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Antibodies against the paramyxovirus SV5 are not specific for cerebrospinal fluid from multiple sclerosis patients
Journal of the Neurological Sciences, 1989, 92:261-266
261
Elsevier JNS 03206
Antibodies against the paramyxovirus SV5 are not specific for cerebrospinal fluid from multiple sclerosis patients B r e n d a n N. M c L e a n and E d w a r d J. T h o m p s o n Department of Neurochemistry, Institute of Neurology, London WCIN 3BG (U.K.)
(Received 21 February, 1989) (Revised, received 12 April, 1989) (Accepted 12 April, 1989)
SUMMARY An aetiological agent for multiple sclerosis has not yet been identified. The paramyxovirus SV5 (Simian virus 5) has been suggested as an important cause in some cases. Using antigen immunoblotting with SV5 virus, we confirmed the binding to SV5 of immunoglobulin G from the cerebrospinal fluid of 58 ~o of multiple sclerosis patients, but also found binding in 70 ~o of patients with a variety of neurological disorders where oligoclonal banding was present. This suggests that the antibodies present are not specific for multiple sclerosis and that the SV5 virus is thus unlikely to be of aetiological significance.
Key words: Multiple sclerosis; Cerebrospinal fluid; Immunoglobulin G; Simian virus 5; Antigen blotting
INTRODUCTION Many viruses have been implicated in the pathogenesis of multiple sclerosis (MS), usually upon the basis of detection of antibodies directed against that virus in cerebrospinal fluid (CSF), or the recovery of virus particles or culture from tissue samples in
Correspondence to." Dr. B.N. McLean, Department of Neurochemistry, 9tb Floor, Institute of Neurology,Queen Square, LondonWC1N 3BG, U.K.
0022-510X/89/$03.50 © 1989Elsevier Science Publishers B.V. (BiomedicalDivision)
262 life or at post mortem (Lisak 1980). The majority of these viruses have been excluded as a cause per se of MS and at best the presence of antibodies described as an epiphenomenon. In the late 1970's and early 1980's, the recovery of the SV5 virus from bone marrow of MS sufferers was reported (Mitchell et al. 1978; Goswami et al. 1982) and subsequently using monoclonal antibodies it was claimed that SV5 was present as a persistent infection in the bone marrow of MS and non-MS patients (Goswami et al~ 1984a). Serological studies on selected populations have claimed a prevalence of anti-SV5 antibodies of about 4 0 ~ (Goswami et al. 1984b), although no disease had been iinked with the virus in humans. Recently, it has been reported by the same workers that in MS patients, the oligoclonal bands in CSF could be adsorbed out by SV5 Virus and not by measles virus (Goswami et al. 1987). They estimated in indexed cases that up to 95 ~o of the CSF immunoglobulin G (IgG) was directed against the SV5 virus, and were able to characterise some of the antibody as being directed against Certain epitopes, notably the haemagglutinin neuraminidase (HN) polypeptide. As a result of this work, using antigen immunobtotting, we set out to investigate the presence of anti-SV5 IgG in the CSF of a group of patients from the South East of England who had clinically definite MS and a control group with other neurological disorders.
