Autologous hematopoietic cell transplantation following high-dose immunosuppressive therapy for advanced multiple sclerosis: long-term results

The purpose of the study was to determine the long-term safety and effectiveness of high-dose immunosuppressive therapy (HDIT) followed by autologous hematopoietic cell transplantation (AHCT) in advanced multiple sclerosis (MS). Total body irradiation, cyclophosphamide, and antithymocyte globulin were followed by transplantation of autologous, CD34-selected peripheral blood stem cells (PBSC). Neurological examinations, brain MRIs and cerebrospinal fluid (CSF) for oligoclonal bands (OCB) were serially evaluated. Patients (n=26, mean EDSS=7.0, 17 secondary progressive, 8 primary progressive, 1 relapsing/remitting) were followed for a median of 48 months after HDIT followed by AHCT. The 72-month probability of worsening ≥ 1.0 EDSS point was 0.52 (95% CI, 0.30 to 0.75). Five patients had an EDSS at baseline of ≤ 6.0; four of these had not failed treatment at last study visit. OCB in CSF persisted with minor changes in the banding pattern. Four new or enhancing lesions were seen on MRI, all within 13 months of treatment. In this population with high baseline EDSS, a significant proportion of patients with advanced MS remained stable as long as 7 years after transplant. Non-inflammatory events may have contributed to neurological worsening after treatment. HDIT/AHCT may be more effective in patients with less advanced relapsing/remitting MS.

Multiple sclerosis conference synopsis and discussion: cellular therapy for treatment of autoimmune diseases (October 2005)

At a conference held in October 2005, participants presented studies on high dose immunosuppression with hematopoietic cell transplant (HCT) for multiple sclerosis (MS), including neuroimmunological and magnetic resonance imaging (MRI) mechanistic approaches, clinical registry reports, and ongoing or newly-designed protocols. A discussion panel considered questions on how to define success, timing of controlled clinical trials, difficulty in patient recruitment, and future direction of high dose therapy.

Autologous stem cell transplantation for progressive multiple sclerosis: update of the European Group for Blood and Marrow Transplantation autoimmune diseases working party database

Over the last decade, hematopoietic stem cells transplantation (HSCT) has been increasingly used in the treatment of severe progressive autoimmune diseases. We report a retrospective survey of 183 multiple sclerosis (MS) patients, recorded in the database of the European Blood and Marrow Transplantation Group (EBMT). Transplant data were available from 178 patients who received an autologous graft. Overall, transplant related mortality (TRM) was 5.3% and was restricted to the period 1995-2000, with no further TRM reported since then. Busulphan-based regimens were significantly associated with TRM. Clinical status at the time of transplant and transplant techniques showed some correlations with toxicity. No toxic deaths were reported among the 53 patients treated with the BEAM (carmustine, etoposide, cytosine-arabinoside, melphalan)/antithymocyte globulin (ATG) regimen without graft manipulation, irrespective of their clinical condition at the time of the transplant. Improvement or stabilization of neurological conditions occurred in 63% of patients at a median follow-up of 41.7 months, and was not associated with the intensity of the conditioning regimen. In this large series, HSCT was shown as a promising procedure to slow down progression in a subset of patients affected by severe, progressive MS; the safety and feasibility of the procedure can be significantly improved by appropriate patient selection and choice of transplant regimen.

Hematopoietic stem cell transplantation for multiple sclerosis. A retrospective multicenter study

RATIONALE

Phase I/II studies of autologous hematopoietic stem cell transplantation (HSCT) for multiple sclerosis ( MS) were initiated, based on results of experimental transplantation in animal models of multiple sclerosis and clinical observations in patients treated concomitantly for malignant disease.

PATIENTS

Eighty-five patients with progressive MS were treated with autologous HSCT in 20 centers and reported to the autoimmune disease working party of the European Group for Blood and Marrow Transplantation (EBMT). 52 (61 %) were female, median age was 39 [20-58] years. The median interval from diagnosis to transplant was 7 [1-26] years. Patients suffered from severe disease with a median EDSS score of 6.5 [4.5-8.5]. Active disease prior to transplant was documented in 79 of 82 evaluable cases.

RESULTS

The stem cell source was bone marrow in 6 and peripheral blood in 79, and stem cells were mobilized into peripheral blood using either cyclophosphamide combined with growth factors or growth factors alone. Three patients experienced transient neurological complications during the mobilization phase. The high dose regimen included combination chemotherapy, with or without anti-lymphocyte antibodies or, with or without, total body irradiation. The stem cell transplants were purged of lymphocytes in 52 patients. Median follow-up was 16 [3-59] months. There were 7 deaths, 5 due to toxicity and infectious complications, 2 with neurological deterioration. The risk of death of any cause at 3 years was 10 (+/-7)% (95 % confidence interval). Neurological deterioration during transplant was observed in 22 patients; this was transient in most but was associated with MS progression in 6 patients. Neurological improvement by > or = 1 point in the EDSS score was seen in 18 (21 %) patients. Confirmed progression-free survival was 74 (+/-12)% at 3 years being 66 (+/-23)% in patients with primary progressive MS but higher in patients with secondary progressive or relapsing-remitting MS, 78 (+/-13)%; p = 0.59. The probability of confirmed disease progression was 20 (+/-11)%. MRI data were available in 78 patients before transplant showing disease activity (gadolinium enhancing, new or enlarging lesions) in 33 %. Posttransplant MRI showed activity at any time in 5/61 (8 %) evaluable cases.

