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Background Chronic granulomatous disease (CGD) is a primary immunodeficiency caused by defective production of reactive oxygen species in phagocytic cells that results in life-threatening infections and severe inflammatory manifestations. The treatment of inflammatory manifestations remains challenging because it can be associated with an increased risk of infections. Previous studies have shown that phagocytes from patients with CGD display a defect in autophagy and a reactive oxygen species–independent activation of the inflammasome. Objective Because the intersections between autophagy and the inflammasome have been observed in patients with various diseases and microbial infections, we investigated the possible benefit of restoring the autophagy defect through rapamycin, a potent autophagy inducer, in the setting of CGD. Methods We studied 15 patients given a diagnosis of CGD and followed in our institution. All patients were free of any active infection at the time of the study. Results We show that patients with CGD present a consistent inflammatory phenotype defined by (1) increased nonclassical and intermediate monocytes, (2) a proinflammatory state of mononuclear phagocytes with increased IL-1β and TNF-α content, (3) a T H 17 bias of CD4 + T cells, (4) and an increase in IL-17A–secreting neutrophil numbers. We document the reversion of CGD inflammatory status by the mammalian target of rapamycin inhibitor rapamycin on the different immune cell subsets. We also provide evidence for the enhancement of rapamycin's inhibitory effect on IL-1β secretion by the IL-1 receptor antagonist anakinra in phagocytes of patients with CGD. Conclusion Altogether, these data open new therapeutic approaches for CGD-related inflammatory manifestations.

Gene therapy for SCID and CID usually leads to a more efficient T-cell reconstitution as compared to HSCT from a mismatched related donor. However, as observed in ADA, SCID X1 and WAS gene therapy trials, T cell recovery is sometimes slow and associated with morbidity and mortality due to viral infections. In order to shorten post-transplant immunodeficiency and to reduce the frequency of these complications, one possible strategy is to transplant gene-corrected T-cell committed precursors. We have recently set up a protocol for transplanting in vitro-committed T-cell precursors able to seed the thymus and generate a wave of mature and polyclonal T-cells significantly faster than is usually observed. This protocol is based on a 3 to 7 day-culture of CD34+ cells in the presence of immobilized Notch ligand Delta-like-4 (DL-4), an adhesion molecule and a combination of cytokines; this culture system enables the in vitro generation of large amounts of T-cell precursor cells that (i) display the phenotypic and molecular signatures (i.e. gene expression pattern and TCR rearrangement pattern) of early thymic progenitor cells and (ii) have a high T-lymphopoietic potential in vitro and in vivo when transferred into NOD/SCPD/γc knock-out (NSG) mice (Reimann C, Stem Cells, 2012). The goal of the present project was to combine exposure to DL-4 and gene therapy approaches (DL-4/GT). For this purpose, gene correction of CD34+ cells from SCID-X1 patients was performed on DL-4 coated plates and the ex vivo transduced cells were either seeded on OP9/DL-1 culture or injected into NSG mice to determine their in vitro and in vivo capacity to generate mature and diverse T cells. In the DL-4/GT condition, the frequency and number of CD7+CD5+commited T-cell precursors was increased as compared to GT condition alone. Experiments to assess if the DL-4/GT condition accelerate T cell differentiation of gene corrected cells are currently ongoing. Altogether, our results suggest that a short exposure to the Notch ligand DL-4 might be an useful tool to generate large amounts of corrected T-cell precursors.