Up regulated complement and fc receptors in juvenile idiopathic arthritis and correlation with disease phenotype.
OBJECTIVE
The progress in identifying immunological mechanisms in juvenile idiopathic arthritis (JIA) has partly been hampered by the fact that the disease is heterogeneous. Here we have investigated complement and Fc receptors, as part of the inflammatory process, in two subgroups of JIA.


METHODS
Blood from 26 patients with oligoarticular or polyarticular course type JIA and 21 healthy age and sex-matched controls were investigated by FACS and immunoassays.


RESULTS
Increased numbers of monocytes and augmented plasma levels of C-reactive protein, C3a and IgG were found in both JIA subgroups. However, only polyarticular patients exhibited increased expression of Fc gamma receptor (FcγR) II and III and complement receptor (CR) 1 on monocytes along with enhanced CR1 expression on B cells. A correlation was observed between degree of receptor expression and C3a levels in the patients.


CONCLUSIONS
Complement and Fc receptors are up regulated in children with multiple joint involvements, thus highlighting these pathways in the pathogenesis of polyarticular JIA.
Department of Cell and Molecular Biology, Uppsala University, SE-75124, Uppsala, Sweden.
Kajsa E
KE
Prokopec
Lillemor
L
Berntson
Anders
A
Öman
Sandra
S
Kleinau
D000293:Adolescent; D001171:Arthritis, Juvenile / Q000097:blood / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology; D002097:C-Reactive Protein / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D003176:Complement C3 / Q000032:analysis*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D007223:Infant; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008297:Male; D010641:Phenotype; D017463:Receptors, Complement 3b / Q000276:immunology*; D017464:Receptors, Complement 3d / Q000276:immunology; D011961:Receptors, Fc / Q000276:immunology*; D015854:Up-Regulation
C509991:CR1 protein, human; D003176:Complement C3; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D017463:Receptors, Complement 3b; D017464:Receptors, Complement 3d; D011961:Receptors, Fc; D002097:C-Reactive Protein