CONCLUSION

Autologous HSCT suggest positive early results in the management of progressive MS and is feasible. These multicentre data suggest an association with significant mortality risks especially in some patient groups and are being utilised in the planning of future trials to reduce transplant related mortality.

Peripheral blood stem cell transplantation in multiple sclerosis with busulfan and cyclophosphamide conditioning: report of toxicity and immunological monitoring

Multiple sclerosis (MS) is an immune-mediated disease that may be amenable to high-dose immunosuppression with peripheral blood stem cell transplantation (SCT) in selected patients. Five MS patients (all women, ages 39-47 years) received granulocyte colony-stimulating factor (G-CSF) for stem cell mobilization, CD34 cell selection for T-cell depletion, a preparatory regimen of busulfan (1 mg/kg x 16 doses) and cyclophosphamide (120 mg/kg), and antithymocyte globulin (10 mg/kg x 3 doses) at the time of stem cell infusion. Days required to recover absolute neutrophil count >500 were 12 to 14 and platelet count >20,000 were 17 to 58. Posttransplantation infectious complications in the first year after SCT occurred in 3 of 5 patients, and 1 patient died at day 22 after SCT from influenza A pneumonia. Neuropathologic study in this patient showed demyelinating plaques with surrounding macrophages but only rare T cells. In 2 patients, MS flared transiently with G-CSF. Magnetic resonance imaging gadolinium enhancement was present in 3 of 5 patients before transplantation and 0 of 4 after SCT. There were cerebrospinal fluid oligoclonal bands at 1 year after SCT, similar to the pretransplantation assays. Sustained suppression of peripheral blood mononuclear cell proliferative responses to myelin antigens occurred after SCT, but new responses to some myelin peptide fragments also developed after SCT. In 1 patient, enzyme-linked immunospot (ELISPOT) assays done 9 months after SCT showed a predominant T helper 2 (Th2) cytokine pattern. Neurological progression of 1 point on the extended disability status scale was seen in 1 patient 17 months after SCT. Another patient who was neurologically stable died abruptly 19 months after SCT from overwhelming S. pneumoniae sepsis. The remaining patients have had stable MS (follow-up, 18 and 30 months). In summary, our experience confirms the high-risk nature of this approach. Further studies and longer follow-up would be needed to determine the significance of new lymphocyte proliferative responses after SCT and the overall effect of this treatment on the natural history of MS.

Gender influences herpes simplex virus type 1 infection in normal and gamma interferon-mutant mice

Gender influences the incidence and severity of some bacterial and viral infections and autoimmune diseases in animal models and humans. To determine a gender-based difference, comparisons were made between male and female mice inoculated with herpes simplex virus type 1 (HSV-1) by the corneal route. Mortality was higher in the male mice of the three strains tested: 129/Sv//Ev wild type, gamma interferon (IFN-gamma) knockout (GKO), and IFN-gamma receptor knockout (RGKO). Similarly, in vivo HSV-1 reactivation occurred more commonly in male mice, but the male-female difference in reactivation was restricted to the two knockout strains and was not seen in the 129/Sv//Ev control. Comparison among male mice of the three strains showed a higher mortality of the RGKO mice and a higher reactivation rate of the GKO and RGKO mice than of the 129/Sv//Ev males. In contrast, female RGKO and GKO mice did not differ from female 129/Sv//Ev controls in either mortality or reactivation. HSV-1 periocular and eyelid disease was also more severe in male and dihydrotestosterone (DHT)-treated female mice than in control female mice. These results show a consistent gender difference in HSV-1 infection, with a worse outcome in male mice. In addition, the results comparing GKO and RGKO mice to controls show differences only in male mice, suggesting that some effects of IFN-gamma, a key immunoregulatory molecule, are gender specific.

Multiple sclerosis flares associated with recombinant granulocyte colony-stimulating factor

Four of 10 patients who were enrolled on protocols of high-dose immunosuppression with peripheral blood stem cell rescue for MS experienced neurologic worsening while receiving recombinant human granulocyte colony-stimulating factor. There was improvement when methylprednisolone was given to three of the patients, but one patient died of respiratory failure. The mechanism of the neurologic worsening is uncertain.