METHODS
Patients Nineteen patients with clinically definite MS, and who had oligoclonal IgG bands in the CSF but not serum, were randomly selected from samples routinely analysed in our laboratory. Twenty-three control patients were selected, comprising 6 with no oligoclonal IgG (motor neurone disease, carpal tunnel syndrome, 4 with pain syndromes) and 17 with neurological disorders associated with local synthesis of otigoclonal IgG bands in the CSF (tuberculous meningitis (2), Guillain-Barr6 syndrome (2), subacute sclerosing panencephatitis (2), neurosarcoidosis (2), neurosyphilis (2), disseminated CNS eytomegalovirus infection (2), mycosis fungoides (1), cerebral lupus (1), herpes zoster encephalitis (1), and encephalitis of unknown cause (2)). Laboratory investigations Antigen blotting was performed as described before (Moyle et al. 1984). Briefly, purified enveloped SV5 virus (provided by K. Goswami, St. Andrews University) was sonicated and then incubated with nitrocellulose membranes for 2 h at room temperature, at a protein concentration of 10/~gper cm 2 of membrane in a total volume of 25 ml phosphate-buffered saline (PBS, pH 7.2) per 20 x t 0 c m sheet. After decanting unbound protein, the membrane was blocked for 1.5 h in 1~ bovine serum albumin/1 gelatin in PBS. IgG (2 #g) from paired unconcentrated CSF and diluted serum samples was loaded using an application foil onto l-ram thick agarose IEF gels with a pH gradient of 3-10.5 made in the laboratory (Seakem agarose 0.3g; Pharmacia
263 ampholytes 2-10, 2 ml; 8-10.5, 0.5 ml; 10~o glycerol 27 ml; D-sorbitol 3.6 g). The samples were focused for 1 500 V/h on LKB-IEF tank at 20 W, 1 500 V, 150 mA, and then antibody passively transferred to the antigen coated nitrocellulose membrane by pressure for 20 min. After washing with 0.05 ~o Tween 20 in 0.05 M PBS 4 times, and distilled water twice to remove unbound antibody, the membrane was incubated with 1 : 1000 dilution goat anti-human IgG Fc specific IgG (Atlantic Antibodies) in 0.1 ~o albumin/gelatin for 1 h then after washing as before, incubated for 1 h with 1 : 1000 dilution of rabbit anti-goat IgG HRP conjugate (Dakopatts) in 0.1 ~o albumin/gelatin before washing and staining with 4-amino-9-ethylcarbazole. Control sonicated antigens, consisting of parainfluenza 2, Sendal, measles and herpes simplex type 1 viruses, were run in parallel, though not all specimens were run against the same controls. In addition, where appropriate, specimens were run with antigens consisting of only the cell line used for viral culture, or with omission of the goat anti-human antibody.
RESULTS
Eleven of the 19 (58~o) patients with MS showed antibody binding in CSF alone (Table 1), usually at a low level, but in some a strong response could be seen. Of the 8 negative patients, one had strong serum binding, with an equivalent CSF response consistent with leakage of antibody from the serum into the CSF. Five of the 11 positive patients had an oligoclonal pattern (Fig. 1), the remaining 6 were polyclonal in
TABLE 1 R E S U L T S O F SV5 V I R U S A N T I G E N B L O T T I N G O N 42 P A T I E N T S
Patients
No.
OCB a + ve
Polyclonal
Negative
MS
19
5
6
8
N o n - M S OCB + ve TBM GBS SSPE Neurosarcoid Neurosyphilis CMV disseminated H Z encephalitis Cerebral lupus Mycosis fungoides Encephalitis Total
2 2 2 2 2 2 1 1 1 2 17
1 I 1
1
N o n - M S OCB - ve a OCB = oligoclonal bands.
6
1 1 1
1 6
1 1 1 1
1 1 1 1 6
1 5
1
5
264
Fig. 1. Representative antigen immunoblots for SV5 virus after isoelectric focusing of CSF and serum. Lanes la,b: MS patient, CSF and serum; lanes 2a,b: $SPE, CSF and serum, pH gradient is 3;-10.5 from left to right.
appearance. Of the 6 oligoclonal negative controls, one showed polyclonal binding in CSF alone (pain syndrome). Twelve of the 17 (70~o) oligoclonal positive controls showed binding in CSF, with 2 having serum binding also. Six patients showed an oligoclonal pattern, the remaining 6 were polyclonal. The largest amount of bound antibody was associated with disorders having a viral aetiology (SSPE, CMV and herpes zoster), but this was not necessarily oligoclonal. There was no consistent response with any disease category: CSFs could be negative, polyclonal or oligoclonal. Where an oligoclonal pattern was seen, the bands were of a different isoetectric point (pI) to those blotted out by the aetiological agent when known (data not shown), Control antigen blots, except where the aetiological agent was used, were negative in the majority of cases, with a few CSF samples showing occasional bands against one or more viruses in both the MS and the oligoclonal positive controls. The banding was always at a different p / t o that seen when there were bands in the SV5 blots on the same patient. When viral free cell suspensions were used as antigens, or the anti-human I g G antibody was ommitted, all lanes were negative: Negative control patients produced no response against any of the antigens used.
