[Anti-cytokine autoantibodies: Review of the literature]. / Anticorps anti-cytokines : quel impact clinique en pathologie humaine ?

Anti-cytokine antibodies (ACA) are an emerging cause of acquired immunodeficiency, especially in previously healthy adults. The most frequently reported are anti-IFN-γ responsible for disseminated non-tuberculous mycobacteria infections, and anti-GM-CSF mainly in mycobacteria, cryptococcosis and nocardiosis infections. The presence of anti-IFN-α in severe COVID-19 infections has recently been described. The search for and detection of these ACAs in an unusual infection situation makes it possible to set up specific therapies in addition to the anti-infective treatment. ACAs are also frequent in various autoimmune pathologies where, in addition to being indicators of the breakdown of immune tolerance, they can modulate the activity of the disease according to their cytokine target. In this review of the literature, we will focus on the epidemiology and the clinical impact of these ACAs in healthy subjects and in infectious or dysimmune diseases.

Spinal cord toxoplasmosis in a young immunocompetent patient.

We report a case of spinal cord toxoplasmosis occurring as a primary infection in a 31-year-old immunocompetent man. Exhaustive immunologic and genetic investigations did not identify any immunodeficiency. The causative agent was a typical type 2 strain. In cases of spinal cord lesions, toxoplasmosis should be considered, even in an immunocompetent patient.

NK cell compartment in the peripheral blood and spleen in adult patients with primary immune thrombocytopenia.

Immune thrombocytopenic purpura (ITP) is a disease characterized by antibody-mediated platelet destruction. The T- and B-cell subsets have been extensively studied in primary ITP, but the NK cell compartment has been less thoroughly explored. We investigated the NK cell receptor repertoire and the functionality of NK cells in the peripheral blood and spleen in patients with primary ITP. An immunophenotypic analysis of peripheral blood lymphocytes from patients revealed that the numbers of CD19+ B lymphocytes, CD4+ and CD8+ T lymphocytes and CD3-CD56+ NK cells were within the normal range. No major alteration to the expression of distinct inhibitory or activating NK cell receptors was observed. The functionality of NK cells, as evaluated by their ability to degranulate in conditions of natural cytotoxicity or antibody-dependent cell cytotoxicity (ADCC), was preserved in these patients. By contrast, these stimuli induced lower levels of IFNγ production by the NK cells of ITP patients than by those of healthy controls. We then compared the splenic NK cell functions of ITP patients with those of cadaveric heart-beating donors (CHBD) as controls. The splenic NK cells of ITP patients tended to be less efficient in natural cytotoxicity conditions and more efficient in ADCC conditions than control splenic NK cells. Finally, we found that infusions of intravenous immunoglobulin led to the inhibition of NK cell activation through the modulation of the interface between target cells and NK cells.