Acute toxoplasma myositis: an immunohistochemical and ultrastructural study

Muscular Sarcocystosis in Sheep Associated With Lymphoplasmacytic Myositis and Expression of Major Histocompatibility Complex Class I and II

Sarcocystosis is a protozoal disease affecting a wide range of animals. The aims of this study were to characterize the following in sheep: (1) the muscle pathology in Sarcocystis infection, (2) the inflammatory infiltrate and its relationship to severity of infection, and (3) immune markers expressed by parasitized muscle fibers and parasitic cysts. Skeletal muscle samples from 78 sheep slaughtered in southern Italy were snap frozen and analyzed by histopathology, immunohistochemistry, and immunofluorescence. Polymerase chain reaction (PCR) and sequencing were used for Sarcocystis species identification. All 40 muscle samples tested were PCR-positive for Sarcocystis tenella. Histologically, cysts were identified in 76/78 cases (97%), associated with an endomysial infiltrate of lymphocytes and plasma cells. The T cells were predominantly CD8+, with fewer CD4+ or CD79α+ cells. Eosinophils were absent. Notably, sarcolemmal immunopositivity for major histocompatibility complex (MHC) I and II was found in 76/78 cases (97%) and 75/78 cases (96%), respectively, both in samples with and in those without evident inflammatory infiltrate. The number of cysts was positively correlated with inflammation. In addition, MHC I was detected in 55/78 cyst walls (72%), and occasionally co-localized with the membrane-associated protein dystrophin. The findings suggest that muscle fibers respond to the presence of cysts by expression of MHC I and II. The possible role of MHC I and II in the inflammatory response and on the cyst wall is also discussed.

Mononucleosis Epstein -Barr negativa: variación poco reconocida de enfermedad popular

Se reporta el caso de un paciente joven, inmunocompetente y sin factores de riesgo, con adenopatías cervicales, fiebre, malestar general compatible síndrome mononucleósico. La persistencia de síntomas a pesar de múltiples tratamientos con antibióticos lleva a los médicos tratantes a echar un segundo vistazo. El hallazgo y desenlace, los hallarás aquí.

Severe polymyositis due to Toxoplasma gondii in an adult immunocompetent patient: a case report and review of the literature

Toxoplasmosis, a worldwide zoonosis caused by a coccidian parasite Toxoplasma gondii, is more often asymptomatic in immunocompetent patients. We report the case of a 38-year-old immunocompetent male with a polymyositis as the presenting manifestation of T. gondii infection. The patient was hospitalized for a 30-day history of fever (T max 39.5°C), muscle pain, and progressive weakness of the muscles. A diagnosis of polymyositis was made, and he was started on corticosteroid treatment, which caused no reduction of symptoms. After finding a positive polymerase chain reaction (PCR) assay for T. gondii, together with additional clinical findings, a diagnosis of acute toxoplasmosis was made. Specific treatment with pyrimethamine and sulfadiazine was started, with a progressive reduction of symptoms and normalization of laboratory tests.

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.

Rheumatic manifestations of parasitic diseases

OBJECTIVES

To consolidate the spectrum and frequency of parasite-related rheumatic syndromes, which have largely been regarded as exceedingly rare by the general medicine, infectious disease, and rheumatology literature.

METHODS

A MEDLINE search was performed for articles on rheumatic syndromes related to parasitic infections published from 1966 through December 2000. Identified articles included clinical and epidemiologic studies describing cases of rheumatic syndromes associated with verified parasitic infection.

RESULTS

Rheumatologic syndromes, including inflammatory arthritis, inflammatory myositis, and vasculitis, have been described among multiple different parasite infections of all parasitic divisions, including Protozoa, Nematoda, and Platyhelminthes. Individual parasitic divisions are often associated with particular rheumatic syndromes, such as reactive arthritis and spondyloarthropathy, inflammatory or infectious myositis, and reactive or parainfectious vasculitis.

