Anticuerpos Anti-Titina en Encefalitis Autoinmune: ¿Casualidad o Causalidad? A propósito de un caso

Las encefalitis autoinmunes son una condición emergente, caracterizada por la aparición repentina de síntomas psicóticos o depresivos "de novo", crisis convulsivas o estatus epiléptico refractario, o demencia rápidamente progresiva. Las encefalitis autoinmunes están asociadas a diversos fenómenos desencadenantes, como infecciones virales previas entre las más comunes, y se asocian con la presencia de anticuerpos antineuronales y/o onconeuronales, que deben estudiarse ante la sospecha de esta entidad. Es muy importante desarrollar un diagnóstico presuntivo y precoz, ya que la terapia con inmunosupresores como los corticoides -iniciados en el momento oportuno-, puede cambiar su evolución hacia la mejoría clínica. Presentamos un paciente con encefalitis autoinmunes y anticuerpos anti-Titina positivos (habitualmente presentes en timoma y miastenia gravis), no asociados a neoplasia conocida y con buena respuesta a esteroides.

Autoimmune Encephalitis, are an emerging condition, characterized by the sudden onset of psychotic or depressive symptoms "de novo", refractory seizures or epilepsy, or rapidly progressive dementias. The autoimmune encephalitis are associated to various triggered phenomena as a previous viral infections among others; it's related to the presence of antineuronal and/or onconeuronal antibodies, and there must be studied when autoimmune encephalitis is suspected. It is very important to develop a presumptive and early diagnosis, since steroid therapy -on opportunity time- can change its evolution towards clinical improvement. We present a patient with autoimmune encephalitis, and positive anti-Titin antibodies (usually presents in thymoma and myasthenia gravis) not associated with known neoplasia, and with a good response to steroids.

Autoantibody profile and clinical characteristics in a cohort of Chinese adult myasthenia gravis patients.

Myasthenia gravis (MG) is an autoimmune disorder with heterogeneity. Antibodies against acetylcholine receptor (AChR), muscle-specific kinase (MuSK), titin and ryanodine receptor (RyR) were examined in 437 adult Chinese MG patients. The AChR, MuSK, titin and RyR antibodies were found in 82.2%, 2.3%, 28.4% and 23.8% of all patients. Autoantibody profiles vary among different MG subgroups. Thymoma MG patients had high frequencies of AChR (99.2%), titin (50.8%) and RyR antibodies (46.9%). The titin and RyR antibodies also showed high frequencies in late onset patients (54.4% and 33.3%, respectively). These two antibodies may indicate an underlying thymoma when combined. The patients with titin and RyR antibodies tend to have more severe disease and worse outcome, and may need more active immunosuppressive treatment.

A case of late-onset, thymoma-associated myasthenia gravis with ryanodine receptor and titin antibodies and concomitant granulomatous myositis.

BACKGROUND: Myasthenia gravis is an autoimmune neuromuscular disorder, which has only rarely been reported to co-manifest with myositis. The diagnosis of concomitant myositis in patients with myasthenia gravis is clinically challenging, and requires targeted investigations for the differential diagnosis, including EMG, autoantibody assays, muscle biopsy and, importantly, imaging of the mediastinum for thymoma screening. CASE PRESENTATION: This report presents a case-vignette of a 72-year-old woman with progressive proximal muscle weakness and myalgias, diagnosed with thymoma-associated myasthenia and bioptically verified granulomatous myositis, with positive autoantibody status for ryanodine receptor and titin antibodies. CONCLUSIONS: The diagnosis of concurrent myositis and myasthenia gravis, especially in the presence of ryanodine receptor and titin antibodies, should lead neurologists to adopt different treatment strategies compared to those applied in myasthenia or myositis alone. Moreover, further evidence is warranted that titin and, particularly, ryanodine receptor antibodies may co-occur or be pathophysiologically involved in myasthenia-myositis cases.

