Peter A. Csurhes

Variation in The Vitamin D Receptor Gene is Associated With Multiple Sclerosis in an Australian Population

Multiple Sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS) resulting in accumulating neurological disability. The disorder is more prevalent at higher latitudes. To investigate VDR gene variation using three intragenic restriction fragment length polymorphisms (Apa I, Taq I and Fok I) in an Australian MS case-control population. One hundred and four Australian MS patients were studied with patients classified clinically as Relapsing Remitting MS (RR-MS), Secondary Progressive MS (SP-MS) or Primary Progressive MS (PP-MS). Also, 104 age-, sex-, and ethnicity-matched controls were investigated as a comparative group. Our results show a significant difference of genotype distribution frequency between the case and control groups for the functional exon 9 VDR marker Taq I (pGen = 0.016) and interestingly, a stronger difference for the allelic frequency (pAll = 0.0072). The Apa I alleles were also found to be associated with MS (pAll = 0.04) but genotype frequencies were not significantly different from controls (pGen = 0.1). The Taq and Apa variants are in very strong and significant linkage disequilibrium (D′ = 0.96, P < 0.0001). The genotypic associations are strongest for the progressive forms of MS (SP–MS and PP–MS). Our results support a role for the VDR gene increasing the risk of developing multiple sclerosis, particularly the progressive clinical subtypes of MS.

Decreased T cell reactivity to Epstein–Barr virus infected lymphoblastoid cell lines in multiple sclerosis

Objective: To investigate T cell and antibody immunity to Epstein–Barr virus (EBV) in multiple sclerosis (MS). Methods: Immunoglobulin G (IgG) immunity to EBV nuclear antigen 1 (EBNA1) and viral capsid antigen was measured by enzyme linked immunosorbent assays, and T cell immunity was assessed using enzyme linked immunospot assays to measure the frequency of peripheral blood mononuclear cells (PBMC) producing interferon γ in response to autologous EBV infected B cell lymphoblastoid cell lines (LCL) in 34 EBV seropositive healthy subjects and 34 EBV seropositive patients with MS who had not received immunomodulatory therapy in the previous 3 months. Results: Patients with MS had increased levels of anti-EBNA1 IgG but a decreased frequency of LCL specific T cells compared with healthy subjects. Using purified populations of CD4+ T cells and CD8+ T cells, we showed that the LCL specific response resides predominantly in the CD8+ population, with a frequency 5–7-fold higher than in the CD4+ population. The decreased CD8+ T cell response to LCL in MS was not caused by decreased HLA class I expression by LCL, and LCL from MS patients could be killed normally by HLA matched EBV specific cytotoxic CD8+ T cell clones from healthy subjects. Furthermore, the decreased CD8+ T cell immunity to EBV was not due to a primary defect in the function of CD8+ T cells because EBV specific cytotoxic CD8+ T cell lines could be generated normally from the PBMC of patients with MS. Conclusion: This quantitative deficiency in CD8+ T cell immunity to EBV might be responsible for the accumulation of EBV infected B cells in the brains of patients with MS.

Surges of Increased T Cell Reactivity to an Encephalitogenic Region of Myelin Proteolipid Protein Occur More Often in Patients with Multiple Sclerosis Than in Healthy Subjects

We have previously shown that patients with multiple sclerosis (MS) have increased T cell responses to the immunodominant region (residues 184–209) of myelin proteolipid protein (PLP). The present study investigated whether this reactivity fluctuates over time and correlates with disease activity. We performed monthly limiting dilution assays for 12–16 mo in four healthy subjects and five patients with relapsing-remitting MS to quantify the frequencies of circulating T cells proliferating in response to PLP41–58, PLP184–199, PLP190–209, myelin basic protein (MBP), MBP82–100, and tetanus toxoid. Disease activity was monitored by clinical assessment and gadolinium-enhanced magnetic resonance imaging of the brain. There were fluctuations in the frequencies of autoreactive T cells in all subjects. Compared with healthy controls, MS patients had significantly more frequent surges of T cells reactive to the 184–209 region of PLP, but infrequent surges of T cell reactivity to MBP82–100. There was temporal clustering of the surges of T cell reactivity to MBP82–100 and MBP, suggesting T cell activation by environmental stimuli. Some clinical relapses were preceded by surges of T cell reactivity to PLP184–209, and in one patient there was significant correlation between the frequency of T cells reactive to PLP184–199 and the total number of gadolinium-enhancing magnetic resonance imaging lesions. However, other relapses were not associated with surges of T cell reactivity to the Ags tested. T cells reactive to PLP184–209 may contribute to the development of some of the CNS lesions in MS.