Gamma interferon (IFN-gamma) receptor null-mutant mice are more susceptible to herpes simplex virus type 1 infection than IFN-gamma ligand null-mutant mice

Mouse strains with null mutations in the gamma interferon gene (Ifng) or the gamma interferon receptor gene (Ifngr) have been engineered. The use of these strains as animal models of viral and bacterial infections has enhanced our understanding of the role of gamma interferon (IFN-gamma) in the host immune response. However, direct comparisons between Ifng-/- (GKO) and Ifngr-/- (RGKO) mice have been problematic because previously available strains of these mice have had different genetic backgrounds (i.e., C57BL/6 and BALB/c for GKO mice and 129/Sv//Ev for RGKO mice). To enable direct comparison of herpes simplex virus type 1 (HSV-1) infections in GKO and RGKO mice, we introduced the IFN-gamma null mutation into the 129/Sv//Ev background. We report that, after HSV-1 inoculation, mortality was significantly greater in RGKO mice than in GKO mice (38 versus 23%, P = 0.0001). Similarly, the mortality from vaccinia virus challenge was significantly greater in RGKO mice than in GKO mice. With differences in genetic background excluded as a confounding issue, these results are consistent with the existence of an alternative ligand(s) for the IFN-gamma receptor that is also capable of mediating protection against viral challenge.

Role for gamma interferon in control of herpes simplex virus type 1 reactivation

Observation of chronic inflammatory cells and associated high-level gamma interferon (IFN-gamma) production in ganglia during herpes simplex type 1 (HSV-1) latent infection in mice (E. M. Cantin, D. R. Hinton, J. Chen, and H. Openshaw, J. Virol. 69:4898-4905, 1995) prompted studies to determine a role of IFN-gamma in maintaining latency. Mice lacking IFN-gamma (GKO mice) or the IFN-gamma receptor (RGKO mice) were inoculated with HSV-1, and the course of the infection was compared with that in IFN-gamma-competent mice with the same genetic background (129/Sv//Ev mice). A time course study showed no significant difference in trigeminal ganglionic viral titers or the timing of establishment of latency. Spontaneous reactivation resulting in infectious virus in the ganglion did not occur during latency in any of the mice. However, 24 h after the application of hyperthermic stress to mice, HSV-1 antigens were detected in multiple neurons in the null mutant mice but in only a single neuron in the 129/Sv//Ev control mice. Mononuclear inflammatory cells clustered tightly around these reactivating neurons, and by 48 h, immunostaining was present in satellite cells as well. The incidence of hyperthermia-induced reactivation as determined by recovery of infectious virus from ganglia was significantly higher in the null mutant than in control mice: 11% in 129/Sv//Ev controls, 50% in GKO mice (P = 0.0002), and 33% in RGKO mice (P = 0.03). We concluded that IFN-gamma is not involved in the induction of reactivation but rather contributes to rapid suppression of HSV once it is reactivated.

Cerebrospinal fluid interleukin 6 in amyotrophic lateral sclerosis: immunological parameter and comparison with inflammatory and non-inflammatory central nervous system diseases

We assayed IL-6 in 105 cerebrospinal fluid (CSF) samples from patients with ALS, MS, HTLV-1 associated myelopathy (HAM), and controls. There was considerable overlap in IL-6 levels in all patient groups. The mean IL-6 in 27 patients with ALS was significantly higher than in 21 patients in the other neurological disease (OND) group (P=0.0075). There were no significant differences in MS or HAM and the OND control group. Overall, CSF IL-6 correlated with protein concentration but not with percentage IgG or IgG-albumin index. Patients with CSF oligoclonal bands were no more likely to have detectable IL-6 than patients without oligoclonal bands. Similarly, IL-6 did not correlate with clinical disease activity in MS when subgroups of patients were compared or when an individual patient was followed over time. The elevated IL-6 in ALS may reflect an ongoing humoral immune response, or IL-6 may be non-specifically expressed in these patients as a putative neurotrophic factor in response to nerve cell degeneration.

Myositis associated with graft-versus-host disease

A polymyositis syndrome has been described as a rare complication in patients who develop chronic graft-versus-host disease after allogeneic bone marrow transplantation. Chronic graft-versus-host disease is a cellular immune-mediated donor bone marrow versus patient rejection reaction, which may also lead to an autoimmune pathologic process. Chronic graft-versus-host disease-related polymyositis appears to be very similar to idiopathic myositis in its clinicopathologic presentation; chronic graft-versus-host disease-related myositis responds well to prednisone but cyclosporine may be an important component of second-line therapy due to its efficacy in controlling underlying chronic graft-versus-host disease.

