Esther Hulsenboom

Identification of delta/notch‐like epidermal growth factor‐related receptor as the Tr antigen in paraneoplastic cerebellar degeneration

Anti‐Tr is among the better described autoantibodies in paraneoplastic cerebellar degeneration (PCD) combined with Hodgkin lymphoma (HL); however, the Tr antigen remains unidentified.

The relevance of VGKC positivity in the absence of LGI1 and Caspr2 antibodies

Objective: To assess the clinical relevance of a positive voltage-gated potassium channel (VGKC) test in patients lacking antibodies to LGI1 and Caspr2. Methods: VGKC-positive patients were tested for LGI1 and Caspr2 antibodies. Patients lacking both antibodies were matched (1:2) to VGKC-negative patients. Clinical and paraclinical criteria were used to blindly determine evidence for autoimmune inflammation in both groups. Patients with an inconclusive VGKC titer were analyzed in the same way. Results: A total of 1,455 patients were tested by VGKC radioimmunoassay. Fifty-six patients tested positive, 50 of whom were available to be included. Twenty-five patients had antibodies to LGI1 (n = 19) or Caspr2 (n = 6) and 25 patients lacked both antibodies. Evidence for autoimmune inflammation was present in 7 (28%) of the VGKC-positive patients lacking LGI1 and Caspr2, compared to 9 (18%) of the VGKC-negative controls (p = 0.38). Evidence for autoimmune inflammation was mainly found in patients with limbic encephalitis/encephalomyelitis (57%), but not in other clinical phenotypes (5%, p < 0.01). VGKC titers were significantly higher in patients with antibodies to LGI1 or Caspr2 (p < 0.001). However, antibodies to Caspr2 could also be detected in patients with inconclusive low VGKC titer, while many VGKC-positive patients had no evidence for autoimmune inflammation. Conclusions: VGKC positivity in the absence of antibodies to LGI1 and Caspr2 is not a clear marker for autoimmune inflammation and seems not to contribute in clinical practice. No cutoff value for the VGKC titer was appropriate to discriminate between patients with and without autoimmune inflammation.

Cerebellar degeneration associated with mGluR1 autoantibodies as a paraneoplastic manifestation of prostate adenocarcinoma

Subacute cerebellar degeneration associated with metabotropic glutamate receptor type 1 (mGluR1) autoantibodies is an uncommon syndrome known to be part of the spectrum of paraneoplastic cerebellar degenerations associated with neuronal autoantibodies. We describe a patient with prostate adenocarcinoma who developed a subacute cerebellar ataxia. Autoantibodies specific to mGluR1 were detected in patients serum and cerebrospinal fluid (CSF). Immunohistochemistry analyses of patients prostate adenocarcinoma revealed abundant mGluR1 expression in luminal acinar epithelial cells and binding of patients IgGs to tumoral mGluR1. These findings suggest that cerebellar degeneration associated with mGluR1 antibodies can be a paraneoplastic accompaniment of prostate adenocarcinoma.

Anti-Yo-Associated Paraneoplastic Cerebellar Degeneration in a Man with Adenocarcinoma of the Gastroesophageal Junction

Anti-Yo-associated paraneoplastic cerebellar degeneration is a cancer-related syndrome affecting the nervous system. This syndrome occurs almost exclusively in middle-aged women with gynecological cancers and it is rarerly found in patients with other types of cancer or in males. In this report we describe a male patient adenocarcinoma of the gastroesophageal junction and PCD with anti-Yo antibodies. To our knowledge, this is only the third report of PCD with positive anti-Yo antibodies in an esophageal tumor and the first report in a tumor of the gastroesophageal junction.

Psychiatric phenomena as initial manifestation of encephalitis by anti-NMDAR antibodies

Objective Autoimmune encephalitis associated with autoantibodies against the N‐methyl‐d‐aspartate receptor (NMDAR) often presents with behavioural change. Our objective was to describe in detail the psychiatric presentation and pathways to care in order to aid the early diagnosis of NMDAR encephalitis. Methods Sera and cerebrospinal fluid (CSF) from patients with suspected NMDAR encephalitis were tested on HEK 293 cells transfected with the NR1 subunit of the NMDAR. Clinical information was obtained from the referring psychiatrists and neurologists and by review of the clinical records. Results Samples from 15 patients (13 female, 2 male, mean age 24 years, range 5–56 years) tested anti‐NMDAR positive. Twelve of the 15 patients (80%) presented with prominent psychiatric symptoms and 8 were initially referred to a psychiatric service. The most prominent initial psychiatric symptoms were anxiety in seven (47%), behavioural change (often bizarre) in six (40%) and agitation in five (33%). All patients developed psychiatric symptoms in the first 6 weeks of illness. Thirteen patients received psychotropic medications: antipsychotics in 12 and benzodiazepines in 11. Treating physicians considered the psychotropic medication not effective in 11 patients resulting in many drug switches. At nadir, all patients were in a very poor condition. However, eight patients (53%) recovered (almost) completely. Outcome tended to be better in patients who had received early immunotherapy or tumour removal. Conclusions Autoimmune encephalitis and anti‐NMDAR testing in serum and CSF should be considered in patients, especially young females, presenting with atypical psychiatric phenomena. Early diagnosis and treatment will likely improve the prognosis of NMDAR encephalitis.

A new paraneoplastic encephalomyelitis autoantibody reactive with the axon initial segment.

