In the early 1960s, George Mackaness showed that macrophages from mice infected with intracellular bacteria could launch an indiscriminate attack against unrelated bacteria. Thus began an explosion of research on the biology of what Mackaness first termed "macrophage activation."

In this issue of Blood, Ishii and colleagues shed new, fresh light on molecular mechanisms underlying one form of macrophage activation.

The authors have reported to the ACCP that no significant conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article. Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal. org/misc/reprints.shtml). Correspondence to: Stuart F. Quan, MD, FCCP, Harvard Med...

Methods We retrospectively evaluated a cohort of 12 patients with MAS and HLH-IA, observed at the U.O.S. Pediatric Rheumatology, from 2005 to 2014. Here we report: sex, ethnicity, RD, age at the onset of the rheumatic disease, age at the onset of MAS, duration of the disease preMAS; clinical and laboratory features; results of the bone marrow biopsy if performed; trigger factors, treatments and...

Results We report on four girls, aged of 13, 13, 10 and 7 years old, initially admitted at our university hospital for prolonged fever. Main infectious disease causes were ruled out and a diagnosis of MAS was made according to the criteria of HLH 2004. During the follow up, all patients presented with SLE symptoms and fulfilled the modified ARA criteria. Glomerular nephropathy was clinically di...

Macrophage activation syndrome (MAS) is a rare and potentially lethal disease, resulting from uncontrolled activation and proliferation of T lymphocytes and macrophages. Adult-onset Still's disease (AOSD) is an inflammatory disease. AOSD resemble reactive MAS in its symptoms and laboratory data. Moreover, AOSD per se induces MAS. It is, therefore, quite difficult to differentiate these syndrome...

Acute acalculous cholecystitis (AAC) is a severe disease seen in critically ill patients, including those with autoimmune diseases. We herein report the case of a 41-year-old female who developed macrophage activation syndrome (MAS) accompanied by a recurrence of Kikuchi disease. Abdominal imaging revealed marked thickening of the gallbladder wall and pericholecystic fluid, typically found in A...

Results Totally 120 patients evaluated in this study including 108 JIA and 12 SLE. Five patients (4 girls and 1 boy) were considered to have evidence of MAS (incidence rate 4.2%). This rate for all JIA patients was 3.7% and for SoJIA, SLE and juvenile idiopaticarthritis (JIA) and polyarticular RF negative JIA was 8.2%, 16.7% and 2.8%, respectively. Mean age of MAS onset was 4.9 years, and durat...

AIMS To review the precipitating events, clinical features, treatment, and outcome of macrophage activation syndrome (MAS). METHODS Retrospective review of cases of MAS from a prospectively collected database of children with rheumatic diseases from 1980 to 2000. RESULTS Nine patients (eight girls) were considered to have evidence of MAS. The primary diagnosis was systemic onset juvenile id...