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Large-scale analysis of herpesviridae in epilepsy-patients with signs of autoimmune encephalitis
Seizure 53 (2017) 100–102
Contents lists available at ScienceDirect
Seizure journal homepage: www.elsevier.com/locate/yseiz
Short communication
Large-scale analysis of herpesviridae in epilepsy-patients with signs of autoimmune encephalitis Freya Poulheima , Laura Espositoa , Christian E. Elgerb , Anna M. Eis-Hübingerc, Albert J. Beckera,d, Pitt Niehusmanna,e,* a
Dept. of Neuropathology, University of Bonn Medical Center, Germany Dept. of Epileptology, University of Bonn Medical Center, Germany Institute of Virology, University of Bonn Medical Center, Germany d Translational Epilepsy Research Section, University of Bonn Medical Center, Germany e Dept. of Neuro-/Pathology, Oslo University Hospital, Norway b c
A R T I C L E I N F O
A B S T R A C T
Article history: Received 18 September 2017 Received in revised form 12 November 2017 Accepted 16 November 2017 Available online xxx
Purpose: Epilepsy is one of the most common primary brain disorders. Nonparaneoplastic autoimmune encephalitis is increasingly recognized as an important cause of adult onset epilepsy. However, only in rare cases an initiating factor of the syndrome can be identified. Autoantibody detection after central nervous herpesvirus infection indicates a postviral etiology in a subgroup of patients. In order to analyze a possible underrecognition of postinfectious autoimmunity we performed a large-scale analysis of herpesvirus DNA in cerebrospinal fluid samples from patients with clinical signs of autoimmune encephalitis. Methods: Real time PCR for HSV 1/2, CMV, EBV, VZV, HHV-6A, HHV-6B, HHV-7 and HHV-8 was performed in cerebrospinal fluid samples from 113 patients with epilepsy and suspected autoimmune encephalitis. Indirect immunofluorescence analysis was used for autoantibody analysis. Results: Antineuronal autoantibodies could be identified in 48 patients with definite autoimmune encephalitis. No autoantibodies were detected in 65 additional patients with probable or possible autoimmune encephalitis. Real-time PCR analysis revealed in three autoantibody-negative patients positive results for HSV, but no evidence for further virus DNA. Conclusion: The findings argue against longstanding herpesvirus infection of the CNS as frequent trigger for autoimmunity. However, appearance of autoantibodies after a short period of active virus infection cannot be excluded. © 2017 Published by Elsevier Ltd on behalf of British Epilepsy Association.
Keywords: Herpesvirus Epilepsy GAD NMDAR Encephalitis
1. Introduction Over the past 10 years the role of neuroinflammation has been increasingly implicated in the pathophysiology of epilepsy. Particularly in patients with adult-onset epilepsy, but increasingly also in children, autoantibody associated autoimmune encephalitis has been identified as a cause of seizures [1]. In most cases the trigger for the formation of autoantibodies is unknown. However, herpes simplex virus (HSV) encephalitis has been reported as a trigger of brain autoimmunity and particularly N-methyl-Daspartate receptor (NMDAR) antibodies were identified in sera and cerebrospinal fluid (CSF) of patients with HSV encephalitis [2].
* Corresponding author at: Dept. of Neuro-/Pathology, Oslo University Hospital, Rikshospitalet, Postbox 4950, Nydalen, 0424, Oslo, Norway. E-mail address: [email protected] (P. Niehusmann). https://doi.org/10.1016/j.seizure.2017.11.012 1059-1311/© 2017 Published by Elsevier Ltd on behalf of British Epilepsy Association.
