TIRC7 and HLA-DR axis contributes to inflammation in multiple sclerosis.

BACKGROUND AND OBJECTIVE: Interactions between TIRC7 (a novel seven-transmembrane receptor on activated lymphocytes) and its ligand HLA-DR might be involved in the inflammatory process in multiple sclerosis (MS). METHODS: Methods comprised immunohistochemistry and microscopy on archival MS autopsies, proliferation-, cytokine-, and surface-staining assays using peripheral blood lymphocytes (PBLs) from MS patients and an in vitro model. RESULTS: TIRC7 was expressed in brain-infiltrating lymphocytes and strongly correlated with disease activity in MS. TIRC7 expression was reduced in T cells and induced in B cells in PBLs obtained from MS patients. After ex vivo activation, T cell expression of TIRC7 was restored in patients with active MS disease. The interaction of TIRC7(+) T lymphocytes with cells expressing HLA-DR on their surface led to T cell proliferation and activation whereas an anti-TIRC7 mAb preventing interactions with its ligand inhibited proliferation and Th1 and Th17 cytokine expression in T cells obtained from MS patients and in myelin basic protein-specific T cell clone. CONCLUSION: Our findings suggest that TIRC7 is involved in inflammation in MS and anti-TIRC7 mAb can prevent immune activation via selective inhibition of Th1- and Th17-associated cytokine expression. This targeting approach may become a novel treatment option for MS.

Cerebral cavernous malformations: congruency of histopathological features with the current clinical definition.

AIM: Cerebral cavernous malformations (CCMs) are defined as a mulberry-like assembly of thin walled vascular sinusoids lined by a thin endothelium lacking smooth muscle and elastin, displaying no intervening brain parenchyma. In this study, we analyse the congruency of histopathological features with the current clinical definition on a large series of neuroradiologically verified CCMs. METHODS: 87 patients who received no primary treatment prior to surgery were included. Preoperative MRIs of all patients were reviewed. 12 histopathological parameters were assessed systematically, using haematoxylin-eosin, Prussian blue, elastica van Gieson and congo red for amyloid detection. RESULTS: 71/87 (81.6%) of the cases fulfilled the basic histological criteria of CCMs. However, the thickness of the vessel walls and the calibre of the malformed vessels were highly variable. 16/87 cases (18.4%) were histologically non-diagnostic. Non-diagnostic specimens were significantly associated with radiological signs of haemorrhage (p = 0.001). A few cases (4.6%) regionally contained capillary-like malformed vessels. Intervening brain parenchyma between malformed vessels throughout the lesion was seen in 50/71 (70.4%) diagnosable lesions. Haemosiderin deposits, gliosis, thrombosis, fibrotic changes, hyalinised vessel walls, calcification and cholesterol crystals were present in a considerable range. In addition, we found amyloid deposits in 14/87 (16.1%) specimens. CONCLUSION: Contrary to the current clinical definition, the absence of intervening brain parenchyma does not represent an essential histopathological criterion of CCMs in our series. Furthermore, the diameter of the vessel lumina and the thickness of vessel walls varied considerably. Based on these findings, adaptation of the current definition on the basis of interdisciplinary interaction needs to be considered.