Lysozyme Evaluation in Myeloma

Lysozyme (serum and urinary) estimations are useful in classifying many hemapoietic disorders (acute myeloid leukemia), in assessing the degree of therapeutic remission and in evaluating certain renal diseases (tubular damage). Renal involvement is a frequent finding in multiple myeloma and so lysozyme studies in this hemapoietic disease are of particular interest. Serum and urine lysozyme levels were measured in ten patients with multiple myeloma. The (turbidimetric) assays of this enzyme are based on its ability to hydrolyze the cell wall of Micrococcus Lysodeictus (spectrophotometric measurement). In normal adults the concentration of lysozyme in serum is 9.2 + 3.46 μg/ml and there is no detectable lysozyme in normal urine. The lysozymuria has been considered in connection with serum levels of the enzyme and with Bence-Jones proteinuria. Our preliminary observations show that 1) Bence-Jones proteinuria is always accompanied by lysozymuria (although normal lysozyme serum levels are found), while 2) high levels of urine lysozyme may be present with no detectable Bence-Jones proteinuria.