265 DISCUSSION Antigen blotting is a very sensitive technique (Moyle et al. 1984), and confers an advantage over adsorption experiments in demonstrating a "positive" result. It can reveal clonally directed antibody not apparent on total IgG staining and when purified antigens are used will lift out clones not visible with crude preparations. Blotting is specific for the agent tested and cross-reactivity can be excluded by examination of the differing patterns produced. Only small volumes of sample are required and provided equal amounts of protein are loaded, direct comparisons can be made regarding antibody binding. This study is the first, to our knowledge, to use a number of oligoclonal positive controls, and has confirmed the findings of Goswami et al. that some patients with M S have clearly demonstrable local synthesis of anti-SV5 antibody in their CSFs. However, binding is not unique to MS, but occurs in the CSF of many other neurological disorders where oligoclonal banding of IgG is present. Even in those other disorders, the response is not disease-specific in that some patients with a particular diagnosis are positive and some are negative. The amount of antibody present as a proportion of total IgG is low in most patients, and does not compare with that seen in other neurological diseases with a viral aetiology such as SSPE and herpes simplex encephalitis, where up to 95~o of the IgG may be viral specific. A positive CS F response was seen in only one of the oligoclonal negative controls, and this was polyclonal. Polyclonal responses are usually associated with nonspecific activation in the CNS, and the patient had a pain syndrome associated with polyclonal activation of other viral specific antibodies. In MS, some of the CSF antibody response may be directed against self antigens, revealed by destructive processes during neurological disease (Cruz et al. 1987). Because the SV5 virus is an RNA virus, and derives a large proportion of its coat from host cell membrane, the response seen may in fact be due to cross-reactivity with non viral proteins. Although it has been suggested that cross-reactivity may be on the basis of the glycolipid coat, such antibodies have not been found (Rostami et al. 1987). Epitopes shared by related viruses could also give rise to positive results, but such cross-reactivities can be excluded by comparison of oligoclonal patterns produced by antigen blotting. The bands found against control antigens, including the paramyxovirus PF2, were not in the same positions as those against SV5, thus eliminating crossreactivity as the sole cause of the response in our patients. The presence of anti-SV5 antibodies thus appears to be a genuine phenomenon, but at a relatively low level in most patients. The similarity of the proportions of MS and non-MS neurological patients (58 and 70~o, respectively) who are positive in CSF suggests that this is a reflection of active neurological disease and does not represent an aetiological phenomenon. In neurological disease having an infective aetiology, the bulk of the antibody response in CSF seen as oligoclonal bands is directed against epitopes on the invading organism. In MS the antibody response is typically related to more than one virus (Felgenhauer et al. 1985), and in many other neurological disorders antibody responses against more than one agent can be demonstrated. All this implies that during a disease process, in addition to specific antibody responses the CNS
266 lymphocytes are non-specifically activated to produce antibodies against agents to which the patient has been previously exposed. Although our results give higher prevalence figures in our diseased patients than the 40~o previously quoted, this could still reflect prior exposure to the virus in our population, and the sensitivity o f the test used. R N A viruses, and in particular retroviruses, are increasingly being recoguised as the causative agents in some chronic neurological disorders in humans, such as tropical spastic paraparesis and H I V dementia. I n these it has been demonstrated that there is both a higher incidence o f C S F antibody response to the virus than in controls, and viral particles are recoverable from C S F or neural tissue. The SV5 virus certainly does not display a disease specificity, and virus has not been isolated from C S F or neural tissue. Our work does not preclude the possibility that in M S an infection with SV5 may act as a trigger for neurological events in somepatients, but it excludes the virus as a primary aetiologlcal agent.
ACKNOWLEDGEMENTS
Dr. K. K. A. Goswami and Dr. W.C. Russell provided the viruses for this study, Mr. Richard Luxton technical assistance.
