BACKGROUND: Hemophagocytic lymphohistiocytosis characterized by hemophagocytosis leading to uncontrolled inflammation; the most common etiology in secondary cases of hemophagocytic lymphohistiocytosis is viral infections, especially Epstein-Barr virus. Visceral leishmaniasis is a vectorborne protozoal disease caused by Leishmania donovani complex. It is common in tropical and subtropical regions, with 50,000-90,000 new cases annually.
METHODS: A 15-month-old Arab female was admitted to our hospital with 15 days of fever and decreased weight. On clinical examination, she had a markedly enlarged liver and spleen that were palpable 4 cm and 6 cm below the costal margin, respectively. The peripheral blood smear showed hypochromic microcytic anemia, poikilocytosis, reactive lymphocytosis, and mild thrombocytopenia. Bone marrow aspiration did not show malignancy or any other pathological findings. The patient was put on antibiotic therapy without improvement. Repeated bone marrow aspiration showed erythrophagocytosis; intracellular small round organisms looked like the amastigote form of Leishmania (Donovan bodies) with no evidence of malignancies. Her lab values showed ferritin greater than 500 ug/L, pancytopenia, and hypertriglyceridemia. The patient was diagnosed with hemophagocytic lymphohistiocytosis secondary to visceral leishmaniasis.
CONCLUSIONS: Hemophagocytic lymphohistiocytosis secondary to visceral leishmaniasis is an extensively rare phenomenon in the medical literature that causes challenges in diagnosis and management. Steroids should be used wisely to not cover the symptoms of infections or malignancy, and amphotericin B resistance should be kept in mind in unresponsive Leishmania cases.

The characteristic expansion of T CD38high/HLA-DR+CD8+ lymphocytes observed in hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) proved able to distinguish HLH/MAS from sepsis and systemic juvenile idiopathic arthritis. However, the performance of this marker in differentiating HLH/MAS from other pediatric febrile conditions with similar clinical onset and yet entirely different treatments remains unexplored. CD38high/HLA-DR+CD8+ frequencies measured in the peripheral fresh blood of pediatric patients attended for suspicion of HLH/MAS were retrospectively recorded and clinical characteristics were retrieved. CD38high/HLA-DR+CD8+ frequencies in HLH/MAS patients (15 patients; median: 22.0%, IQR: 11.0-49.0%) were compared with those who presented febrile conditions other-than-HLH (28 patients; median: 13.0%, IQR: 3.9-28.7%; p = 0.24). HLH and non-HLH patients were subsequently regrouped based on the presence of an identified infection (22 patients; median: 27.0%, IQR: 15.2-72.1%) and compared with those without infections (21 patients; median: 7.6%, IQR: 3.7-24.3%; p = 0.0035). CD38high/HLA-DR+CD8+ percentages were significantly higher only in the infection group compared with the noninfection one, with a patent pathogen-specific expansion in Epstein-Barr virus primoinfection and visceral leishmaniasis regardless of the presence of HLH. CD38high/HLA-DR+CD8+ frequencies do not appear as an HLH-specific marker as they naturally expand in other clinical situations that are common in childhood and may mimic HLH initial presentation.