There is evidence, that virus induced autoimmune response with autoantibody generation is a more widespread mechanism not confined to HSV and NMDAR antibodies [3]. Indeed, infection with another member of the herpesvirus family, human herpes virus 6 (HHV-6), has been reported in patients with autoimmune encephalitis and autoantibodies against glutamic acid decarboxylase (GAD) [4–6]. In a recent study on 346 fresh frozen epilepsy surgery tissue samples, we detected a higher HHV–6 B virus load in epilepsy samples than in controls [7]. HHV–6 B DNA was particularly observed in patients with clinical signs of previous brain inflammation (15%) and less frequent in patients without history of febrile seizures or meningoencephalitis. Based on these observations, we aimed to address in detail a potential connection between CNS infection with herpesviruses and autoimmune encephalitis. As immunotherapy is the treatment
F. Poulheim et al. / Seizure 53 (2017) 100–102
of choice in patients with autoimmune encephalitis, biopsy tissue is only exceptionally available. Therefore, we collected CSF samples from patients with proven or highly suspected autoimmune encephalitis for analysis. 2. Patients and methods 2.1. Patients Archived and frozen CSF samples from 113 patients with seizures, and MRI features suggestive of autoimmune encephalitis, new onset working memory deficit, altered mental status or psychiatric symptoms were included in the study. Patients with reasonable alternative cause of symptoms (e.g. trauma, brain malformation, metabolic encephalopathy, drug toxicity, neoplastic disorder) were excluded. 93 patients (82%) had a seizure onset within the last 5 years before CSF sampling. In 61 patients (54%) the CSF sampling was performed within 24 months after the first reported seizure. The remaining patients had substantial progressive symptoms within the last 5 years, which resulted in referral to the tertiary care center as well as MRI features suggestive of autoimmune encephalitis, new onset working memory deficit, altered mental status or psychiatric symptoms. All patients were treated at the Bonn Epilepsy Center. All procedures were conducted in accordance with the Declaration of Helsinki. Informed written consent was obtained from all patients. 2.2. DNA extraction The QIAamp MinElute Virus Spin Kit (Qiagen; Hilden, Germany) was used according to the manufacturers’ instructions for DNA extraction from CSF. DNA from 200 ml CSF was extracted if available (n = 92). Less CSF was available from few patients (100– 150 ml in 16 cases and 50–80 ml in 5 cases). 2.3. Screening for herpesvirus DNA Real-time PCR was performed for HSV-1, HSV-2, varicellazoster virus (VZV), Epstein-Barr virus (EBV), cytomegalovirus (CMV), HHV-6A, HHV-6B, HHV-7 and HHV-8 as previously described [7].
101
2.4. Autoantibody testing Serum samples and/or CSF were tested for antibodies against GAD (n = 113) and NMDAR (n = 106) by indirect immunofluorescence using a biochip mosaic containing transfected HEK293 cells expressing the respective recombinant target antigens (Euroimmun AG; Lübeck, Germany). Most samples were additionally tested for further antibodies including “well-characterized” onconeuronal paraneoplastic antibodies (amphiphysin, Hu, Ri, Ma, Ta, Yo; n = 110) [8], voltage gated potassium channels (VGKCs; n = 110), leucine-rich glioma inactivated1 protein (LGI1; n = 56), contactin-associated protein-like2 (CASPR2; n = 56), a-amino-3hydroxy-5-methyl-4-isoxazol-propionic acid receptor (AMPAR; N = 57), g-amino-butyric acid B-receptor (GABAbR; n = 54), recoverin (n = 21), SOX1 (n = 35), titin (n = 21), aquaporin 4 (n = 56), dipeptidyl-peptidaselike protein-6 (DPPX; n = 6). 3. Results CSF samples from 113 patients with seizures as well as MRI features suggestive of autoimmune encephalitis, new onset working memory status, altered mental status or psychiatric symptoms were available for herpesvirus PCR analysis. Mean age at epilepsy onset was 41.8 1.7 years. MRI analysis revealed temporomesial hyperintensity in the T2/FLAIR-sequence and/or swelling of the temporomesial structures in 91.2% of the patients (n = 103). All patients were treated with antiepileptic drugs. Immunomodulatory treatment with steroids, intravenous immunoglobulin (IVIG) or plasmapheresis was performed in 77.0% of the patients (n = 87). 