Peripheral blood T lymphocytes in systemic vasculitis: increased T cell receptor V beta 2 gene usage in microscopic polyarteritis.
Antigen recognition by T lymphocytes is mediated by cell surface receptors T cell specificity depends on the variable, diversity and junctional (VDJ) regions of the alpha and beta polypeptide chains of the T cell receptor (TCR). The expression of the variable region genes of the beta chain (V beta) has been analysed to study the involvement of peripheral blood T cells in systemic vasculitis. RNA was extracted from peripheral blood lymphocytes of 12 patients with microscopic polyarteritis, 10 with Wegener's granulomatosis, six with unclassified vasculitis, and 28 healthy age- and sex-matched individuals. Complementary DNA was made from RNA and amplified by the anchored polymerase chain reaction (PCR) using redundant oligonucleotide primers for the TCR V beta genes. To determine if the dominant usage of a V beta gene family reflected the presence of particular T cell clones, cDNA was amplified with primers for the specific V beta gene family. The product was screened for sequence homogeneity by single-stranded conformational polymorphism (SSCP) and cloned to sequence the adjoining TCR (D beta) J beta region. A significant increase in the mean percentage expression of the V beta 2.1 gene was seen in vasculitis patients (11.4 + 1.0% (mean + s.e.m.)) compared with controls (6.6 + 0.6%; P < 0.003). The most marked increase was seen in microscopic polyarteritis (13.9 + 1.7%; P < 0.0001). There were also increases in the expression of V beta 3, 13 and 14 in peripheral blood of vasculitis patients compared with controls. SSCP analysis of V beta 2.1 amplified products indicated the presence of oligoclonal bands in a smaller proportion of patients (8/27) than controls (12/28). There was no strong evidence for the conservation of the TCR V beta 2.1 junctional region sequence data from a sample group of three patients with oligoclonal bands. Thus, a subset of patients with systemic vasculitis, particularly those with microscopic polyarteritis, have increased TCR V beta 2.1 gene expression in their peripheral blood T cell repertoire. As superantigens binding V beta 2.1 are postulated to activate T cells with diverse CDR3 sequences, it is proposed that a superantigen is involved in the immunopathogenesis of vasculitis.
Simpson
I J
IJ
Department of Medicine, University of Auckland, New Zealand.
Skinner
M A
MA
Geursen
A
A
Peake
J S
JS
Abbott
W G
WG
Fraser
J D
JD
Lockwood
C M
CM
Tan
P L
PL
D000328:Adult; D000368:Aged; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D000939:Epitopes; D005260:Female; D005784:Gene Amplification; D015870:Gene Expression; D006801:Humans; D046911:Macromolecular Substances; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D012313:RNA / Q000097:blood / Q000235:genetics; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D012680:Sensitivity and Specificity; D013601:T-Lymphocytes / Q000276:immunology / Q000502:physiology* / Q000648:ultrastructure; D014657:Vasculitis / Q000097:blood* / Q000235:genetics
D018076:DNA, Complementary; D000939:Epitopes; D046911:Macromolecular Substances; D016693:Receptors, Antigen, T-Cell, alpha-beta; D012313:RNA