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

Causality between immunocytes and polymyositis: A Mendelian randomization analysis

Polymyositis is a prominent subgroup of idiopathic inflammatory myopathy, considered to have an autoimmune etiology. However, research exploring the condition between immunocytes and polymyositis remains limited, indicating the need for further investigation to unravel these intricate associations. We employed bidirectional Mendelian randomization (MR) analysis to ascertain causality between 731 immunocytes and polymyositis. We also compared the positive immunocytes with dermatomyositis. Our primary analytical method was inverse variance weighted, supplemented by 4 other MR techniques. Additionally, Cochran Q test was performed to assess heterogeneity, MR-Egger to appraise pleiotropy, and MR-PRESSO to identify and eliminate potential outliers. Furthermore, the leave-one-out test evaluated the impact of each instrumental variable (IV) on the causal effect. The inverse variance weighted results revealed that 10 immunocytes exert a protective effect against polymyositis (P < .05, OR < 1), while 16 immunocytes are connected with an elevated risk of the disease (P < .05, OR > 1). In reverse MR, polymyositis was found to decrease the levels of 2 immune cells (P < .05, OR < 1) and elevate the expression of 5 immune cell phenotypes (P < .05, OR > 1). A complex correlation was found between polymyositis and the immunocyte phenotypes CD8, CD33dim, HLA-DR, CD11b, and CD45. Additionally, it was discovered that 15 types of immune cells share a causal relationship between polymyositis and dermatomyositis. All analyses demonstrated no heterogeneity or horizontal pleiotropy (P > .05). Our study provides compelling evidence regarding the intricate causal relationships between immunocytes and polymyositis. Polymyositis and dermatomyositis share common immunocytes' regulatory mechanisms. CD8, CD33dim, HLA-DR, CD11b, and CD45 may represent potential immune cell markers for polymyositis. These findings hold implications for planning prognosis and therapeutic strategies for polymyositis, offering novel insights for drug development.

Electrophysiological and clinical examination of polymyositis: a retrospective analysis

BACKGROUND

We retrospectively analyzed electromyogram (EMG), laboratory and clinical data of 93 patients with polymyositis (PM) to help improve early diagnostic accuracy.

METHODS

Data were collected from hospitalized patients who were diagnosed with PM between January 1, 2006 and April 1, 2010 at Chinese People's Liberation Army General Hospital.

RESULTS

Eighty-six (92.47%) patients exhibited an isolated myopathic EMG pattern, 3 (3.23%) showed myopathy combined with neuropathy and 1 (1.08%) had diabetes mellitus. Among the 4 without myopathic EMG, 1 had inflammatory myopathy, and 3 had prior corticosteroid treatment with clinical improvement before EMG examination. Muscle biopsy, performed in 40 cases, inclusive of the 7 cases that did not show an isolated myopathic EMG patterns, revealed that 80% exhibited typical pathological features of PM, 17.5% showed nonspecific muscle fiber necrosis and 2.5% were normal. EMG showed that tibialis anterior and biceps brachii exhibited more abnormal EMG results than abductor pollicis brevis. Patients with disease duration >3 months had significantly higher alanine aminotransferase and reduced motor unit potential (MUP) amplitudes compared to patients with shorter disease duration. Statistical analysis revealed a significant association between disease duration and MUP amplitude reduction. Patients without interstitial lung disease showed significantly longer disease duration and higher creatine kinase and lactate dehydrogenase levels than patients with interstitial lung disease.

CONCLUSIONS

Our results show that MUP is a sensitive yardstick for diagnosis of PM and is inversely related to disease duration. Our study also highlights that selecting specific muscles for EMG may improve diagnostic accuracy in PM.

HTLV-1 and its neurological complications

BACKGROUND

Since its discovery in 1980, human T-cell lymphotropic virus type-1 (HTLV-1) has been associated with a number of neurological diseases. The distribution of HTLV-1-associated neurological disease is worldwide. In endemic areas, up to 30% of the population may be infected with HTLV-1; however, only a small percentage of infected persons develops neurological disease.

REVIEW SUMMARY

In 1986, HTLV-1 infection was reported in patients of chronic progressive myelopathy of uncertain etiology, and the disease entity was called HTLV-1-associated myelopathy/tropical spastic paraparesis. Recently, HTLV-1 infection has been associated with polymyositis and uveitis. Interestingly, a single patient may display more than one syndrome. Although other neurological syndromes occur in HTLV-1-infected individuals, there is not enough epidemiologic data that show a strong association. Treatment of HTLV-1-associated neurological disease is challenging, and well-controlled studies are lacking.

CONCLUSION

As neurologists and other scientists begin to understand the pathophysiology of HTLV-1 infection, improved therapies should be developed. Randomized trials with longer follow-up are required to understand the effect of treatment on disability and quality of life.

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.