REFERENCES Cruz, M., T. Olsson, J. Emerudh, B. Hoj¢berg and H. Link (1987) lmmunobtot detection of ollgoclonal anti-myelin basic protein IgG antibodies in cerebrospinal fluid in multiple sclerosis. Neurology, 37: 1515-1519. Felgenhauer, K., H.-J. Shadlich, M. Nekic and R. Ackermann (1985) Ccrebrospinal fluid virus antibodies. A diagnostic indicator for multiple sclerosis? .L Neueol. Sci., 71: 291-299. Goswami, K. K.A. and W.C. Russell (1982) A comparison ofparamyxoviruses by immunoprecipitation. J. Gen. Virol., 60: 177-183. Goswami, K. K. A., L. S. Lange, D.N. Mitchell, K. R. Cameron and W. C. Russell (1984a) Do¢s simian virus 5 infect humags? J. Gen. Virol., 65:1295-1 303. Goswami, K. K. A., K.R. Cameron, W.C. Russell, L. S. Lange and D.N. Mitchell (1984b)Evidence for the persistence of paramyxoviruses in human bone marrows. J. Gen. Vtrol., 65:1881-1888. Goswami, K.K.A., R.E. Randall, L.S. Lan4~ and W.C. Russell (1987} Antibodies against the paramyxovirus SV5 in the cerebrospinal fluids of some multiple sclerosis patients. Nature, 327: 244-247. Lisak, R.P. (1980) Multiple sclerosis: evidcnoe for immunopathogenesis. Neurology, 30(2): 99-105. MitcheLl, D. N., J. S. Porterfield, R. Mieheketti, L. S. Lange, K. K.A. Goswami, P. Taylor, J.P: Jacobs, D.J. Hockley and A.J. Salisbury (1978) Isolation of an ~ u s agent from bone-marrows ofpati~ats with multiple sclerosis. Lancet, ii: 387-391. Moyle, S., G. Keir and E.J. Thompson (1984) Viral immunoblotting: A sensitive method for detecting viral-specific oligoetonal bands in tmconeentratcd cercbroslrimd fluid, B/osd. Rep., 4: 505-510. Rostami, A. M., J. B. Barns, P.A. Eedcston, M.C. Minning, R. P. Lisak and D.H. Silvorherg(1987) Search for antibodies to galactoecrcbrosid¢ in the serum and ecrebrospinat fluid in human d~ayelinating disorders. Ann. NeuroL, 22: 381-383.
261
Elsevier JNS 03206
Antibodies against the paramyxovirus SV5 are not specific for cerebrospinal fluid from multiple sclerosis patients B r e n d a n N. M c L e a n and E d w a r d J. T h o m p s o n Department of Neurochemistry, Institute of Neurology, London WCIN 3BG (U.K.)
(Received 21 February, 1989) (Revised, received 12 April, 1989) (Accepted 12 April, 1989)
SUMMARY An aetiological agent for multiple sclerosis has not yet been identified. The paramyxovirus SV5 (Simian virus 5) has been suggested as an important cause in some cases. Using antigen immunoblotting with SV5 virus, we confirmed the binding to SV5 of immunoglobulin G from the cerebrospinal fluid of 58 ~o of multiple sclerosis patients, but also found binding in 70 ~o of patients with a variety of neurological disorders where oligoclonal banding was present. This suggests that the antibodies present are not specific for multiple sclerosis and that the SV5 virus is thus unlikely to be of aetiological significance.
Key words: Multiple sclerosis; Cerebrospinal fluid; Immunoglobulin G; Simian virus 5; Antigen blotting
INTRODUCTION Many viruses have been implicated in the pathogenesis of multiple sclerosis (MS), usually upon the basis of detection of antibodies directed against that virus in cerebrospinal fluid (CSF), or the recovery of virus particles or culture from tissue samples in
Correspondence to." Dr. B.N. McLean, Department of Neurochemistry, 9tb Floor, Institute of Neurology,Queen Square, LondonWC1N 3BG, U.K.
