Failure to detect HTLV-I by in situ hybridization in the biopsied muscles of viral carriers with polymyositis

Clinical presentation of axial myopathy in two siblings with HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP)

Background

The clinical features of myositis related with Human T-cell leukemia virus type 1 (HTLV-1) remains unclear despite epidemiological studies suggesting inflammatory myopathy associated with the virus.

Case presentation

Here, we described the clinical presentations, muscle biopsy studies and laboratory results of two siblings with HTLV-1-associated myelopathy / tropical spastic paraparesis (HAM/TSP) who were affected with lumbar lordosis. Computed tomography (CT) scans demonstrated marked paraspinal muscle atrophy in both patients. Immunohistochemical studies of biopsy tissue obtained from one of the patients revealed inflammatory change of the muscle. Upon oral prednisolone therapy, the patient showed improvement in muscle strength and serum creatine kinase (CK) level.

Conclusion

Myopathy or specifically axial myopathy should be considered as clinical symptom when treating the patients with HTLV-1 infection.

Visualization of HTLV-1-specific cytotoxic T lymphocytes in the spinal cords of patients with HTLV-1-associated myelopathy/tropical spastic paraparesis

Activated human T-lymphotropic virus type-1 (HTLV-1)–specific CD8-positive cytotoxic T lymphocytes (CTLs) are markedly increased in the periphery of patients with HTLV-1–associated myelopathy/tropical spastic paraparesis (HAM/TSP), an HTLV-1–induced inflammatory disease of the CNS. Although virus-specific CTLs play a pivotal role to eliminate virus-infected cells, the potential role of HTLV-1–specific CTLs in the pathogenesis of HAM/TSP remains unclear. To address this issue, we evaluated the infiltration of HTLV-1–specific CTLs and the expression of HTLV-1 proteins in the spinal cords of 3 patients with HAM/TSP. Confocal laser scanning microscopy with our unique staining procedure made it possible to visualize HTLV-1–specific CTLs infiltrating the CNS of the HAM/TSP patients. The frequency of HTLV-1–specific CTLs was more than 20% of CD8-positive cells infiltrating the CNS. In addition, HTLV-1 proteins were detected in CD4-positive infiltrating T lymphocytes but not CNS resident cells. Although neurons were generally preserved, apoptotic oligodendrocytes were frequently in contact with CD8-positive cells; this likely resulted in demyelination. These findings suggest that the immune responses of the CTLs against HTLV-1–infected CD4-positive lymphocytes migrating into the CNS resulted in bystander neural damage.

Neuroimmunological aspects of human T cell leukemia virus type 1-associated myelopathy/tropical spastic paraparesis

Human T cell leukemia virus type 1 (HTLV-1) is a human retrovirus etiologically associated with adult T cell leukemia/lymphoma and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Only approximately 0.25-4 % of infected individuals develop HAM/TSP; the majority of infected individuals remain lifelong asymptomatic carriers. Recent data suggest that immunological aspects of host-virus interactions might play an important role in the development and pathogenesis of HAM/TSP. This review outlines and discusses the current understanding, ongoing developments, and future perspectives of HAM/TSP research.

Human T-lymphotropic virus 1 (HTLV-1) infection--dermatological implications

Human T-lymphotropic virus type 1 (HTLV-1) is a type C retrovirus primarily endemic to Japan, Central and South America, the Middle East, regions of Africa, and the Caribbean. Currently, an estimated 10-20 million people worldwide are infected with this virus. Although the majority of infected individuals remain asymptomatic, HTLV-1 is the causative agent of a number of disorders, notably adult T-cell leukemia/lymphoma (ATLL) and a progressive demyelinating neurological disorder, HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). In addition to ATLL and HAM/TSP, HTLV-1 has been associated with a spectrum of skin disorders, such as infective dermatitis associated with HTLV-1, crusted scabies, and leprosy. The understanding of the interaction between virus and host response has improved markedly, but there are still few treatment options.

Neuroimmunity of HTLV-I Infection

Human T-lymphotrophic virus type I (HTLV-I) is an oncogenic retrovirus and its infection is associated with a variety of human diseases including HTLV-I-associated myelopathy/tropic spastic paraparesis (HAM/TSP). Large numbers of epidemiological, virological, immunological, and clinical studies on HTLV-I- and HTLV-I-associated diseases have been published, although the pathogenesis of HAM/TSP remains to be fully understood. In the last several years, researchers have shown that several key factors are important in HTLV-I-associated neurologic disease including high HTLV-I proviral load and a strong immune response to HTLV-I. Here, we review pathophysiological findings on HAM/TSP and focus on viral-host immune responses to the virus in HTLV-I infected individuals. In particular, the role of HTLV-I-specific CD8+ T cell response is highlighted.