10 patients (8.9%) underwent epilepsy-surgical resection of the presumed epileptogenic focus. Further clinical information are given in Table 1 and Supplemental Table 1. Immunblot and indirect immunohistochemistry revealed in 48 patients presence of antineuronal autoantibodies, which allowed classification as definite autoimmune encephalitis. This included GAD-antibody encephalitis (n = 22), VGKC complex-antibody encephalitis (n = 21; thereof LGI1, n = 10 and CASPR2, n = 5), NMDAR-antibody encephalitis (n = 7) and 9 patients with “wellcharacterized” onconeuronal autoantibodies [8]. Eleven patients had autoantibodies against two antigens (GAD + VGKC complex: n = 4; GAD + NMDAR: n = 2; VGKC + NMDAR: n = 3;
Table 1 Clinical parameters. Group
Number of casesa
Age at epilepsy-onset
Treatment strategy
Positive herpesvirus PCR
48
41.52 2.863
0%
GAD
22
33.13 3.801
NMDAR
7
39.86 10.91
VGKC-complex
21
48.38 4.240
Onconeuronal
9
40.44 6.140
65
41.94 2.073
AED: n = 48 (100%) IT: n = 42 (88%) ES: n = 6 (13%) AED: n = 22 (100%) IT: n = 18 (82%) ES: n = 4 (18%) AED: n = 7 (100%) IT: n = 7 (100%) ES: n = 1 (14%) AED: n = 21 (100%) IT: n = 20 (95%) ES: n = 1 (5%) AED: n = 9 (100%) IT: n = 7 (78%) ES: n = 1 (11%) AED: n = 65 (100%) IT: n = 43 (66%) ES: n = 4 (6%)
Subgroups
Autoantibody positive patients
Autoantibody negative patients
Abbreviations: AED: Antiepileptic drug; IT: Immunomodulatory treatment; ES: Epilepsy surgery. a Eleven patients were positive for two autoantibodies, see supplemental Table 1 for further details.
0%
0%
0%
0%
4.6%
102
F. Poulheim et al. / Seizure 53 (2017) 100–102
VGKC + onconeuronal autoantibodies). No autoantibody was detected in 65 cases. Real-time PCR revealed in three CSF samples from patients without detection of an antineuronal autoantibody a positive result for HSV 1/2. These patients had a preceding antiepileptic treatment with lamotrigine, levetiracetam or valproate, but no preceding immunomodulatory or antiviral treatment. CSF samples from the remaining 111 patients revealed no evidence for DNA from any of the nine herpesviruses HSV 1/2, VZV, EBV, CMV, HHV6A/B, HHV-7, and HHV-8. 4. Discussion Autoimmune encephalitis can manifest with classical symptoms of infectious encephalitis, but development of predominant neurologic and psychiatric symptoms, without fever or CSF pleocytosis is frequent [1]. Clinical studies show evidence consistent with autoimmune limbic encephalitis in around half of the patients with adult-onset temporal lobe epilepsy [9]. From an etiological point of view, autoimmune encephalitis can be subdivided in paraneoplastic and non-paraneoplastic syndromes. Autoantibodies against intracellular, often intranuclear, epitopes can be detected in the majority of patients with paraneoplastic autoimmune encephalitis [10]. Autoimmune encephalitis with antibodies against cell-surface antigens, e.g. antiNMDAR, is less frequently associated with an underlying neoplastic disease. Indeed is the etiology of non-paraneoplastic autoimmune encephalitis largely cryptogenic. However, postviral autoimmune encephalitis has been accepted as one established disease mechanism for NMDAR antibody positive encephalitis after HSV encephalitis [3]. Further findings indicate that postinfectious autoimmune response is not confined to HSV encephalitis and NMDAR antibodies. NMDAR-antibodies were also detected in patients with EBV-positive CSF [10]. Single reports revealed evidence for a central nervous HHV-6 infection in patients with autoimmune encephalitis and GAD-autoantibodies [4–6]. The possible role of HHV-6 as a trigger of autoimmune disease by promoting inflammatory processes was summarized by Broccolo and colleagues [11]. Although several patients in our collective show mesial temporal MRI changes suggestive for