IMMUNOAFFINITY RESIN FOR PURIFICATION OF URINARY LEUKOTRIENE E-4

Urinary leukotriene E-4 (LTE4) has been used as an index of total leuk otriene synthesis. A wide variety of methods have been applied to meas ure LTE4 which has made direct comparison of urinary levels reported b y different laboratories difficult. A new peptidoleukotriene immunoaff inity resin was utilized for urinary LTE4 purification in a method tha t is easy and inexpensive, utilizing commercially available reagents. This method is described and compared to other methods. LTE4 (50-250 p g/mL) added to a urine extract was quantitatively recovered using the immunoaffinity resin. Similarly, LTE4 (50-400 pg/mL) added to urine wa s recovered between 63 and 76%. The coefficient of variation of sample s purified and quantified on the same or on different days ranged from 8-10%. There was a strong correlation (r(2) = 0.95) between LTE4 conc entrations determined after immunofiltration and immunoaffinity purifi cation. Although there was a good correlation between urinary LTE4 lev els measured without purification compared to after immunoaffinity pur ification, the high y-intercept of 179 indicates the presence of inter fering substances in unpurified; urine. Urinary LTE4 in normal healthy adults was 80 +/- 7 pg/mg creatinine, similar to that previously repo rted following HPLC or immunofiltration purification. Urinary LTE4 was also measured in healthy children (age 3-12) and found to be 103 +/- 9.