Muramic acid in human peripheral blood leucocytes in different age groups

Presence of muramic acid (as a marker for bacterial cell wall peptidoglycan) was analysed by gas chromatography and mass spectrometry in the peripheral blood leucocytes of subjects from a range of ages (9-80 years) and groups (healthy individuals, patients with rheumatoid arthritis, osteoarthrosis, essential hypertension or multiple sclerosis). Sixty per cent of the sample from the youngest subjects contained detectable muramic acid. The percentage of people with circulating leucocytes containing muramic acid decreased gradually with age, being less than 5% in all groups over 40 years; No clear correlation between the presence of muramic acid and the disease was observed.