Downloaded from jnnp.bmj.com on August 29, 2014 - Published by group.bmj.com
JNNP Online First, published on August 28, 2014 as 10.1136/jnnp-2014-308240 PostScript
LETTER
Brain histopathology in three cases of Susac’s syndrome: implications for lesion pathogenesis and treatment Susac’s syndrome (SS) is the triad of encephalopathy, branch retinal artery occlusions and sensorineural hearing loss. While rare, it has become increasingly recognised since characteristic ‘snowball’
corpus callosum lesions were appreciated on MRI.1 We present clinical and histopathological findings on three patients with SS. Our findings demonstrate a T-cell-mediated inflammatory contribution to lesion pathogenesis. Treatment with the tumour necrosis factor (TNF) inhibitor, infliximab was beneficial in two patients, including in one previously reported,2 and in another who failed rituximab. This report provides a histological rationale for the observed benefit of infliximab, and suggests that infliximab should be considered as an adjunct therapy in patients with refractory SS.
Three patients with SS most recently diagnosed among the authors’ practices who had undergone brain biopsy as part of their diagnostic clinical workup were identified. The clinical features, radiology, treatment and outcomes for the three patients are presented as online supplementary data (tables S1–S5 and figures S1 and S2). Extensive serum autoantibody screening was negative. Headache was present in all patients, highlighting the fact that it is a common manifestation of encephalopathy in SS. All three cases reported relatively non-specific auditory and visual symptoms, emphasising that
Figure 1 Histopathology of Susac’s syndrome. Representative sections from case 3 showing (A) an area of infarction involving Purkinje cell and internal granule cell layer, (B) more clearly visible following immunostaining with CD68. (C) Section from biopsy of the right frontal lobe and leptomeninges in case 2 showing an infarct in the superficial neocortex more clearly seen with CD68 immunostaining (inset). (D) An intraparenchymal blood vessel from case 2 showing thickened hyalinised wall due to collagen deposition and patchy infiltration with CD8+ T cells (insets; CD8 immunohistochemistry (left), Masson Trichrome stain (right)). (E) Perivascular lymphocytic cuffing seen in leptomeninges of case 1 with enlarged/reactive endothelial cells (arrows) leading to near occlusion of the vessel (inset). (F) The perivascular lymphocytes are predominantly CD3+ T cells, with 70% also expressing CD8 (not shown). J Neurol Neurosurg Psychiatry Monthby 2014 Vol 0 Publishing No 0 Copyright Article author (or their employer) 2014. Produced BMJ Group Ltd under licence.
1
Downloaded from jnnp.bmj.com on August 29, 2014 - Published by group.bmj.com
PostScript fluorescein angiography±audiology testing should be considered in the diagnostic workup of patients with unexplained encephalopathy. Two patients underwent cerebellar biopsies and one a frontal lobe biopsy. One biopsy was from a treatment-naïve patient (case 1). All contained variable numbers of wedge-shaped microinfarcts surrounded by microglia. In cerebellar biopsies (cases 1 and 3), infarcts were found mostly in the molecular layer (superficial, middle and deep portions), with neuropil rarefaction, microvacuolation and upregulated microglia. Occasional infarcts showed extension into the Purkinje layer and the internal granule layer (figure 1A), with focal Purkinje cell loss and proliferation of Bergmann glia. Infarcts were best visualised by CD68 immunostaining, reflecting microglial activation (figure 1B). The frontal biopsy (case 2) included superficial neocortex and leptomeninges, and contained a single, superficial microinfarct (figure 1C). Several blood vessels in case 2 had thickened, hyalinised walls (figure 1D) with near-complete absence of the elastica. No perivascular inflammation was present, but scattered CD3/CD8+ T cells were present within the vessel wall (figure 1D, inset left) and in parenchyma. Perivascular lymphocytic