T cell reactivity to P0, P2, PMP-22, and myelin basic protein in patients with Guillain-Barré syndrome and chronic inflammatory demyelinating polyradiculoneuropathy

Objectives: It has been suggested that autoimmunity to peripheral myelin proteins is involved in the pathogenesis of Guillain-Barré syndrome (GBS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). We aimed to compare reactivity of peripheral blood mononuclear cells (PBMC) to antigens of peripheral myelin proteins in patients with GBS and patients with CIDP with that of healthy controls and patients with other non-immune mediated neuropathies (ON). Methods: We prepared PBMC from blood from 83 healthy controls and from 64 patients with GBS, 54 with CIDP, and 62 with ON. PBMC were tested in antigen specific proliferation assays against peptides from myelin proteins P0, P2, PMP22, and myelin basic protein (MBP), which is identical to myelin P1, and against whole human MBP. Interferon-gamma (IFN-γ) and interleukin (IL)-5 enzyme linked immunospot (ELISPOT) assays were also performed in some subjects to assess spontaneous and peripheral myelin antigen specific PBMC cytokine secretion. Results: Antigen specific PBMC proliferation assays showed no significant elevation of peptide specific T cell responsiveness in patients with GBS or CIDP compared with healthy controls or patients with ON. Levels of spontaneous ELISPOT IFN-γ secretion were increased in patients with GBS and significantly increased in those with CIDP compared with healthy controls and patients with ON. No convincing differences in antigen specific ELISPOT IFN-γ secretion levels to individual peptides were detectable in patients with GBS. The proportion of patients with CIDP with an increased number of PBMC producing IFN-γ in response to peptide PMP-2251–64 was significantly increased compared with healthy controls and patients with ON. No significant differences in antigen specific ELISPOT IL-5 secretion levels were detectable in patients with GBS or CIDP compared with controls, but levels of spontaneous IL-5 secretion were significantly higher in patients with CIDP than in healthy controls or patients with ON. Conclusions: Although the lack of significantly increased antigen specific PBMC proliferation in GBS and CIDP does not support a role for T cells, the more sensitive ELISPOT technique detected increased numbers of PBMC secreting IFN-γ spontaneously in 25% of patients with GBS, providing further evidence for a role of T cells in the immunopathology of GBS. Increased numbers of spontaneous IFN-γ and IL-5 secreting cells, and increased IFN-γ secretion in response to PMP-2251–64, in patients with CIDP provide further evidence for a role of myelin specific T cells in CIDP.

Increased circulating T cell reactivity to GM3 and GQ1b gangliosides in primary progressive multiple sclerosis

We have previously shown that patients with primary progressive multiple sclerosis (MS) have significantly elevated plasma levels of antibody to GM3 ganglioside compared to patients with relapsing-remitting MS, healthy subjects and patients with other neurological diseases. Anti-GM3 antibody levels were elevated also in patients with secondary progressive MS but to a lesser extent than in primary progressive MS. As gangliosides are particularly enriched in the axonal membrane, these findings suggested that antiganglioside immune responses might contribute to the axonal damage in progressive forms of MS. The present study was performed to determine whether peripheral blood T cell responses to GM3 are also increased in progressive MS. Blood was collected from 98 untreated patients with MS (40 with relapsing-remitting, 27 with secondary progressive and 31 with primary progressive MS), 50 healthy subjects and 24 patients with other disorders of the CNS, and reactivity to GM1, GM3, GD1a, GD1b, GD3, GT1b, GQ1b and sulphatide was assessed by 6-day T cell proliferation assays. Increased T cell reactivity to GM3 and GQ1b occurred significantly more often in patients with primary progressive MS than in healthy subjects and patients with other CNS diseases. These findings suggest that ganglioside-specific T cells may contribute to the axonal damage in primary progressive MS.

Antibody responses to peptides of peripheral nerve myelin proteins P0 and P2 in patients with inflammatory demyelinating neuropathy

Background: Antibodies with reactivity to peripheral nerve myelin have previously been found in the serum, and bound to peripheral nerves of patients with Guillain–Barré syndrome (GBS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Aim: To investigate the presence of antibodies reactive to specific peptide sequences within the myelin proteins P0 and P2 in patients with GBS, in patients with CIDP, in healthy controls and in patients with other neuropathies (ON). Methods: Blood was obtained from 48 patients with GBS, 36 with CIDP, 48 with ON and 38 controls. ELISA was used to detect antibody responses to peptides of the human peripheral myelin proteins P0 and P2. Blood samples were collected from patients with GBS in early, peak and recovery stages of GBS to analyse antibody levels throughout the course of the disease. Results: Significantly increased total IgG levels were found in patients with GBS compared with other groups. A higher percentage of patients with GBS at the peak of disease had antibody reactivity to P214–25 compared with patients with CIDP and control groups. In patients with GBS and CIDP, the percentages of patients with antibody reactivity to P261–70, and peptides derived from P0, were comparable to the control groups. Although some individual patients with GBS had high titres of reactivity to the peptide antigens tested, most patients with GBS and CIDP had levels of antibody similar to controls. Conclusion: Our data suggest that increased IgG levels and increased antibody reactivity to P2 14–25 in patients with GBS at the peak of disease may play a contributory role in the disease process in some patients with demyelinating forms of GBS.