Muscle wasting induced by HTLV-1 tax-1 protein: an in vitro and in vivo study

Besides tropical spastic paraparesis/human T-cell leukemia virus type-1 (HTLV-1)-associated myelopathy, the human retrovirus HTLV-1 causes inflammatory disorders such as myositis. Although the pathogenesis of HTLV-1-associated myositis is primarily unknown, a direct effect of cytokines or viral proteins in myocytotoxicity is suspected. We have developed an in vitro cell culture model to study the interactions between primary human muscle cells and HTLV-1 chronically infected cells. When HTLV-1-infected cell lines were added to differentiated muscle cultures, cytopathic changes such as fiber shrinking were observed as early as 1 day after contact. This was accompanied by alterations in desmin and vimentin organization, occurring in the absence of muscle cell infection but with Tax-1 present in myotubes. Cytopathic changes were also observed when infected culture supernatants were added to the muscle cells. Fiber atrophy and cytoskeletal disorganization were confirmed in muscle biopsies from two HTLV-1-infected patients with myositis. Transduction of cultured muscle cells with a lentiviral vector containing the HTLV-1 Tax gene reproduced such effects in vitro. The present data indicate that the myocytotoxicity that is observed in HTLV-1-associated myopathies can be due to a direct effect of the Tax-1 protein expressed in infected inflammatory cells, in the absence of muscle cell infection.

Genetic and environmental risk factors for idiopathic inflammatory myopathies

Although the studies discussed are beginning to reveal a number of genetic and possible environmental risk factors for myositis, further investigations are needed to fully understand and classify these syndromes. The difficulties in this process include small numbers of subjects with varying disease phenotypes available for study, polygenic risk factors for which it remains unclear which are primary and which are secondary or linked genes, and the lack of validated environmental exposure assessment tools. New technologies and international collaborative approaches, however, may overcome some of these difficulties and allow us to identify genetic and environmental risk factors, as well as the critical gene-environment interactions in the IIM and its subgroups. Nonetheless, our understanding of these diseases is still in the early stages. Although we have learned a great deal about these disorders through detailed investigations over the last several decades, we have even further to go to understand the environmental triggers and genetic susceptibilities for the myositis syndromes.

HTLV-1 associated polymyositis in Jamaica

The clinical, laboratory and epidemiological characteristics of 38 adult Jamaican patients with polymyositis were evaluated. Twenty-four patients (63%) were human T-lymphotropic virus 1 (HTLV-1) seropositive and 14 patients (37%) were HTLV-1 seronegative. Polymyositis runs a more protracted course in seropositive patients who had more frequent hospital admissions and a significantly longer duration of symptoms prior to presentation. Joint swelling, chest pain and dyspnoea were more frequent complaints among the seronegative patients. There was no significant difference between the two serological groups in muscle enzyme levels, antinuclear antibody positivity or frequency of Jo-1 antibodies. HTLV-1 infection may define a subgroup of polymyositis patients with a more insidious presentation and poorer response to corticosteroid therapy.

Inflammatory myopathy on HTLV-I infection: case report

We describe a 41 years old woman who 17 years ago presented hypotonia and proximal muscular weakness in the upper and lower limbs. On neurological examination, the biceps, triceps and Achilles reflexes were absent; the brachioradialis reflexes were decreased and the patellar reflexes were normal. There was bilateral Babinski sign. The remainder of the neurological examination was unremarkable. In the investigation a myopathic pattern was found in the electromyography. The nerve-conduction study was normal; a ELISA method for HTLV-I antibodies was positive in the blood and in the cerebral spinal fluid. The muscle biopsy showed inflammatory myopathy, compatible with polymyositis. This paper focuses the polymyositis in the beginning of an HTLV-I infection case.

CD8 and CD4 T cell-mediated polymyositis complicating the HTLV-1 associated myelopathy. Quantitative evaluation of corticosteroid treatment

INTRODUCTION

Inflammatory myopathy is a treatable cause of worsening in the spectrum of neurological conditions that may develop during the course of HTLV-1 infection.

MATERIAL AND METHODS

To investigate the cause of subacute worsening in the strength of a 46-y-old black male with HTLV-1 associated myelopathy we performed electrodiagnostic examination and a muscle biopsy which was studied with histochemistry, immunocytochemistry and electron microscopy. Serial measurements of isometric muscle strength were performed during the course of corticosteroid treatment.

