Hemophagocytic Lymphohistiocytosis Associated With Cytomegalovirus Infection: 5 Cases and a Systematic Review of the Literature

Macrophage Activation Syndrome in Viral Sepsis

Macrophage activation syndrome (MAS) is a life-threatening systemic hyperinflammatory syndrome triggered by various infections, particularly viral infections, autoimmune disorders, and malignancy. The condition is characterized by an increased production of proinflammatory cytokines resulting in a cytokine storm and has been associated with poor clinical outcomes. During the COVID-19 pandemic, patients with severe manifestations developed features similar to those of MAS, although these characteristics remained well defined within the lung. Additionally, other viral infections including EBV, the herpes family of viruses, hepatitis viruses, influenza, HIV, and hemorrhagic fevers can be complicated by MAS. The diagnosis and management of the condition remain challenging due to the lack of consensus on specific guidelines, especially among the adult population. Currently, therapeutic options primarily rely on medications that are typically used to treat primary hemophagocytic lymphohistiocytosis, such as corticosteroids and etoposide. In addition, cytokine-targeted therapies present promising treatment options. The objective of this review is to discuss the emergence of MAS in the context of viral infections including, but not limited to, its occurrence in COVID-19.

Cytomegalovirus-Induced Hemophagocytic Lymphohistiocytosis in an Immunocompromised Patient with Inflammatory Bowel Disease

Hemophagocytic lymphohistiocytosis (HLH) is a rare and often fatal syndrome of immune hyperactivation, cytokine dysregulation, and severe inflammation. This severe syndrome is commonly triggered by infection, malignancy, autoimmunity, or immunosuppression. We present herein the case of a 56-year-old-female diagnosed with HLH triggered by an acute cytomegalovirus (CMV) infection with viremia in the context of immunosuppression for inflammatory bowel disease. This case highlights the importance of utilizing multiple diagnostic tools, prompt initiation of anti-hemophagocytic treatment, and management of the underlying etiology, to prevent significant morbidity and mortality.

Low interleukin-10 level indicates a good prognosis in Salmonella enterica serovar typhimurium-induced pediatric hemophagocytic lymphohistiocytosis: A case report

BACKGROUND

Secondary hemophagocytic lymphohistiocytosis (sHLH) triggered by Salmonella enterica serovar Typhimurium is rare in pediatric patients. There is no consensus on how to treat S. typhimurium-triggered sHLH.

CASE SUMMARY

A 9-year-old boy with intermittent fever for 3 d presented to our hospital with positive results for S. typhimurium, human rhinovirus, and Mycoplasma pneumoniae infections. At the time of admission to our institution, the patient's T helper 1/T helper 2 cytokine levels were 326 pg/mL for interleukin 6 (IL-6), 9.1 pg/mL for IL-10, and 246.7 pg/mL for interferon-gamma (IFN-γ), for which the ratio of IL-10 to IFN-γ was 0.04. In this study, the patient received meropenem, linezolid, and cefoperazone/sulbactam in combination with high-dose methylprednisolone therapy (10 mg/kg/d for 3 d) and antishock supportive treatment twice. After careful evaluation, this patient did not receive HLH chemotherapy and recovered well.

CONCLUSION

S. Typhimurium infection-triggered sHLH patient had a ratio of IL-10 to IFN-γ ≤ 1.33, an IL-10 concentration ≤ 10.0 pg/mL, and/or an IFN-γ concentration ≤ 225 pg/mL at admission. Early antimicrobial and supportive treatment was sufficient, and the HLH-94/2004 protocol was not necessary under these conditions.

Infectious Diseases Evaluation of the Child With Suspected Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of excessive and maladaptive inflammation. In this review, we discuss how the clinical and laboratory features of HLH overlap with infection and propose a diagnostic and treatment strategy to identify patients with infections mimicking HLH.

Histiocytic necrotizing lymphadenitis with hemophagocytic lymphohistiocytosis in adults: A single-center analysis of 5 cases

BACKGROUND

Histiocytic necrotizing lymphadenitis (HNL) is a self-limited inflammatory disease of unknown pathogenesis. A very small fraction of patients with HNL could develop hemophagocytic lymphohistiocytosis (HLH), a hyperinflammatory disorder. These patients are diagnosed as HNL with HLH (HNL-HLH). HNL-HLH in the pediatric population has been systemically studied, however, the clinical, laboratory, and radiological features and outcomes of adult patients with HNL-HLH remain to be explored. We aimed to explore the clinical, laboratory, and radiological features and outcomes of adult patients with HNL-HLH.

METHODS

We collected the clinical data of patients with HNL-HLH admitted to the First Affiliated Hospital of Nanjing Medical University from October 2010 to June 2015. All the patients underwent lymph node biopsy and have a pathological diagnosis of HNL. The age, gender, clinical presentation, lymph node signs, laboratory findings and imaging data, and pathological findings of the patients were collected.

RESULTS

In this study, we reported five adult patients with HNL-HLH. All five patients showed enlarged lymph nodes and prolonged fever. Laboratory findings were consistent with the diagnosis of HLH. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) showed enlarged lymph nodes with increased FDG uptake and splenic hypermetabolism could be present. All the patients responded well to corticosteroids and had a good prognosis. Two of the five patients were diagnosed with systemic lupus erythematosus during the follow-up.

CONCLUSIONS

Our study demonstrated that adult patients with HNL-HLH showed distinct clinical, laboratory, and radiological features. And the prognosis is good and patients could be managed with steroids and supportive care.