Correlation of Blood T Cell and Antibody Reactivity to Myelin Proteins with HLA Type and Lesion Localization in Multiple Sclerosis

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the CNS. The numbers of autoimmune T cells and Abs specific for proteins of CNS myelin are increased in the blood in some patients with MS. The aim of this study was to investigate whether there are correlations between the specificity of the autoimmune responses in the blood, the HLA molecules carried by the patient, and the clinical features of MS, because studies on experimental autoimmune encephalomyelitis, an animal model of MS, indicate that autoimmune responses targeting particular myelin proteins and the genetic background of the animal play a role in determining the pattern of lesion distribution. We tested blood T cell immunoreactivity to myelin proteins in 100 MS patients, 70 healthy controls, and 48 patients with other neurological disorders. Forty MS patients had strongly increased T cell reactivity to one or more myelin Ags. In these 40 patients, the most robust correlation was between CD4+ T cell reactivity to myelin proteolipid protein residues 184–209 (PLP184–209) and development of lesions in the brainstem and cerebellum. Furthermore, carriage of HLA-DR4, -DR7, or -DR13 molecules by MS patients correlated with increased blood T cell immunoreactivity to PLP184–209, as well as the development of lesions in the brainstem and cerebellum. Levels of PLP190–209-specific Abs in the blood also correlated with the presence of cerebellar lesions. These findings show that circulating T cells and Abs reactive against specific myelin Ags can correlate with lesion distribution in MS and suggest that they are of pathogenic relevance.

Epstein–Barr virus-specific adoptive immunotherapy for progressive multiple sclerosis

Defective control of Epstein–Barr virus (EBV) infection by cytotoxic CD8+ T cells might predispose to multiple sclerosis (MS) by allowing EBV-infected autoreactive B cells to accumulate in the central nervous system. We have treated a patient with secondary progressive MS with in vitro-expanded autologous EBV-specific CD8+ T cells directed against viral latent proteins. This adoptive immunotherapy had no adverse effects and the patient showed clinical improvement with reduced disease activity on magnetic resonance imaging and decreased intrathecal immunoglobulin production. This is the first report of the use of EBV-specific adoptive immunotherapy to treat MS or any other autoimmune disease.

Increased circulating T cell reactivity to GM1 ganglioside in patients with Guillain–Barré syndrome

This study was performed to determine whether increased ganglioside-specific T cell reactivity can be detected in the peripheral blood of patients with Guillain-Barre syndrome (GBS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). T cell responsiveness to the gangliosides GM1, GM3, GD1a, GD1b, GD3, GT1b, GQ1b and sulphatide was assessed in peripheral blood mononuclear cells from untreated GBS patients (57), CIDP patients (43), patients with other peripheral neuropathies (55) and healthy control subjects (74) in a standard 6-day proliferation assay. Increased T cell reactivity to GM1 occurred in GBS patients compared to healthy controls and patients with other neuropathies. There was increased reactivity to GM3 in GBS patients compared to patients with other neuropathies but not compared to healthy controls. The frequencies of increased T cell reactivity to GM1 and GM3 in CIDP patients were intermediate between those of GBS patients and controls. We suggest that T cell reactivity to gangliosides might play a contributory role in the pathogenesis of GBS and perhaps CIDP.

Early pregnancy factor suppresses the infiltration of lymphocytes and macrophages in the spinal cord of rats during experimental autoimmune encephalomyelitis but has no effect on apoptosis.

Early pregnancy factor (EPF) is a secreted protein with immunosuppressive and growth factor properties that has been shown to suppress acute experimental autoimmune encephalomyelitis (EAE) induced with myelin basic protein (MBP) in Lewis rats. EAE is associated with infiltration of the central nervous system (CNS) with inflammatory cells. Spontaneous recovery involves the loss of T lymphocytes from the CNS and the selective apoptosis of Vbeta8.2+ cells. In the present study, T cell, macrophage (CD11b/c+) and B cell (CD45RA+) populations in spinal cord and popliteal lymph nodes (LN) of Lewis rats with EAE were quantitated and apoptosis was studied. Rats were treated with EPF or vehicle. Following treatment on day 14 after inoculation with MBP, neither 1 x 100 microg nor 2 x 100 microg doses of EPF affected the total number of cells infiltrating the spinal cord on day 15, although the higher dose caused a decrease in the number of CD5+ and CD11b/c+ cells. Treatment with 2 x 100 microg/day from days 10 to 14 decreased the total number of infiltrating cells, and the numbers of CD5+, CD11b/c+ and CD45RA+ cells. Apoptosis was unaffected. No alteration on the number or type of inflammatory cells in the popliteal LN was observed after treatment on days 10-14. However, treatment with EPF from days 0 to 11 increased the total number of T and B cells and CD5+ T cells found on day 12 in the LN. Similarly, there was an increase in the frequency of MBP-reactive cells in the LN as determined by limiting dilution analysis. These results suggest that EPF treatment reduces the numbers of lymphocytes and macrophages in the CNS, possibly through an effect on cell trafficking.