Both B‐1a and B‐1b cells exposed to Mycobacterium tuberculosis lipids differentiate into IgM antibody‐secreting cells

Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis. The cellular immune response to mycobacteria has been characterized extensively, but the antibody response remains underexplored. The present study aimed to examine whether host or bacterial phospholipids induce secretion of IgM, and specifically anti‐phospholipid IgM, antibodies by B cells and to identify the responsible B‐cell subset. Here we show that peritoneal B cells responded to lipid antigens by secreting IgM antibodies. Specifically, stimulation with M. tuberculosis H37Rv total lipids resulted in significant induction of total and anti‐phosphatidylcholine IgM. Similarly, IgM antibody production increased significantly with stimulation by whole Mycobacterium bovis bacillus Calmette–Guérin. The B‐1 subset was the dominant source of IgM antibodies after exposure to cardiolipin. Both CD5⁺ B‐1a and CD5^? B‐1b cell subsets secreted total IgM antibodies after exposure to M. tuberculosis H37Rv total lipids in vitro. Overall, our results suggest that the poly‐reactive B‐1 cell repertoire contributes to non‐specific anti‐phospholipid IgM antibody secretion in response to M. tuberculosis lipids.     

Sepsis in end-stage renal disease patients: are they at an increased risk of mortality?

ObjectivesThis study aims to examine the outcome of end-stage renal disease (ESRD) patients admitted with sepsis to the intensive care unit (ICU).DesignSingle centre, retrospective cohort studySettingThe study was conducted in the Intensive Care Department of King Abdulaziz Medical City, Riyadh, Saudi Arabia.ParticipantsData were extracted from a prospectively collected ICU database from 2002 to 2017. Patients were considered to have sepsis based on the sepsis-3 definition and were stratified into 2 groups based on the presence or absence of ESRD.Primary and secondary outcomesThe primary outcome of the study was in-hospital mortality. Secondary outcomes included ICU mortality, ICU and hospital lengths of stay, and mechanical ventilation duration.ResultsA total of 8803 patients were admitted to the ICU with sepsis during the study period. 730 (8.3%) patients had ESRD. 49.04% of ESRD patients with sepsis died within their hospital stay vs. 31.78% of non-ESRD patients. ESRD septic patients had 1.44 greater odds of dying within their hospital stay as compared to septic non-ESRD patients (OR 1.44, 95% CI 1.03–1.53). Finally, the predictors of hospital mortality in septic ESRD patients were found to be mechanical ventilation (OR 3.36; 95% CI 2.27–5.00), a history of chronic liver disease (OR 2.26; 95% CI 1.26–4.07), and use of vasopressors (OR 1.74; 95% CI 1.19–2.54). Among patients with ESRD, hospital mortality was higher in subgroups of patients with chronic cardiac (OR 1.86 (1.36–2.53) vs. 1.19 (0.96–1.47)) and chronic respiratory illnesses (OR 2.20 (1.52–3.20) vs. 1.21 (0.99–1.48)).ConclusionESRD patients admitted to the intensive care unit with sepsis are at greater odds of mortality compared to patients with non-ESRD. This risk is particularly increased if these patients have a concomitant history of chronic cardiac and respiratory illnesses.

Key Messages

• Sepsis and bacterial infections are very common in ESRD patients and following cardiovascular disease; sepsis is the second leading cause of death in patients with ESRD.
• This study aims to examine the outcome of patients with end-stage renal disease (ESRD) patients admitted with sepsis to the intensive care unit (ICU).
• The results of this study have shown that end-stage renal disease is associated with greater odds of ICU and hospital mortality among septic patients admitted to an intensive care unit.
• ESRD patients were also more likely to be started on vasopressors and mechanical ventilation.

     

Outcomes of septic cirrhosis patients admitted to the intensive care unit: A retrospective cohort study

