Evidence of cellular immune response to outer membrane protein of Salmonella typhimurium in patients with enthesitis-related arthritis subtype of juvenile idiopathic arthritis.
OBJECTIVE
enthesitis-related arthritis subtype of juvenile idiopathic arthritis (JIA-ERA) clinically resembles reactive arthritis (ReA). In patients with ReA the immune response is targeted at the outer membrane protein (OMP) of Salmonella typhimurium. We studied the immune response in JIA-ERA to S. typhimurium OMP.


METHODS
synovial fluid mononuclear cells (SFMC) and peripheral blood mononuclear cells (PBMC) were isolated from blood and SF of patients with JIA-ERA. Lymphocyte transformation test was done with S. typhimurium OMP and crude bacterial lysates of Yersinia enterocolitica, Shigella flexneri, and S. typhimurium. IgG and IgA ELISA were performed in serum and SF using S. typhimurium OMP as antigen and compared with sera from healthy controls.


RESULTS
in PBMC samples (n = 25) an antigen-specific proliferative response was seen in 13 patients and a cross-reactive response in 6. Among these 19 patients, 12 showed response to OMP. In SFMC (n = 15) antigen-specific responses were seen in 3 patients and cross-reactive responses in 9. Among these 12 patients, 11 showed response to OMP. The IgG and IgA anti-OMP antibody concentrations in serum and SF were similar in patients and controls.


CONCLUSIONS
in JIA-ERA, OMP is the major antigenic target recognized by both SFMC and PBMC. Response to OMP is independent of specific bacterial response, suggesting that OMP is the immunodominant antigen. In these patients, absence of significant humoral response suggests response to OMP is mainly T cell mediated.
Department of Immunology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India 226014.
Yogesh Preet
YP
Singh
Amit Kumar
AK
Singh
Amita
A
Aggarwal
Ramnath
R
Misra
D000293:Adolescent; D001171:Arthritis, Juvenile / Q000276:immunology* / Q000382:microbiology*; D016918:Arthritis, Reactive / Q000276:immunology* / Q000382:microbiology*; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000276:immunology; D008213:Lymphocyte Activation; D008297:Male; D000091402:Prohibitins; D012486:Salmonella typhimurium / Q000276:immunology*; D013582:Synovial Fluid / Q000166:cytology; D055815:Young Adult
D001425:Bacterial Outer Membrane Proteins; C000717331:PHB2 protein, human; D000091402:Prohibitins