cuffing was seen in the other two cases, and was more prominent in case 1 (figure 1E). Inflammation occurred around small-sized to medium-sized leptomeningeal vessels in both cases, and small intraparenchymal vessels in case 1. They were predominantly CD3+ T cells (figure 1F). In case 1, the majority were CD8+, and in case 3 there were equal numbers of CD8+ and CD4+ cells. Only an occasional cell was immunoreactive with granzyme/perforin. CD20+ B cells were rare and plasma cells were absent. Enlarged, reactive endothelial cells with prominent nucleoli were seen in case 1 (figure 1E). In this case, some small vessel lumina appeared almost completely occluded by hypertrophic endothelial cells (figure 1E, inset). Intravascular fibrin thrombi were not observed in any of the three cases. We assessed involvement of complement cascade by immunohistochemistry for C4d, C3d, IgG and C9neo. Cerebral and cerebellar tissues obtained from neurosurgical resections and from autopsy cases without significant neurological disease were used as controls. In case 1 only, vascular wall deposition of C4d and to a lesser extent C3d was identified. However, similar
2
immunoreactivity was seen in 7 of our control cases (four surgical and three autopsy) and hence was considered nonspecific. No specific staining for IgG or C9neo was seen. Detailed methodologies are presented as online supplementary data. Our study confirms that abnormalities of microvascular endothelium and vessel wall structure are important in lesion pathogenesis. Microinfarctions were seen frequently, with one case showing luminal occlusion due to reactive and hypertrophied endothelial cells. Previous reports have shown that endothelial cell proliferation and basement membrane thickening are features of SS,3 4 and thickening of precapillary arteriolar adventitia and loss of internal elastica have also been observed.3–5 Perhaps of most interest is the identification of T-cell inflammation involving small-sized to medium-sized vessels in all cases. Sparse perivascular lymphocytic inflammation has been inconsistently identified in some case reports,2 4 6 but this lymphoid population has not been previously immunophenotyped. CD8+ T cells predominated in cases 1 and 2, while CD4 and CD8 T cells were found equally in case 3. A role for humoral immunity in SS has been proposed,6 partly based on the finding of C3d and C4d deposition in capillaries and venules in two brain biopsies from a single patient.6 We also found granular and homogeneous endothelial and subendothelial C4d and C3d deposition in some small vessels in case 1; however, similar staining patterns were observed in several of our control cases, so this staining was considered non-specific. The association of SS with anti-endothelial cell antibodies (AECAs)6 indicates that both humoral and cellular mechanisms may be involved in disease pathogenesis, as is proposed for other central nervous system inflammatory diseases such as multiple sclerosis. Unfortunately, serum was not available for AECA testing in our patients. Differences in the reported histopathology of Susac’s cases may reflect the location and timing of biopsy, lesion age and treatment prior to biopsy. Interestingly, case 1 underwent cerebellar biopsy prior to any treatment and it was in this case that the perivascular CD8+ T lymphocytes and endothelial cell changes were most marked. It is also in this case that we might expect to see an unadulterated expression of the acute-to-subacute histopathology of SS. Cases 2 and 3 received corticosteroids 4 and 3 weeks prior to biopsy, respectively.