0022-510X/89/$03.50 © 1989Elsevier Science Publishers B.V. (BiomedicalDivision)
262 life or at post mortem (Lisak 1980). The majority of these viruses have been excluded as a cause per se of MS and at best the presence of antibodies described as an epiphenomenon. In the late 1970's and early 1980's, the recovery of the SV5 virus from bone marrow of MS sufferers was reported (Mitchell et al. 1978; Goswami et al. 1982) and subsequently using monoclonal antibodies it was claimed that SV5 was present as a persistent infection in the bone marrow of MS and non-MS patients (Goswami et al~ 1984a). Serological studies on selected populations have claimed a prevalence of anti-SV5 antibodies of about 4 0 ~ (Goswami et al. 1984b), although no disease had been iinked with the virus in humans. Recently, it has been reported by the same workers that in MS patients, the oligoclonal bands in CSF could be adsorbed out by SV5 Virus and not by measles virus (Goswami et al. 1987). They estimated in indexed cases that up to 95 ~o of the CSF immunoglobulin G (IgG) was directed against the SV5 virus, and were able to characterise some of the antibody as being directed against Certain epitopes, notably the haemagglutinin neuraminidase (HN) polypeptide. As a result of this work, using antigen immunobtotting, we set out to investigate the presence of anti-SV5 IgG in the CSF of a group of patients from the South East of England who had clinically definite MS and a control group with other neurological disorders.
METHODS
Patients Nineteen patients with clinically definite MS, and who had oligoclonal IgG bands in the CSF but not serum, were randomly selected from samples routinely analysed in our laboratory. Twenty-three control patients were selected, comprising 6 with no oligoclonal IgG (motor neurone disease, carpal tunnel syndrome, 4 with pain syndromes) and 17 with neurological disorders associated with local synthesis of otigoclonal IgG bands in the CSF (tuberculous meningitis (2), Guillain-Barr6 syndrome (2), subacute sclerosing panencephatitis (2), neurosarcoidosis (2), neurosyphilis (2), disseminated CNS eytomegalovirus infection (2), mycosis fungoides (1), cerebral lupus (1), herpes zoster encephalitis (1), and encephalitis of unknown cause (2)). Laboratory investigations Antigen blotting was performed as described before (Moyle et al. 1984). Briefly, purified enveloped SV5 virus (provided by K. Goswami, St. Andrews University) was sonicated and then incubated with nitrocellulose membranes for 2 h at room temperature, at a protein concentration of 10/~gper cm 2 of membrane in a total volume of 25 ml phosphate-buffered saline (PBS, pH 7.2) per 20 x t 0 c m sheet. After decanting unbound protein, the membrane was blocked for 1.5 h in 1~ bovine serum albumin/1 gelatin in PBS. IgG (2 #g) from paired unconcentrated CSF and diluted serum samples was loaded using an application foil onto l-ram thick agarose IEF gels with a pH gradient of 3-10.5 made in the laboratory (Seakem agarose 0.3g; Pharmacia
263 ampholytes 2-10, 2 ml; 8-10.5, 0.5 ml; 10~o glycerol 27 ml; D-sorbitol 3.6 g). The samples were focused for 1 500 V/h on LKB-IEF tank at 20 W, 1 500 V, 150 mA, and then antibody passively transferred to the antigen coated nitrocellulose membrane by pressure for 20 min. After washing with 0.05 ~o Tween 20 in 0.05 M PBS 4 times, and distilled water twice to remove unbound antibody, the membrane was incubated with 1 : 1000 dilution goat anti-human IgG Fc specific IgG (Atlantic Antibodies) in 0.1 ~o albumin/gelatin for 1 h then after washing as before, incubated for 1 h with 1 : 1000 dilution of rabbit anti-goat IgG HRP conjugate (Dakopatts) in 0.1 ~o albumin/gelatin before washing and staining with 4-amino-9-ethylcarbazole. Control sonicated antigens, consisting of parainfluenza 2, Sendal, measles and herpes simplex type 1 viruses, were run in parallel, though not all specimens were run against the same controls. In addition, where appropriate, specimens were run with antigens consisting of only the cell line used for viral culture, or with omission of the goat anti-human antibody.
RESULTS
Eleven of the 19 (58~o) patients with MS showed antibody binding in CSF alone (Table 1), usually at a low level, but in some a strong response could be seen. Of the 8 negative patients, one had strong serum binding, with an equivalent CSF response consistent with leakage of antibody from the serum into the CSF. Five of the 11 positive patients had an oligoclonal pattern (Fig. 1), the remaining 6 were polyclonal in
TABLE 1 R E S U L T S O F SV5 V I R U S A N T I G E N B L O T T I N G O N 42 P A T I E N T S
Patients
No.