active inflammation, our PCR-analysis detected herpesvirus DNA in only three of 113 CSF samples (2.7%) from patients with definite, probable or possible autoimmune encephalitis. Linnoila and co-workers reported recently four samples with detection of herpes virus DNA in a similar series of 77 CSF specimens from patients with synaptic autoantibodies (5.2%) [10]. These findings argue against herpesvirus infection as an important trigger of brain autoimmunity in such patients. While the reported cases of autoimmune encephalitis in relapsing virus encephalitis clearly indicate autoantibody detection in those patients, current evidence does not support general testing for herpesviruses among patients with autoimmune encephalitis. However, our collective contains a certain selection
bias as patients with active HSV infection are usually not transferred to an epilepsy center and exclusion of active HSV infection is usually performed before the diagnosis of autoimmune encephalitis. In addition, the clinical sensitivity of PCR analysis may be affected by different aspects. An initial herpesvirus infection may be missed due to a subclinical course of disease or due to a delay of several weeks between symptom onset and CSF analysis. Negative PCR results for HSV in the second phase of a relapsing post-herpes simplex virus encephalitis with detection of NMDAR antibodies has been described before [2]. This aspect could be analyzed by serial CSF-examinations starting as soon as possible after symptom onset. However, availability of such longitudinal CSF samples is rare. In light of the mentioned limitations the number of HSV-DNA positive CSF samples within our present collective appears considerable. Analysis of additional biomarkers of prior central nervous infection, e.g. presence of virus reactive oligoclonal bands [12], is needed to address the incidence of postviral autoimmune encephalitis. Conflicts of interest None of the authors has any conflict of interest to disclose. Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at https://doi.org/10.1016/j.seizure.2017.11.012. References [1] Leypoldt F, Armangue T, Dalmau J. Autoimmune encephalopathies. Ann NY Acad Sci 2015;1338:94–114. [2] Armangue T, Leypoldt F, Malaga I, et al. Herpes simplex virus encephalitis is a trigger of brain autoimmunity. Ann Neurol 2014;75(2):317–23. [3] Pruss H. Postviral autoimmune encephalitis: manifestations in children and adults. Curr Opin Neurol 2017;30(3):327–33. [4] Mata S, Muscas GC, Naldi I, et al. Non-paraneoplastic limbic encephalitis associated with anti-glutamic acid decarboxylase antibodies. J Neuroimmunol 2008;199(1-2):155–9. [5] Niehusmann P, Mittelstaedt T, Bien CG, et al. Presence of human herpes virus 6 DNA exclusively in temporal lobe epilepsy brain tissue of patients with history of encephalitis. Epilepsia 2010;51(12):2478–83. [6] Niehusmann P, Widman G, Eis-Hubinger AM, et al. Non-paraneoplastic limbic encephalitis and central nervous HHV-6B reactivation: causality or coincidence? Neuropathology 2016;36(4):376–80. [7] Esposito L, Drexler JF, Braganza O, et al. Large-scale analysis of viral nucleic acid spectrum in temporal lobe epilepsy biopsies. Epilepsia 2015;56(2):234–43. [8] Graus F, Delattre JY, Antoine JC, et al. Recommended diagnostic criteria for paraneoplastic neurological syndromes. J Neurol Neurosurg Psychiatry 2004;75(8):1135–40. [9] Bien CG, Elger CE. Limbic encephalitis: a cause of temporal lobe epilepsy with onset in adult life. Epilepsy Behav: E & B 2007;10(4):529–38. [10] Linnoila JJ, Binnicker MJ, Majed M, et al. CSF herpes virus and autoantibody profiles in the evaluation of encephalitis. Neurol(R) Neuroimmunol Neuroinflamm 2016;3(4):e245. [11] Broccolo F, Fusetti L, Ceccherini-Nelli L. Possible role of human herpesvirus 6 as a trigger of autoimmune disease. Sci World J 2013;2013:867389. [12] Virtanen JO, Wohler J, Fenton K, et al. Oligoclonal bands in multiple sclerosis reactive against two herpesviruses and association with magnetic resonance imaging findings. Mult Scler 2014;20(1):27–34.
