Cytotoxic CD8⁺ T lymphocytes expressing ALS-causing SOD1 mutant selectively trigger death of spinal motoneurons.

Adaptive immune response is part of the dynamic changes that accompany motoneuron loss in amyotrophic lateral sclerosis (ALS). CD4 <sup>+</sup> T cells that regulate a protective immunity during the neurodegenerative process have received the most attention. CD8 <sup>+</sup> T cells are also observed in the spinal cord of patients and ALS mice although their contribution to the disease still remains elusive. Here, we found that activated CD8 <sup>+</sup> T lymphocytes infiltrate the central nervous system (CNS) of a mouse model of ALS at the symptomatic stage. Selective ablation of CD8 <sup>+</sup> T cells in mice expressing the ALS-associated superoxide dismutase-1 (SOD1) <sup>G93A</sup> mutant decreased spinal motoneuron loss. Using motoneuron-CD8 <sup>+</sup> T cell coculture systems, we found that mutant SOD1-expressing CD8 <sup>+</sup> T lymphocytes selectively kill motoneurons. This cytotoxicity activity requires the recognition of the peptide-MHC-I complex (where MHC-I represents major histocompatibility complex class I). Measurement of interaction strength by atomic force microscopy-based single-cell force spectroscopy demonstrated a specific MHC-I-dependent interaction between motoneuron and SOD1 <sup> G93A </sup> CD8 <sup>+</sup> T cells. Activated mutant SOD1 CD8 <sup>+</sup> T cells produce interferon-γ, which elicits the expression of the MHC-I complex in motoneurons and exerts their cytotoxic function through Fas and granzyme pathways. In addition, analysis of the clonal diversity of CD8 <sup>+</sup> T cells in the periphery and CNS of ALS mice identified an antigen-restricted repertoire of their T cell receptor in the CNS. Our results suggest that self-directed immune response takes place during the course of the disease, contributing to the selective elimination of a subset of motoneurons in ALS

How to implement medical and patient associations in low‐income countries: A proposition from the African French Alliance for the Treatment of Haemophilia (AFATH)

International audienceIntroduction: There is a lack of joint recommendations by healthcare professionals (HCP) and patient organizations when a partnership between high and low-income countries in the field of haemophilia is planned.Aim: To draft recommendations to clarify the methodology when a partnership between low- and high-income countries is planned with the objective of a long-term implication. This methodology is to be implemented for fulfilling both medical and associative aims.Methods: Based on the available literature, a first document was written, then diffused to AFATH (Alliance Franco-Africaine pour le Traitement de l'Hémophilie) members, and after a one-day meeting and further amendments, a second draft was approved by all members before submission for publication.Results: Based on 6 years experience, several recommendations regarding the joint and separate roles of patient association and HCP for a first mission in French-speaking sub-Saharan African countries have been established. The proposed methodology for establishing preliminary contacts, the first visit and the key points for diagnostic action, medical follow-up, patient education and advocacy strategy outlines a model of partnership between patients and HCP.Conclusion: This paper written jointly by patients and physicians underlines the importance of reciprocal expert guidance and a partnership based on complementary inputs