[Opioid peptides in RA: modulation of immunologic mechanisms and mental states]

Rheumatoid arthritis (RA) patients were investigated for relationships between the concentrations of various plasma opioid peptides (beta-endorphin (beta-end), methionine-enkephalin (Met-enk), leucine-enkephalin (Leu-enk) and the lymphocyte subsets, serum immunoglobulins, the patient's mood or emotion, and the RA activity. A mental state and patient mood were assessed by the Cornell Medical Index (CMI) and the Face Scale. RA activity was expressed by Lansbury's index. The plasma Met-enk concentration was correlated significantly with the %Leu11+ and %Leu11+Leu7+ cells. The plasma Leu-enk concentration also correlated significantly with the %Leu2a+Leu15- cells. The plasma Leu-enk concentration and pain score were higher while the %Leu11+Leu7- cells was lower in proportion of the degree of neurosis of the RA patient as indicated by the CMI. The plasma Met-enk concentration, the %Leu2a+Leu15-, IgG, pain score and Lansbury's index were significantly higher in the group of RA patients whose facial expression was more severe. These findings suggest that enkephalins have some relationship with the patient's mood and immunologic functions, and that enkephalins have a possibility of exerting indirect effects on RA.