RESULTS

The muscle biopsy showed evidence of denervation atrophy and prominent inflammatory changes with autoaggressive features. Lymphocyte typing showed a predominance of CD8+ T cells. The patient had sustained, marked improvement in strength, especially of the upper extremities, with oral, high single-dose, alternate-day prednisone therapy.

CONCLUSION

A muscle biopsy should be considered in all patients with HTLV-1 associated weakness, especially when electromyography indicates possible coexisting primary muscle involvement and/or serum creatine kinase levels are elevated. HTLV-1-associated polymyositis can be successfully treated with corticosteroids.

HAM/TSP: recent perspectives in Japan

Neurologic diseases associated with human T-cell lymphotropic virus type I (HTLV-I) infection have a clinical spectrum that includes myelopathy (HTLV-I-associated myelopathy/tropical spastic paraparesis, HAM/TSP) as the central manifestation. Many clinical signs of involvement outside the central nervous system (CNS) have been described in some patients with HAM/TSP and have triggered and advanced the discovery of some HTLV-I-associated concepts in HTLV-I-infected individuals without signs of CNS involvement. Most of these HTLV-I-associated diseases exhibit common viroimmunologic characteristics that include a distributional bias of HTLV-I activation between the blood flow and the affected lesions and accumulated cellular immune responses in the lesions. These facts suggest that the vulnerable tissue(s) in some HTLV-I-infected individuals may not be defined by an exclusive tissue specificity, but that common steps of HTLV-I-versus-host interactions may have an important role in the pathologic process(es) in these diseases. This review summarizes the recent perspectives of the clinical spectrum and the pathogenesis of HAM/TSP in Japan. Furthermore, the feasible pathogenic involvement of cellular interactions between infected cells and responding immunocompetent cells in the affected tissues is emphasized.

Clinical characteristics of HTLV-1 associated dermato-polymyositis. Seven cases from Martinique

Myositis linked to HTLV-1 is unfrequent. Over a period of 8 years, 14 patients with inflammatory myopathy were diagnosed in Martinique. Seven were seropositive for HTLV 1 antibody; the clinical and pathological data of whom are presented herein. Five patients presented with polymyositis, two with dermatomyositis. All seven patients had extra-muscular clinical features including neuropathy (4/7) and myelopathy (6/7), resulting in a quite peculiar clinical picture. Muscle biopsy showed a neurogenic process combined with myositic changes in 3/7 patients. Corticotherapy led to dramatic improvement in only one case, but with no sustained effect. HTLV 1 may be considered the etiological agent of this form of dermato-polymyositis, characterized by a clearly distinctive clinico-pathological picture, and a poor response to corticotherapy. As in the case of tropical spastic paraparesis/HTLV 1 associated myelopathy, careful assessment of non-steroidal therapy is now warranted.

In situ polymerase chain reaction detection of HTLV-I provirus and expression of the p53 tumor suppressor gene in infiltrating cells in skeletal muscle from a patient with adult T cell leukemia

We report the pathological changes in skeletal muscle from a patient with acute adult T cell leukemia (ATL). HTLV-I provirus was detected in infiltrating cells using in situ polymerase chain reaction in frozen sections. Furthermore, aberrant expression of the p53 protein was observed in the infiltrating cells. As p53 protein was not observed in mononuclear inflammatory cells in patients with polymyositis, expression of the p53 protein was considered to be one of the characteristic findings in ATL cells. This is the first direct detection of ATL cells in skeletal muscle.

Detection of HTLV-I provirus by in situ polymerase chain reaction in mononuclear inflammatory cells in skeletal muscle of viral carriers with polymyositis

We tested for HTLV-I proviral DNA in skeletal muscle from patients with polymyositis infected with HTLV-I using the in situ polymerase chain reaction. We found the HTLV-I provirus in some of the CD4-positive cells in HTLV-I-positive polymyositis cases but not in HTLV-I-negative polymyositis ones. We could not detect HTLV-I within the muscle fibers. We suggest that HTLV-I-associated polymyositis is not due to direct, persistent infection of the muscle fiber by the virus, but to a T-cell-mediated immunological process triggered by the HTLV-I-infected cells.

Identification of human T cell leukemia/lymphoma virus type I antibodies, DNA, and protein in patients with polymyositis

OBJECTIVE

To investigate a possible association between human T cell leukemia/lymphoma virus type I (HTLV-I) and polymyositis (PM).

