Studies here respond to two long-standing questions: Are human "pre/pro-B" CD34 + CD10 − CD19 + and "common lymphoid progenitor (CLP)/early-B" CD34 + CD10 + CD19 − alternate precursors to "pro-B" CD34 + CD19 + CD10 + cells, and do the pro-B cells that arise from these progenitors belong to the same or distinct B-cell development pathways? Using flow cytometry, gene expression profiling, and Ig V H -D-J H sequencing, we monitor the initial 10 generations of development of sorted cord blood CD34 high Lineage − pluripotential progenitors growing in bone marrow S17 stroma cocultures. We show that (i) multipotent progenitors (CD34 + CD45RA + CD10 − CD19 − ) directly generate an initial wave of Pax5 + TdT − "unilineage" pre/ pro-B cells and a later wave of "multilineage" CLP/early-B cells and (ii) the cells generated in these successive stages act as precursors for distinct pro-B cells through two independent layered pathways. Studies by others have tracked the origin of B-lineage leukemias in elderly mice to the mouse B-1a pre/pro-B lineage, which lacks the TdT activity that diversifies the V H -D-J H Ig heavy chain joints found in the early-B or B-2 lineage. Here, we show a similar divergence in human B-cell development pathways between the Pax5 + TdT − pre/ pro-B differentiation pathway that gives rise to infant B-lineage leukemias and the early-B pathway. Ordered stages in the current human model are termed the "common lymphoid progenitor" (CLP) and the "early-B," "progenitor-B," and "precursor-B" subsets that follow it (i.e., SC → CLP → early-B → pro-B → pre-B → B) (5). In this pathway, CLP and early-B stages, which both express the CD34 + CD45RA + CD10 + CD19 − surface phenotype, are actually "multilineage" progenitors of B, T, dendritic (DC), and natural killer (NK) cells (5, 10-12).Pro-B cells, which retain CD34 and CD10 expression but also express CD19 (CD34 + CD10 + CD19 + ), constitute the first Pax-5 + committed B-lineage stage, which is followed by pre-B (CD34 − CD10 + CD19 + ) cells that have ceased expression of CD34 and now express the surface μH-VpreB-λ5/CD79 surrogate Ig receptor complex (1-5, 13-15). Development of the latter CD34 − pre-B cells and their B-cell and Ig-secreting plasma cell progeny can be reconstituted after coculture of purified CD34 + Lineage − (Lin − ) progenitors with bone marrow (BM) stroma lines (e.g., S17) (15-18).Before the CLP subset and the above developmental pathway were recognized, a subset called "pre/pro-B," which expresses the CD34 + CD10 − CD19 + surface phenotype, was commonly considered to be the first human B-lineage stage (19). It occurs in fetal liver, fetal bone marrow (FBM), and umbilical cord blood (CB) (19-21). An FBM pre/pro-B cell stage was shown to distinctively lack TdT and to bear CD7 unlike concurrent conventional CD10 + CD19 − B-cell progenitors, leading to the idea that these cells might belong to a distinct B lineage (20). This lack of TdT-mediated "N-nucleotide additions" between D and J H segments is further associated with differential V-D-J gene...

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CD39/NTPDase1 has emerged as an important molecule that contributes to maintain inflammatory and coagulatory homeostasis. Various studies have hypothesized the possible role of CD39 in COVID-19 pathophysiology since no confirmatory data shed light in this regard. Therefore, we aimed to quantify CD39 expression on COVID-19 patients exploring its association with severity clinical parameters and ICU admission, while unraveling the role of purinergic signaling on thromboinflammation in COVID-19 patients. We selected a prospective cohort of patients hospitalized due to severe COVID-19 pneumonia (n=75), a historical cohort of Influenza A pneumonia patients (n=18) and sex/age-matched healthy controls (n=30). CD39 was overexpressed in COVID-19 patients’ plasma and immune cell subsets and related to hypoxemia. Plasma soluble form of CD39 (sCD39) was related to length of hospital stay and independently associated with intensive care unit admission (adjusted odds ratio 1.04, 95%CI 1.0-1.08, p=0.038), with a net reclassification index of 0.229 (0.118-0.287; p=0.036). COVID-19 patients showed extracellular accumulation of adenosine nucleotides (ATP and ADP), resulting in systemic inflammation and pro-coagulant state, as a consequence of purinergic pathway dysregulation. Interestingly, we found that COVID-19 plasma caused platelet activation, which was successfully blocked by the P2Y12 receptor inhibitor, ticagrelor. Therefore, sCD39 is suggested as a promising biomarker for COVID-19 severity. As a conclusion, our study indicates that CD39 overexpression in COVID-19 patients could be indicating purinergic signaling dysregulation, which might be at the basis of COVID-19 thromboinflammation disorder.

