Langerhans cell histiocytosis complicated with hemophagocytic lymphohistiocytosis in a boy with a novel XIAP mutation: A case report

Adult-Onset Familial Hemophagocytic Lymphohistiocytosis Presenting with Annular Erythema following COVID-19 Vaccination

Familial hemophagocytic lymphohistiocytosis (HLH) is a rare genetic and life-threatening immunodeficiency disease. Here, we present a 38-year-old male who initially developed multiple annular to irregular erythema accompanied by a fever after COVID-19 vaccination. He was diagnosed with HLH with evidence of leukocytopenia in a full blood test, elevations of ferritin and sCD25, decreased NK cell function, and hemophagocytosis of a bone marrow biopsy specimen. A genetic examination revealed two probable disease-causing heterozygous mutations on UNC13D associated with type 3 familial HLH. A review of the case reports relevant to HLH following COVID-19 vaccination and the cutaneous manifestations of HLH with genetic defects suggests the necessity that individuals with preexisting immune dysregulation or diseases not classified should be cautious about COVID-19 vaccination and reminds clinicians that various recalcitrant skin lesions may be a sign of HLH.

Hemophagocytic Lymphohistiocytosis in Langerhans Cell Histiocytosis: A Case Series and Literature Review

Langerhans cell histiocytosis (LCH) is characterized pathologically by langerin-positive (CD207+) dendritic cell proliferation and is considered by some as a myeloid neoplastic disorder. Hemophagocytic lymphohistiocytosis (HLH) is associated with immune dysregulation characterized by the accumulation of activated macrophages and hypercytokinemia. However, these 2 histiocytosis rarely coexist. Currently, the etiology, risk factors, optimal therapy, and outcomes of LCH-HLH remain unclear. We reviewed the medical records of 7 LCH-HLH patients from our hospital and analyzed 50 LCH-HLH patients reported in scientific literature. The median age of LCH onset of these 57 LCH-HLH patients was 1 year, and 91% (52/57) of patients diagnosed as LCH were less than 2 years old. Fifty-six LCH-HLH patients belonged to the multisystem LCH category and 84% (47/56) patients had risk-organ involvement. Twenty-three LCH-HLH patients were complicated with infection and 3 patients had a primary pathogenic mutation of HLH. Overall, 90% of LCH patients developed HLH at the diagnosis or during chemotherapy. Of the 57 LCH-HLH patients, 15 died. Multisystem LCH patients with risk-organ involvement under 2 years old were most likely to develop HLH when complicated with infection at diagnosis or during chemotherapy. Identifying LCH-HLH patients during early stages and treating them with prompt chemotherapy, hematopoietic stem cell transplantation, or supportive therapies are important for better survival.

Effective treatment of progressive nodular histiocytosis by intermediate-dose cytarabine: a case report and literature review

BACKGROUND

Progressive nodular histiocytosis (PNH) is a rare, clinically distinct non-Langerhans cell histiocytic neoplasm affecting the skin and mucous membranes with no signs of spontaneous regression of the lesions. Patients typically have hundreds of lesions of superficial xanthomatous papules to nodules and deep larger fibrous nodules, which can be life-threatening if laryngeal mucosa was involved. So far, few cases of PNH have been reported and no effective treatment has been shown to reverse the progressive clinical course.

CASE PRESENTATION

Here we describe a case of PNH presenting as diffuse, progressively enlarging papules, nodules and even leonine appearance in a young woman. The diagnosis was confirmed by histological and immunohistochemical findings. Next-generation sequencing (NGS) showed identical missense mutation in XIAP ^Y404C and in-frame deletion in MAPK1 ^A2[6>5]. Since ERK inhibitor has not been on the market yet, the patient received chemotherapy instead. Traditional chemotherapy with intermediate-dose of cytarabine (500 mg/m² cytarabine by 3-hour infusion every 12 hours for 3 days every 5 weeks) achieved favorable therapeutic effect as confirmed by clinical symptoms and PET/CT imaging.