PANoptosis is an emerging form of regulated cell death (RCD) characterized by simultaneous activation of pyroptotic, apoptotic, and necroptotic signaling that not only participates in pathologies of inflammatory diseases but also has a critical role against pathogenic infections. Targeting PANoptosis represents a promising therapeutic strategy for related inflammatory diseases, but identification of inhibitors for PANoptosis remains an unmet demand. Baicalin () is an active flavonoid isolated from Scutellaria baicalensis Georgi (Huangqin), a traditional Chinese medicinal herb used for heat-clearing and detoxifying. Numerous studies suggest that baicalin possesses inhibitory activities on various forms of RCD including apoptosis/secondary necrosis, pyroptosis, and necroptosis, thereby mitigating inflammatory responses. In this study we investigated the effects of baicalin on PANoptosis in macrophage cellular models. Primary macrophages (BMDMs) or J774A.1 macrophage cells were treated with 5Z-7-oxozeaenol (OXO, an inhibitor for TAK1) in combination with TNF-α or LPS. We showed that OXO plus TNF-α or LPS induced robust lytic cell death, which was dose-dependently inhibited by baicalin (50-200 μM). We demonstrated that PANoptosis induction was accompanied by overt mitochondrial injury, mitochondrial DNA (mtDNA) release and Z-DNA formation. Z-DNA was formed from cytosolic oxidized mtDNA. Both oxidized mtDNA and mitochondrial Z-DNA puncta were co-localized with the PANoptosome (including ZBP1, RIPK3, ASC, and caspase-8), a platform for mediating PANoptosis. Intriguingly, baicalin not only prevented mitochondrial injury but also blocked mtDNA release, Z-DNA formation and PANoptosome assembly. Knockdown of ZBP1 markedly decreased PANoptotic cell death. In a mouse model of hemophagocytic lymphohistiocytosis (HLH), administration of baicalin (200 mg/kg, i.g., for 4 times) significantly mitigated lung and liver injury and reduced levels of serum TNF-α and IFN-γ, concomitant with decreased levels of PANoptosis hallmarks in these organs. Baicalin also abrogated the hallmarks of PANoptosis in liver-resident macrophages (Kupffer cells) in HLH mice. Collectively, our results demonstrate that baicalin inhibits PANoptosis in macrophages by blocking mitochondrial Z-DNA formation and ZBP1-PANoptosome assembly, thus conferring protection against inflammatory diseases. PANoptosis is a form of regulated cell death displaying simultaneous activation of pyroptotic, apoptotic, and necroptotic signaling. This study shows that induction of PANoptosis is linked to mitochondrial dysfunction and mitochondrial Z-DNA formation. Baicalin inhibits PANoptosis in macrophages in vitro via blocking mitochondrial dysfunction and the mitochondrial Z-DNA formation and thereby impeding the assembly of ZBP1-associated PANoptosome. In a mouse model of hemophagocytic lymphohistiocytosis (HLH), baicalin inhibits the activation of PANoptotic signaling in liver-resident macrophages (Kupffer cells) in vivo, thus mitigating systemic inflammation and multiple organ injury in mice.

BACKGROUND: Lymphoma is the most common secondary cause of hemophagocytic lymphohistiocytosis (HLH) in adults. Lymphoma-associated HLH (LA-HLH) in the elderly population is not rare, however, little has been reported regarding clinicopathological characteristics, prognostic factors, and outcomes of LA-HLH in the elderly population.
METHODS: We retrospectively analyzed a multicenter cohort of elderly patients with LA-HLH. Clinicopathological features and treatment information were collected. The impacts of baseline characteristics and treatments on survival outcomes were analyzed.
RESULTS: A total of 173 elderly patients with LA-HLH were included. Compared with young patients, elderly patients showed different clinical and laboratory features. Regarding lymphoma subtypes, B-cell lymphoma was more common in elderly patients (elderly 61.3% vs. young 32.3%, p < 0.001) while T/NK-cell lymphoma was more common in young patients (65.3% vs. 35.3%, p < 0.001). The median survival of elderly patients with LA-HLH was only 92 days. The prior use of HLH therapy or etoposide-containing HLH therapy was not associated with improved overall survival. T/NK-cell subtype, a lower platelet count (≤53 × 109/L), a lower albumin level (≤32.1 g/L), a higher LDH level (>1407 U/L), and a higher creatinine level (>96.8 μmol/L) were independent predictors of decreased overall survival and 60-day survival. A prognostic index was established and demonstrated to be robust in predicting the overall survival and 60-day survival of elderly patients with LA-HLH.
CONCLUSIONS: LA-HLH in elderly patients displayed heterogeneous clinicopathological features and survival outcomes. Treatments need to be optimized to improve the outcomes of elderly patients with LA-HLH.