Contents lists available at ScienceDirect
Seizure journal homepage: www.elsevier.com/locate/yseiz
Short communication
Large-scale analysis of herpesviridae in epilepsy-patients with signs of autoimmune encephalitis Freya Poulheima , Laura Espositoa , Christian E. Elgerb , Anna M. Eis-Hübingerc, Albert J. Beckera,d, Pitt Niehusmanna,e,* a
Dept. of Neuropathology, University of Bonn Medical Center, Germany Dept. of Epileptology, University of Bonn Medical Center, Germany Institute of Virology, University of Bonn Medical Center, Germany d Translational Epilepsy Research Section, University of Bonn Medical Center, Germany e Dept. of Neuro-/Pathology, Oslo University Hospital, Norway b c
A R T I C L E I N F O
A B S T R A C T
Article history: Received 18 September 2017 Received in revised form 12 November 2017 Accepted 16 November 2017 Available online xxx
Purpose: Epilepsy is one of the most common primary brain disorders. Nonparaneoplastic autoimmune encephalitis is increasingly recognized as an important cause of adult onset epilepsy. However, only in rare cases an initiating factor of the syndrome can be identified. Autoantibody detection after central nervous herpesvirus infection indicates a postviral etiology in a subgroup of patients. In order to analyze a possible underrecognition of postinfectious autoimmunity we performed a large-scale analysis of herpesvirus DNA in cerebrospinal fluid samples from patients with clinical signs of autoimmune encephalitis. Methods: Real time PCR for HSV 1/2, CMV, EBV, VZV, HHV-6A, HHV-6B, HHV-7 and HHV-8 was performed in cerebrospinal fluid samples from 113 patients with epilepsy and suspected autoimmune encephalitis. Indirect immunofluorescence analysis was used for autoantibody analysis. Results: Antineuronal autoantibodies could be identified in 48 patients with definite autoimmune encephalitis. No autoantibodies were detected in 65 additional patients with probable or possible autoimmune encephalitis. Real-time PCR analysis revealed in three autoantibody-negative patients positive results for HSV, but no evidence for further virus DNA. Conclusion: The findings argue against longstanding herpesvirus infection of the CNS as frequent trigger for autoimmunity. However, appearance of autoantibodies after a short period of active virus infection cannot be excluded. © 2017 Published by Elsevier Ltd on behalf of British Epilepsy Association.
Keywords: Herpesvirus Epilepsy GAD NMDAR Encephalitis
1. Introduction Over the past 10 years the role of neuroinflammation has been increasingly implicated in the pathophysiology of epilepsy. Particularly in patients with adult-onset epilepsy, but increasingly also in children, autoantibody associated autoimmune encephalitis has been identified as a cause of seizures [1]. In most cases the trigger for the formation of autoantibodies is unknown. However, herpes simplex virus (HSV) encephalitis has been reported as a trigger of brain autoimmunity and particularly N-methyl-Daspartate receptor (NMDAR) antibodies were identified in sera and cerebrospinal fluid (CSF) of patients with HSV encephalitis [2].
* Corresponding author at: Dept. of Neuro-/Pathology, Oslo University Hospital, Rikshospitalet, Postbox 4950, Nydalen, 0424, Oslo, Norway. E-mail address: [email protected] (P. Niehusmann). https://doi.org/10.1016/j.seizure.2017.11.012 1059-1311/© 2017 Published by Elsevier Ltd on behalf of British Epilepsy Association.