Peripheral neuropathy after bone marrow transplantation

Peripheral neuropathy after bone marrow transplantation can produce motor disability with significant morbidity and mortality, particularly when the neuropathy occurs within the first few months of the transplant. Most of these severe neuropathies have demyelinating features on electrophysiologic tests and histopathology, characteristic of immunologically-mediated neuropathies. The specific immune mechanism is uncertain. It is possible that cyclosporin, FK-506, and interferon-alpha may all trigger immunologically mediated neuropathies in rare patients. Transplants in patients with pre-existing demyelinating neuropathy may result in abrupt exacerbation of the neuropathy. Other causes of severe neuropathies include high-dose cytosine arabinoside and critical illness polyneuropathy. Less severe neuropathies with primarily sensory deficits may result from etoposide conditioning, thalidomide treatment for graft-versus-host disease, and the chemotherapeutic agents cisplatin and paclitaxel when used at high-dose with peripheral stem cell support. When encountering patients with disabling motor neuropathies, transplant physicians must identify (with the aid of nerve conduction tests) those neuropathies that are likely to be immunologically mediated and then empirically add or alter immunosuppressant therapies. Unfortunately, experience has been too limited to suggest specific regimens or the optimal sequence of immunosuppressant therapies.

Eye movement disorders in bone marrow transplant patients on cyclosporin and ganciclovir

After 582 allogeneic bone marrow transplants, we have encountered four patients (0.7%) who developed transient unilateral or bilateral sixth nerve palsies. Three of the four patients also had bilateral ptosis. These signs resolved 24-48 h after cyclosporin and ganciclovir were discontinued. One patient had MRI T2 abnormalities compatible with cyclosporin neurotoxicity. We postulate that cyclosporin, possibly together with ganciclovir, can produce transient brain stem or neuromuscular dysfunction with eye movement abnormality in occasional patients.

Genetic and functional complementation of the HSV1 UL27 gene and gB glycoprotein by simian alpha-herpesvirus homologs

Utilizing co-transfection of DNA from glycoprotein gB- strain of HSV1 and cloned fragments of several simian alpha-herpesviruses containing the UL26, UL27 (gB glycoprotein), and UL28 gene homologs, replication-competent recombinant viruses were produced. Genetic analysis of one HSV1/SA8 recombinant (HSV1/SgB) demonstrated the presence of SA8 DNA comprising the entire UL27 (gB) gene and parts of the UL28 and UL26 ORFs in an otherwise HSV1 genome. The recombinant was shown to express the SA8 gB and p40 proteins (UL27 & UL26.5 gene products, respectively); all other proteins were indistinguishable from those of HSV1. The recombinant behaved like SA8 in gB-specific virus neutralization and cell surface antibody binding assays, while plaque morphology and replication kinetics were very similar to HSV1. Despite its overwhelming HSV1 genetic constitution, the recombinant displayed a pathogenic phenotype in mice very different from the parental HSV1. While HSV1 produced corneal disease in ocularly infected mice and readily spread to the nervous system. HSV1/SgB was markedly impaired in both respects. These results demonstrate the functional equivalency of the cercopithecine monkey virus gB glycoproteins and genes (including transcriptional regulatory elements) in HSV1, the functional nature of HSV1/SA8 chimeric UL28 and UL26 genes/proteins, and that UL28, gB and/or p40 proteins may effect the pathogenicity of HSV1.

Acute polyneuropathy after high dose cytosine arabinoside in patients with leukemia

BACKGROUND

Peripheral nerve toxicity has been reported but is not a commonly recognized complication of high dose cytosine arabinoside (HDAC) therapy. This study was undertaken to estimate the prevalence and describe the clinical spectrum of acute polyneuropathy associated with HDAC therapy for leukemia.

METHODS

Records of 153 acute leukemia patients who received 194 courses of HDAC at the City of Hope were reviewed for evidence of severe peripheral neuropathy with onset 2-3 weeks after HDAC therapy.

RESULTS

Two patients were identified who developed motor disability 2-3 weeks after HDAC therapy, and the disability progressed in a monophasic course to quadriparesis. There was neurophysiologic evidence of peripheral nerve demyelination with slowed nerve conduction velocities and conduction block. One patient who was autopsied had demyelination identified in luxol-fast blue sections of peripheral nerve (with Bielschowsky-stained sections showing intact peripheral nerve axons). There were foamy macrophages in the peripheral nerve but no chronic inflammatory cells. For comparison, data from these two patients were combined with those from four published case reports of polyneuropathy associated with HDAC therapy. Quadriparesis occurred in five of six cases with the need for ventilatory support in four. Cerebrospinal fluid protein was elevated in five of six cases. Etiologic evidence incriminating HDAC included simultaneous cerebellar signs in two of six cases and a narrow interval of clinical onset after HDAC therapy.

CONCLUSIONS

Demyelinating polyneuropathy occurs in approximately 1% of HDAC courses and produces severe motor disability. HDAC immunosuppression could trigger an immune-mediated neuropathy; alternatively, a direct neurotoxic effect of HDAC on Schwann cells is also an etiologic possibility.