Thymus histology and concomitant autoimmune diseases in Japanese patients with muscle-specific receptor tyrosine kinase-antibody-positive myasthenia gravis.

BACKGROUND AND PURPOSE: The differences in the characteristics of thymus histology, coexisting autoimmune diseases and related autoantibodies between anti-muscle-specific receptor tyrosine kinase (MuSK)-antibody (Ab)-positive myasthenia gravis (MG) patients, and anti-acetylcholine receptor (AChR)-Ab-positive MG patients are not clearly defined. METHODS: The types of thymus histology, coexisting autoimmune diseases and associated Abs in 83 MuSK-Ab-positive patients nationwide were investigated and were compared with those in AChR-Ab-positive patients followed at our institute (n = 83). As for the autoantibodies associated with thymoma, titin Abs were measured. RESULTS: Thymoma was not present in any of the MuSK-Ab-positive patients but presented in 21 patients (25.3%) amongst the AChR-Ab-positive patients. Titin Abs were absent in MuSK-Ab-positive patients but positive in 25 (30.1%) of the AChR-Ab-positive patients. Concomitant autoimmune diseases were present in eight MuSK-Ab-positive patients (9.6%) amongst whom Hashimoto's thyroiditis and rheumatoid arthritis predominated, whereas 22 AChR-Ab-positive patients (26.5%) had one or more concomitant autoimmune diseases of which Graves' disease predominated. CONCLUSIONS: Differences in frequency of thymoma and thymic hyperplasia, coexisting autoimmune diseases and autoantibody positivity between MuSK-Ab-positive and AChR-Ab-positive MG were indicated, suggesting that, in contrast with AChR-Ab-positive MG, thymus does not seem to be involved in the pathogenic mechanisms of MuSK-Ab-positive MG.

Immunoadsorption therapy in late-onset myasthenia gravis / 中华肾脏病杂志

Objective To investigate the removal effect of immunoadsorption (IA) on associated antibodies and the efficacy in late-onset myasthenia gravis (MG). Methods A total of 25 late-onset MG patients were randomly selected to enroll in this study. IA therapy was given to 10 patients (IA group), while immunoglobin (0.4 g·kg-1·d-1) was administrated to the other 15 patients for 5 days(Ig group). The titers of Titin antibody (Titin-ab), acetylcholine receptor antibody (AchR-ab) and presynaptic membrane antibody (PrsmR-ab) were detected before and after the treatment. Quantitive MG (QMG) score was assessed before and immediately after the entire course of treatment. The clinical efficacy, the duration of respiratory support and in-hospital were compared between two groups. The correlation between three antibodies and QMG score was also analyzed. Results Compared with that before treatment, the Titin-ab PIN values, the AchR-ab PIN values, and the PrsmR-ab P/N values of IA group were all decreased significantly after treatment (P<0.05, respectively). The P/N value of Titin-ab in IA group was decreased by 54.7%～3.5%, which was significantly higher than that in Ig group(19.9%±3.1%) (P<0.01). QMG score reduced by 42.4%± 4.2% and 23.8%±3.7% in IA group and Ig group respectively (P<0.01, respectively). Symptoms were effectively ameliorated by both treatments, but the effective power of IA group was higher than that of Ig group (70% vs 40%, P<0.05). Remission time of IA group was significantly shorter than that of Ig group [(5.38±0.42) d vs (8.4±1.54) d, P=0.008), so was the duration of in-hospital [(13.50±0.50) d vs (16.50±0.50) d, P<0.05). The number of respiratory support in IA group was less than that in Ig group (1/10 vs 6/15, P<0.05). By the Pearson correlation analysis, the decrease of Titin-ab showed a better longitudinal correlation with the decrease of QMG score than the other two antibodies (r=0.6315, P<0.01). Conclusion IA can rapidly and effectively clear the pathogenic antibodies of late-onset MG patients and its short-term clinical efficacy is better than immunoglobin.