The predominance of T cells in the inflammatory response seen in our study provides a histological rationale for the observed benefit of the TNF-α inhibitor infliximab in two of our patients, including in one case reported previously.2 Candidate modes of action of infliximab include reducing expression of endothelial cell adhesion molecules leading to reduced T-cell migration through the vascular endothelium.7 Given our findings, infliximab should be considered as an adjunct therapy in patients with refractory SS. Todd A Hardy,1,2 Billy O’Brien,3 Natasha Gerbis,4 Michael H Barnett,2,5,6 Stephen W Reddel,1 Janice Brewer,7 Geoffrey K Herkes,4 Paul Silberstein,4 Roger J Garsia,8 John D G Watson,9,10 Ruta Gupta,11 John D E Parratt,4,12 Michael E Buckland5,13 1 Neuroimmunology Clinic, Concord Hospital and University of Sydney, Sydney, New South Wales, Australia 2 MS Australia Clinic, Brain & Mind Research Institute, Sydney, New South Wales, Australia 3 Department of Neurology, Gosford Hospital, Gosford, New South Wales, Australia 4 Department of Neurology, Royal North Shore Hospital, Sydney, New South Wales, Australia 5 Brain & Mind Research Institute, Sydney, New South Wales, Australia 6 Department of Neurology, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia 7 Department of Anatomical Pathology, PaLMS, Royal North Shore Hospital, Sydney, New South Wales, Australia 8 Department of Immunology, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia 9 Section of Neurology, Sydney Adventist Hospital, Sydney, New South Wales, Australia 10 Discipline of Medicine, Sydney Adventist Hospital Clinical School, University of Sydney, Sydney, New South Wales, Australia 11 Department of Tissue Pathology and Diagnostic Oncology, Royal Prince Alfred Hospital and the University of Sydney, Sydney, New South Wales, Australia 12 Department of Medicine, Institute of Clinical Neurosciences, University of Sydney, Camperdown, New South Wales, Australia 13 Department of Neuropathology, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
Correspondence to Dr Todd A Hardy, Department of Neurology, Neuroimmunology Clinic, Concord Repatriation General Hospital, Concord, NSW 2139, Australia; [email protected] Contributors BO’B and JDEP conceived the idea for the article and collected the cases. TAH, BO’B, JDEP, RJG and MEB drafted the article. Pathology was reviewed by RG, JDEP and MEB. All authors revised the manuscript critically for important intellectual content, and gave final approval of the version to be published. Competing interests JDEP is funded by Multiple Sclerosis Research Australia. Patient consent Obtained. Ethics approval Written, informed consent to publish was obtained from all patients. Use of control tissues was authorised under RPA Hospital HREC approval numbers X11/0202 & X09/0371.
J Neurol Neurosurg Psychiatry Month 2014 Vol 0 No 0
Downloaded from jnnp.bmj.com on August 29, 2014 - Published by group.bmj.com
PostScript Provenance and peer review Not commissioned; externally peer reviewed.
J Neurol Neurosurg Psychiatry 2014;0:1–3. doi:10.1136/jnnp-2014-308240
▸ Additional material is published online only. To view please visit the journal online (http://dx.doi.org/10. 1136/jnnp-2014-308240).
REFERENCES
To cite Hardy TA, O’Brien B, Gerbis N, et al. J Neurol Neurosurg Psychiatry Published Online First: [please include Day Month Year] doi:10.1136/jnnp-2014308240 Received 5 May 2014 Revised 15 July 2014 Accepted 10 August 2014
J Neurol Neurosurg Psychiatry Month 2014 Vol 0 No 0
1 2
3
Susac J, Murtagh F, Egan R, et al. MRI findings in Susac’s syndrome. Neurology 2003;61:1783–7. Hardy TA, Garsia RJ, Halmagyi GM, et al. Tumour necrosis factor (TNF) inhibitor therapy in Susac’s syndrome. J Neurol Sci 2011;302:126–8. Heiskala H, Somer H, Kovanen J, et al. Microangiopathy with encephalopathy, hearing loss and retinal arteriolar occlusions: two new cases. J Neurol Sci 1988;86:239–50.
4
5
6
7
Fox RJ, Costello F, Judkins AR, et al. Treatment of Susac syndrome with gamma globulin and corticosteroids. J Neurol Sci 2006;251:17–22. Monteiro ML, Swanson RA, Coppeto JR, et al. A microangiopathic syndrome of encephalopathy, hearing loss, and retinal arteriolar occlusions. Neurology 1985;35:1113–21. Magro CM, Poe JC, Lubow M, et al. Susac syndrome: an organ-specific autoimmune endotheliopathy syndrome associated with anti-endothelial cell antibodies. Am J Clin Pathol 2011;136:903–12. Smolen JS, Emery P. Infliximab: 12 years of experience. Arthritis Res Ther 2011;13(Suppl 1):S2.
