Peripheral nerve P2 basic protein and the Guillain-Barré syndrome. In vitro demonstration of P2-specific antibody-secreting cells

Cancer immunotherapy: it's time to better predict patients' response

In less than a decade, half a dozen immune checkpoint inhibitors have been approved and are currently revolutionising the treatment of many cancer (sub)types. With the clinical evaluation of novel delivery approaches (e.g. oncolytic viruses, cancer vaccines, natural killer cell-mediated cytotoxicity) and combination therapies (e.g. chemo/radio-immunotherapy) as well as the emergence of novel promising targets (e.g. TIGIT, LAG-3, TIM-3), the 'immunotherapy tsunami' is not about to end anytime soon. However, this enthusiasm in the field is somewhat tempered by both the relatively low percentage (<15%) of patients who display an effective anti-cancer immune response and the inability to accurately identify them. Recently, several existing or acquired features/parameters have been shown to impact the efficacy of immune checkpoint inhibitors. In the present review, we critically discuss current knowledge regarding predictive biomarkers for checkpoint inhibitor-based immunotherapy, highlight the missing/unclear links and emphasise the importance of characterising each neoplasm and its microenvironment in order to better guide the course of treatment.

Manual plasmapheresis in the treatment of Guillain-Barré syndrome

We report on 41 patients with Guillain-Barré Syndrome (GBS) with disability grade 4 and 5 who were treated with manual plasma exchange (PE). Approximately 20-40 ml/kg body weight of plasma was removed with each manual PE; 63% of patients needed one PE, 24% needed two, 10% needed three, and 2% needed four plasma exchanges. Normal saline, human serum albumin (NSA) and fresh frozen plasma were used in varying proportions as replacement solutions. Ninety-one percent of the patients resumed walking with very little assistance ranging from 4 to 56 days with an average of 25 days from the commencement of the first PE. Manual PE in our series was effective and safe as the reported experience of automated apheresis and less volume of plasma was exchanged in our patients undergoing manual PE when compared to those treated in other studies employing automated PE.

Proximal motor neuropathy, IgA paraproteinaemia and anti-myelin-associated glycoprotein reactivity

We report a case with proximal motor neuropathy associated with benign IgA lambda paraproteinaemia. Immunoblot demonstrated reactivity to myelin-associated glycoprotein and not to P2 protein of peripheral nerve. Dramatic improvement of the polyneuropathy was observed with steroid treatment alone within 4 weeks.

Monoclonal antibodies to P2 basic protein and their use in the investigation of some aspects of the Guillain-Barré syndrome

The production and characterization of two mouse monoclonal antibodies (MAbs) raised against human basic protein P2 is described. The two MAbs recognise two non-overlapping epitopes on P2. Using these two MAbs as a probe, a search was made for the presence of anti-idiotype (Ab2) antibodies directed against anti-P2 (Ab1) autoantibodies in sera of patients with Guillain-Barré syndrome (GBS). In sera of twenty GBS patients no such Ab2 antibodies could be demonstrated. Epitopes present on cytomegalo virus- or Epstein-Barr virus-infected cells, which may play a part in triggering GBS, were not recognised by the two MAbs.

Bovine P2 myelin basic protein crystallizes in three different forms

P2 protein is a minor component of the myelin membrane. We have crystallized this protein for high-resolution crystallographic study. Three crystal morphologies are available. Two of them are from ammonium sulfate, and one is from polyethyleneglycol (PEG). The unit cell of the most suitable crystals from PEG 4000 has the dimensions a = 91.3 A, b = 99.8 A, c = 56.0 A; is of space group P2(1)2(1)2(1); and contains up to four molecules per asymmetric unit. The limit of resolution is 2.7 A.

A prospective study of acute idiopathic neuropathy. III. Immunological studies

The immune responses of 100 patients who presented with an acute idiopathic neuropathy were compared with those of age and sex matched controls. Blood lymphocytes and their subsets were counted with a fluorescent activated cell sorter. CD8+ (putative suppressor) lymphocytes were significantly reduced in the first week of the disease but total lymphocytes, total T and CD4+ (putative helper) cells were not altered. This reduction depended on the nature of the preceding infection. Serum complement C3 and C4 concentrations remained normal and immune complexes were rarely detected with a C1q binding assay. Complement-fixing antibodies to human peripheral nerve antigens were discovered in the serum of 7% of patients but only 1% of controls. Complement-fixing antibodies to galactocerebroside were not discovered in any sera. Enzyme-linked immunoassays detected increased antibody responses to galactocerebroside but none at all to human P2 myelin protein in the patient sera. Forty microliter of serum from five patients injected into the sciatic nerves of rats did not induce significantly more demyelination than the serum from control patients. It is concluded that auto-immune responses can only be detected by these techniques in a small minority of patients with acute idiopathic neuropathy.

Isolation of P2 protein--reactive T-cell lines from human blood

Human T-cell lines reactive with the peripheral nerve myelin protein, P2 protein, were isolated from the peripheral blood of 4 normal persons and 1 patient with Guillain-Barré syndrome. These predominantly helper phenotype T-cell lines were isolated and maintained in vitro by antigen stimulation followed by culture with interleukin 2. Myelin basic protein-reactive T cells were also isolated in parallel from the same subjects as antigen specificity controls. T cells recognizing myelin basic protein did not respond to P2 protein, nor did P2-reactive cells respond to myelin basic protein. These findings suggest that a potential for autoimmune reactivity with peripheral nervous system myelin antigens may exist for both normal persons and some patients with neurological disease.