Lysozyme and its biological value in rheumatoid arthritis (RA)

Lysozyme or muramidase catalyzes the hydrolysis of 1,4-beta-linkages between N-aacetylmuramic acid and N-acetyl-D-glucosamine residues in peptidoglycan. A basic enzyme that is present in saliva, tears, egg white and many animal fluids. Its function is an antibacterial agent. Lysozyme is well known for the ability to hydrolize the cell wall of bacteria.

Objective

The aim of study was to measure the concentration of lysozyme in synovial fluid in RA patients.

Methods

We measured the lytic activity of lysozyme towards micrococcus lysodeikticus (1, 2, 3), bacteria which are highly suspectible to lysis by lysozyme by the turbidometric method 30 synovial fluid of RA patients. In order to obtain a method covering a wider range of lysozyme concentrations, Osserman and Lawlor worked out the so-called lyso-plate method (4).

The test measured the zone of clearing by lysozyme in an agar plate, in which microccocus lysodeikticus is embedded. After about 18 hours the diameter of the zone of clearing is measured.

Results

In all our RA synovial fluid we observed increased level of lysozyme.

Conclusions

The increased levels of lysozyme in synovial fluid in RA could indicate of monocyte/macrofage activity and might be used to study disease activity in RA.