3
Downloaded from jnnp.bmj.com on August 29, 2014 - Published by group.bmj.com
Brain histopathology in three cases of Susac's syndrome: implications for lesion pathogenesis and treatment Todd A Hardy, Billy O'Brien, Natasha Gerbis, et al. J Neurol Neurosurg Psychiatry published online August 28, 2014
doi: 10.1136/jnnp-2014-308240
Updated information and services can be found at: http://jnnp.bmj.com/content/early/2014/08/28/jnnp-2014-308240.full.html
These include:
References
This article cites 7 articles, 1 of which can be accessed free at: http://jnnp.bmj.com/content/early/2014/08/28/jnnp-2014-308240.full.html#ref-list-1
P
JNNP Online First, published on August 28, 2014 as 10.1136/jnnp-2014-308240 PostScript
LETTER
Brain histopathology in three cases of Susac’s syndrome: implications for lesion pathogenesis and treatment Susac’s syndrome (SS) is the triad of encephalopathy, branch retinal artery occlusions and sensorineural hearing loss. While rare, it has become increasingly recognised since characteristic ‘snowball’
corpus callosum lesions were appreciated on MRI.1 We present clinical and histopathological findings on three patients with SS. Our findings demonstrate a T-cell-mediated inflammatory contribution to lesion pathogenesis. Treatment with the tumour necrosis factor (TNF) inhibitor, infliximab was beneficial in two patients, including in one previously reported,2 and in another who failed rituximab. This report provides a histological rationale for the observed benefit of infliximab, and suggests that infliximab should be considered as an adjunct therapy in patients with refractory SS.
Three patients with SS most recently diagnosed among the authors’ practices who had undergone brain biopsy as part of their diagnostic clinical workup were identified. The clinical features, radiology, treatment and outcomes for the three patients are presented as online supplementary data (tables S1–S5 and figures S1 and S2). Extensive serum autoantibody screening was negative. Headache was present in all patients, highlighting the fact that it is a common manifestation of encephalopathy in SS. All three cases reported relatively non-specific auditory and visual symptoms, emphasising that
Figure 1 Histopathology of Susac’s syndrome. Representative sections from case 3 showing (A) an area of infarction involving Purkinje cell and internal granule cell layer, (B) more clearly visible following immunostaining with CD68. (C) Section from biopsy of the right frontal lobe and leptomeninges in case 2 showing an infarct in the superficial neocortex more clearly seen with CD68 immunostaining (inset). (D) An intraparenchymal blood vessel from case 2 showing thickened hyalinised wall due to collagen deposition and patchy infiltration with CD8+ T cells (insets; CD8 immunohistochemistry (left), Masson Trichrome stain (right)). (E) Perivascular lymphocytic cuffing seen in leptomeninges of case 1 with enlarged/reactive endothelial cells (arrows) leading to near occlusion of the vessel (inset). (F) The perivascular lymphocytes are predominantly CD3+ T cells, with 70% also expressing CD8 (not shown). J Neurol Neurosurg Psychiatry Monthby 2014 Vol 0 Publishing No 0 Copyright Article author (or their employer) 2014. Produced BMJ Group Ltd under licence.
1
Downloaded from jnnp.bmj.com on August 29, 2014 - Published by group.bmj.com
PostScript fluorescein angiography±audiology testing should be considered in the diagnostic workup of patients with unexplained encephalopathy. Two patients underwent cerebellar biopsies and one a frontal lobe biopsy. One biopsy was from a treatment-naïve patient (case 1). All contained variable numbers of wedge-shaped microinfarcts surrounded by microglia. In cerebellar biopsies (cases 1 and 3), infarcts were found mostly in the molecular layer (superficial, middle and deep portions), with neuropil rarefaction, microvacuolation and upregulated microglia. Occasional infarcts showed extension into the Purkinje layer and the internal granule layer (figure 1A), with focal Purkinje cell loss and proliferation of Bergmann glia. Infarcts were best visualised by CD68 immunostaining, reflecting microglial activation (figure 1B). The frontal biopsy (case 2) included superficial neocortex and leptomeninges, and contained a single, superficial microinfarct (figure 1C). Several blood vessels in case 2 had thickened, hyalinised walls (figure 1D) with near-complete absence of the elastica. No perivascular