METHODS

Sera and muscle biopsy samples from 9 Jamaican PM patients were compared with specimens from American HTLV-I-positive PM patients and normal controls. Sera were evaluated for HTLV antibodies by enzyme-linked immunosorbent assay and Western blot. The biopsy samples were analyzed for HTLV-I/II DNA by polymerase chain reaction and were also immunohistochemically stained for HTLV gp46 envelope protein.

RESULTS

Seven of the 8 Jamaican PM patients from whom sera were available were HTLV-I seropositive. The muscle biopsies of all 9 Jamaican patients demonstrated severe lymphocytic infiltration, cellular degeneration, myofiber atrophy, and fibrosis. Each muscle biopsy specimen contained HTLV-I DNA. Two of 6 samples demonstrated intense staining for HTLV-I gp46 in many of the invading mononuclear cells and weak staining for HTLV-I gp46 in many of the invading mononuclear cells and weak staining in the adjacent myocytes. Two other specimens were weakly positive for gp46 in rare mononuclear cells. All control specimens were negative for the presence of HTLV-I DNA and protein.

CONCLUSION

HTLV-I is associated with an inflammatory muscle disease characterized by direct invasion of the affected muscle by HTLV-I-infected mononuclear cells.

Polymyositis in patients infected with human T-cell leukemia virus type I: the role of the virus in the cause of the disease

To investigate the mechanism of polymyositis in human T-cell leukemia virus type I (HTLV-I) infection, we studied 6 HTLV-I-positive patients, 3 with polymyositis and 3 with adult T-cell leukemia but without clinical signs of muscle disease, by (a) quantitative single or double immunocytochemistry on serial 4-microns-thick muscle biopsy sections using antibodies to lymphocyte subsets, major histocompatibility complex (MHC) antigens, and HTLV-I proteins; (b) polymerase chain reaction using HTLV-I primers in the RNA and DNA extracted from 50 micrograms of muscle tissue or from serial 5-microns-thick fresh-frozen tissue sections; and (c) cocultures of the patients' HTLV-I-positive peripheral blood lymphocytes with their homologous muscles searching for replication of HTLV-I within the myotubes. In the muscle of patients with HTLV-I-associated myopathy, the predominant endomysial cells surrounding healthy muscle fibers were CD8+ cells followed by CD4+ cells and macrophages. MHC-I antigens were ubiquitous in the muscles of all 6 patients, even in those without endomysial inflammation. HTLV-I sequences were amplified from the whole muscle biopsy specimens but the cells harboring viral antigens were rare endomysial macrophages and not muscle fibers. Although HTLV-I sequences were amplified from all the patients' peripheral blood lymphocytes, these cells did not exert myotoxicity or resulted in viral replication in cocultures with their homologous myotubes.(ABSTRACT TRUNCATED AT 250 WORDS)

Skeletal muscle involvement in tropical spastic paraparesis/HTLV-1-associated myelopathy

The frequency of muscle involvement in TSP/HAM is not known, nor is the precise role that HTLV-1 and the diverse cytokines play in the genesis of HTLV-1-associated diseases. In order to better define the frequency and characteristics of the skeletal muscle involvement in TSP/HAM, we studied 11 affected patients. EMG was performed in 9 patients and muscle biopsy was performed in all 11. Muscle tissue was analyzed using: reverse transcriptase PCR for interleukin-1 in 8; PCR for HTLV-1 proviral DNA in 5; and electron microscopy for viral particles in 3. We found pathologic alterations in all 11 patients. Four patients (36%) had a neurogenic process, while a primary muscle involvement was observed in the rest (64%). Four patients (36%) had polymyositis, and 3 (27%) had a noninflammatory myopathy. Muscle weakness in the upper limbs was significantly associated with inflammation in the muscle biopsy. EMG was abnormal in only 2 of 9 patients. Reverse transcriptase PCR did not demonstrate message for interleukin-1 in any sample examined. PCR did identify HTLV-1 proviral DNA in the muscle of 3 patients. Retroviral-like particles were found, by EM, in only one biopsy. HTLV-1 may play an important role in the pathogenesis of the frequent myopathies associated with HAM/TSP.