Polymyositis as a manifestation of chronic graft-versus-host disease

A syndrome indistinguishable from idiopathic polymyositis occurred in 11 patients as a manifestation of chronic GVHD. All patients had elevation of creatine phosphokinase (CPK). Immunohistology demonstrated the effector cells in the muscle infiltrates as cytotoxic T cells, a finding similar to idiopathic polymyositis. Polymyositis is a rarely reported complication of chronic graft-versus-host disease (GVHD) with only 8 cases described in the literature. We encountered this syndrome in a small but significant percentage of our patients with chronic GVHD. Polymyositis associated with chronic GVHD does not affect the overall prognosis for the patient. Moreover, polymyositis can be the only manifestation of chronic GVHD. Awareness of this complication is important because it can be confused with other causes of muscle weakness after bone marrow transplantation. Finally, prompt initiation of corticosteroid therapy results in a rapid improvement of the associated symptoms.

Deletion of the carboxy-terminus of herpes simplex virus type 1 (HSV-1) glycoprotein B does not affect oligomerization, heparin-binding activity, or its ability to protect against HSV challenge

A recombinant vaccinia virus designated VgBt which expresses a truncated secreted herpes simplex virus gB (gBt) was constructed and compared to V11gB, a vaccinia recombinant previously studied which expresses gB exclusively on the surface of infected cells. Indirect immunofluorescence assay (IFA) revealed that gBt was strongly associated with the surface of infected cells despite being released slowly into the cell culture medium. Both gB and gBt existed as oligomers, and both membrane bound and secreted forms of gBt exhibited heparin-binding activity. In protection studies VgBt and V11gB conferred equivalent protection against both homologous (HSV-1) and heterologous (HSV-2) challenge with HSV.

Gamma interferon expression during acute and latent nervous system infection by herpes simplex virus type 1

This study was initiated to evaluate a role for gamma interferon (IFN-gamma) in herpes simplex virus type 1 (HSV-1) infection. At the acute stage of infection in mice, HSV-1 replication in trigeminal ganglia and brain stem tissue was modestly but consistently enhanced in mice from which IFN-gamma was by ablated monoclonal antibody treatment and in mice genetically lacking the IFN-gamma receptor (Rgko mice). As determined by reverse transcriptase PCR, IFN-gamma and tumor necrosis factor alpha transcripts were present in trigeminal ganglia during both acute and latent HSV-1 infection. CD4+ and CD8+ T cells were detected initially in trigeminal ganglia at day 5 after HSV-1 inoculation, and these cells persisted for 6 months into latency. The T cells were focused around morphologically normal neurons that showed no signs of active infection, but many of which expressed HSV-1 latency-associated transcripts. Secreted IFN-gamma was present up to 6 months into latency in areas of the T-cell infiltration. By 9 months into latency, both the T-cell infiltrate and IFN-gamma expression had cleared, although there remained a slight increase in macrophage levels in trigeminal ganglia. In HSV-1-infected brain stem tissue, T cells and IFN-gamma expression were present at 1 month but were gone by 6 months after infection. Our hypothesis is that the persistence of T cells and the sustained IFN-gamma expression occur in response to an HSV-1 antigen(s) in the nervous system. This hypothesis is consistent with a new model of HSV-1 latency which suggests that limited HSV-1 antigen expression occurs during latency (M. Kosz-Vnenchak, J. Jacobson, D.M. Coen, and D.M. Knipe, J. Virol. 67:5383-5393, 1993). We speculate that prolonged secretion of IFN-gamma during latency may modulate a reactivated HSV-1 infection.

Herpes simplex virus DNA in normal corneas: persistence without viral shedding from ganglia

Herpes simplex virus type 1 (HSV-1) DNA has been shown to persist in the cornea not only after inoculation of experimental animals but also in surgical samples from patients with herpes keratitis. The further observation of corneal HSV-1 DNA in subjects without known HSV eye disease prompted the present study of the presence and distribution of HSV-1 in eye bank corneas. Prior to DNA extraction, the corneas were trephined, separating the central and peripheral cornea. With polymerase chain reaction (PCR) for HSV-1 thymidine kinase (TK) and glycoprotein D (gD) gene sequences, we found HSV-1 in 10 of 24 eye bank corneas, from the 4 mm wide corneal rim in 8 eyes and from the 8 mm diameter central cornea in 2 eyes. In 9 subjects, both eyes were assayed, and HSV-1 was detected in 6 subjects. In only one subject was HSV-1 detected in both eyes and in only one subject was HSV-1 detected in the central and peripheral cornea of the same eye. The biological role of HSV-1 DNA corneal sequences is unknown. To investigate this, a rabbit animal model was established by transplantation of corneas containing viral DNA sequences in HSV-1 naive recipients. Followed for 5 months, there was no evidence of sheeding of HSV-1 in the tear film or seroconversion of the recipient rabbits. At the end of this time, HSV-1 DNA was detected in the corneal graft at a similar intensity to the PCR signal from the donor rims.(ABSTRACT TRUNCATED AT 250 WORDS)

