Goran Rakocevic

Placebo-Controlled Trial of Rituximab in IgM Anti-Myelin-Associated Glycoprotein Antibody Demyelinating Neuropathy

Report a double‐blind, placebo‐controlled study of rituximab in patients with anti–MAG demyelinating polyneuropathy (A‐MAG‐DP).

Effect of Alemtuzumab (CAMPATH 1-H) in patients with inclusion-body myositis

Sporadic inclusion-body myositis (sIBM) is the most common disabling, adult-onset, inflammatory myopathy histologically characterized by intense inflammation and vacuolar degeneration. In spite of T cell-mediated cytotoxicity and persistent, clonally expanded and antigen-driven endomysial T cells, the disease is resistant to immunotherapies. Alemtuzumab is a humanized monoclonal antibody that causes an immediate depletion or severe reduction of peripheral blood lymphocytes, lasting at least 6 months. We designed a proof-of-principle study to examine if one series of Alemtuzumab infusions in sIBM patients depletes not only peripheral blood lymphocytes but also endomysial T cells and alters the natural course of the disease. Thirteen sIBM patients with established 12-month natural history data received 0.3 mg/kg/day Alemtuzumab for 4 days. The study was powered to capture ≥10% increase strength 6 months after treatment. The primary end-point was disease stabilization compared to natural history, assessed by bi-monthly Quantitative Muscle Strength Testing and Medical Research Council strength measurements. Lymphocytes and T cell subsets were monitored concurrently in the blood and the repeated muscle biopsies. Alterations in the mRNA expression of inflammatory, stressor and degeneration-associated molecules were examined in the repeated biopsies. During a 12-month observation period, the patients’ total strength had declined by a mean of 14.9% based on Quantitative Muscle Strength Testing. Six months after therapy, the overall decline was only 1.9% (P < 0.002), corresponding to a 13% differential gain. Among those patients, four improved by a mean of 10% and six reported improved performance of daily activities. The benefit was more evident by the Medical Research Council scales, which demonstrated a decline in the total scores by 13.8% during the observation period but an improvement by 11.4% (P < 0.001) after 6 months, reaching the level of strength recorded 12 months earlier. Depletion of peripheral blood lymphocytes, including the naive and memory CD8+ cells, was noted 2 weeks after treatment and persisted up to 6 months. The effector CD45RA+CD62L cells, however, started to increase 2 months after therapy and peaked by the 4th month. Repeated muscle biopsies showed reduction of CD3 lymphocytes by a mean of 50% (P < 0.008), most prominent in the improved patients, and reduced mRNA expression of stressor molecules Fas, Mip-1a and αB-crystallin; the mRNA of desmin, a regeneration-associated molecule, increased. This proof-of-principle study provides insights into the pathogenesis of inclusion-body myositis and concludes that in sIBM one series of Alemtuzumab infusions can slow down disease progression up to 6 months, improve the strength of some patients, and reduce endomysial inflammation and stressor molecules. These encouraging results, the first in sIBM, warrant a future study with repeated infusions (Clinical Trials. Gov NCT00079768).

Inclusion body myositis with human immunodeficiency virus infection: Four cases with clonal expansion of viral‐specific T cells

Sporadic inclusion body myositis (sIBM), a common adult‐onset myositis, is characterized by an antigen‐driven inflammatory response and vacuolar degeneration. The cause is unknown. We report the association of sIBM with human immunodeficiency virus (HIV) infection and explore the clonality and viral specificity of the autoinvasive T cells.

Stiff person syndrome with cerebellar disease and high-titer anti-GAD antibodies

We report five of 38 patients with stiff person syndrome (SPS), who also had cerebellar disease, gait ataxia, dysarthria, and oculomotor dysfunction (SPS-Cer). Cerebellar manifestations either preceded SPS or occurred concurrently. Brain MRI was normal. The intrathecal production of glutamic acid decarboxylase antibodies was elevated. γ-Aminobutyric acid–enhancing drugs and immunotherapies improved only the stiffness. SPS-Cer is a distinct subset of SPS causing a more severe and complex clinical phenotype.