Clinical treatment with glucocorticoids (GC) can be complicated by cytokine-induced glucocorticoid low-responsiveness (GC-resistance, GCR), a condition associated with a homogeneous reduction in the expression of GC-receptor- (GR-) driven anti-inflammatory genes. However, GR level and phosphorylation changes modify the expression of individual GR-responsive genes differently. As sustained IL-1β exposure is key in the pathogenesis of several major diseases with prevalent GCR, we examined GR signaling and the mRNA expression of six GR-driven genes in cells cultured in IL-1β and afterwards challenged with GC. After a GC challenge, sustained IL-1β exposure reduced the cytoplasmic GR level, GRSer203 and GRSer211 phosphorylation, and GR nuclear translocation and led to selective GCR in the expression of the studied genes. Compared to GC alone, in a broad range of GC doses plus sustained IL-1β, FKBP51 mRNA expression was reduced by 1/3, TTP by 2/3, and IRF8 was completely knocked down. In contrast, high GC doses did not change the expression of GILZ and DUSP1, while IGFBP1 was increased by 5-fold. These effects were cytokine-selective, IL-1β dose- and IL-1R1-dependent. The integrated gain and loss of gene functions in the “split GCR” model may provide target cells with a survival advantage by conferring resistance to apoptosis, chemotherapy, and GC.

Background: Phosphoglucomutase-3 (PGM3) deficiency is a congenital disorder of glycosylation (CDG) with hyperimmunoglobulin IgE, atopy, and a variable immunological phenotype; most reported patients display dysmorphic features. The aim of the study was to characterize the genotype and phenotype of individuals with newly identified compound heterozygous variants in the phosphate-binding domain of PGM3 in order to better understand phenotypic differences between these patients and published cases. Methods: We analyzed PGM3 protein expression, PGM3 enzymatic activity, the presence of other gene variants within the N-glycosylation pathway, and the clinical and immunological manifestations of two affected siblings. Results: Patients belonged to a non-consanguineous family, presenting with atopic dermatitis, elevated levels of IgE, and CD4 + lymphopenia (a more severe phenotype was observed in Patient 2), but lacked dysmorphic features or neurocognitive | 567 GARCÍA-GARCÍA et Al.

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The CARD-BCL10-MALT1 (CBM) complex is critical for the proper assembly of human immune responses. The clinical and immunological consequences of deficiencies in some of its components such as CARD9, CARD11, and MALT1 have been elucidated in detail. However, the scarcity of BCL10 deficient patients prevented gaining that knowledge for this genetic disease. Only two patients with BCL10 deficiency have been reported to date. Here we describe in more depth an additional patient with autosomal recessive BCL10 complete deficiency caused by a nonsense mutation that leads to a loss of expression (K63X). Using mass cytometry coupled with unsupervised clustering and machine learning computational methods, we obtained a thorough characterization of the consequences of BCL10 deficiency in different populations of leukocytes. We showed that in addition to the almost absence of memory B and T cells reported before, this patient display a reduction in NK, gdT, Tregs, and TFH cells. The patient suffered from recurrent respiratory infections since early in life, and showed a family history of lethal severe infectious diseases. Fortunately, hematopoietic stem-cell transplantation (HSCT) cured her. Overall, this report highlights the importance of early genetic diagnosis for the management of BCL10 deficient patients and HSCT as the recommended treatment to cured this disease.

CD39/NTPDase1 has emerged as an important molecule that contributes to maintain inflammatory and coagulatory homeostasis. Various studies have hypothesized the possible role of CD39 in COVID-19 pathophysiology since no confirmatory data shed light in this regard. Therefore, we aimed to quantify CD39 expression on COVID-19 patients exploring its association with severity clinical parameters and ICU admission, while unraveling the role of purinergic signaling on thromboinflammation in COVID-19 patients. We selected a prospective cohort of patients hospitalized due to severe COVID-19 pneumonia (n=75), a historical cohort of Influenza A pneumonia patients (n=18) and sex/age-matched healthy controls (n=30). CD39 was overexpressed in COVID-19 patients' plasma and immune cell subsets and related to hypoxemia. Plasma soluble form of CD39 (sCD39) was related to length of hospital stay and independently associated with intensive care unit admission (adjusted odds ratio 1.04, 95%CI 1.0-1.08, p=0.038), with a net reclassification index of 0.229 (0.118-0.287; p=0.036). COVID-19 patients showed extracellular accumulation of adenosine nucleotides (ATP and ADP), resulting in systemic inflammation and pro-coagulant state, as a consequence of purinergic pathway dysregulation. Interestingly, we found that COVID-19 plasma caused platelet activation, which was successfully blocked by the P2Y12 receptor inhibitor, ticagrelor. Therefore, sCD39 is suggested as a promising biomarker for COVID-19 severity. As a conclusion, our study indicates that CD39 overexpression in COVID-19 patients could be indicating purinergic signaling dysregulation, which might be at the basis of COVID-19 thromboinflammation disorder