Matrix changes in articular cartilage in the knee of patients with rheumatoid arthritis after biological therapy: 1-year follow-up evaluation by T2 and T1ρ MRI quantification.

AIM: To estimate the morphological changes in the articular cartilage of the knees of patients with rheumatoid arthritis treated with biological disease-modifying anti-rheumatic drugs (bDMARDs). MATERIALS AND METHODS: Cartilage-specific magnetic resonance imaging (MRI) results, including T2 and T1ρ mapping of the femorotibial joint of 17 patients, were obtained before and 1 year after starting treatment with bDMARDs. Regions of interest were selected on the sagittal images of the cartilage of the medial and lateral femoral condyles (MFC, LFC) and the tibial plateau (MTP, LTP). Cartilage thickness, T2, and T1ρ were measured, and the correlations of their changes were evaluated. RESULTS: The mean changes in cartilage thickness tended to decrease in all four condyles, and the rate was significant in the MFC. T2 and T1ρ tended to increase, and T2 in the MFC significantly increased. Changes in cartilage thickness after 1 year showed a moderate correlation with the baseline T2 in the MFC as well as changes in T2 in the MTP. CONCLUSIONS: Decreasing cartilage thickness and matrix changes appeared in the MFC after 1 year of treatment with bDMARDs. Microstructural damage of the cartilage at baseline is a predictor for further cartilage damage in the knee joint, even if treatment with bDMARDs is effective.

A complete genomic screen for multiple sclerosis underscores a role for the major histocompatability complex. The Multiple Sclerosis Genetics Group.

Multiple sclerosis (MS), an inflammatory autoimmune demyelinating disorder of the central nervous system, is the most common cause of acquired neurological dysfunction arising in the second to fourth decades of life. A genetic component to MS is indicated by an increased relative risk of 20-40 to siblings compared to the general population (lambda s), and an increased concordance rate in monozygotic compared to dizygotic twins. Association and/or linkage studies to candidate genes have produced many reports of significant genetic effects including those for the major histocompatability complex (MHC; particularly the HLA-DR2 allele), immunoglobulin heavy chain (IgH), T-cell receptor (TCR) and myelin basic protein (MBP) loci. With the exception of the MHC, however, these results have been difficult to replicate and/or apply beyond isolated populations. We have therefore conducted a two-stage, multi-analytical genomic screen to identify genomic regions potentially harbouring MS susceptibility genes. We genotyped 443 markers and 19 such regions were identified. These included the MHC region on 6p, the only region with a consistently reported genetic effect. However, no single locus generated overwhelming evidence of linkage. Our results suggest that a multifactorial aetiology, including both environmental and multiple genetic factors of moderate effect, is more likely than an aetiology consisting of simple mendelian disease gene(s).

HTLV-1-mediated immunopathological CNS disease.

HAM/TSP is a chronic inflammatory disease of the spinal cord. It is rather rare in HTLV-1-infected individuals. Immunogenetic factors of the HLA complex have been identified that support or prevent the development of the disease. In HAM/TSP patients a characteristic constellation of high proviral loads and increased cellular and humoral immune responses have been established. Immune dysfunction in HAM/TSP patients might be partly explained by HTLV-1 tax p40 transactivation of cellular genes in infected CD4+ T lymphocytes. The oligoclonal expansion of infected T lymphocytes, the variation of tax p40 within HTLV-1 carriers, and the regulation of proviral gene expression are possible determinants for disease development and need to be clarified in future studies.

T-cell receptors: germline polymorphism and patterns of usage in demyelinating diseases.

The genomic organization of the T-cell receptor (TCR) gene complexes accounts for many central aspects of T-cell immunobiology, including specificity and diversity. Recent data indicate that polymorphism of TCR genes is present within a species and may influence the immune phenotype of an individual. Such polymorphism has been detected by RFLP, by the presence of large regions of insertion or deletion of germline DNA, and by allelic variability of individual gene segments that are expressed. In addition to allelic variation of TCR genes, immune responses may also be influenced by the repertoire of the TCR molecules that are expressed by responding T-cell populations. In some situations, pathogenic T-cell responses may involve expression of limited numbers of TCR gene families. This is true, for example, in experimental allergic encephalomyelitis, an autoimmune nervous system disease mediated by T-cells reactive to myelin basic protein. In the human disease counterpart, multiple sclerosis, a more complex pattern of T-cell recognition to the putative autoantigen is generally present, although in some individuals a restricted response may occur. Specific therapies targeted to certain TCR molecules represents a promising approach to chronic inflammatory diseases in humans. The efficacy of such therapies will be determined in part by the TCR repertoire expressed in individual disease situations and by the potential for plasticity in the pathogenic T-cell response that may exist.

Apoptosis of T lymphocytes in the spinal cord lesions in HTLV-I-associated myelopathy: a possible mechanism to control viral infection in the central nervous system.

Immunocytochemical staining of spinal cords from five autopsied patients with HAM/TSP was performed using the monoclonal antibody TIA-1, a marker of cytotoxic T lymphocytes (CTL). Many TIA-1+, CD8+ cells are distributed in active inflammatory lesions. The number of TIA-1+ cells is related to the amount of HTLV-I proviral DNA in situ. The protein TIA-1 has been associated with the induction of apoptosis in target cells. In active inflammatory lesions, we found cells undergoing apoptosis, most of them identified as helper-inducer CD45RO T lymphocytes, which were consistent with in vivo cellular tropism of HTLV-I in patients with HAM/TSP. These findings suggest that CTL-induced apoptosis of T lymphocytes may be one of the possible mechanisms which eliminate HTLV-I-infected cells from the central nervous system. In addition, many T lymphocytes in the inflammatory lesions expressed bcl-2 oncoprotein, suggesting that infiltrated T lymphocytes may be resistant to apoptosis. Expression of bcl-2 oncoprotein may explain the longstanding inflammatory process in the central nervous system of HAM/TSP.

