Factors influencing human polymorphonuclear leukocyte chemiluminescence

Divalent cations (Mg2+, Ca2+) regenerated chemiluminescence (CL) of zymosan-stimulated human polymorphonuclear leukocytes (PMNs) abolished by 0.1 mM EGTA. Phenol red, erythrocytes and free haemoglobin reduced CL. To obtain maximal CL response, the reaction mixture should contain small amounts of protein and glucose. High protein concentrations reduced CL. The test had a pH optimum of 7.1. With respect to stability, however, the most favourable pH was 7.4. The CL response was highly temperature-dependent, and expressed as the initial rate constant of the CL time curve it increased linearly with increasing temperatures from 20 to 37 degrees C. Several factors influence the CL response by human PMNs and test procedures should be standardized.