This prospective study, including inceptive and validation cohorts of unselected intensive care unit patients, demonstrates the high performance of a bioscore combining the PMN CD64 index together with PCT and sTREM-1 serum levels in diagnosing sepsis in the critically ill patient.

Shwachman-Diamond syndrome (SDS) (OMIM #260400) is a rare inherited bone marrow failure syndrome (IBMFS) that is primarily characterized by neutropenia and exocrine pancreatic insufficiency. Seventy-five to ninety percent of patients have compound heterozygous loss-of-function mutations in the Shwachman-Bodian-Diamond syndrome (SBDS) gene. Using trio whole-exome sequencing (WES) in an SBDS-negative SDS family and candidate gene sequencing in additional SBDS-negative SDS cases or molecularly undiagnosed IBMFS cases, we identified 3 independent patients, each of whom carried a de novo missense variant in SRP54 (encoding signal recognition particle 54 kDa). These 3 patients shared congenital neutropenia linked with various other SDS phenotypes. 3D protein modeling revealed that the 3 variants affect highly conserved amino acids within the GTPase domain of the protein that are critical for GTP and receptor binding. Indeed, we observed that the GTPase activity of the mutated proteins was impaired. The level of SRP54 mRNA in the bone marrow was 3.6-fold lower in patients with SRP54-mutations than in healthy controls. Profound reductions in neutrophil counts and chemotaxis as well as a diminished exocrine pancreas size in a SRP54-knockdown zebrafish model faithfully recapitulated the human phenotype. In conclusion, autosomal dominant mutations in SRP54, a key member of the cotranslation protein-targeting pathway, lead to syndromic neutropenia with a Shwachman-Diamond-like phenotype.

No abstract

Immune thrombocytopenia (ITP) is an autoimmune disease with a complex pathogenesis. As in many B cell-related autoimmune diseases, rituximab (RTX) has been shown to increase platelet counts in some ITP patients. From an immunologic standpoint, the mode of action of RTX and the reasons underlying its limited efficacy have yet to be elucidated. Because splenectomy is a cornerstone treatment of ITP, the immune effect of RTX on this major secondary lymphoid organ was in-

Disinhibition of cortical excitatory cell gate information flow through and between cortical columns. The major contribution of Martinotti cells (MC) is providing dendritic inhibition to excitatory neurons and therefore they are a main component of disinhibitory connections. Here we show by means of optogenetics that MC in layers II/III of the mouse primary somatosensory cortex are inhibited by both parvalbumin (PV)- and vasoactive intestinal polypeptide (VIP)-expressing cells. Paired recordings revealed stronger synaptic input onto MC from PV cells than from VIP cells. Moreover, PV cell input showed frequency-independent depression, whereas VIP cell input facilitated at high frequencies. These differences in the properties of the two unitary connections enable disinhibition with distinct temporal features.