Intravenous immune globulin in hereditary inclusion body myopathy: a pilot study

BackgroundHereditary Inclusion Body Myopathy (HIBM) is an autosomal recessive, adult onset, non-inflammatory neuromuscular disorder with no effective treatment. The causative gene, GNE, codes for UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase, which catalyzes the first two reactions in the synthesis of sialic acid. Reduced sialylation of muscle glycoproteins, such as α-dystroglycan and neural cell adhesion molecule (NCAM), has been reported in HIBM.MethodsWe treated 4 HIBM patients with intravenous immune globulin (IVIG), in order to provide sialic acid, because IgG contains 8 μmol of sialic acid/g. IVIG was infused as a loading dose of 1 g/kg on two consecutive days followed by 3 doses of 400 mg/kg at weekly intervals.ResultsFor all four patients, mean quadriceps strength improved from 19.0 kg at baseline to 23.2 kg (+22%) directly after IVIG loading to 25.6 kg (+35%) at the end of the study. Mean shoulder strength improved from 4.1 kg at baseline to 5.9 kg (+44%) directly after IVIG loading to 6.0 kg (+46%) at the end of the study. The composite improvement for 8 other muscle groups was 5% after the initial loading and 19% by the end of the study. Esophageal motility and lingual strength improved in the patients with abnormal barium swallows. Objective measures of functional improvement gave variable results, but the patients experienced improvements in daily activities that they considered clinically significant. Immunohistochemical staining and immunoblotting of muscle biopsies for α-dystroglycan and NCAM did not provide consistent evidence for increased sialylation after IVIG treatment. Side effects were limited to transient headaches and vomiting.ConclusionThe mild benefits in muscle strength experienced by HIBM patients after IVIG treatment may be related to the provision of sialic acid supplied by IVIG. Other sources of sialic acid are being explored as treatment options for HIBM.

Rituximab induces sustained reduction of pathogenic B cells in patients with peripheral nervous system autoimmunity

The B cell-depleting IgG1 monoclonal antibody rituximab can persistently suppress disease progression in some patients with autoimmune diseases. However, the mechanism underlying these long-term beneficial effects has remained unclear. Here, we evaluated Ig gene usage in patients with anti-myelin-associated glycoprotein (anti-MAG) neuropathy, an autoimmune disease of the peripheral nervous system that is mediated by IgM autoantibodies binding to MAG antigen. Patients with anti-MAG neuropathy showed substantial clonal expansions of blood IgM memory B cells that recognized MAG antigen. The group of patients showing no clinical improvement after rituximab therapy were distinguished from clinical responders by a higher load of clonal IgM memory B cell expansions before and after therapy, by persistence of clonal expansions despite efficient peripheral B cell depletion, and by a lack of substantial changes in somatic hypermutation frequencies of IgM memory B cells. We infer from these data that the effectiveness of rituximab therapy depends on efficient depletion of noncirculating B cells and is associated with qualitative immunological changes that indicate reconfiguration of B cell memory through sustained reduction of autoreactive clonal expansions. These findings support the continued development of B cell-depleting therapies for autoimmune diseases.

T cell receptor profiling in muscle and blood lymphocytes in sporadic inclusion body myositis.

