Vasculitis, Autoimmunity, and Cytokines: How the Immune System Can Harm the Brain.

More and more findings suggest that neurological disorders could have an immunopathological cause. Thus, immune-targeted therapies are increasingly proposed in neurology (even if often controversial), as anakinra, inhibiting IL-1 for febrile inflammatory illnesses, and JAK inhibitors for anti-interferons treatment. Precision medicine in neurology could be fostered by a better understanding of the disease machinery, to develop a rational use of immuno-modulators in clinical trials. In this review, we focus on monogenic disorders with neurological hyper-inflammation/autoimmunity as simplified "models" to correlate immune pathology and targeted treatments. The study of monogenic models yields great advantages for the elucidation of the pathogenic mechanisms that can be reproduced in cellular/animal models, overcoming the limitations of biological samples to study. Moreover, monogenic disorders provide a unique tool to study the mechanisms of neuroinflammatory and autoimmune brain damage, in all their manifestations. The insight of clinical, pathological, and therapeutic aspects of the considered monogenic models can impact knowledge about brain inflammation and can provide useful hints to better understand and cure some neurologic multifactorial disorders.

Hepatitis B and C in hematopoietic stem cell transplant.

Although the risk of acquisition of hepatitis B or hepatitis C virus through blood products has considerably reduced since the last decade, some infected patients are candidates to stem cell transplantation. Others may have no alternative than an infected donor. In all these cases, recipients of transplant are prone to short and long term liver complications. The evolution of liver tests under chemotherapy before transplant may give useful information to anticipate on the risk of hepatitis reactivation after transplant, both for HBv and HCv. More than sixty percent of the patients who are HBsAg-positive before transplant reactivate after transplant, and 3% develop acute severe liver failure. Because both viral replication and immune reconstitution are the key factors for reactivation, it is crucial to closely follow liver function tests and viral load during the first months of transplant, and to pay a special attention in slowly tapering the immunosuppression in these patients. Lamivudine reduces HBv viremia, but favors the emergence of HBv polymerase gene mutants and should be individually discussed. Both in case of HBv or HCv hepatitis reactivation with ALT ≥ 10N concomitantly to an increase in viral load at time of immune reconstitution, steroids should be given. In case there is no alternative than a HBv or HCv positive geno-identical donor, the risk of viral hepatitis, including acute liver failure and late complications, should be balanced with the benefit of transplant in a given situation.