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We report the case of a patient with disseminated toxoplasmosis who presented with cervical lymphadenopathies and pneumonia. Although the infection was successfully treated with co-trimoxazole, the patient developed reactive macrophage activation syndrome (rMAS). To our knowledge, this is the first reported case of rMAS triggered by toxoplasmosis in the medical literature.

Objective: To investigate whether prolonged exposure to interleukin-6 (IL-6) affects the inflammatory response induced by Toll-like receptor (TLR) ligands., Methods: IL-6-transgenic mice and wild-type mice were stimulated with different TLR ligands; survival rates, blood cell counts, and biochemical parameters were analyzed. Murine splenic mononuclear cells and peritoneal macrophages were stimulated with lipopolysaccharide (LPS), lipoteichoic acid, poly(I-C), or CpG. Human macrophages were cultured for 4 days in the presence of IL-6 and then stimulated with LPS. Inflammatory cytokine expression was measured by enzyme-linked immunosorbent assay or reverse transcription-polymerase chain reaction. Activation of STAT-3, ERK-1/2 (MAPK), and p65 NF-κB was evaluated by Western blotting or confocal analysis., Results: Treatment of IL-6-transgenic mice with TLR ligands led to an increased fatality rate and elevated levels of IL-1β, tumor necrosis factor α (TNFα), IL-6, and IL-18. Macrophages from IL-6-transgenic mice produced increased levels of inflammatory cytokines, which were associated with increased phosphorylation of STAT-3 and ERK-1/2 and with increased NF-κB nuclear translocation. Human macrophages treated with IL-6 and then stimulated with LPS showed elevated levels of cytokines and similarly elevated signaling pathway activation. After LPS administration, IL-6-transgenic mice showed an increase in ferritin and soluble CD25 levels, as well as a decrease in platelet and neutrophil counts and in hemoglobin levels compared to wild-type mice., Conclusion: Our findings indicate that prolonged exposure to IL-6 in vivo and in vitro leads to an exaggerated inflammatory response to TLR ligands. Hematologic and biochemical abnormalities in IL-6-transgenic mice treated with LPS show striking similarities to macrophage activation syndrome., (Copyright © 2012 by the American College of Rheumatology.)

Lysinuric protein intolerance (LPI) is an inherited defect of cationic amino acid (lysine, arginine and ornithine) transport at the basolateral membrane of intestinal and renal tubular cells caused by mutations in SLC7A7 encoding the y(+)LAT1 protein. LPI has long been considered a relatively benign urea cycle disease, when appropriately treated with low-protein diet and l-citrulline supplementation. However, the severe clinical course of this disorder suggests that LPI should be regarded as a severe multisystem disease with uncertain outcome. Specifically, immune dysfunction potentially attributable to nitric oxide (NO) overproduction secondary to arginine intracellular trapping (due to defective efflux from the cell) might be a crucial pathophysiological route explaining many of LPI complications. The latter comprise severe lung disease with pulmonary alveolar proteinosis, renal disease, hemophagocytic lymphohistiocytosis with subsequent activation of macrophages, various auto-immune disorders and an incompletely characterized immune deficiency. These results have several therapeutic implications, among which lowering the l-citrulline dosage may be crucial, as excessive citrulline may worsen intracellular arginine accumulation., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Common variable immunodeficiency (CVID) is a heterogeneous group of disorders with varied immunologic phenotypes and clinical manifestations. Patients with CVID are mainly characterized by decreased serum immunoglobulin levels, and increased susceptibility to recurrent bacterial infections, autoimmune disorders, and malignancies. Here we present a CVID patient who has developed a clinical polyclonal lymphocytic infiltration phenotype associated with severe and irreversible pancytopenia with unknown etiology. Progressive unilateral loss of vision and cytomegalovirus retinitis indicated the cause of patient's pancytopenia.

We report a 16-year-old female case of intractable adult-onset Still's disease accompanied by macrophage activation syndrome, who went into full remission after switching from infliximab to etanercept. Although the disease promptly relapsed when etanercept was discontinued, she again responded fully upon the reintroduction of etanercept. Furthermore, the effect of etanercept was apparently enhanced by combining it with a sufficient dose of methotrexate. This combination therapy should be considered as one of treatment options for the disease.

Purpose of Review: Macrophage activation syndrome (MAS), a major cause of morbidity and mortality in pediatric rheumatology, is most strongly associated with systemic juvenile idiopathic arthritis (SJIA). There are no validated diagnostic criteria and early diagnosis is difficult. This review summarizes the progress in understanding of MAS pathophysiology that may help define specific diagnostic biomarkers., Recent Findings: MAS is similar to the autosomal recessive disorders collectively known as familial hemophagocytic lymphohistiocytosis (FHLH), all associated with various genetic defects affecting the cytolytic pathway. Cytolytic function is profoundly depressed in SJIA with MAS as well. This immunologic abnormality distinguishes SJIA from other rheumatic diseases and is caused by both genetic and acquired factors. Phenotypic characterization of hemophagocytic macrophages has been another focus of research. These macrophages express CD163, a scavenger receptor that binds hemoglobin-haptoglobin complexes, and initiate pathways important for adaptation to oxidative stress induced by free iron. Expansion of these macrophages is seen in more than 30% of SJIA patients perhaps representing early stages of MAS. Recent gene expression studies linked expansion of these macrophages to distinct signatures., Summary: Recent advances in understanding of pathophysiologic conditions that favor expansion of hemophagocytic macrophages provide a source of new MAS biomarkers with applicability to clinical practice.