Immune-mediated myelopathy after allogeneic marrow transplantation

We describe two patients who developed myelopathy 15 and 27 months after allogeneic marrow transplantation. Exacerbations of the myelopathy occurred, with the development of optic neuropathy in one patient when corticosteroid therapy was tapered. The other patient had two exacerbations, 28 months and 40 months after transplantation, both of which resolved with plasma-pheresis. These case reports suggest that immune-mediated disease after transplantation can affect the central nervous system.

Antiviral effects of herpes simplex virus specific anti-sense nucleic acids

We have targeted mRNA sequences encompassing the translation initiation codon of the essential herpes simplex virus type 1 (HSV-1) IE3 gene with three kinds of anti-sense molecule. Addition of a 15mer oligodeoxyribonucleoside methylphosphonate to tissue culture cells resulted in suppression of viral replication. HSV-1 replication was also inhibited in cultured cells containing anti-sense vectors expressing transcripts complementary to the IE3 mRNA. We have also constructed a ribozyme which upon base pairing with the target IE3 mRNA induces cleavage at the predicted GUC site. A major obstacle to anti-sense studies in animals is drug delivery of preformed antisense molecules to ganglionic neurons, the site of HSV latency and reactivation. We speculate as to how this may be accomplished through carrier compounds which are taken up by nerve terminals and transported by retrograde axoplasmic flow. By the same route, HSV itself may be used as an anti-sense vector.

Exacerbation of inflammatory demyelinating polyneuropathy after bone marrow transplantation

Two patients with hematologic malignancy and quiescent inflammatory demyelinating polyneuropathy developed severe exacerbations of polyneuropathy at the time of bone marrow transplantation. The clinical course in both patients was progressive despite therapy with immuno-suppressive agents, plasmapheresis, and high dose immunoglobulin. The polyneuropathy resulted in quadriplegia which contributed to the patients' deaths 175 and 48 days after transplantation. Sections of multiple peripheral nerves sampled post mortem in the first case revealed prominent demyelination with heavy infiltration of macrophages and lymphocytes. Immunohistochemical studies demonstrated that most of the lymphocytes were of the CD8+, cytotoxic/suppressor cell class and that many of the Schwann cells expressed class II (HLA-DR) antigen. This report suggests that bone marrow transplantation can exacerbate inflammatory demyelinating polyneuropathy.

Early loss of astrocytes in herpes simplex virus-induced central nervous system demyelination

Immunohistochemistry was used to study herpes simplex virus type 1-induced central nervous system demyelination in the trigeminal root entry zone of mice inoculated with herpes simplex virus type 1 by the corneal route. There was no change in peripheral nervous system myelin as shown by immunostaining for P0 glycoprotein. Double immunoperoxidase staining for herpes simplex virus type 1 antigens and glial fibrillary acidic protein showed that most of the infected cells were astrocytes. Glial fibrillary acidic protein immunostaining was completely lost in the inferior medial portion of the trigeminal root entry zone at 6 days after herpes simplex virus type 1 inoculation, a time when central nervous system myelin was preserved as indicated by immunostaining for myelin basic protein. The pattern of glial fibrillary acidic protein staining did not change and herpes simplex virus type 1 antigens were no longer detected after day 8. There was a progressive loss of myelin basic protein staining within the area unstained by glial fibrillary acidic protein antisera on days 8 to 14. This pattern of astrocyte loss before central nervous system demyelination is strikingly different from the reactive astrocytosis seen in other demyelinating lesions, such as acute experimental allergic encephalomyelitis, progressive multifocal leukoencephalopathy, or acute multiple sclerosis. Herpes simplex virus type 1 infection in mice provides an unusual model of acute central nervous system demyelination preceded by a loss of astrocytes.

Detection of herpes simplex virus DNA sequences in corneal transplant recipients by polymerase chain reaction assays

Polymerase chain reaction (PCR) assays were used to amplify herpes simplex virus type 1 (HSV-1) thymidine kinase (TK) sequences in DNA extracted from formalin-fixed, paraffin embedded corneas of patients undergoing corneal transplantation. PCR reamplification with an internal (nested) set of primers was required for detection in 10 of the 12 positive corneas indicating very low abundance of viral sequences. Three of the positive corneal samples were from failed corneal grafts. Overall, TK sequences were detected in 8 of 11 corneas from subjects with a past history of herpes keratitis and in 4 of 11 corneas from subjects with no past history of herpetic eye disease.

