Immune recovery uveitis in Whipple's disease: an unusual ocular presentation.

PURPOSE: To describe an unusual case of Whipple's disease (WD) complicated by uveitis, and subsequent paradoxical worsening after effective antibiotic treatment targeting Tropheryma whipplei (TW). METHODS: Case report. RESULTS: A 53-year-old male presented with bilateral knee arthritis, weight loss, chronic low-grade fever, and cognitive disorders. He was under treatment with tumor necrosis factor α inhibitors (TNFi) for seronegative spondyloarthritis. Given this unusual clinical presentation, further investigations were performed and revealed blood, saliva, stool, synovial fluid and cerebrospinal fluid positivity for TW, confirming the diagnosis of systemic WD. Ophthalmologic examination revealed bilateral posterior uveitis and an aqueous humor sample confirmed the presence of intraocular TW. TNFi were stopped, and the patient was subsequently treated with adequate antibiotics (ceftriaxone, followed by doxycycline and hydroxychloroquine), and subconjunctival corticosteroid injections. After a transient improvement of the ocular symptoms, he presented a recurrence of posterior segment inflammation, leading to repeated PCR testing for TW which were negative. Therefore, paradoxical worsening of the inflammation in the context of immune recovery uveitis (IRU) was thought to be the culprit. The patient was treated with systemic corticosteroid therapy, allowing for rapid improvement of the ocular findings. CONCLUSIONS: This case underlines the possibility of IRU complicating WD. Ophthalmologists, rheumatologists, and internists should be aware of this rare complication, particularly in the context of previous immunosuppressive therapy.

Spatial Transcriptomics Reveals Signatures of Histopathological Changes in Muscular Sarcoidosis.

Sarcoidosis is a multisystemic disease characterized by non-caseating granuloma infiltrating various organs. The form with symptomatic muscular involvement is called muscular sarcoidosis. The impact of immune cells composing the granuloma on the skeletal muscle is misunderstood. Here, we investigated the granuloma-skeletal muscle interactions through spatial transcriptomics on two patients affected by muscular sarcoidosis. Five major transcriptomic clusters corresponding to perigranuloma, granuloma, and three successive muscle tissue areas (proximal, intermediate, and distal) around the granuloma were identified. Analyses revealed upregulated pathways in the granuloma corresponding to the activation of T-lymphocytes and monocytes/macrophages cytokines, the upregulation of extracellular matrix signatures, and the induction of the TGF-ß signaling in the perigranuloma. A comparison between the proximal and distal muscles to the granuloma revealed an inverse correlation between the distance to the granuloma and the upregulation of cellular response to interferon-γ/α, TNF-α, IL-1,4,6, fibroblast proliferation, epithelial to mesenchymal cell transition, and the downregulation of muscle gene expression. These data shed light on the intercommunications between granulomas and the muscle tissue and provide pathophysiological mechanisms by showing that granuloma immune cells have a direct impact on proximal muscle tissue by promoting its progressive replacement by fibrosis via the expression of pro-inflammatory and profibrosing signatures. These data could possibly explain the evolution towards a state of disability for some patients.

OCT2 expression in histiocytoses.

Diagnosis of histiocytosis can be difficult and one of the biggest challenges is to distinguish between reactive and neoplastic histiocytes on histology alone. Recently, OCT2 nuclear expression was reported in Rosai-Dorfman disease (RDD). Our purpose was to expand the testing of OCT2 on a broader variety of sporadic or H syndrome-related histiocytoses. Cases of histiocytoses were retrieved from the files of Ambroise Paré Pathology Department. All slides and molecular analyses were reviewed, and staining was completed with immunohistochemistry for OCT2. A total of 156 samples from different localizations were tested. Among sporadic cases, 52 patients had RDD, and 10 patients had mixed histiocytosis combining RDD with Erdheim Chester disease (ECD, n = 8), Langerhans cell histiocytosis (LCH, n = 2) or juvenile xanthogranuloma (JXG, n = 1). All these patients were positive for OCT2 in RDD characteristic histiocytes. Twenty-three patients had ECD and all but two (91% - 21/23) were negative for OCT2. By contrast, OCT2 was positive in 11/27 (41%) LCH and 6/16 (38%) JXG. Among the 10 samples of H syndrome-associated histiocytosis, 3 had typical RDD histology, 6 had unclassified histiocytosis, and one had mixed RDD-LCH; all were positive for OCT2. On 16 samples of granulomatous lymphadenitis, OCT2 was negative in epithelioid histiocytes. Our study shows that OCT2 has a sensitivity of 100% for RDD cases and mixed histiocytoses with an RDD component. It is negative in 92% of ECD but expressed in at least 38% of LCH, JXG, and C group histiocytoses. Finally, OCT2 is positive in all H syndrome-related histiocytoses, independent of their histology.

Tetanus-induced rhythmic seizures mimicking the clinical and electroencephalographic presentation of status epilepticus.

We describe the case of a woman in her 60s admitted to the intensive care unit after a first generalised tonic-clonic seizure in the context of alcohol withdrawal. She was placed under invasive mechanical ventilation due to persistence of coma despite antiepileptic treatment. Despite continuous sedation with propofol, the frequency and intensity of seizure increased. Seizures were very similar to epileptic tonic-clonic seizures and were recorded with video and electroencephalogram (EEG). A diagnosis of tetanus was considered after a scalp wound was discovered. The patient's husband revealed that a trismus had appeared a few days before hospital admission after a head trauma. EEG showed a pattern of diffuse spikes, which disappeared after a cisatracurium bolus. The diagnosis of tetanus was later confirmed by cultures from wound samples. Therefore, severe tetanus can mimic both the clinical and EEG features of status epilepticus and could be added to the differential diagnosis of epilepsy.

Crystal-storing histiocytosis and Bing-Neel-like syndrome revealing a small B-cell lymphoma with plasmacytic differentiation, presumed to be a marginal zone lymphoma.

Crystal-storing histiocytosis and Bing-Neel syndrome are two diseases induced by paraproteins. Herein, we report a rare case of crystal-storing histiocytosis associated with Bing-Neel-like neurological manifestations in the context of a small B-cell lymphoma with plasmacytic differentiation, presumed to be a marginal zone lymphoma.