In the urine, the function of polymorphonuclear leukocytes (PMNs) is t
hought to be impaired because of the high osmolality and low pH along
with a high concentration of inorganic salts. We investigated the effe
ct of the properties of urine and its components on the chemiluminesen
ce (CL) response of PMNs. This was helped by using an artificial urine
. The CL response was measured by automatic luminometer following stim
ulation of phorbol myristate acetate. We found the CL response of PMNs
to be significantly suppressed at a pH of 6 or 5, but not suppressed
at a pH of 7 or 8. The CL response was significantly reduced when the
osmolality was increased to 580 or 800 mOsm/kg H2O by the addition of
urea as compared to the response in the standard artificial urine at a
n osmolality of 425 mOsm/kg H2O. A change in the osmolality by the add
ition of mannitol only minimally influenced the CL responses. In addit
ion, the CL response was significantly impaired by both low and high c
oncentrations of sodium at 12 and 300 mEq/L as compared to 77.5 mEq/L
in the standard artificial urine. Potassium significantly reduced the
CL response in a concentration-dependent manner in the range of from 4
to 31 mEq/L as compared to 52.3 mEq/L in the standard artificial urin
e. A high concentration of calcium at 8.1 or 9.9 mg/dL reduced CL resp
onse as compared to 3.9 mg/dL, whereas CL response was not reduced by
the change in the concentration of magnesium. A high concentration of
creatinine significantly reduced the CL response as compared to the st
andard artificial urine. We conclude that the function of PMNs in urin
e is reduced mainly by wine pH, concentration of urea, sodium, potassi
um, and creatinine. We suggest that reversal of these change in urine
may restore functions of PMN's to clear bacteria in patients with urin
ary tract infections.