The aim of this study is to examine the outcome of septic patients with cirrhosis admitted to the intensive care unit (ICU) and predictors of mortality.Single center, retrospective cohort study.The study was conducted in Intensive care Department of King Abdulaziz Medical City, Riyadh, Saudi Arabia.Data was extracted from a prospectively collected ICU database managed by a full time data collector. All patients with an admission diagnosis of sepsis according to the sepsis-3 definition were included from 2002 to 2017. Patients were categorized into 2 groups based on the presence or absence of cirrhosis.The primary outcome of the study was in-hospital mortality. Secondary outcomes included ICU mortality, ICU and hospital lengths of stay and mechanical ventilation duration.A total of 7906 patients were admitted to the ICU with sepsis during the study period, of whom 497 (6.29%) patients had cirrhosis. 64.78% of cirrhotic patients died during their hospital stay compared to 31.54% of non-cirrhotic. On multivariate analysis, cirrhosis patients were at greater odds of dying within their hospital stay as compared to non-cirrhosis patients (Odds ratio {OR} 2.53; 95% confidence interval {CI} 2.04 – 3.15) independent of co-morbidities, organ dysfunction or hemodynamic status. Among cirrhosis patients, elevated international normalization ratio (INR) (OR 1.69; 95% CI 1.29-2.23), hemodialysis (OR 3.09; 95% CI 1.76-5.42) and mechanical ventilation (OR 2.61; 95% CI 1.60–4.28) were the independent predictors of mortality.Septic cirrhosis patients admitted to the intensive care unit have greater odds of dying during their hospital stay. Among septic cirrhosis patients, elevated INR and the need for hemodialysis and mechanical ventilation were associated with increased mortality.     

Assessment of the Possible Association of Air Pollutants PM10, O3, NO2 With an Increase in Cardiovascular,Respiratory, and Diabetes Mortality in Panama City: A 2003 to 2013 Data Analysis

In recent years, Panama has experienced a marked economic growth, and this, in turn, has been associated with rapid urban development and degradation of air quality. This study is the first evaluation done in Panama on the association between air pollution and mortality. Our objective was to assess the possible association between monthly levels of PM₁₀, O₃, and NO_2, and cardiovascular, respiratory, and diabetes mortality, as well as the seasonal variation of mortality in Panama City, Panama.The study was conducted in Panama City, using air pollution data from January 2003 to December 2013. We utilized a Poisson regression model based on generalized linear models, to evaluate the association between PM₁₀, NO₂, and O₃ exposure and mortality from diabetes, cardiovascular, and respiratory diseases. The sample size for PM₁₀, NO₂, and O₂ was 132, 132, and 108 monthly averages, respectively.We found that levels of PM₁₀, O₃, and NO₂ were associated with increases in cardiovascular, respiratory, and diabetes mortality. For PM₁₀ levels ≥ 40 μg/m³, we found an increase in cardiovascular mortality of 9.7% (CI 5.8–13.6%), and an increase of 12.6% (CI 0.2–24.2%) in respiratory mortality. For O₃ levels ≥ 20 μg/m³ we found an increase of 32.4% (IC 14.6–52.9) in respiratory mortality, after a 2-month lag period following exposure in the 65 to <74 year-old age group. For NO₂ levels ≥20 μg/m³ we found an increase in respiratory mortality of 11.2% (IC 1.9–21.3), after a 2-month lag period following exposure among those aged between 65 and <74 years.There could be an association between the air pollution in Panama City and an increase in cardiovascular, respiratory, and diabetes mortality. This study confirms the urgent need to improve the measurement frequency of air pollutants in Panama.     

Prevention of peritonitis in children receiving peritoneal dialysis

Peritonitis and catheter-related (exit-site/tunnel) infections are major causes of morbidity in children receiving peritoneal dialysis (PD). Our objective was to evaluate the impact of a combination of prophylactic measures on the rate of peritonitis and catheter-related infections subsequent to their implementation in 2001. This is a single center review of incident patients who received automated peritoneal dialysis (APD) from 1997 to 2004. The causal microorganisms, annualized peritonitis and catheter-related infections rates and the time to infection were reviewed using pooled data from 1997 to 2000 and from 2001 to 2004. Fifty-four patients received PD over 1099 patient months (pm). Twenty-eight peritonitis episodes occurred in 15 patients over 599 pm from 1997 to 2000 (annualized rate (AR): 0.56 infections/patient year). Eight episodes of peritonitis occurred in five patients over 500 pm from 2001 to 2004 (AR: 0.19 infections/patient year) (P = 0.01). Prior to 2001, the median time from dialysis initiation to the first peritonitis episode was 500 days (95% CI, 400–660 days), compared to 1137 days (95% CI, 1050 to +Infinity) from 2001 to 2004 (P = 0.008). The rate of catheter-related infections and time to initial infection during the two periods was not different. We conclude that measures to decrease the frequency of peritonitis can be successfully applied to children and should be incorporated as part of standard care.