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Background: Patients with X-linked hyper-IgM syndrome (X-HIGM) due to CD40 ligand (CD40L) mutations are susceptible to fungal pathogens; however, the underlying susceptibility mechanisms remain poorly understood. Objective: To determine whether monocyte-derived dendritic cells (DCs) from patients with X-HIGM exhibit normal responses to fungal pathogens. Methods: DCs from patients and controls were evaluated for the expression of costimulatory (CD80 and CD86) and MHC class II molecules and for their ability to produce IL-12 and IL-10 in response to Candida albicans and Paracoccidioides brasiliensis. We also evaluated the ability of C albicans– and P brasiliensis–pulsed mature DCs to induce autologous T-cell proliferation, generation of T helper (TH) 17 cells, and production of IFN-γ, TGF-β, IL-4, IL-5, and IL-17. Results: Immature DCs from patients with X-HIGM showed reduced expression of CD80, CD86, and HLA-DR, which could be reversed by exogenous trimeric soluble CD40L. Most important, mature DCs from patients with X-HIGM differentiated by coculturing DCs with fungi secreted minimal amounts of IL-12 but substantial amounts of IL-10 compared with mature DCs from normal individuals. Coculture of mature DCs from X-HIGM patients with autologous T cells led to low IFN-γ production, whereas IL-4 and IL-5 production was increased. T-cell proliferation and IL-17 secretion were normal. Finally, in vitro incubation with soluble CD40L reversed the decreased IL-12 production and the skewed TH2 pattern response. Conclusion: Absence of CD40L during monocyte/DC differentiation leads to functional DC abnormalities, which may contribute to the susceptibility to fungal infections in patients with X-HIGM. [ABSTRACT FROM AUTHOR]

Background Patients with X-linked hyper-IgM syndrome caused by CD40 ligand (CD40L) deficiency often present with episodic, cyclic, or chronic neutropenia, suggesting abnormal neutrophil development in the absence of CD40L-CD40 interaction. However, even when not neutropenic and despite immunoglobulin replacement therapy, CD40L-deficient patients are susceptible to life-threatening infections caused by opportunistic pathogens, suggesting impaired phagocyte function and the need for novel therapeutic approaches. Objectives We sought to analyze whether peripheral neutrophils from CD40L-deficient patients display functional defects and to explore the in vitro effects of recombinant human IFN-γ (rhIFN-γ) on neutrophil function. Methods We investigated the microbicidal activity, respiratory burst, and transcriptome profile of neutrophils from CD40L-deficient patients. In addition, we evaluated whether the lack of CD40L in mice also affects neutrophil function. Results Neutrophils from CD40L-deficient patients exhibited defective respiratory burst and microbicidal activity, which were improved in vitro by rhIFN-γ but not soluble CD40L. Moreover, neutrophils from patients showed reduced CD16 protein expression and a dysregulated transcriptome suggestive of impaired differentiation. Similar to CD40L-deficient patients, CD40L knockout mice were found to have impaired neutrophil responses. In parallel, we demonstrated that soluble CD40L induces the promyelocytic cell line HL-60 to proliferate and mature by regulating the expression of genes of the same Gene Ontology categories (eg, cell differentiation) when compared with those dysregulated in peripheral blood neutrophils from CD40L-deficient patients. Conclusion Our data suggest a nonredundant role of CD40L-CD40 interaction in neutrophil development and function that could be improved in vitro by rhIFN-γ, indicating a potential novel therapeutic application for this cytokine. [ABSTRACT FROM AUTHOR]