Application of polymerase chain reaction assays to studies of herpes simplex virus latency

We have amplified herpes simplex virus type 1 (HSV-1) DNA sequences from individual latently infected mouse trigeminal ganglia by polymerase chain reaction (PCR) assays. This report presents two useful modifications in the PCR technique. The first involves the use of two sets of closely spaced, oppositely oriented oligonucleotide primers and two rounds of 20-40 PCR cycles, first with the more widely spaced outer primers and then with the internal nested primers. This method enhanced the sensitivity of PCR detection as shown by assays of HSV-1 sequences in human brain. The second modification was designed to detect selectively HSV-1 sense or anti-sense RNA transcripts when both are present by adding a single primer during an initial reverse-transcriptase-mediated cDNA synthesis reaction. After destruction of the RNA template, standard PCR is initiated by the addition of the second primer and thermus aquaticus DNA polymerase (Taq). We show here applications of both of these modifications to amplify HSV-1 sequences from nervous system tissue.

Ocular acyclovir delivery by collagen discs: a mouse model to screen anti-viral agents

Discs 1.6 mm in diameter trephined from corneal collagen shields were used to deliver acyclovir (ACV) to the cornea of mice inoculated with herpes simplex virus type 1 (HSV-1). In the first minute after application to the cornea, there was a 23% decrease of ACV in the discs. After the first minute, ACV clearance from the discs appeared to be exponential with a half-life of 21 minutes. Treatment given 3 times a day reduced HSV-1 titer in tear film, corneal tissue, and trigeminal ganglia. This animal model should be useful to conserve novel potential anti-viral drugs undergoing initial screening.

A recombinant vaccinia virus expressing herpes simplex virus type 1 glycoprotein B induces cytotoxic T lymphocytes in mice

Spleen cells from BALB/c (H-2d) mice vaccinated with vgB11, a recombinant vaccinia virus which expresses glycoprotein B (gB) of herpes simplex virus type 1 (HSV-1), lysed EMT6 (H-2d) target cells infected with vgB11 or with HSV-1 but did not lyse uninfected EMT6 cells or infected L-929 (H-2k) target cells. Unlabelled target cell competition of lysis showed that only syngeneic cells infected with vgB11 or HSV-1 inhibited lysis of radiolabelled HSV-1-infected targets. These results demonstrate that vgB11 induces H-2-restricted anti-HSV-1 cytotoxic T lymphocytes and that gB is the target antigen.

Idiopathic third cranial nerve palsy associated with herpes simplex virus infection

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Expression of herpes simplex virus 1 glycoprotein B by a recombinant vaccinia virus and protection of mice against lethal herpes simplex virus 1 infection

The herpes simplex virus 1 (HSV-1) strain F gene encoding glycoprotein gB was isolated and modified at the 5' end by in vitro oligonucleotide-directed mutagenesis. The modified gB gene was inserted into the vaccinia virus genome and expressed under the control of a vaccinia virus promoter. The mature gB glycoprotein produced by the vaccinia virus recombinant was glycosylated, was expressed at the cell surface, and was indistinguishable from authentic HSV-1 gB in terms of electrophoretic mobility. Mice immunized intradermally with the recombinant vaccinia virus produced gB-specific neutralizing antibodies and were resistant to a lethal HSV-1 challenge.

Immunocytochemical localization of herpes simplex virus antigen in the trigeminal ganglia of experimentally infected mice

The peroxidase anti-peroxidase (PAP) technique was used to study the distribution of herpes simplex virus (HSV) antigens in mouse ganglia during the acute infection and the transition into the latent infection. At 2 days after HSV inoculation by the corneal route, immunoperoxidase staining was present in occasional isolated neurons of the trigeminal ganglion and also in scattered satellite cells. By 4 days, more cells were stained with the infection centered in the medial portion of the ganglion. Inflammatory cells were present around PAP-labeled fragments from lysed cells. Stained satellite cells often with a hypertrophic appearance surrounded labeled or unlabeled neurons in a ring-like array. At 6 days after HSV inoculation, there was a decrease both in the number of cells stained and in the intensity of staining. By 8 days, HSV antigens could be detected by weak PAP staining only in neurons. Otherwise, these neurons appeared morphologically normal. No immunoperoxidase staining was present after the 8th day. These results are compatible with retrograde axoplasmic transport of HSV and cell to cell spread of virus in ganglia. Also the appearance of infected ganglion cells during the transition to latency suggests that neurons can be switched from an HSV-permissive to a non-permissive (latent) state.

