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Mannose-binding lectin (MBL)-associated serine protease-2 (MASP-2) is an indispensable enzyme for the activation of the lectin pathway of complement. Its deficiency is classified as a primary immunodeficiency associated to pyogenic bacterial infections, inflammatory lung disease, and autoimmunity. In Europeans, MASP-2 deficiency, due to homozygosity for c.359A > G (p.D120G), occurs in 7 to 14/10,000 individuals. We analyzed the presence of the p.D120G mutation in adults (increasing the sample size of our previous studies) and children. Different groups of patients (1495 adults hospitalized with community-acquired pneumonia, 186 adults with systemic lupus erythematosus, 103 pediatric patients with invasive pneumococcal disease) and control individuals (1119 healthy adult volunteers, 520 adult patients without history of relevant infectious diseases, and a pediatric control group of 311 individuals) were studied. Besides our previously reported MASP-2-deficient healthy adults, we found a new p.D120G homozygous individual from the pediatric control group. We also reviewed p.D120G homozygous individuals reported so far: a total of eleven patients with a highly heterogeneous range of disorders and nine healthy controls (including our four MASP-2-deficient individuals) have been identified by chance in association studies. Individuals with complete deficiencies of several pattern recognition molecules of the lectin pathway (MBL, collectin-10 and collectin-11, and ficolin-3) as well as of MASP-1 and MASP-3 have also been reviewed. Cumulative evidence suggests that MASP-2, and even other components of the LP, are largely redundant in human defenses and that individuals with MASP-2 deficiency do not seem to be particularly prone to infectious or autoimmune diseases.

[This corrects the article DOI: 10.1186/s13054-016-1208-6.].

RATIONALE: Detection of the C-polysaccharide of Streptococcus pneumoniae in urine by an immune-chromatographic test is increasingly used to evaluate patients with community-acquired pneumonia. OBJECTIVES: We assessed the sensitivity and specificity of this test in the largest series of cases to date and used logistic regression models to determine predictors of positivity in patients hospitalized with community-acquired pneumonia. METHODS: We performed a multicenter, prospective, observational study of 4,374 patients hospitalized with community-acquired pneumonia. MEASUREMENTS AND MAIN RESULTS: The urinary antigen test was done in 3,874 cases. Pneumococcal infection was diagnosed in 916 cases (21%); 653 (71%) of these cases were diagnosed exclusively by the urinary antigen test. Sensitivity and specificity were 60 and 99.7%, respectively. Predictors of urinary antigen positivity were female sex; heart rate>/=125 bpm, systolic blood pressure/=30 mg/dl. With at least six of all these predictors present, the probability of positivity was 52%. With only one factor present, the probability was only 12%. CONCLUSIONS: The urinary antigen test is a method with good sensitivity and excellent specificity in diagnosing pneumococcal pneumonia, and its use greatly increased the recognition of community-acquired pneumonia due to S. pneumoniae. With a specificity of 99.7%, this test could be used to direct simplified antibiotic therapy, thereby avoiding excess costs and risk for bacterial resistance that result from broad-spectrum antibiotics. We also identified predictors of positivity that could increase suspicion for pneumococcal infection or avoid the unnecessary use of this test.

BACKGROUND: Active smoking increases the risk of developing community-acquired pneumonia (CAP) and invasive pneumococcal disease, although its impact on mortality in pneumococcal CAP outcomes remains unclear. The aim of this study was to investigate the influence of current smoking status on pneumococcal CAP mortality. METHODS: We performed a multicenter, prospective, observational cohort study in 4,288 hospitalized patients with CAP. The study group consisted of 892 patients with pneumococcal CAP: 204 current smokers (22.8%), 387 nonsmokers (43.4%), and 301 exsmokers (33.7%). RESULTS: Mortality at 30 days was 3.9%: 4.9% in current smokers vs 4.3% in nonsmokers and 2.6% in exsmokers. Current smokers with CAP were younger (51 years vs 74 years), with more alcohol abuse and fewer cardiac, renal, and asthma diseases. Current smokers had lower CURB-65 (confusion, uremia, respiratory rate, BP, age >= 65 years) scores, although 40% had severe sepsis at diagnosis. Current smoking was an independent risk factor (OR, 5.0; 95% CI, 1.8-13.5; P = .001) for 30-day mortality of pneumococcal CAP aft er adjusting for age (OR, 1.06; P = .001), liver disease (OR, 4.5), sepsis (OR, 2.3), antibiotic adherence to guidelines, and first antibiotic dose given, 6 h. The independent risk effect of current smokers remained when compared only with nonsmokers (OR, 4.0; 95% CI, 1.3-12.6; P = .015) or to exsmokers (OR, 3.9; 95% CI, 1.09-4.95; P = .02). CONCLUSIONS: Current smokers with pneumococcal CAP oft en develop severe sepsis and require hospitalization at a younger age, despite fewer comorbid conditions. Smoking increases the risk of 30-day mortality independently of tobacco-related comorbidity, age, and comorbid conditions. Current smokers should be actively targeted for preventive strategies.

The natural history of the resolution of infectious parameters in patients with community-acquired pneumonia (CAP) is not completely known. The aim of our study was to identify those factors related to host characteristics, the severity of pneumonia, and treatment that influence clinical stability.

An inadequate response to initial empirical treatment of community acquired pneumonia (CAP) represents a challenge for clinicians and requires early identification and intervention. A study was undertaken to quantify the incidence of failure of empirical treatment in CAP, to identify risk factors for treatment failure, and to determine the implications of treatment failure on the outcome.

Lung lymphomas frequently present a diagnostic challenge. The diagnosis of malignant lymphoma is possible when lymphocyte subpopulations show aneuploidy or a definable monoclonal surface marker or both. We present a case of lymphoma of the lung in which DNA analysis of bronchoalveolar lavage fluid was the first successful method in the time course of diagnosis.