inflammation was present, but scattered CD3/CD8+ T cells were present within the vessel wall (figure 1D, inset left) and in parenchyma. Perivascular lymphocytic cuffing was seen in the other two cases, and was more prominent in case 1 (figure 1E). Inflammation occurred around small-sized to medium-sized leptomeningeal vessels in both cases, and small intraparenchymal vessels in case 1. They were predominantly CD3+ T cells (figure 1F). In case 1, the majority were CD8+, and in case 3 there were equal numbers of CD8+ and CD4+ cells. Only an occasional cell was immunoreactive with granzyme/perforin. CD20+ B cells were rare and plasma cells were absent. Enlarged, reactive endothelial cells with prominent nucleoli were seen in case 1 (figure 1E). In this case, some small vessel lumina appeared almost completely occluded by hypertrophic endothelial cells (figure 1E, inset). Intravascular fibrin thrombi were not observed in any of the three cases. We assessed involvement of complement cascade by immunohistochemistry for C4d, C3d, IgG and C9neo. Cerebral and cerebellar tissues obtained from neurosurgical resections and from autopsy cases without significant neurological disease were used as controls. In case 1 only, vascular wall deposition of C4d and to a lesser extent C3d was identified. However, similar
2
immunoreactivity was seen in 7 of our control cases (four surgical and three autopsy) and hence was considered nonspecific. No specific staining for IgG or C9neo was seen. Detailed methodologies are presented as online supplementary data. Our study confirms that abnormalities of microvascular endothelium and vessel wall structure are important in lesion pathogenesis. Microinfarctions were seen frequently, with one case showing luminal occlusion due to reactive and hypertrophied endothelial cells. Previous reports have shown that endothelial cell proliferation and basement membrane thickening are features of SS,3 4 and thickening of precapillary arteriolar adventitia and loss of internal elastica have also been observed.3–5 Perhaps of most interest is the identification of T-cell inflammation involving small-sized to medium-sized vessels in all cases. Sparse perivascular lymphocytic inflammation has been inconsistently identified in some case reports,2 4 6 but this lymphoid population has not been previously immunophenotyped. CD8+ T cells predominated in cases 1 and 2, while CD4 and CD8 T cells were found equally in case 3. A role for humoral immunity in SS has been proposed,6 partly based on the finding of C3d and C4d deposition in capillaries and venules in two brain biopsies from a single patient.6 We also found granular and homogeneous endothelial and subendothelial C4d and C3d deposition in some small vessels in case 1; however, similar staining patterns were observed in several of our control cases, so this staining was considered non-specific. The association of SS with anti-endothelial cell antibodies (AECAs)6 indicates that both humoral and cellular mechanisms may be involved in disease pathogenesis, as is proposed for other central nervous system inflammatory diseases such as multiple sclerosis. Unfortunately, serum was not available for AECA testing in our patients. Differences in the reported histopathology of Susac’s cases may reflect the location and timing of biopsy, lesion age and treatment prior to biopsy. Interestingly, case 1 underwent cerebellar biopsy prior to any treatment and it was in this case that the perivascular CD8+ T lymphocytes and endothelial cell changes were most marked. It is also in this case that we might expect to see an unadulterated expression of the acute-to-subacute histopathology of SS. Cases 2 and 3 received corticosteroids 4 and 3 weeks prior to biopsy, respectively.
The predominance of T cells in the inflammatory response seen in our study provides a histological rationale for the observed benefit of the TNF-α inhibitor infliximab in two of our patients, including in one case reported previously.2 Candidate modes of action of infliximab include reducing expression of endothelial cell adhesion molecules leading to reduced T-cell migration through the vascular endothelium.7 Given our findings, infliximab should be considered as an adjunct therapy in patients with refractory SS. Todd A Hardy,1,2 Billy O’Brien,3 Natasha Gerbis,4 Michael H Barnett,2,5,6 Stephen W Reddel,1 Janice Brewer,7 Geoffrey K Herkes,4 Paul Silberstein,4 Roger J Garsia,8 John D G