Background CD40 ligand (CD40L) deficiency predisposes to opportunistic infections, including those caused by fungi and intracellular bacteria. Studies of CD40L-deficient patients reveal the critical role of CD40L-CD40 interaction for the function of T, B, and dendritic cells. However, the consequences of CD40L deficiency on macrophage function remain to be investigated. Objectives We sought to determine the effect of CD40L absence on monocyte-derived macrophage responses. Methods After observing the improvement of refractory disseminated mycobacterial infection in a CD40L-deficient patient by recombinant human IFN-γ (rhIFN-γ) adjuvant therapy, we investigated macrophage functions from CD40L-deficient patients. We analyzed the killing activity, oxidative burst, cytokine production, and in vitro effects of rhIFN-γ and soluble CD40 ligand (sCD40L) treatment on macrophages. In addition, the effect of CD40L absence on the macrophage transcriptome before and after rhIFN-γ treatment was studied. Results Macrophages from CD40L-deficient patients exhibited defective fungicidal activity and reduced oxidative burst, both of which improved in the presence of rhIFN-γ but not sCD40L. In contrast, rhIFN-γ and sCD40L ameliorate impaired production of inflammatory cytokines. Furthermore, rhIFN-γ reversed defective control of Mycobacterium tuberculosis proliferation by patients' macrophages. The absence of CD40L dysregulated the macrophage transcriptome, which was improved by rhIFN-γ. Additionally, rhIFN-γ increased expression levels of pattern recognition receptors, such as Toll-like receptors 1 and 2, dectin 1, and dendritic cell–specific intercellular adhesion molecule 3–grabbing nonintegrin in macrophages from both control subjects and patients. Conclusion Absence of CD40L impairs macrophage development and function. In addition, the improvement of macrophage immune responses by IFN-γ suggests this cytokine as a potential therapeutic option for patients with CD40L deficiency. [ABSTRACT FROM AUTHOR]

Neonates born to renal transplanted women are exposed in utero to immunosuppressors and to antenatal conditions that may predispose the neonate to a high risk of prematurity and intrauterine growth retardation. These factors might interfere with the transfer of maternal IgG immunity. Total IgG levels and specific antibodies to measles, varicella, tetanus, Haemophilus influenzae type b (Hib) and Streptococcus pneumoniae (serotypes 4,6B,9V,14,18C,19F and 23F) were evaluated on maternal and cord blood samples of 23 sets of renal transplanted women and their newborns and 32 sets of healthy women-newborns at term. Total IgG levels were measured by nephelometry and specific antibodies, by ELISA. Renal transplanted mothers had lower median tetanus antibodies (0.67 IU/mL) than controls (1.53 IU/mL; p = 0.017). Neonates from renal transplanted mothers had lower median tetanus antibodies (0.95 IU/mL) than controls (1.97 IU/mL, p = 0.008). Antibodies to measles, varicella, Hib and the 7 serotypes of S. pneumoniae were similar between groups. Maternal antibodies were associated with an increase in neonatal antibodies for all antigens; gestational age was associated with an increase in Hib neonatal antibodies. Preeclampsia was associated with a decrease in neonatal total IgG and serotype 4 S. pneumoniae antibodies; chronic hypertension was associated with a decrease in neonatal serotype 6B S. pneumoniae antibodies. As neonates from transplanted women may be born with lower tetanus antibodies than controls, efforts should be made to keep maternal vaccines up-to-date. Clinical antenatal care with control of preeclampsia, chronic hypertension and prevention of premature delivery might also contribute to neonatal antibody levels to specific antigens at birth. [ABSTRACT FROM AUTHOR]

Intravenous immunoglobulin (IVIG) is increasingly recommended for many diseases apart from primary immunodeficiency diseases (PID). Although effective and safe, adverse reactions may occur. We conducted a 2-year prospective observational study in 117 patients with PID who received regular IVIG replacement therapy at a median dose of 600 mg/kg every 3 to 4 weeks to examine IVIG's adverse effects; 1765 infusions were performed (mean = 15/patient) in 75 males and 42 females (aged 3 months to 77 years) in 3 groups: ≤ 9 years (34.2%), 10–19 years (26.5%), and ≥ 20 years (39.3%). Fifty patients had common variable immunodeficiency (CVID), 11 had X-linked agammaglobulinemia (XLA), and 55 had other immune system disorders. The drugs administered were Octagam® (49.1%), Tegeline® (17.3%), Imunoglobulin® (18.6%), Flebogama® (12.9%), Vigam® (1.2%), and Kiovig® (0.4%). Immediate infusion-related adverse reactions occurred in the cases of 38 out 1765 infusions (2.15%, IC95% 1.53%–2.94%), which were classified as mild (81.6%), moderate (10.5%), or severe (7.9%). Time until reaction ranged from 10 to 240 min (mean = 85.7, median = 60). Reaction rates were similar across age groups. The most common reactions were malaise, headache, and abdominal pain. Reported severe events were tightness of the throat and seizure. All symptoms improved with temporary or complete IVIG interruption and symptomatic medications. Sixteen of 38 reactions to infusions occurred in the presence of an acute infection (p = 0.09). Tegeline® represented a greater reaction risk factor than Octagam® (p < 0.001). These results indicate that IVIG infusion can be considered a safe procedure. Low reaction incidence and few severe immediate infusion-related adverse reactions were observed. [ABSTRACT FROM AUTHOR]