[Show abstract][Hide abstract] ABSTRACT: Purpose of reviewNext-generation sequencing is revolutionizing the molecular taxonomy of human disease. Recent studies of patients with unexplained autoinflammatory disorders reveal germline genetic mutations that target important regulators of innate immunity.Recent findingsWhole-exome analyses of previously undiagnosed patients have catalyzed the recognition of two new disease genes. First, a phenotypic spectrum, including livedo racemosa, fever with early-onset stroke, polyarteritis nodosa, and Sneddon syndrome, is caused by loss-of-function mutations in cat eye syndrome chromosome region, candidate 1 (CECR1), encoding adenosine deaminase 2. Adenosine deaminase 2 is a secreted protein expressed primarily in myeloid cells, and a regulator of macrophage differentiation and endothelial development. Disease-associated mutations impair anti-inflammatory M2 macrophage differentiation. Second, patients presenting with cold-induced urticaria, granulomatous rash, autoantibodies, and common variable immunodeficiency, or with blistering skin lesions, bronchiolitis, enterocolitis, ocular inflammation, and mild immunodeficiency harbor distinct mutations in phospholipase C-2, encoding a signaling molecule expressed in natural killer cells, mast cells, and B lymphocytes. These mutations inhibit the function of a phospholipase C-2 autoinhibitory domain, causing increased or constitutive signaling.SummaryThese findings underscore the power of next-generation sequencing, demonstrating how the primary deficiency of key molecular regulators or even regulatory motifs may lead to autoinflammation, and suggesting a possible role for cat eye syndrome chromosome region, candidate 1 and phospholipase C-2 in common diseases.
Current Opinion in Allergy and Clinical Immunology 12/2014; 14(6):491-500. DOI:10.1097/ACI.0000000000000117 · 3.66 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Secondary bacterial infections are a common complication of influenza. Innate immune host defenses appear to be impaired following influenza, leading to susceptibility to subsequent bacterial infections. Alternatively activated macrophages (AAM) in the lungs may play a critical role in eliciting the hypersusceptibility to secondary bacterial pneumonia.
C57BL6 mice were challenged with sublethal doses of the mouse-adapted A/PR/8/34 (PR8) influenza virus or saline and allowed to recover. At complete recovery (day 14), mice were re-challenged with sublethal doses of Streptococcus pneumoniae serotype 3 (Sp3).
PR8-recovered mice developed a rapidly fatal pulmonary infection to a 100-fold sublethal pneumococcal challenge, whereas PR8-naive mice demonstrated no mortality or illness. The cytokines which induce AAM (IL-4 and IL-13) and the expression of genes associated with AAM (Arginase-1, FIZZ1, and YM1) were elevated after PR8 infection. Flow cytometry suggests that alveolar macrophages demonstrate the AAM-phenotype, as indicated by MGL-1 and MHCII expression, in response to PR8 infection. Recovery from PR8 was associated with blunted cytokine responses to TLR ligands.
The mechanisms of immune regulation during recovery from influenza are being elucidated. We provide evidence that pulmonary AAM are induced during influenza infection and may contribute to the elicitation of hypersusceptibility to a secondary bacterial infection.
[Show abstract][Hide abstract] ABSTRACT: We assessed the association between exercise capacity and mortality in hypertensive men with and without additional cardiovascular risk factors. A cohort of 4631 hypertensive veterans, who successfully completed a graded exercise test at the Veterans Affairs Medical Center in Washington, DC, and Palo Alto, California, was followed for 7.7+/-5.4 years (35,629 person-years) for all-cause mortality. Fitness categories were established based on peak metabolic equivalent (MET) levels achieved. In each fitness category, we defined individuals with and without additional cardiovascular risk factors. Exercise capacity was the strongest predictor of all-cause mortality. The adjusted mortality risk was 13% lower for every 1-MET increase in exercise capacity. Compared with the very low fit (< or =5.0 MET), the adjusted risk was 34% lower for those achieving 5.1 to 7.0 MET (low fit; hazard ratio: 0.66; CI: 0.58 to 0.76; P<0.001), 59% lower for the moderate fit (7.1 to 10.0 MET; hazard ratio: 0.41; CI: 0.35 to 0.50; P<0.001), and 71% lower for the high-fit category (>10.0 MET; hazard ratio: 0.29; CI: 0.21 to 0.40; P<0.001). Within the very-low-fit category, mortality risk was 47% higher for those with additional risk factors compared with individuals with no risk factors. This risk was eliminated for those in the next fitness category (5.1 to 7.0 MET) and was progressively reduced for the moderate and high-fit categories regardless of the presence or absence of additional risk factors. In conclusion, exercise capacity was the strongest predictor of all-cause mortality in hypertensive men. The increased risk imposed by low fitness and additional cardiovascular risk factors was eliminated by relatively small increases in exercise capacity and declined progressively with higher exercise capacity.