Biological therapies for hemophagocytic lymphohistiocytosis: current knowledge and future perspectives.

INTRODUCTION: Hemophagocytic lymphohistiocytosis (HLH) is a hyperinflammatory syndrome with a dismal prognosis. The underlying causes of HLH are diverse. However, the overabundance of cytokines was shared by all forms of HLH. Cytokine-targeted biotherapies have been increasingly used in HLH treatment. AREAS COVERED: In this review, we aim to provide an overview of biological treatment options for HLH. EXPERT OPINION: Biological therapies offer alternative treatment options for patients with refractory/relapsed HLH or who are intolerant to conventional chemotherapies. As a complement to traditional treatment, biological agents improve response rates, maintain more protracted periods of remission, and reduce treatment related toxicity. A combination of biological agents may be a promising direction for HLH treatment. However, they may induce HLH to deteriorate and even trigger HLH.

Anakinra versus etoposide-based therapy added to high-dose steroids for the treatment of secondary hemophagocytic lymphohistiocytosis.

OBJECTIVE: Hemophagocytic lymphohistiocytosis (HLH) is a rare life-threatening, hyperinflammatory syndrome usually treated with high-dose steroids (HDS), often complemented with adjunct therapies, such as etoposide (HLH-94 protocol). Anakinra has been reported to effectively treat HLH; however, has not been comparatively examined with etoposide-based therapies. We sought to evaluate the effectiveness and durability of these treatment approaches. METHODS: We performed a retrospective analysis of all adult patients diagnosed with secondary HLH between January 2011 and November 2022 who received anakinra and HDS, the HLH-94 protocol, HDS alone, or supportive care. RESULTS: Thirty adult patients with secondary HLH were included. Cumulative incidence (CI) of response at 30 days was 83.3%, 60%, and 36.4% for patients treated with anakinra, the HLH-94 protocol, and HDS alone, respectively. CI of relapse at 1 year was 50%, 33.3%, and 0% with the HLH-94 protocol, HDS, and anakinra and HDS, respectively. Overall survival at 1 year was higher with anakinra and HDS compared to the HLH-94 protocol, yet was not statistically significant (77.8% vs. 33.3%; hazard ratio: 0.29; p = .25). CONCLUSION: Treatment with anakinra and HDS in adults with secondary HLH was associated with higher response rates with longer survival compared with alternative therapies and should be further investigated in this setting.

Clinical and molecular characteristics of Streptococcus pneumoniae-associated hemophagocytic lymphohistiocytosis in children / 中华儿科杂志

Objective: To summarize the clinical features of Streptococcus pneumoniae-associated hemophagocytic syndrome (SP-HLH), and the serotypes and drug-resistant characteristics of the isolated strains. Methods: There were 15 children with SP-HLH admitted to the Pediatric Intensive Care Unit (PICU) of Beijing Children's Hospital, Capital Medical University from January 2013 to December 2020 were included in this study. Clinical data including children's general characteristics, clinical features, laboratory examinations, treatments, prognosis and the outcomes of follow-up by May 2021 were analyzed retrospectively. The serotypes and drug resistance of the isolated strains were identified. All children were divided into the clinical improvement group and the death group. Mann-Whitney U test, Fisher's exact test were used to compare the data of the two groups. Results: Among the 15 children with SP-HLH, 8 were males and 7 were females. The age of these children was 1.0 (1.0, 2.5) years. Regarding the primary infection, there were 9 cases of severe pneumonia, 3 cases of meningitis and 3 cases of blood stream infection. None of these children had received pneumoniae conjugate vaccine (PCV) and all of them were admitted to the PICU. Respiratory failure was observed in 10 patients, acute renal injury in 5, and hemolytic uremic syndrome in 3 patients. All children received glucocorticoids and high-dose intravenous immunogloblin (IVIG) in addition to anti-infective treatment. Eight of the children were cured while the other 7 died. The neutrophil count in the death group was lower than that in the clinical improvement group ((5.0 (1.7, 9.3) × 109 vs. 5.2 (3.4, 10.5) ×109/L, Z =-2.43, P<0.015), and the length of hospital stay and days of PICU stay in the death group were both shorter than those in the improvement group statistically (3 (1, 11) vs. 39 (34, 48) d, 2 (1, 4) vs. 19 (12, 31) d, Z=-3.25, -3.24, both P=0.001). Ten serotypes of Streptococcus pneumoniae were identified, including 4 strains of 19F, 3 of 19A, 1 of 23F, 1 of 15A and 1 of 14, among which 9 strains (9/10) were covered by PCV13. All strains were resistant to erythromycin yet sensitive to vancomycin and linezolid. Conclusions: SP-HLH is more common in children under the age of 3, with a high mortality rate. The death cases have lower neutrophil count and rapid disease progression. The comprehensive treatment is anti-infective combined with glucocorticoids and high-dose IVIG. The predominant serotypes are 19F and 19A and all isolated strains were susceptible to vancomycin and linezolid.

Hemophagocytic Syndrome Complicated with Dermatomyositis Controlled Successfully with Infliximab and Conventional Therapies.

A 57-year-old woman was admitted to our hospital because of a high fever, anemia, and hyperferritinemia. Since a bone marrow examination revealed hemophagocytosis, she was diagnosed with hemophagocytic syndrome (HPS). During treatment of HPS, a heliotrope rash and Gottron's sign appeared with elevated levels of serum aldolase. She also developed heart failure. She was diagnosed with dermatomyositis (DM) and associated myocarditis. Although the administration of glucocorticoids, calcineurin inhibitors, intravenous immunoglobulins, and etoposide ameliorated the clinical findings of DM and cytopenia, the fever and hyperferritinemia remained. The addition of infliximab to glucocorticoids and tacrolimus improved the fever and hyperferritinemia and enabled a reduction in the dose of prednisolone without relapse of the diseases.

Hemophagocytic lymphohistiocytosis in total parenteral nutrition dependent children: description of 5 cases and practical tips for management.

Although total parenteral nutrition (TPN) is mandatory in children with intestinal failure, this treatment is not risk free. The main complications of TPN include catheter-related sepsis, thrombosis, hepatic cholestasis and cirrhosis, metabolic bone disease, and, rarely, reactive hemophagocytic lymphohistiocytosis (HLH). The pathogenesis of HLH in patients with TPN is not known, although some authors hypothesized that it can result from the activation of macrophages because of "fat overload." We reported 5 cases of HLH that occurred in patients with 4 different underlying disorders, all requiring TPN for a long term. In our series, an underlying immunological defect or a serious infection (sepsis) can have triggered HLH. Therefore, it could be reasonable to hypothesize that besides TPN in itself, minor immune defects and infections may act together by overcoming a threshold of immune stimulation, which ultimately leads to HLH.