There is evidence, that virus induced autoimmune response with autoantibody generation is a more widespread mechanism not confined to HSV and NMDAR antibodies [3]. Indeed, infection with another member of the herpesvirus family, human herpes virus 6 (HHV-6), has been reported in patients with autoimmune encephalitis and autoantibodies against glutamic acid decarboxylase (GAD) [4–6]. In a recent study on 346 fresh frozen epilepsy surgery tissue samples, we detected a higher HHV–6 B virus load in epilepsy samples than in controls [7]. HHV–6 B DNA was particularly observed in patients with clinical signs of previous brain inflammation (15%) and less frequent in patients without history of febrile seizures or meningoencephalitis. Based on these observations, we aimed to address in detail a potential connection between CNS infection with herpesviruses and autoimmune encephalitis. As immunotherapy is the treatment
F. Poulheim et al. / Seizure 53 (2017) 100–102
of choice in patients with autoimmune encephalitis, biopsy tissue is only exceptionally available. Therefore, we collected CSF samples from patients with proven or highly suspected autoimmune encephalitis for analysis. 2. Patients and methods 2.1. Patients Archived and frozen CSF samples from 113 patients with seizures, and MRI features suggestive of autoimmune encephalitis, new onset working memory deficit, altered mental status or psychiatric symptoms were included in the study. Patients with reasonable alternative cause of symptoms (e.g. trauma, brain malformation, metabolic encephalopathy, drug toxicity, neoplastic disorder) were excluded. 93 patients (82%) had a seizure onset within the last 5 years before CSF sampling. In 61 patients (54%) the CSF sampling was performed within 24 months after the first reported seizure. The remaining patients had substantial progressive symptoms within the last 5 years, which resulted in referral to the tertiary care center as well as MRI features suggestive of autoimmune encephalitis, new onset working memory deficit, altered mental status or psychiatric symptoms. All patients were treated at the Bonn Epilepsy Center. All procedures were conducted in accordance with the Declaration of Helsinki. Informed written consent was obtained from all patients. 2.2. DNA extraction The QIAamp MinElute Virus Spin Kit (Qiagen; Hilden, Germany) was used according to the manufacturers’ instructions for DNA extraction from CSF. DNA from 200 ml CSF was extracted if available (n = 92). Less CSF was available from few patients (100– 150 ml in 16 cases and 50–80 ml in 5 cases). 2.3. Screening for herpesvirus DNA Real-time PCR was performed for HSV-1, HSV-2, varicellazoster virus (VZV), Epstein-Barr virus (EBV), cytomegalovirus (CMV), HHV-6A, HHV-6B, HHV-7 and HHV-8 as previously described [7].
101
2.4. Autoantibody testing Serum samples and/or CSF were tested for antibodies against GAD (n = 113) and NMDAR (n = 106) by indirect immunofluorescence using a biochip mosaic containing transfected HEK293 cells expressing the respective recombinant target antigens (Euroimmun AG; Lübeck, Germany). Most samples were additionally tested for further antibodies including “well-characterized” onconeuronal paraneoplastic antibodies (amphiphysin, Hu, Ri, Ma, Ta, Yo; n = 110) [8], voltage gated potassium channels (VGKCs; n = 110), leucine-rich glioma inactivated1 protein (LGI1; n = 56), contactin-associated protein-like2 (CASPR2; n = 56), a-amino-3hydroxy-5-methyl-4-isoxazol-propionic acid receptor (AMPAR; N = 57), g-amino-butyric acid B-receptor (GABAbR; n = 54), recoverin (n = 21), SOX1 (n = 35), titin (n = 21), aquaporin 4 (n = 56), dipeptidyl-peptidaselike protein-6 (DPPX; n = 6). 3. Results CSF samples from 113 patients with seizures as well as MRI features suggestive of autoimmune encephalitis, new onset working memory status, altered mental status or psychiatric symptoms were available for herpesvirus PCR analysis. Mean age at epilepsy onset was 41.8 1.7 years. MRI analysis revealed temporomesial hyperintensity in the T2/FLAIR-sequence and/or swelling of the temporomesial structures in 91.2% of the patients (n = 103). All patients were treated with antiepileptic drugs. Immunomodulatory treatment with steroids, intravenous immunoglobulin (IVIG) or plasmapheresis was performed in 77.0% of the patients (n = 87). 