Serum from a patient with paraneoplastic encephalomyelitis (PEM) and small cell lung cancer (SCLC) showed high titer immunohistochemical staining of the axon initial segment (AIS) on rat and human brain sections. EM studies showed that the antigen was localized in close proximity of the microtubules in the AIS. Double labeling experiments and absence of staining at the nodes of Ranvier excluded the previously identified betaIV spectrin as autoantigen. Screening a rat hippocampal cDNA library resulted in the isolation of ubiquitin-conjugating enzyme E2E1 (UBE2E1). However, blocking and elution experiments excluded UBE2E1 as the AIS autoantigen.

No evidence for the presence of HuD-specific T cells in the cerebrospinal fluid of patients with Huassociated paraneoplastic neurological syndromes

JO N 3051 CD8+ T cells in nervous and tumor tissues and HuD-specific CD8+ T cells in blood of Hu-PNS patients suggests their involvement in neuronal degradation [9, 10, 13, 15]. To investigate the putative role of HuD-specific cellular immunity in the pathogenesis of Hu-PNS, we determined the presence of HuDspecific T cells in the CSF of HuPNS patients. Based on our previous successful detection of virus-specific T cells using the HLA class I multimer technique and IFN-γ ELISPOT assays, we employed the same state-of-the-art techniques here [1–3, 14]. Thirteen patients with high-titer serum Hu-antibodies, a “definite” diagnosis of PNS [4] and progressive neurological disease were included in the study. Their characteristics are shown in Table 1. Four patients with non-inflammatory neurological diseases (i. e., normal pressure hydrocephalus and herniated cervical disc) were included as controls (all male, aged between 52 and 79, Hu-antibody seronegative, no prior chemotherapy or immunosuppression, and expression of either the HLA-A*0101 [n = 2], HLA-A*0201 [n = 1] alleles, or both [n = 1]). Our Institutional Review Board approved the study and all patients provided written informed consent. CSF-derived T cells of patients and controls were expanded [7, 14] and assayed for reactivity against a HuD-protein spanning peptide pool consisting of 15-mer peptides with 11 amino acids overlaps and HuD-derived 9-mer pepJanet W. de Beukelaar Johannes C. Milikan Georges M. Verjans Marieke T. de Graaf Yvette van Norden Cor H. Lamers Martin J. van den Bent Jacoline E. Bromberg Esther Hulsenboom Kees Sintnicolaas Jan W. Gratama Peter A. Sillevis Smitt

Antibodies to TRIM46 are associated with paraneoplastic neurological syndromes

Paraneoplastic neurological syndromes (PNS) are often characterized by the presence of antineuronal antibodies in patient serum or cerebrospinal fluid. The detection of antineuronal antibodies has proven to be a useful tool in PNS diagnosis and the search for an underlying tumor. Here, we describe three patients with autoantibodies to several epitopes of the axon initial segment protein tripartite motif 46 (TRIM46). We show that anti‐TRIM46 antibodies are easy to detect in routine immunohistochemistry screening and can be confirmed by western blotting and cell‐based assay. Anti‐TRIM46 antibodies can occur in patients with diverse neurological syndromes and are associated with small‐cell lung carcinoma.

Plasticity-related gene 5: A novel surface autoantigen in paraneoplastic cerebellar degeneration

Paraneoplastic cerebellar degeneration (PCD) is one of the most frequent paraneoplastic syndromes affecting the CNS. It is associated with antibodies targeting intracellular neuronal antigens (Hu, Yo, Ri, CV2/CRMP5), which are not thought to be directly pathogenic, and surface antigens (DNER, mGluR1, VGCC), which are potentially pathogenic.1,2 However, in many patients the immunologic target remains unidentified, resulting in diagnostic and therapeutic challenges. We report a patient with PCD and a squamous cell lung carcinoma with antibodies to a novel neuronal surface antigen, plasticity-related gene 5 (PRG5).

Abstract 4822: Identifiying the anti-Tr antigen in paraneoplastic cerebellar degeneration

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL Introduction: Paraneoplastic cerebellar degeneration (PCD) is characterized by subacute cerebellar ataxia which coincides with the presence of specific tumour types and antineuronal antibodies. One particular form of PCD is associated with Hodgkin Lymphoma (HL) and the presence of antibodies against cerebellar Purkinje cells in several of these patients’ sera. These later called anti-Tr antibodies recognize a specific punctuate immunoreactivity in the large dendritic tree as well as the soma of the Purkinje cells, but not in the axons. Although this characteristic immunoreactive pattern is considered to be a good hallmark for the presence of anti-Tr antibodies, further diagnosis is elaborate. In order to aid this diagnosis, and to understand the pathogenic nature of the PCD we aimed to identify the antigen recognized by anti-Tr antibodies. Objective: We aimed to identify the long sought antigen recognized by anti-Tr antibodies. Methods: To identify the antigen we performed immunoprecipitation using four anti-Tr positive sera on total rat brain extract followed by mass spectrometry. By Western blotting and cell-based assays we subsequently determined the region of the epitope recognized by the anti-Tr antibodies. Deletion and mutant constructs were generated to further map the antigenic region. Results: We identified Delta/Notch-like epidermal growth factor (EGF)-related Receptor (DNER) as the Tr antigen. In a cell-based screening assay 191 control samples were negative, whereas all of the 12 anti-Tr positive sera stained HA-tagged-DNER expressing cells. Using deletion constructs we pinpointed the main epitope to the extracellular domain. Glycosylation inhibitor tunicamycin and N-glycosylation mutations in DNER abolished the anti-Tr staining, indicating that DNER must be glycosylated to be recognized by anti-Tr antibodies. Conclusion: Anti-Tr positive sera recognize DNER. Using the cell based assay, presence of anti-Tr antibodies in patients with PCD and HL can now be screened both quickly and reliably. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4822. doi:1538-7445.AM2012-4822