Lysozyme † Levels in the Kidneys of Cancer Patients.

Abstract

Lysozyme found to be present in many organs and secretions of humans has been described (1–5). Litwack has isolated chromatographically pure human lysozyme from the kidneys(6) and Jolles and Jolles recently have purified lysozyme from human milk (7). The authors have reported a 70–100 fold increase of lysozyme concentration in the kidneys of Sprague-Dawley rats bearing Jensen Sarcoma (8,9). Surgical removal or spontaneous regression of the tumor results in a return to its normal value in the kidney(10). Similar results have been published for other host-tumor systems by Cappuccino (11). Therefore, it was thought to be of interest to study the lysozyme levels in the kidneys of cancer patients.

Materials and methods. The kidney samples utilized for these experiments were obtained upon autopsy of cancer patients as soon as possible and kept at −20°C. They were homogenized by the technique already described (7,9). And the resulting extracts, after precipitation of most of the proteins with 1% acetic acid in 95% ethanol and centrifugation, were examined. Lysozyme activity was determined by a modification of Litwack method (12) by addition of supernatant's aliquots to a suspension of acetone dried Micrococcus lysodeickticus (Rutgers strain 19) in buffer (chloride-phosphate pH 6.2, OD. 0.600–0.700 mμ) and measurement of the change of OD. per minute. The results are expressed in mg equivalent of EGG WHITE LYSOZYME∗ per gram of wet tissue.

Results. The results of analysis performed on 29 kidney samples and reported in Table I show that the lysozyme values obtained vary over a wide range. If the normal value for lysozyme in human kidneys is considered to be 200 γ/g of wet tissue(13), the values found for the cancer-bearing human patient examined are both greater and lesser than the normal figure and no correlation between the presence of a neoplastic growing mass and levels of lysozyme found in the kidneys is apparent. Some occasional high values are found (cases #7, 22, Table I).