Lack of association between peripheral neuropathy and HTLV-I infection in west Africa. Epidemiological, serological and nerve biopsy study

Patients (n = 1166) with various neurological disorders hospitalized in Dakar, Abidjan, Lomé and Ouagadougou were examined prospectively over a 42-month period. Seropositivity for HTLV-I alone was found to be 1.8%, which is comparable to that estimated for the general population in Africa. Eighteen of the patients with TSP and only 5 with PN were HTLV-I positive, but co-infections were found in 30-40% of cases. Discrete and unspecific lesions were observed on light and electron microscopic examination of peripheral nerve biopsies from 11 patients. Since spastic paraparesis emerges as the disorder containing the largest number of HTLV-I-positive individuals, it may be premature to conclude that HTLV-I is a causal agent in PN. Nevertheless, their rarity and the frequency of retroviral co-infections distinguish these cases of African HTLV-I-associated myelopathy from comparable cases observed in other parts of the world.

Immunohistochemical characteristics of polymyositis in patients with HTLV-I-associated myelopathy and HTLV-I carriers

The immunohistochemical characteristics of polymyositis in patients with HTLV-I-associated myelopathy (HAM) and HTLV-I carriers were studied. Infiltrating cells were predominantly T cells and were not different from in the control group. All specimens contained positively staining muscle fibers for MHC class I antigens, but class II antigens were also expressed in some muscle fibers in 1 patient with HTLV-I-negative polymyositis, 3 patients with HTLV-I-positive polymyositis, and all 5 HAM patients with polymyositis. Expression of the neural cell adhesion molecule was lowest in the HAM patients. These findings may suggest a different immune environment in polymyositis with HAM.

Search for HIV proviral DNA and amplified sequences in the muscle biopsies of patients with HIV polymyositis

We searched for the presence of human immunodeficiency virus (HIV) in fresh-frozen muscle biopsy specimens from 10 patients with HIV-associated polymyositis (HIV-PM) using (a) 35S-labeled HIV-RNA transcript of the virus and in situ hybridization, and (b) polymerase chain reaction and slot-blot hybridization utilizing primers amplifying sequences from the gag and pol genes of the HIV genome. With in situ hybridization, positive signals were detected in sparse lymphoid cells surrounding the muscle fibers, but not within the muscle fibers, in up to two consecutive sections in 6 of the 10 specimens. By the polymerase chain reaction, amplified HIV-specific sequences were noted in 2 specimens, but in only 2 of 8 consecutive sections, implying infection of lymphoid cells rather than muscle fibers. Muscle cultures from six specimens failed to show integrated HIV sequences within the myotubes. We conclude that HIV sequences or transcriptional products are not present within the muscle fibers or the cultured myotubes of patients with HIV-PM. This indicates that: (a) viral replication does not take place within the muscle; (b) integration of HIV proviral genome does not occur within the myonuclei or satellite cells; and (c) HIV-PM does not seem to be due to a persistent infection of the muscle fiber by the virus.

Retroviruses and nervous system disease

During the past decade retroviruses have been recognized as causes of human neurological disease. A wide clinical spectrum of neurological and neuromuscular diseases have been reported with HIV infections, and studies of these diseases have raised novel and exciting hypotheses of pathogenesis. As yet the full clinical spectrum of diseases associated with HTLV-1 has yet to be defined, and the pathogenesis of the chronic spastic paraparesis remains a mystery. Chronic neurological diseases in animals caused by both oncoviruses and lentiviruses can provide some clues to the pathogenesis of these newly recognized human neurological illnesses.

Pathological changes in skeletal muscle in HTLV-I-associated myelopathy

The main lesion site of HTLV-I-associated myelopathy or tropical spastic paraparesis (HAM/TSP) is the pyramidal tract. In some HAM patients, clinical symptoms and findings indicate neuromuscular involvement, such as muscular atrophy, fasciculation, elevated serum creatine kinase (CK) or significant electrophysiological data. Cases of HAM/TSP complicated with polymyositis or motor neuron disease have been reported. But no investigation has been directed to muscular pathology in many patients of HAM/TSP. We conducted muscle biopsies on 13 HAM patients. Four patients showed neurogenic changes. Six patients showed histological findings indicative of inflammatory myopathy. We investigated surface marker of invading cells in these 6 patients. In all patients, T lymphocytes were more predominant than B lymphocytes and in three of them T helper/inducer cells were more predominant than T suppressor cells. In 2 patients, only slight myopathic change could be seen, such as variation in fiber diameter and increase in the number of internal nuclei. In 1 patient, type 2 fiber atrophy was seen, and was possibly the result of disuse. Disturbance of secondary motor neurons or inflammatory myopathy is thus shown to be possibly associated with HAM/TSP.