolone treatment. The mean LTE4 level in patients after predni solone treatment did not significantly differ from that in patients du ring 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 corre lated with PaO, and relatively with FEVI in the patients during acute exacerbation before prednisolone treatment. Thus, we suggest that leuk otriene E4 levels in arterial blood reflect the severity of COPD lung and oral prednisolone reduces the plasma levels of leukotriene E4 in p atients with COPD.