Aneurysmal Lesions of Patients with Abdominal Aortic Aneurysm Contain Clonally Expanded T Cells

Abdominal aortic aneurysm (AAA) is a common disease with often life-threatening consequences. This vascular disorder is responsible for 1-2% of all deaths in men aged 65 years or older. Autoimmunity may be responsible for the pathogenesis of AAA. Although it is well documented that infiltrating T cells are essentially always present in AAA lesions, little is known about their role in the initiation and/or progression of the disease. To determine whether T cells infiltrating AAA lesions contain clonally expanded populations of T cells, we amplified beta-chain TCR transcripts by the nonpalindromic adaptor-PCR/Vbeta-specific PCR and/or Vbeta-specific PCR, followed by cloning and sequencing. We report in this article that aortic abdominal aneurysmal lesions from 8 of 10 patients with AAA contained oligoclonal populations of T cells. Multiple identical copies of beta-chain TCR transcripts were identified in these patients. These clonal expansions are statistically significant. These results demonstrate that alphabeta TCR(+) T lymphocytes infiltrating aneurysmal lesions of patients with AAA have undergone proliferation and clonal expansion in vivo at the site of the aneurysmal lesion, in response to unidentified self- or nonself Ags. This evidence supports the hypothesis that AAA is a specific Ag-driven T cell disease

Clonally Expanded Alpha-Chain T-Cell Receptor (TCR) Transcripts are Present in Aneurysmal Lesions of Patients With Abdominal Aortic Aneurysm (AAA)

Abdominal aortic aneurysm (AAA) is a life-threatening immunological disease responsible for 1 to 2% of all deaths in 65 year old or older individuals. Although mononuclear cell infiltrates have been demonstrated in AAA lesions and autoimmunity may be responsible for the initiation and account for the propagation of the disease, the information available about the pathogenesis of AAA is limited. To examine whether AAA lesions from patients with AAA contain clonally expanded α-chain TCR transcripts, we amplified by the non-palindromic adaptor-PCR (NPA-PCR)/Vα-specific PCR and/or the Vα-specific PCR these α-chain TCR transcripts. The amplified transcripts were cloned and sequenced. Substantial proportions of identical α-chain TCR transcripts were identified in AAA lesions of 4 of 5 patients, demonstrating that clonally expanded T cells are present in these AAA lesions. These results were statistically significant by the bimodal distribution. Three of 5 of these patients were typed by DNA-based HLA-typing and all three expressed DRB1 alleles containing the DRβGln70 amino acid residue that has been demonstrated to be associated with AAA. All three patients exhibited clonally expanded T cells in AAA lesions. Four of the 5 patients with AAA who exhibited clonal expansions of α-chain TCR transcripts, also exhibited clonal expansions of β-chain TCR transcripts in AAA lesions, as we have demonstrated previously (J Immunol 192:4897, 2014). αβ TCR-expressing T cells infiltrating AAA lesions contain T-cell clones which have undergone proliferation and clonal expansion in vivo in response to as yet unidentified specific antigens that may be self or nonself. These results provide additional evidence supporting the hypothesis that AAA is a specific antigen-driven T-cell autoimmune disease

Decreased Expression of the CD3ζ Chain in T Cells Infiltrating the Synovial Membrane of Patients with Osteoarthritis

Osteoarthritis (OA) is a heterogeneous disease which rheumatologists consider to be noninflammatory. However, recent studies suggest that, at least in certain patients, OA is an inflammatory disease and that patients often exhibit inflammatory infiltrates in the synovial membranes (SMs) of macrophages and activated T cells expressing proinflammatory cytokines. We report here that the expression of CD3ζ is significantly decreased in T cells infiltrating the SMs of patients with OA. The CD3ζ chain is involved in the T-cell signal transduction cascade, which is initiated by the engagement of the T-cell antigen receptor and which culminates in T-cell activation. Double immunofluorescence of single-cell suspensions derived from the SMs from nine patients with OA revealed significantly increased proportions of CD3ɛ-positive (CD3ɛ(+)) cells compared with the proportions of CD3ζ-positive (CD3ζ(+)) T cells (means ± standard errors of the means, 80.48% ± 3.92% and 69.02% ± 6.51%, respectively; P = 0.0096), whereas there were no differences in the proportions of these cells in peripheral blood mononuclear cells (PBMCs) from healthy donors (94.73% ± 1.39% and 93.79% ± 1.08%, respectively; not significant). The CD3ζ(+) cell/CD3ɛ(+) cell ratio was also significantly decreased for T cells from the SMs of patients with OA compared with that for T cells from the PBMCs of healthy donors (0.84 ± 0.17 and 0.99 ± 0.01, respectively; P = 0.0302). The proportions of CD3ɛ(+) CD3ζ(+) cells were lower in the SMs of patients with OA than in the PBMCs of healthy donors (65.04% ± 6.7% and 90.81% ± 1.99%, respectively; P = 0.0047). Substantial proportions (about 15%) of CD3ɛ(+) CD3ζ-negative (CD3ζ(−)) and CD3ɛ-negative (CD3ɛ(−)) CD3ζ(−) cells were found in the SMs of patients with OA. Amplification of the CD3ζ and CD3δ transcripts from the SMs of patients with OA by reverse transcriptase PCR consistently exhibited stronger bands for CD3δ cDNA than for CD3ζ cDNA The CD3ζ/CD3δ transcript ratio in the SMs of patients with OA was significantly lower than that in PBMCs from healthy controls (P < 0.0001). These results were confirmed by competitive MIMIC PCR. Immunoreactivities for the CD3ζ protein were detected in the SMs of 10 of 19 patients with OA, and they were of various intensities, whereas SMs from all patients were CD3ɛ(+) (P = 0.0023). The decreased expression of the CD3ζ transcript and protein in T cells from the SMs of patients with OA relative to that of the CD3ɛ transcript is suggestive of chronic T-cell stimulation and supports the concept of T-cell involvement in OA

Theiler's Virus Infection: a Model for Multiple Sclerosis

Both genetic background and environmental factors, very probably viruses, appear to play a role in the etiology of multiple sclerosis (MS). Lessons from viral experimental models suggest that many different viruses may trigger inflammatory demyelinating diseases resembling MS. Theiler's virus, a picornavirus, induces in susceptible strains of mice early acute disease resembling encephalomyelitis followed by late chronic demyelinating disease, which is one of the best, if not the best, animal model for MS. During early acute disease the virus replicates in gray matter of the central nervous system but is eliminated to very low titers 2 weeks postinfection. Late chronic demyelinating disease becomes clinically apparent approximately 2 weeks later and is characterized by extensive demyelinating lesions and mononuclear cell infiltrates, progressive spinal cord atrophy, and axonal loss. Myelin damage is immunologically mediated, but it is not clear whether it is due to molecular mimicry or epitope spreading. Cytokines, nitric oxide/reactive nitrogen species, and costimulatory molecules are involved in the pathogenesis of both diseases. Close similarities between Theiler's virus-induced demyelinating disease in mice and MS in humans, include the following: major histocompatibility complex-dependent susceptibility; substantial similarities in neuropathology, including axonal damage and remyelination; and paucity of T-cell apoptosis in demyelinating disease. Both diseases are immunologically mediated. These common features emphasize the close similarities of Theiler's virus-induced demyelinating disease in mice and MS in humans