Background: Sporadic IBM (sIBM) is characterized by invasion of non-necrotic MHC-I class-expressing muscle fibers by clonally expanded CD8+ cells. Whether the endomysial cells expand in situ or are recruited from the circulation is unclear. Methods: We used CDR3 spectratyping of the T cell receptor (TCR) Vβ chains to determine clonal expansion of T cells in simultaneously obtained muscle and peripheral blood lymphocytes (PBL) from 12 patients with sIBM, and compared the difference between the two compartments. To determine whether the identified clones belonged to autoinvasive T cells, we performed immunohistochemistry on the same muscle specimens. Spectratyping was repeated in four muscle biopsies 1 year after the first. Results: In control PBL, all 24 TCR Vβ subfamilies had a polyclonal or Gaussian distribution. In sIBM PBL, 5% of the Vβ subfamilies demonstrated a single and 16% up to three peaks. In contrast, in their corresponding muscles, 27% (p = 0.0003) of the Vβ subfamilies demonstrated a single and 71% (p < 0.0001) up to three peaks. Among the amplified subfamilies, Vβ 9, 10, 11, 16, 18, 23, and 24 showed the highest degree of restriction within muscle. Immunohistochemistry demonstrated that the clonally expanded CD8+ cells were autoinvasive. In follow-up biopsies the clonality persisted with an unchanged degree of restriction, but not always of the same subfamilies, suggesting epitope spreading. Conclusion: In sporadic inclusion body myositis, the endomysial T cells are specifically recruited to the muscle or expand in situ. The restriction of multiple Vβ subfamilies and their change over time suggests recognition of various local antigens and epitope spreading. GLOSSARY: CDR3 = complementarity-determining-region 3; CK = creatine kinase (normal range 52 to 386 U/L); DAPI = 6-diamidino-2-phenylindole; MRC = Medical Research Council; PBL = peripheral blood lymphocytes; RT-PCR = reverse transcription PCR; sIBM = sporadic inclusion body myositis; TCR = T cell receptor.

Autoimmune stiff person syndrome and related myelopathies: Understanding of electrophysiological and immunological processes

Stiff person syndrome (SPS) is a disabling autoimmune central nervous system disorder characterized by progressive muscle rigidity and gait impairment with superimposed painful spasms that involve axial and limb musculature, triggered by heightened sensitivity to external stimuli. Impaired synaptic GABAergic inhibition resulting from intrathecal B‐cell–mediated clonal synthesis of autoantibodies against various presynaptic and synaptic proteins in the inhibitory neurons of the brain and spinal cord is believed to be an underlying pathogenic mechanism. SPS is most often idiopathic, but it can occur as a paraneoplastic condition. Despite evidence that anti‐GAD and related autoantibodies impair GABA synthesis, the exact pathogenic mechanism of SPS is not fully elucidated. The strong association with several MHC‐II alleles and improvement of symptoms with immune‐modulating therapies support an autoimmune etiology of SPS. In this review, we discuss the clinical spectrum, neurophysiological mechanisms, and therapeutic options, including a rationale for agents that modulate B‐cell function in SPS. Muscle Nerve, 2012

A neuropsychological assessment of phobias in patients with stiff person syndrome

A neuropsychological assessment was performed in 10 patients with stiff person syndrome (SPS) to determine whether their anxiety and phobic symptoms precede stiffness and spasms or represent a reaction to disability. No neurocognitive dysfunction was noted. Patients perceived fears and anxiety as realistic and caused by SPS rather than due to an inherent phobic neurosis.

HIV Infection and Antiretroviral Therapy Have Divergent Effects on Mitochondria in Adipose Tissue

BACKGROUND Although human immunodeficiency virus (HIV) infection and antiretroviral therapy (ART) affect mitochondrial DNA (mtDNA) content and function, comprehensive evaluations of their effects on mitochondria in muscle, adipose tissue, and blood cells are limited. METHODS Mitochondrial DNA quantification, mitochondrial genome sequencing, and gene expression analysis were performed on muscle, adipose tissue, and peripheral blood mononuclear cell (PBMC) samples from untreated HIV-positive patients, HIV-positive patients receiving nucleoside reverse transcriptase inhibitor (NRTI)-based ART, and HIV-negative controls. RESULTS The adipose tissue mtDNA/nuclear DNA (nDNA) ratio was increased in untreated HIV-infected patients (ratio, 353) and decreased in those receiving ART (ratio, 162) compared with controls (ratio, 255; P < .05 for both comparisons); the difference between the 2 HIV-infected groups was also significant (P = .002). In HIV-infected participants, mtDNA/nDNA in adipose tissue correlated with the level of activation (CD38+ /HLA-DR+) for CD4+ and CD8+ lymphocytes. No significant differences in mtDNA content were noted in muscle or PMBCs among groups. Exploratory DNA microarray analysis identified differential gene expression between patient groups, including a subset of adipose tissue genes. CONCLUSIONS HIV infection and ART have opposing effects on mtDNA content in adipose tissue; immune activation may mediate the effects of HIV, whereas NRTIs likely mediate the effects of ART.