OBJECTIVE: Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening condition characterized by a massive overactivation of the immune system. Because the clinical findings are nonspecific, the development of assays to facilitate rapid diagnosis is critical for patient care. The objectives of this study were to evaluate the performance of a microfluidic enzyme-linked immunosorbent assay (ELISA) for HLH biomarkers and investigate the impact of insourcing this testing on workflow, cost, and turnaround time in a tertiary-care cancer hospital.
METHODS: Trends in order volume were evaluated for C-X-C motif chemokine ligand 9 (CXCL9) and soluble interleukin 2 receptor ɑ (sIL2R), and a microfluidic ELISA was used to measure these analytes in serum samples. Analyte values, turnaround time, and costs were compared for this assay relative to reference laboratory testing.
RESULTS: Test ordering has increased from 187 to 1030 requests annually over the past 5 years. Insourcing these analytes on a semiautomated ELISA can decrease time to result by approximately 2 days and generate a cost savings of roughly $140,000 annually within our laboratory.
CONCLUSIONS: Using a semiautomated ELISA for sIL2R and CXCL9 may help physicians arrive at a diagnosis and monitor therapy for patients with HLH while decreasing turnaround time and costs within the clinical laboratory.

Juvenile xanthogranuloma (JXG) is primarily limited to the skin, and systemic JXG (sJXG) is rarely reported. Reports of sJXG patients with hemophagocytic lymphohistiocytosis (HLH) are particularly rare. Herein, we conducted a retrospective study of children diagnosed with sJXG in the Hematology Centre of Beijing Children\'s Hospital from Jan. 2016 to Dec. 2021. The clinical features, laboratory parameters, treatments and outcomes of 17 sJXG patients were investigated, including five complicated with HLH. All sJXG-HLH patients had intermittent fever, rash, hepatosplenomegaly, cytopenia and high levels of soluble CD25, but interferon-γ was almost normal. Patients with sJXG-HLH had a younger diagnosis age (P = 0.035) and were more likely to have skin, liver, and spleen involvement than those without HLH (P = 0.029, P = 0.003, P = 0.003, respectively). Corticosteroids and/or ruxolitinib could be used to control the hyperinflammatory status when HLH was diagnosed. The treatment of sJXG varied, including Langerhans cell histiocytosis (LCH)-based chemotherapy and targeted therapy. The overall response rate of sJXG for first-line and second-line chemotherapy was 50.0% (5/10) and 50% (4/8), respectively. Patients with BRAF V600E mutation showed a response to dabrafenib. There was no significant difference in the overall survival and progression-free survival between sJXG patients without and with HLH (P = 0.12 and P = 0.46, respectively). Therefore, LCH-based chemotherapy could serve as an effective treatment for sJXG patients, and dabrafenib, to some extent, showed efficacy in controlling sJXG in patients with BRAF V600E mutation. The prognosis of sJXG-HLH patients seemed to be comparable to patients without HLH.

Pure erythroid leukemia (AML-M6) is a rare variant of acute myeloid leukemia (AML) with predominant erythroid lineage proliferation. The incidence of AIDS defining cancers including Kaposi sarcoma and non-Hodgkins lymphoma are on declining trends due to effective use of HAART (Highly Active Antiretroviral Therapy). Correspondingly, there have been increasing cases of leukemia in persons living with HIV. Our case is a 43 years old male living with HIV who was admitted with high grade fever and mucosal bleeds. On examination, he had periorbital swelling and ecchymosis with hepatosplenomegaly. The laboratory investigations revealed bicytopenia with high ferritin, low fibrinogen and hypertriglyceridemia. A diagnosis of hemophagocytic lymphohistiocytosis (HLH) with H score of 222 was made. Bone marrow examination revealed hypercellular marrow with more than 80% cells of erythroid lineage with 47% proerythroblasts. Suggesting pure erythroid leukemia (AML-M6). This diagnosis with secondary HLH carries a very poor prognosis in persons living with HIV.