Encephalitis resulting from reactivation of latent herpes simplex virus in mice

Herpes simplex virus (HSV) encephalitis was produced in mice from reactivation of latent virus. Two experimental models were used: the trigeminal model after corneal inoculation of HSV, and the hypoglossal model after tongue inoculation of HSV. In the trigeminal model, cyclophosphamide treatment induced reactivation of latent virus in ganglia but not in central nervous system tissue. Spread of the reactivated virus from ganglia to brain occurred only in mice deficient in anti-HSV antibody. In the hypoglossal model, sectioning of the hypoglossal nerve provoked chromatolysis in the corresponding central nervous system motor neurons and occasionally reactivated latent HSV in the brains of mice. These results suggest that HSV encephalitis can result from the spread of reactivated virus from ganglia to brain and also from in situ reactivation in brain.

Different sizes of restriction endonuclease fragments from the terminal repetitions of the herpes simplex virus type 1 genome latent in trigeminal ganglia of mice

Trigeminal ganglion DNA from mice latently infected with herpes simplex virus type 1 was analysed by restriction enzyme digestion, agarose gel electrophoresis and blot hybridization to 32P-labelled viral DNA. Viral DNA from parental virions and from virions obtained as a consequence of reactivation by ganglion neurectomy were similarly analysed. The BamHI restriction fragments of parental and reactivated virions were almost indistinguishable from each other, and several of the larger BamHI fragments of viral DNA were also found in latently infected ganglion at unaltered sizes. In contrast, fractionation of EcoRI fragments of latently infected ganglion DNA by reverse phase column (RPC-5) chromatography, followed by gel electrophoresis and blot hybridization to a viral DNA probe from the S component terminal repetition, revealed the presence of several terminal fragments at discrete sizes ranging from 1 kb to 15 kb, quite unlike the 5.7 kb terminal EcoRI K fragment of virion-derived DNA. These results indicate that structural changes occur in the viral genome concomitantly with the establishment of latency, such as may result from extensive gene rearrangement or integration into cellular DNA.

Herpes simplex virus infection of motor neurons: hypoglossal model

Herpes simplex virus type 1 (HSV) was inoculated into the tongue muscle of A/J mice. Typical HSV vesicles developed on the tongue surface 4 days after HSV inoculation. Virus was isolated from hypoglossal nerve explants, and inflammatory cells appeared where the hypoglossal nerve exists from the ventral medulla. HSV viral capsids were present in astroglial cells near the point of nerve exit. A focal encephalitis ensued with immunoperoxidase staining of HSV antigens in neurons of the hypoglossal nucleus. These findings indicate that HSV can penetrate the neuromuscular junction, travel in a pure motor nerve, and produce a focal encephalitis in the corresponding central nervous system motor nucleus.

Latency of herpes simplex virus in ocular tissue of mice

At 5 to 7 months after corneal inoculation of herpes simplex virus type 1 in mice, explants of ocular tissue yielded virus. Immunoperoxidase study of explants undergoing reactivation revealed herpes simplex virus antigens in retinal tissue. These results indicate that herpes simplex virus can establish and maintain latency in ocular tissue, most probably in the retina.

Latency of herpes simplex virus in absence of neutralizing antibody: model for reactivation

Mice inoculated with herpes simplex virus (type 1) by the lip or corneal route and then passively immunized with rabbit antibody to herpes simplex virus developed a latent infection in the trigeminal ganglia within 96 hours. Neutralizing antibody to herpes simplex virus was cleared from the circulation and could not be detected in most of these mice after 2 months. Examination of ganglia from the antibody-negative mice revealed latent virus in over 90 percent of the animals, indicating that serum neutralizing antibody is not necessary to maintain the latent state. When the lips or corneas of these mice were traumatized, viral reactivation occurred in up to 90 percent of the mice, as demonstrated by the appearance of neutralizing antibody. This study provides a model for identifying factors that trigger viral reactivation.

Herpes simplex virus DNA sequences in the CNS of latently infected mice

It has been amply documented that herpes simplex virus (HSV) persists in sensory ganglia of the peripheral nervous system (PNS). In contrast, HSV latency in the central nervous system (CNS) has not been well characterized. Corneal inoculation of virus results in a productive viral infection in the CNS during the first week after inoculation, indicating that the virus can progress from the PNS to the CNS. During latency, HSV has been found by co-cultivation of CNS tissue in only a very small fraction of inoculated mice. We have used here molecular hybridization techniques to analyse the fate of viruses that reach the CNS by anatomical pathways. We show that 6 days after corneal inoculation of HSV-1 a productive viral infection was present in brain tissue as well as in peripheral ganglia in at least 90%F of the inoculated mice. The mortality during this acute phase was only 2%. In the survivors, latent HSV could be recovered by explantation from 95% of the trigeminal ganglia, but only 5% of the brain tissue explants of the same mice yielded infectious virus. However, HSV DNA sequences were detected in the brains of 30% of mice which harboured latent HSV in their trigeminal ganglia. These results suggest that viruses that progress from the PNS into the CNS are not eliminated, but are capable of establishing a latent infection in the CNS that cannot be reactivated by explantation techniques.