The definition of acute-on-chronic liver failure (ACLF) remains contested. In Europe and North America, the term is generally applied according to the European Association for the Study of the Liver-Chronic Liver Failure (EASL-CLIF) Consortium guidelines, which defines this condition as a syndrome that develops in patients with cirrhosis and is characterized by acute decompensation, organ failure and high short-term mortality. One-third of patients who are hospitalized for acute decompensation present with ACLF at admission or develop the syndrome during hospitalization. ACLF frequently occurs in a closed temporal relationship to a precipitating event, such as bacterial infection or acute alcoholic, drug-induced or viral hepatitis. However, no precipitating event can be identified in approximately 40% of patients. The mechanisms of ACLF involve systemic inflammation due to infections, acute liver damage and, in cases without precipitating events, probably intestinal translocation of bacteria or bacterial products. ACLF is graded into three stages (ACLF grades 1-3) on the basis of the number of organ failures, with higher grades associated with increased mortality. Liver and renal failures are the most common organ failures, followed by coagulation, brain, circulatory and respiratory failure. The 28-day mortality rate associated with ACLF is 30%. Depending on the grade, ACLF can be reversed using standard therapy in only 16-51% of patients, leaving a considerable proportion of patients with ACLF that remains steady or progresses. Liver transplantation in selected patients with ACLF grade 2 and ACLF grade 3 increases the 6-month survival from 10% to 80%.

Efficient activation of neutrophils is a key requirement for effective immune responses. We found that neutrophils released cellular adenosine triphosphate (ATP) in response to exogenous stimuli such as formylated bacterial peptides and inflammatory mediators that activated receptors for Fcγ, interleukin-8, C5a complement, and leukotriene B4. The release of ATP in response to stimulation of the formyl peptide receptor (FPR) occurred through pannexin-1 hemichannels that colocalized with FPR and P2Y2 nucleotide receptors on the cell surface to form a purinergic signaling system that facilitated the activation of neutrophils. Disruption of this purinergic signaling system by inhibiting or silencing pannexin-1 hemichannels or P2Y2 receptors blocked the activation of neutrophils and impaired innate host responses to bacterial infection. Thus, purinergic signaling is a fundamental mechanism that is required for neutrophil activation and immune defense.

Intravesical bacillus Calmette-Guerin (BCG) has been established as an effective treatment of superficial bladder cancer (Parker and Kommu, 2013). However, major side effects, including pneumonitis, sepsis, and even death, may occur in <5% of patients (Gonzalez et al., 2003). Here we present a case of severe disseminated Mycobacterium bovis following intravesical BCG administration. Our patient is a 76-year-old gentleman with newly diagnosed superficial transitional cell carcinoma of the bladder who recently received his first intravesical BCG treatment. He initially presented with hemoptysis and was found to have extensive patchy infiltrates bilaterally. He was treated for pneumonia with antibiotics and then with steroids for hypersensitivity pneumonitis but continued to deteriorate. Due to the temporal proximity of his exposure to BCG, we administered treatment for presumed disseminated BCG infection with rifampin, isoniazid, and ethambutol. Within a 48-hour period, the patient improved dramatically. The reported cases of infection from intravesical BCG illustrate an insidious onset with initial symptoms of low-grade fevers and cystitis but may progress to pneumonitis. If the symptoms persist for more than 7 days or if there is clinical deterioration, RIPE therapy (with rifampin, isoniazid, pyridoxine, and ethambutol) and a fluoroquinolone should be administered for a 6–9-month course along with steroids for 4–6 weeks (Naudžiunas et al., 2012).

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