CONCLUSIONS AND RELEVANCE

Parasitic infection may underlie the clinical presentation of some rheumatic conditions. Given the continued and growing number of patients at risk for parasitosis by virtue of their country of origin, travel habits, and an immunocompromised state, potential parasitosis must be considered in patients undergoing evaluation for rheumatic complaints.

Toxoplasmic polymyositis revisited: case report and review of literature

Toxoplasmosis can cause polymyositis either by reactivation or by recent infection. Inconsistent response to antiprotozoal therapy has been the strongest argument against toxoplasmic polymyositis as a separate entity. We report a biopsy-proven case of toxoplasmic polymyositis in a cardiac transplant patient presenting with a severe proximal weakness, myopathic, electromyographic changes and ten-fold increase of anti-Toxoplasma antibodies. An early antiprotozoal therapy and plasmapheresis led to recovery. A review of previously reported cases of toxoplasmic polymyositis suggests that an early antiprotozoal therapy is the most important variable affecting the outcome of this disease. We propose that toxoplasmic polymyositis has two phases: acute, responsive to antiprotozoal therapy, and chronic, manifested by altered immune response requiring steroids. We suggest that all patients presenting with polymyositis should have serological tests for toxoplasmosis as a part of their initial evaluation and an early trial of antiprotozoal therapy in case of positive findings.

Pulsed intravenous methylprednisolone therapy for inflammatory myopathies: evaluation of the effect by comparing two consecutive biopsies from the same muscle

To examine the effect of pulsed intravenous methylprednisolone (IVMP) on polymositis (PM) and dermatomyositis (DM), two biopsies were taken from the same muscle before and after IVMP in one case each of PM and DM. After IVMP, numerous muscle fibers were seen undergoing regeneration. Among all subsets of infiltrating cells that decreased in number, macrophages in the perivascular area decreased markedly. Also conspicuous was decrease of CD8+ cells in the endomysium in PM and that of B-cells in the perivascular area in DM. Among infiltrating cells, frequency of those which expressed the signal transducers and activators of transcription 1 (STAT-1) fell considerably, but remained still abnormally high. Regions on the endothelial cells of blood vessels that expressed MHC antigens and intercellular adhesion molecules 1 (ICAM-1) also decreased but remained more widespread than normal. These results agreed with the favorable clinical effect of IVMP, but showed that many of the immunological parameters remained abnormal.

Rheumatic syndromes associated with parasites

A variety of musculoskeletal syndromes has been described in association with numerous parasitic infestations. Arthritis, enthesitis, myositis and vasculitis have been described in infected individuals resident in, or visitors to, endemic areas. The diagnosis of parasitic rheumatism is supported by poor response to anti-inflammatory drugs and improvement following antiparasitic treatment.

Skeletal muscle toxoplasmosis in patients with acquired immunodeficiency syndrome: a clinical and pathological study

The present article describes the clinical and pathological findings in 5 human immunodeficiency virus (HIV)-infected patients with muscle toxoplasmosis. The patients had marked lymphopenia (5/5), with less than five CD4+ cells/mm3 (3/3), when they developed fever (5/5), and multiorgan failure (5/5), including diffuse encephalitis, pneumonia, pancytopenia, and myopathy. Muscle involvement included weakness and wasting (4/5), myalgias (3/5), and high serum creatine kinase levels (3/3). Serology for toxoplasmosis showed high IgG titers in 3 patients (3/4). Anti-Toxoplasma therapy resulted in complete recovery in 2 patients. Muscle toxoplasmosis was detected by biopsy (3/5) or postmortem evaluation (2/5), and was identified using immunocytochemistry and electron microscopy. Toxoplasma cysts were detected in 0.5 to 4% of muscle fibers close to or remote from necrotic fibers and inflammatory infiltrates. Muscle fibers strongly expressed the major histocompatibility complex class I antigen (2/2) as in polymyositis. We suggest that Toxoplasma gondii should be sought by muscle biopsy in patients who have acquired immunodeficiency syndrome with fever, encephalitis, multiorgan dysfunction, and elevated serum creatine kinase levels of obscure origin.