[Plasma amino acids in ankylosing spondylitis (author's transl)].

The plasma amino acids of male patients with ankylosing spondylitis (ASp) and male controls were analysed and the concentrations statistically evaluated. The total concentration of all 28 amino acids in ASp-patients did not differ from the controls, but there were some distinct differences in the levels of individual amino acids, e. g. arginine and isoleucine which showed raised concentration (29% and 27%). A higher concentration was also detectable with rare amino acids, e. g. alpha-amino-adipinic acid (23%) and 1-methyl-histidine (32%). Correlation between the amino acid concentration and age was detected only in the case of citrulline. Some amino acids showed a significant correlation to one another which was sometimes evident in both groups and other times was noted in the control- or ASp-group only. If such correlations were found to be disease-dependent this finding could be helpful in the diagnosis of certain diseases.