10 patients (8.9%) underwent epilepsy-surgical resection of the presumed epileptogenic focus. Further clinical information are given in Table 1 and Supplemental Table 1. Immunblot and indirect immunohistochemistry revealed in 48 patients presence of antineuronal autoantibodies, which allowed classification as definite autoimmune encephalitis. This included GAD-antibody encephalitis (n = 22), VGKC complex-antibody encephalitis (n = 21; thereof LGI1, n = 10 and CASPR2, n = 5), NMDAR-antibody encephalitis (n = 7) and 9 patients with “wellcharacterized” onconeuronal autoantibodies [8]. Eleven patients had autoantibodies against two antigens (GAD + VGKC complex: n = 4; GAD + NMDAR: n = 2; VGKC + NMDAR: n = 3;
Table 1 Clinical parameters. Group
Number of casesa
Age at epilepsy-onset
Treatment strategy
Positive herpesvirus PCR
48
41.52 2.863
0%
GAD
22
33.13 3.801
NMDAR
7
39.86 10.91
VGKC-complex
21
48.38 4.240
Onconeuronal
9
40.44 6.140
65
41.94 2.073
AED: n = 48 (100%) IT: n = 42 (88%) ES: n = 6 (13%) AED: n = 22 (100%) IT: n = 18 (82%) ES: n = 4 (18%) AED: n = 7 (100%) IT: n = 7 (100%) ES: n = 1 (14%) AED: n = 21 (100%) IT: n = 20 (95%) ES: n = 1 (5%) AED: n = 9 (100%) IT: n = 7 (78%) ES: n = 1 (11%) AED: n = 65 (100%) IT: n = 43 (66%) ES: n = 4 (6%)
Subgroups
Autoantibody positive patients
Autoantibody negative patients
Abbreviations: AED: Antiepileptic drug; IT: Immunomodulatory treatment; ES: Epilepsy surgery. a Eleven patients were positive for two autoantibodies, see supplemental Table 1 for further details.
0%
0%
0%
0%
4.6%
102
F. Poulheim et al. / Seizure 53 (2017) 100–102
VGKC + onconeuronal autoantibodies). No autoantibody was detected in 65 cases. Real-time PCR revealed in three CSF samples from patients without detection of an antineuronal autoantibody a positive result for HSV 1/2. These patients had a preceding antiepileptic treatment with lamotrigine, levetiracetam or valproate, but no preceding immunomodulatory or antiviral treatment. CSF samples from the remaining 111 patients revealed no evidence for DNA from any of the nine herpesviruses HSV 1/2, VZV, EBV, CMV, HHV6A/B, HHV-7, and HHV-8. 4. Discussion Autoimmune encephalitis can manifest with classical symptoms of infectious encephalitis, but development of predominant neurologic and psychiatric symptoms, without fever or CSF pleocytosis is frequent [1]. Clinical studies show evidence consistent with autoimmune limbic encephalitis in around half of the patients with adult-onset temporal lobe epilepsy [9]. From an etiological point of view, autoimmune encephalitis can be subdivided in paraneoplastic and non-paraneoplastic syndromes. Autoantibodies against intracellular, often intranuclear, epitopes can be detected in the majority of patients with paraneoplastic autoimmune encephalitis [10]. Autoimmune encephalitis with antibodies against cell-surface antigens, e.g. antiNMDAR, is less frequently associated with an underlying neoplastic disease. Indeed is the etiology of non-paraneoplastic autoimmune encephalitis largely cryptogenic. However, postviral autoimmune encephalitis has been accepted as one established disease mechanism for NMDAR antibody positive encephalitis after HSV encephalitis [3]. Further findings indicate that postinfectious autoimmune response is not confined to HSV encephalitis and NMDAR antibodies. NMDAR-antibodies were also detected in patients with EBV-positive CSF [10]. Single reports revealed evidence for a central nervous HHV-6 infection in patients with autoimmune encephalitis and GAD-autoantibodies [4–6]. The possible role of HHV-6 as a trigger of autoimmune disease by promoting inflammatory processes was summarized by Broccolo and colleagues [11]. Although several patients in our collective show mesial temporal MRI changes suggestive for