OCB a + ve
Polyclonal
Negative
MS
19
5
6
8
N o n - M S OCB + ve TBM GBS SSPE Neurosarcoid Neurosyphilis CMV disseminated H Z encephalitis Cerebral lupus Mycosis fungoides Encephalitis Total
2 2 2 2 2 2 1 1 1 2 17
1 I 1
1
N o n - M S OCB - ve a OCB = oligoclonal bands.
6
1 1 1
1 6
1 1 1 1
1 1 1 1 6
1 5
1
5
264
Fig. 1. Representative antigen immunoblots for SV5 virus after isoelectric focusing of CSF and serum. Lanes la,b: MS patient, CSF and serum; lanes 2a,b: $SPE, CSF and serum, pH gradient is 3;-10.5 from left to right.
appearance. Of the 6 oligoclonal negative controls, one showed polyclonal binding in CSF alone (pain syndrome). Twelve of the 17 (70~o) oligoclonal positive controls showed binding in CSF, with 2 having serum binding also. Six patients showed an oligoclonal pattern, the remaining 6 were polyclonal. The largest amount of bound antibody was associated with disorders having a viral aetiology (SSPE, CMV and herpes zoster), but this was not necessarily oligoclonal. There was no consistent response with any disease category: CSFs could be negative, polyclonal or oligoclonal. Where an oligoclonal pattern was seen, the bands were of a different isoetectric point (pI) to those blotted out by the aetiological agent when known (data not shown), Control antigen blots, except where the aetiological agent was used, were negative in the majority of cases, with a few CSF samples showing occasional bands against one or more viruses in both the MS and the oligoclonal positive controls. The banding was always at a different p / t o that seen when there were bands in the SV5 blots on the same patient. When viral free cell suspensions were used as antigens, or the anti-human I g G antibody was ommitted, all lanes were negative: Negative control patients produced no response against any of the antigens used.
265 DISCUSSION Antigen blotting is a very sensitive technique (Moyle et al. 1984), and confers an advantage over adsorption experiments in demonstrating a "positive" result. It can reveal clonally directed antibody not apparent on total IgG staining and when purified antigens are used will lift out clones not visible with crude preparations. Blotting is specific for the agent tested and cross-reactivity can be excluded by examination of the differing patterns produced. Only small volumes of sample are required and provided equal amounts of protein are loaded, direct comparisons can be made regarding antibody binding. This study is the first, to our knowledge, to use a number of oligoclonal positive controls, and has confirmed the findings of Goswami et al. that some patients with M S have clearly demonstrable local synthesis of anti-SV5 antibody in their CSFs. However, binding is not unique to MS, but occurs in the CSF of many other neurological disorders where oligoclonal banding of IgG is present. Even in those other disorders, the response is not disease-specific in that some patients with a particular diagnosis are positive and some are negative. The amount of antibody present as a proportion of total IgG is low in most patients, and does not compare with that seen in other neurological diseases with a viral aetiology such as SSPE and herpes simplex encephalitis, where up to 95~o of the IgG may be viral specific. A positive CS F response was seen in only one of the oligoclonal negative controls, and this was polyclonal. Polyclonal responses are usually associated with nonspecific activation in the CNS, and the patient had a pain syndrome associated with polyclonal activation of other viral specific antibodies. In MS, some of the CSF antibody response may be directed against self antigens, revealed by destructive processes during neurological disease (Cruz et al. 1987). Because the SV5 virus is an RNA virus, and derives a large proportion of its coat from host cell membrane, the response seen may in fact be due to cross-reactivity with non viral proteins. Although it has been suggested that cross-reactivity may be on the basis of the glycolipid coat, such antibodies have not been found (Rostami et al. 1987). Epitopes shared by related viruses could also give rise to positive results, but such cross-reactivities can be