A 14-year-old girl was diagnosed with macrophage activation syndrome, based on clinical presentation, laboratory tests, and bone marrow aspirate findings. She developed severe central nervous system involvement in the form of seizure disorder and severe diffuse occlusive cerebral vasculopathy, with extensive collateral circulation consistent with moyamoya disease. To our knowledge, this description is the first of these findings in association with macrophage activation syndrome., (Copyright 2010 Elsevier Inc. All rights reserved.)

Macrophage activation syndrome in rheumatological disorders is rare. A 3-year-old girl with incomplete Kawasaki disease complicated by macrophage activation syndrome is reported.

Objective: Macrophage activation syndrome (MAS) is a rare but life-threatening complication in children with rheumatic diseases, particularly systemic-onset juvenile idiopathic arthritis (SOJIA). Because of the potential fatality of this condition, prompt recognition and immediate therapeutic intervention are important. This study reviewed the data of MAS in 13 cases with SOJIA., Methods: Retrospective review was performed on the precipitating events, clinical manifestations, laboratory data, treatment, and outcome of macrophage activation syndrome in 13 children with SOJIA seen from 1996 to 2005., Results: Over the past 10 years the unit has had 90 new patients with SOJIA. Thirteen of those patients (14.4%) developed MAS during the course of their primary SOJIA, of whom ten were male. All patients were noted to have active SOJIA prior to developing MAS; 3 patients had medications, which were considered as trigger factors; 8 had infections prior to MAS, in two of them the infections were possible triggers. All the patients had high grade fever; 12 cases (92.3%) had hepatomegaly; 10 patients (76.9%) had coagulopathy, and eight patients (61.5%) had central nervous system dysfunction. The counts of platelet, white blood cells and the mean erythrocyte sedimentation rate fell dramatically in all patients; hyperferritinemia was identified in 8 patients, in 5 of whom serum ferritin (SF) was >or= 10,000 microg/L; in 8 (72.7%) of 11 cases fibrinogen was or= 2.5 mmol/L in 9 (69.2%) of 13 cases., Conclusion: MAS is a rare and potentially fatal complication of children with SOJIA. Primary disease activity, medications and infections preceding MAS were all important triggers. The strongest clinical discriminators were hepatomegaly, hemorrhages and central nervous system dysfunction. The strongest laboratory tests were decreased counts of platelet and white blood cells, decreased ESR and fibrinogen, dramatically increased SF and TG. It calls for the immediate treatments, particularly with cyclosporin A, which are often effective.

Objective: To study the clinical manifestations of rheumatic disorders with macrophage activation syndrome (MAS) in children., Methods: The authors characterized MAS by carrying out a retrospective study on patients who were identified during the past 12 years in Tianjin Children's Hospital., Results: Six cases (4 females, 2 males) were studied. Four had typical systemic onset juvenile idiopathic arthritis (SOJIA), two had systemic lupus erythematosus (SLE) with lupus nephritis. Clinical manifestations at diagnosis, which occurred in the lower activity state of these primary diseases, included high spiking fever (in 5 cases) or high fever (in 1), hepatosplenomegaly (in 6), lymphadenopathy (in 6), profound decrease of all 3 blood cell lines (in 6), significant injury of liver (in 6), diseminated intravascular coagulation (DIC)-like picture (in 2), and central nervous system dysfunction (in 3). Hypofibrinogenemia, elevated liver enzymes and hypertriglyceridemia were found consistently. The phagocytic histiocytes with plasmacytosis were found in 3 bone marrow smears (not done in others). MAS was presumed to have been precipitated by viral infections in 3 patients, two had evidences for herpes simplex virus infection and one for hepatitis A virus infection. The treatment regimen was tailored to each patient, as the clinical course was variable., Conclusions: MAS may not only be most frequently seen in children with SOJIA, but also in those with other rheumatic diseases, and may be a syndrome that is more common than previously thought. Infection may be main trigger factor for MAS. The immunoapheresis combined with immunochemotherapy may be optimal for severe injury of the liver in patients with MAS.

Objective: To review and analyze the clinical features, treatment, and outcome of macrophage activation syndrome (MAS) in children with systemic onset juvennil rheumatoid arthritis (SOJRA)., Method: Retrospective review and analysis were performed on cases with MAS from a prospectively collected database of children with SOJRA from the year of 2003 to 2006 in the Hospital., Results: Twenty four patients (21 boys, 3 girls) were diagnosed as having MAS with SOJRA. Mean age of the patients with MAS at diagnosis was 7 years, and the duration prior to diagnosis of MAS was 12 months. No trigger factors were found except in one case whose MAS was triggered by use of methotrexate and in another by parvovirus B19 infection. High grade fever, new onset hepatosplenomegaly and lymphadenopathy, pancytopenia, liver dysfunction were common clinical features in all the 24 cases (100%). Bleeding from skin, mucous membrane and gastrointestinal tract were noted in 9 cases (38%). Twelve (50%) cases had CNS dysfunction (high intracranial pressure, seizure and coma). Six cases (25%) developed ARDS. One patient suffered from renal damage. The laboratory test revealed elevated live enzymes and ferritin, decreased value of ESR, albumin, complete blood count and fibrinogen in all the 24 cases. Bone marrow examination supported the diagnosis of definite hemophagocytosis in the 24 cases. Lymph node biopsy was done for one case and histopathological examination showed that the node was full of activated macrophage. As to treatment, five cases only received high dose steroids (three of them died), 14 cases were treated with high dose steroids plus cyclosporine (one died), two were treated with steroids plus cyclosporine and etoposide (none died). The causes of deaths were ARDS and CNS involvement. In three of the cases who died, treatment was given up by their parents., Conclusions: MAS is a rare and potentially fatal complication of SOJRA. Most of our patients were male. Bone marrow studies support the diagnosis. CNS involvement and ARDS were poor prognostic signs. Early diagnosis and aggressive therapy are essential.