BACKGROUND: Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening disorder caused by abnormal histiocytes and T cell activation. In adults, it is predominantly associated with infections, cancers, and autoimmune diseases. Relapsing polychondritis (RP), another rare disease, is diagnosed based on symptoms without specific tests, featuring cartilage inflammation characterized by swelling, redness, and pain, rarely inducing HLH.
METHODS: A 74-year-old woman visited the emergency room with a fever of 38.6 °C. Blood tests, cultures, and imaging were performed to evaluate fever. Results showed increased fluorescent antinuclear antibody levels and mild cytopenia, with no other specific findings. Imaging revealed lymph node enlargement was observed; however, biopsy results were inconclusive. Upon re-evaluation of the physical exam, inflammatory signs suggestive of RP were observed in the ears and nose, prompting a tissue biopsy for confirmation. Simultaneously, persistent fever accompanied by cytopenia prompted a bone marrow examination, revealing hemophagocytic cells. After finding no significant results in blood culture, viral markers, and tissue examination of enlarged lymph nodes, HLH was diagnosed by RP. Treatment involved methylprednisolone followed by azathioprine. After two months, bone marrow examination confirmed resolution of hemophagocytosis, with normalization of hyperferritinemia and pancytopenia.
CONCLUSIONS: Thorough physical examination enabled diagnosis and treatment of HLH triggered by RP in patients presenting with fever of unknown origin.

BACKGROUND: The hyperinflammatory condition and lymphoproliferation due to Epstein-Barr virus (EBV)-associated hemophagocytic lymphohistiocytosis (HLH) affect the detection of lymphomas by 18F-FDG PET/CT. We aimed to improve the diagnostic capabilities of 18F-FDG PET/CT by combining laboratory parameters.
METHODS: This retrospective study involved 46 patients diagnosed with EBV-positive HLH, who underwent 18F-FDG PET/CT before beginning chemotherapy within a 4-year timeframe. These patients were categorized into two groups: EBV-associated HLH (EBV-HLH) (n = 31) and EBV-positive lymphoma-associated HLH (EBV + LA-HLH) (n = 15). We employed multivariable logistic regression and regression tree analysis to develop diagnostic models and assessed their efficacy in diagnosis and prognosis.
RESULTS: A nomogram combining the SUVmax ratio, copies of plasma EBV-DNA, and IFN-γ reached 100% sensitivity and 81.8% specificity, with an AUC of 0.926 (95%CI, 0.779-0.988). Importantly, this nomogram also demonstrated predictive power for mortality in EBV-HLH patients, with a hazard ratio of 4.2 (95%CI, 1.1-16.5). The high-risk EBV-HLH patients identified by the nomogram had a similarly unfavorable prognosis as patients with lymphoma.
CONCLUSIONS: The study found that while 18F-FDG PET/CT alone has limitations in differentiating between lymphoma and EBV-HLH in patients with active EBV infection, the integration of a nomogram significantly improves the diagnostic accuracy and also exhibits a strong association with prognostic outcomes.

Autoinflammatory diseases (AIDs) are conditions characterized by dysfunction of innate immunity, causing systemic inflammation and various clinical symptoms. The field of AIDs has expanded due to improved comprehension of pathophysiological mechanisms and advancements in genomics techniques. A new emerging category of AIDs is characterized by a significant increase in interleukin 18 (IL-18), a pro-inflammatory cytokine synthesized in macrophages and activated by caspase 1 via various inflammasomes. IL-18 plays a role in the regulation of innate and adaptive immunity. IL-18 is involved in various functions, such as the proliferation, survival, and differentiation of immune cells, tissue infiltration of immune cells, polarization of immune responses, and production of other pro-inflammatory cytokines. This review analyzes the literature on IL-18 regarding its functions and its implications in the diagnosis and treatment of AIDs. IL-18-associated AIDs comprise Still\'s disease and diseases associated with mutations in NLRC4, XIAP, CDC42, and PSTPIP1, as well as IL-18BP deficiencies. With the exception of PSTPIP1-associated diseases, these conditions all carry a risk of macrophagic activation syndrome. Measuring IL-18 levels in serum can aid in the diagnosis, prognosis, and monitoring of these diseases. Therapies targeting IL-18 and its signaling pathways are currently under investigation.