excluded by comparison of oligoclonal patterns produced by antigen blotting. The bands found against control antigens, including the paramyxovirus PF2, were not in the same positions as those against SV5, thus eliminating crossreactivity as the sole cause of the response in our patients. The presence of anti-SV5 antibodies thus appears to be a genuine phenomenon, but at a relatively low level in most patients. The similarity of the proportions of MS and non-MS neurological patients (58 and 70~o, respectively) who are positive in CSF suggests that this is a reflection of active neurological disease and does not represent an aetiological phenomenon. In neurological disease having an infective aetiology, the bulk of the antibody response in CSF seen as oligoclonal bands is directed against epitopes on the invading organism. In MS the antibody response is typically related to more than one virus (Felgenhauer et al. 1985), and in many other neurological disorders antibody responses against more than one agent can be demonstrated. All this implies that during a disease process, in addition to specific antibody responses the CNS
266 lymphocytes are non-specifically activated to produce antibodies against agents to which the patient has been previously exposed. Although our results give higher prevalence figures in our diseased patients than the 40~o previously quoted, this could still reflect prior exposure to the virus in our population, and the sensitivity o f the test used. R N A viruses, and in particular retroviruses, are increasingly being recoguised as the causative agents in some chronic neurological disorders in humans, such as tropical spastic paraparesis and H I V dementia. I n these it has been demonstrated that there is both a higher incidence o f C S F antibody response to the virus than in controls, and viral particles are recoverable from C S F or neural tissue. The SV5 virus certainly does not display a disease specificity, and virus has not been isolated from C S F or neural tissue. Our work does not preclude the possibility that in M S an infection with SV5 may act as a trigger for neurological events in somepatients, but it excludes the virus as a primary aetiologlcal agent.
ACKNOWLEDGEMENTS
Dr. K. K. A. Goswami and Dr. W.C. Russell provided the viruses for this study, Mr. Richard Luxton technical assistance.
REFERENCES Cruz, M., T. Olsson, J. Emerudh, B. Hoj¢berg and H. Link (1987) lmmunobtot detection of ollgoclonal anti-myelin basic protein IgG antibodies in cerebrospinal fluid in multiple sclerosis. Neurology, 37: 1515-1519. Felgenhauer, K., H.-J. Shadlich, M. Nekic and R. Ackermann (1985) Ccrebrospinal fluid virus antibodies. A diagnostic indicator for multiple sclerosis? .L Neueol. Sci., 71: 291-299. Goswami, K. K.A. and W.C. Russell (1982) A comparison ofparamyxoviruses by immunoprecipitation. J. Gen. Virol., 60: 177-183. Goswami, K. K. A., L. S. Lange, D.N. Mitchell, K. R. Cameron and W. C. Russell (1984a) Do¢s simian virus 5 infect humags? J. Gen. Virol., 65:1295-1 303. Goswami, K. K. A., K.R. Cameron, W.C. Russell, L. S. Lange and D.N. Mitchell (1984b)Evidence for the persistence of paramyxoviruses in human bone marrows. J. Gen. Vtrol., 65:1881-1888. Goswami, K.K.A., R.E. Randall, L.S. Lan4~ and W.C. Russell (1987} Antibodies against the paramyxovirus SV5 in the cerebrospinal fluids of some multiple sclerosis patients. Nature, 327: 244-247. Lisak, R.P. (1980) Multiple sclerosis: evidcnoe for immunopathogenesis. Neurology, 30(2): 99-105. MitcheLl, D. N., J. S. Porterfield, R. Mieheketti, L. S. Lange, K. K.A. Goswami, P. Taylor, J.P: Jacobs, D.J. Hockley and A.J. Salisbury (1978) Isolation of an ~ u s agent from bone-marrows ofpati~ats with multiple sclerosis. Lancet, ii: 387-391. Moyle, S., G. Keir and E.J. Thompson (1984) Viral immunoblotting: A sensitive method for detecting viral-specific oligoetonal bands in tmconeentratcd cercbroslrimd fluid, B/osd. Rep., 4: 505-510. Rostami, A. M., J. B. Barns, P.A. Eedcston, M.C. Minning, R. P. Lisak and D.H. Silvorherg(1987) Search for antibodies to galactoecrcbrosid¢ in the serum and ecrebrospinat fluid in human d~ayelinating disorders. Ann. NeuroL, 22: 381-383.