Cytotoxic and suppressor activities in patients with HTLV-I-associated myelopathy.

Since there are several immune abnormalities and autoimmune-like features in human T-cell lymphotropic virus type I (HTLV-I)-associated myelopathy/HTLV-I-associated tropical spastic paraparesis (HAM/TSP), we examined cytotoxic and suppressor cell functions in HAM/TSP. In this study, we assayed cell-mediated cytotoxicity of CD8+ T-cell lines established from cerebrospinal fluid lymphocytes of two patients with HAM and concanavalin A-induced suppressor cell activities of peripheral blood lymphocytes from five patients with HAM. Our study revealed that three of four CD8+ T-cell lines showed cytotoxic activities against autologous CD4+ T-cell lines infected with HTLV-I, and two of the three lines showed major histocompatibility complex class I-restricted cytotoxicity. We also demonstrated that the concanavalin A-induced suppressor function was not defective in HAM patients. Therefore, the immune abnormalities and autoimmune-like features observed in HAM/TSP may not result from defective cytotoxic or suppressor cell activities.

Predominant expression of Fas ligand mRNA in CD8+ T lymphocytes in patients with HTLV-1 associated myelopathy.

To determine if Fas ligand (FasL) mediated apoptosis is involved in the pathogenesis of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), we examined the expression of FasL mRNA in fresh uncultured peripheral blood mononuclear cells (PBMC) from 17 Japanese patients with HAM/TSP, four adult T-cell leukemia/lymphoma (ATL) patients, three asymptomatic HTLV-1 carriers and three normal individuals. Using competitive PCR with primers specific for FasL mRNA, we demonstrated that nine of 17 HAM/TSP and one of four ATL patients expressed significant levels of FasL mRNA, whereas asymptomatic carriers, normal controls and both HTLV-1 infected and uninfected T-cell lines did not. Cell separation analysis following PCR revealed that FasL mRNA was expressed in CD8 + T lymphocytes. FasL mRNA was preferentially expressed in patients with increased proviral load and longer duration of clinical illness. These results suggest that FasL mediated mechanisms contribute to the pathogenesis of HAM/TSP.

Detection of the soluble form of the Fas molecule in patients with multiple sclerosis and human T-lymphotropic virus type I-associated myelopathy.

We evaluated the presence of soluble Fas molecule (sFas) in the cerebrospinal fluids (CSF) and the sera of patients with multiple sclerosis (MS) or human T-lymphotropic virus type I (HTLV-I) associated myelopathy (HAM) using an enzyme-linked immunosorbent assay (ELISA). Patients with multiple sclerosis in the active phase had higher sFas serum levels than control (p < 0.005). In addition, significantly increased serum levels of sFas were found in patients with HAM (p < 0.005). We found a significantly increased CSF levels of sFas in patients with HAM and patients with MS in the active stage (p < 0.005). These results suggest that serum sFas may be related to clinical activity in patients with MS and that Fas may play an important role in the pathogenesis of HAM.

CD44 splice variant involvement in the chronic inflammatory disease of the spinal cord: HAM/TSP.

Splice variants of CD44 molecule-harboring exon 10 (v6), often called v6 variants (v6v), are shown to confer tumor progressive, metastatic or invasive capacities. Furthermore, CD44 molecule on activated T-cells are shown to be required for infiltration of these cells into the inflammatory site and for accelerated immune response. Human T-cell lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is caused by HTLV-I infection and characterized by spastic paraparesis and urinary disturbance with perivascular HTLV-I-infected and activated CD4+ T-cell infiltration. In order to explore the underlying mechanism causing the disease after HTLV-I infection, we analyzed CD44 variant expression on peripheral blood mononuclear cells (PBMC) and in the spinal cord specimens from patients with HAM/TSP, and compared them with those from other HTLV-I-infected individuals and controls. We found that v6v expression with special direct link of exons 10 (v6) and 14(v10) was highly expressed in PBMC from patients with HAM/TSP and that v6v and CD4 double positive T-cell infiltration into the spinal cord lesion of HAM/TSP. This combination of CD44 splice variant has not been previously reported in the study of chronic inflammatory disorders and may be a marker molecule for T-cells infiltrating into the central nervous system (CNS), especially the spinal cord.

Preferential recognition of synthetic peptides from HTLV-I gp21 envelope protein by HLA-DRB1 alleles associated with HAM/TSP (HTLV-I-associated myelopathy/tropical spastic paraparesis).

To determine CD4+ T-cell epitopes of HTLV-I-envelope protein recognized by the HLA alleles associated with HAM/TSP, we established 20 CD4+ T-cell lines from peripheral blood mononuclear cells (PBMCs) of naive healthy donors using a panel of synthetic peptides spanning the entire length of HTLV-I-envelope proteins, gp46 and gp21. We quantitated the precursor frequencies of HTLV-1-envelope specific CD4+ T-cells and analyzed epitope specificity in the context of HLA alleles. The precursor frequencies ranged from 3.0 to 10.6 per 10(7) PBMCs in the naive healthy donors. The CD4+ T-cell epitopes of HTLV-I-envelope protein were clustered in amino acids 76 to 90, 136 to 160, 171 to 185 and 196 to 210 of gp46, and in amino acids 366 to 400 and 436 to 485 of gp21. The CD4+ T-cell epitopes of gp21 were preferentially recognized by HLA-DRB1 0101 and 1502 which were known to be associated with HAM/TSP. Thus, it was suggested that HTLV-I gp21 might contain the major CD4+ T-cell epitopes recognized by HLA-DRB1 alleles of HAM/TSP.