active inflammation, our PCR-analysis detected herpesvirus DNA in only three of 113 CSF samples (2.7%) from patients with definite, probable or possible autoimmune encephalitis. Linnoila and co-workers reported recently four samples with detection of herpes virus DNA in a similar series of 77 CSF specimens from patients with synaptic autoantibodies (5.2%) [10]. These findings argue against herpesvirus infection as an important trigger of brain autoimmunity in such patients. While the reported cases of autoimmune encephalitis in relapsing virus encephalitis clearly indicate autoantibody detection in those patients, current evidence does not support general testing for herpesviruses among patients with autoimmune encephalitis. However, our collective contains a certain selection
bias as patients with active HSV infection are usually not transferred to an epilepsy center and exclusion of active HSV infection is usually performed before the diagnosis of autoimmune encephalitis. In addition, the clinical sensitivity of PCR analysis may be affected by different aspects. An initial herpesvirus infection may be missed due to a subclinical course of disease or due to a delay of several weeks between symptom onset and CSF analysis. Negative PCR results for HSV in the second phase of a relapsing post-herpes simplex virus encephalitis with detection of NMDAR antibodies has been described before [2]. This aspect could be analyzed by serial CSF-examinations starting as soon as possible after symptom onset. However, availability of such longitudinal CSF samples is rare. In light of the mentioned limitations the number of HSV-DNA positive CSF samples within our present collective appears considerable. Analysis of additional biomarkers of prior central nervous infection, e.g. presence of virus reactive oligoclonal bands [12], is needed to address the incidence of postviral autoimmune encephalitis. Conflicts of interest None of the authors has any conflict of interest to disclose. Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at https://doi.org/10.1016/j.seizure.2017.11.012. References [1] Leypoldt F, Armangue T, Dalmau J. Autoimmune encephalopathies. Ann NY Acad Sci 2015;1338:94–114. [2] Armangue T, Leypoldt F, Malaga I, et al. Herpes simplex virus encephalitis is a trigger of brain autoimmunity. Ann Neurol 2014;75(2):317–23. [3] Pruss H. Postviral autoimmune encephalitis: manifestations in children and adults. Curr Opin Neurol 2017;30(3):327–33. [4] Mata S, Muscas GC, Naldi I, et al. Non-paraneoplastic limbic encephalitis associated with anti-glutamic acid decarboxylase antibodies. J Neuroimmunol 2008;199(1-2):155–9. [5] Niehusmann P, Mittelstaedt T, Bien CG, et al. Presence of human herpes virus 6 DNA exclusively in temporal lobe epilepsy brain tissue of patients with history of encephalitis. Epilepsia 2010;51(12):2478–83. [6] Niehusmann P, Widman G, Eis-Hubinger AM, et al. Non-paraneoplastic limbic encephalitis and central nervous HHV-6B reactivation: causality or coincidence? Neuropathology 2016;36(4):376–80. [7] Esposito L, Drexler JF, Braganza O, et al. Large-scale analysis of viral nucleic acid spectrum in temporal lobe epilepsy biopsies. Epilepsia 2015;56(2):234–43. [8] Graus F, Delattre JY, Antoine JC, et al. Recommended diagnostic criteria for paraneoplastic neurological syndromes. J Neurol Neurosurg Psychiatry 2004;75(8):1135–40. [9] Bien CG, Elger CE. Limbic encephalitis: a cause of temporal lobe epilepsy with onset in adult life. Epilepsy Behav: E & B 2007;10(4):529–38. [10] Linnoila JJ, Binnicker MJ, Majed M, et al. CSF herpes virus and autoantibody profiles in the evaluation of encephalitis. Neurol(R) Neuroimmunol Neuroinflamm 2016;3(4):e245. [11] Broccolo F, Fusetti L, Ceccherini-Nelli L. Possible role of human herpesvirus 6 as a trigger of autoimmune disease. Sci World J 2013;2013:867389. [12] Virtanen JO, Wohler J, Fenton K, et al. Oligoclonal bands in multiple sclerosis reactive against two herpesviruses and association with magnetic resonance imaging findings. Mult Scler 2014;20(1):27–34.