To determine if the germ line gene VH4-34 (VH4.21) encodes the antimonophosphoryl lipid A (MPL) polyspecific antibodies found in oligoarticular arthritis of childhood.
Sera from a range of rheumatic diseases of childhood were assayed for VH4-34 derived antibodies by ELISA using the antiidiotype monoclonal antibody 9G4. Results were compared to assays for anti-MPL antibodies, C4d, and Bb, and for HLA type, joint count, and sedimentation rate.
VH4-34 derived antibodies were elevated in all diseases studied except rheumatoid factor positive polyarticular disease. In oligoarticular arthritis, VH4-34 gene expression correlated with C4d concentration, and VH4-34 encoded globulins were more concentrated in synovial fluid than in blood. No association was found with HLA type. An association between VH4-34 expression and IgG anti-MPL was found in sera from patients from Cincinnati but not from Stanford. No other evidence supported a direct association between VH4-34 derived and anti-MPL antibodies in these children.
The expression of VH4-34 is increased in several rheumatic diseases of childhood, but, as in adults, not in rheumatoid arthritis. VH4-34 expression is not associated with HLA type. The polyspecific autoantibody nature of some VH4-34 derived antibodies may explain the wide range of the unusual antibodies found in oligoarticular arthritis.