Watson,9,10 Ruta Gupta,11 John D E Parratt,4,12 Michael E Buckland5,13 1 Neuroimmunology Clinic, Concord Hospital and University of Sydney, Sydney, New South Wales, Australia 2 MS Australia Clinic, Brain & Mind Research Institute, Sydney, New South Wales, Australia 3 Department of Neurology, Gosford Hospital, Gosford, New South Wales, Australia 4 Department of Neurology, Royal North Shore Hospital, Sydney, New South Wales, Australia 5 Brain & Mind Research Institute, Sydney, New South Wales, Australia 6 Department of Neurology, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia 7 Department of Anatomical Pathology, PaLMS, Royal North Shore Hospital, Sydney, New South Wales, Australia 8 Department of Immunology, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia 9 Section of Neurology, Sydney Adventist Hospital, Sydney, New South Wales, Australia 10 Discipline of Medicine, Sydney Adventist Hospital Clinical School, University of Sydney, Sydney, New South Wales, Australia 11 Department of Tissue Pathology and Diagnostic Oncology, Royal Prince Alfred Hospital and the University of Sydney, Sydney, New South Wales, Australia 12 Department of Medicine, Institute of Clinical Neurosciences, University of Sydney, Camperdown, New South Wales, Australia 13 Department of Neuropathology, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
Correspondence to Dr Todd A Hardy, Department of Neurology, Neuroimmunology Clinic, Concord Repatriation General Hospital, Concord, NSW 2139, Australia; [email protected] Contributors BO’B and JDEP conceived the idea for the article and collected the cases. TAH, BO’B, JDEP, RJG and MEB drafted the article. Pathology was reviewed by RG, JDEP and MEB. All authors revised the manuscript critically for important intellectual content, and gave final approval of the version to be published. Competing interests JDEP is funded by Multiple Sclerosis Research Australia. Patient consent Obtained. Ethics approval Written, informed consent to publish was obtained from all patients. Use of control tissues was authorised under RPA Hospital HREC approval numbers X11/0202 & X09/0371.
J Neurol Neurosurg Psychiatry Month 2014 Vol 0 No 0
Downloaded from jnnp.bmj.com on August 29, 2014 - Published by group.bmj.com
PostScript Provenance and peer review Not commissioned; externally peer reviewed.
J Neurol Neurosurg Psychiatry 2014;0:1–3. doi:10.1136/jnnp-2014-308240
▸ Additional material is published online only. To view please visit the journal online (http://dx.doi.org/10. 1136/jnnp-2014-308240).
REFERENCES
To cite Hardy TA, O’Brien B, Gerbis N, et al. J Neurol Neurosurg Psychiatry Published Online First: [please include Day Month Year] doi:10.1136/jnnp-2014308240 Received 5 May 2014 Revised 15 July 2014 Accepted 10 August 2014
J Neurol Neurosurg Psychiatry Month 2014 Vol 0 No 0
1 2
3
Susac J, Murtagh F, Egan R, et al. MRI findings in Susac’s syndrome. Neurology 2003;61:1783–7. Hardy TA, Garsia RJ, Halmagyi GM, et al. Tumour necrosis factor (TNF) inhibitor therapy in Susac’s syndrome. J Neurol Sci 2011;302:126–8. Heiskala H, Somer H, Kovanen J, et al. Microangiopathy with encephalopathy, hearing loss and retinal arteriolar occlusions: two new cases. J Neurol Sci 1988;86:239–50.
4
5
6
7
Fox RJ, Costello F, Judkins AR, et al. Treatment of Susac syndrome with gamma globulin and corticosteroids. J Neurol Sci 2006;251:17–22. Monteiro ML, Swanson RA, Coppeto JR, et al. A microangiopathic syndrome of encephalopathy, hearing loss, and retinal arteriolar occlusions. Neurology 1985;35:1113–21. Magro CM, Poe JC, Lubow M, et al. Susac syndrome: an organ-specific autoimmune endotheliopathy syndrome associated with anti-endothelial cell antibodies. Am J Clin Pathol 2011;136:903–12. Smolen JS, Emery P. Infliximab: 12 years of experience. Arthritis Res Ther 2011;13(Suppl 1):S2.
3
Downloaded from jnnp.bmj.com on August 29, 2014 - Published by group.bmj.com
Brain histopathology in three cases of Susac's syndrome: implications for lesion pathogenesis and treatment Todd A Hardy, Billy O'Brien, Natasha Gerbis, et al. J Neurol Neurosurg Psychiatry published online August 28, 2014
doi: 10.1136/jnnp-2014-308240
Updated information and services can be found at: http://jnnp.bmj.com/content/early/2014/08/28/jnnp-2014-308240.full.html
These include:
References
This article cites 7 articles, 1 of which can be accessed free at: http://jnnp.bmj.com/content/early/2014/08/28/jnnp-2014-308240.full.html#ref-list-1
P
