Bo Höjeberg

Immunoblot detection of oligoclonal anti‐myelin basic protein IgG antibodies in cerebrospinal fluid in multiple sclerosis

Migration properties and occurrence of antibodies against myelin basic protein (MBP) in paired CSF and serum specimens from patients with multiple sclerosis (MS) were demonstrated after agarose isoelectric focusing, immunoblot transfer, and immunoperoxidase staining. Oligoclonal IgG antibody bands directed against MBP were found in the CSF of 9 of 28 patients with MS (32%), but not in the CSF of any of 34 patients with other neurologic diseases. No serum showed anti-MBP antibody bands. The CSF anti-MBP antibodies migrated to the anodal region of the IgG area in a different fashion from oligoclonal IgG and anti-measles IgG antibodies, which were detected in parallel. The anti-MBP bands were transient in three of seven patients whom we studied consecutively. Enzyme-linked immunosorbent assay (ELISA) of serum and CSF for detection of IgG reactivity against MBP showed absorbance values above 2 standard deviations of controls in 44% of the MS patients and in 21% of those with other neurologic diseases. Results of this assay correlated partly with those of the immunoblot assay. ELISA positive and immunoblot negative results might be due to a broad polyclonal anti-MBP antibody response.

Organ‐specific autoantigens induce interferon‐γ and interleukin‐4 mRNA expression in mononuclear cells in multiple sclerosis and myasthenia gravis

T cells recognizing the myelin components myelin basic protein (MBP) and proteolipid protein (PLP) are increased in multiple sclerosis (MS), and there are elevated numbers of T cells recognizing the nicotinic acetylcholine receptor (AChR) in myasthenia gravis (MG). However, the cytokine repertoires in these diseases are largely unknown. We adopted in situ hybridization with radiolabeled complementary DNA oligonucleotide probes to enumerate mononuclear cells that expressed the T-helper type 1 (Th1) cell-related interferon-γ (IFN-γ) and Th2-associated interleukin-4 (IL-4) after short-term culture in the presence of autoantigen. High numbers of IFN-γ and IL-4 mRNA-expressing cells in response to MBP and PLP were detected in patients with untreated MS, and to AChR in MG. The levels of IFN-γ and IL-4 mRNA-positive cells in MS after culture in the presence of AChR, and in MG after culture in the presence of MBP or PLP, did not differ from those detected after culture without antigen. The CSF of MS patients contained four- to eightfold more myelin protein-reactive IFN-γ and IL-4 expressing cells. The findings imply that MS and MG are associated with mixed Th1- and Th2-like cell responses directed to organ-specific target antigens.

Cells secreting antibodies to myelin basic protein in cerebrospinal fluid of patients with Lyme neuroborreliosis

An autoimmune response to myelin basic protein (MBP) has been proposed to participate in the development of the chronic neurologic manifestations that may accompany Borrelia burgdorferi-induced Lyme disease. Using an immunospot assay, we counted cells secreting antibodies to MBP. Anti-MBP IgG antibody-secreting cells were detected in CSF from eight of 13 consecutive patients with Lyme neuroborreliosis irrespective of stage of disease. The numbers were between 1/370 and 1/5,000 CSF cells (mean, 1/1,250 in the 13 patients). The highest numbers were encountered in two patients with severe signs of CNS involvement. The numbers decreased in parallel with clinical improvement after treatment. Anti-MBP IgG antibody-secreting cells were also observed in the CSF from patients with a variety of other inflammatory diseases of the nervous system, and their role in the development of tissue damage remains unsettled. Anti-MBP IgG antibody-secreting cells were not detected in the patients blood, reflecting accumulation of this autoantibody response to CSF.

Shift from anti-to proinflammatory cytokine profiles in microglia through Lps-or Ifn-γ-mediated pathways

In this study, cytokine mRNA profiles in microglia from newborn rats were detected by in situ hybridization. Under natural culture conditions, microglia expressed the immunosuppressive transforming growth factor-beta 1 (TGF-beta 1) and interleukin (IL) 10 to a greater degree than the pro-inflammatory cytokines IL-1 beta, IL-6, IL-12, interferon-gamma (IFN-gamma) and TNF-alpha. High TGF-beta 1 and IL-10 levels could reflect one mechanism for immune privilege within the CNS under physiological conditions. Stimulation of microglia with LPS or IFN gamma resulted in strong up-regulation of proinflammatory cytokines, while TGF-beta 1 and IL-10 were down-regulated. These effects of LPS or IFN-gamma are anticipated to reflect immunopathogenic processes within the CNS.

Increased systemic B- and T-lymphocyte responses in hereditary motor and sensory neuropathy (HMSN I).

Immune mechanisms of possible importance for the development and maintenance of peripheral nerve myelin breakdown in HMSN I were analysed by measuring B- and T-cell activation in blood, bone marrow and cerebrospinal fluid. Patients with polyneuropathies of other etiologies served as one control group and patients with tension headache as another. Flow cytometry of blood and bone marrow mononuclear cells revealed that an increased number of CD3+, CD4+ and CD4- CD8- T-cells expressed a late stage activation marker (Ta1). Analysis of T-cells primed for myelin antigens, by studies of IFN-gamma secretion in response to antigen in vitro, showed that both HMSN I and other polyneuropathy patients had low (but significant) numbers of T-cells recognizing whole PNS-myelin. Increased numbers of IgG- and IgM-producing cells were found in blood and bone marrow in the HMSN I patients. Patients with both HMSN I and the other polyneuropathies had few cells in peripheral blood and in bone marrow producing antibodies binding to P2, MAG and MBP in a solid phase immunospot assay. Many cells in the cerebrospinal fluid produced antibodies against MAG. Thus, there was a strong general activation of B- and T-cells in HMSN I while the immunity directed toward peripheral nerve was only slightly elevated. It is an open question if this immune activation is related to the primary gene defect or a secondary event to the nerve damage. The pathogenetic importance of the immune response in maintaining the nerve damage in HMSN I is unclear.