CONCLUSIONS

PNH is a rare, proliferative disorder with disfiguring lesions and deteriorative quality of life. Mutations in MAPK1, XIAP may play crucial roles in the pathogenesis of PNH. Intermediate-dose cytarabine can be considered as a promising treatment option for PNH patients.

Evolution of Our Understanding of XIAP Deficiency

X-linked inhibitor of apoptosis (XIAP) deficiency is a rare inborn error of immunity first described in 2006. XIAP deficiency is characterised by immune dysregulation and a broad spectrum of clinical manifestations, including haemophagocytic lymphohistiocytosis (HLH), inflammatory bowel disease (IBD), hypogammaglobulinemia, susceptibility to infections, splenomegaly, cytopaenias, and other less common autoinflammatory phenomena. Since the first description of the disease, many XIAP deficient patients have been identified and our understanding of the disease has grown. Over 90 disease causing mutations have been described and more inflammatory disease manifestations, such as hepatitis, arthritis, and uveitis, are now well-recognised. Recently, following the introduction of reduced intensity conditioning (RIC), outcomes of allogeneic haematopoietic stem cell transplantation (HSCT), the only curative treatment option for XIAP deficiency, have improved. The pathophysiology of XIAP deficiency is not fully understood, however it is known that XIAP plays a role in both the innate and adaptive immune response and in immune regulation, most notably through modulation of tumour necrosis factor (TNF)-receptor signalling and regulation of NLRP3 inflammasome activity. In this review we will provide an up to date overview of both the clinical aspects and pathophysiology of XIAP deficiency.

Epstein-Barr virus-related hemophagocytic lymphohistiocytosis complicated with coronary artery dilation and acute renal injury in a boy with a novel X-linked inhibitor of apoptosis protein (XIAP) variant: a case report

Background

X-linked lymphoproliferative disease (XLP) is a rare inherited X-linked primary immunodeficiency diseases (PID). One such disease, X-linked inhibitor of apoptosis protein (XIAP) deficiency, is characterized by Epstein–Barr virus-related hemophagocytic lymphohistiocytosis (EBV-HLH). However, EBV-HLH with coronary artery dilation and acute renal injury (AKI) in children is unusual.

Case presentation

We report the case of a young boy aged 17 months with a novel XIAP variant. He was initially diagnosed with EBV-HLH based on the HLH-2004 diagnostic criteria and the condition was accompanied by coronary artery dilation and acute renal injury. The comprehensive genetic analysis of peripheral blood-derived DNA revealed a hemizygous variant of the XIAP gene [c.116G > C(p.G39A)], which was inherited from his mother (heterozygous condition). After combined treatment with rituximab, intravenous immunoglobulin, corticosteroids, antiviral drugs, and mycophenolate mofetil (MMF) in addition to supportive therapy, his clinical manifestations and laboratory indexes were improved. The patient achieved complete remission with MMF treatment in the 8-month follow-up.

Conclusions

We report the [c.116G > C(p.G39A)] variant in the XIAP gene for the first time in a case of XLP-2 associated with EBV-HLH. For male patients with severe EBV-HLH, the possibility of XLP should be considered and molecular genetic testing should be used early in auxiliary diagnosis. Reports of EBV-HLH with coronary artery dilation and AKI in children are rare. In the patients with EBV-HLH, color Doppler echocardiography and urine tests should be monitored regularly. If necessary, renal biopsy can be performed to clarify the pathology. Treatment with rituximab, immunosuppressors and supportive therapy achieved a good effect, but long-term follow-up is required.

Eosinophilic colitis in a boy with a novel XIAP mutation: a case report

Background

X-linked inhibitor of apoptosis (XIAP) deficiency is a rare primary immunodeficiency disease characterized by haemophagocytic lymphohistiocytosis, recurrent splenomegaly and inflammatory bowel disease (IBD). The only curative treatment is haematopoietic stem cell transplant (HSCT).

Case presentation

Here, we report the case of a 22-month-old male with a long history of abdominal distension and anaemia. Clinical and laboratory findings were consistent with eosinophilic colitis. To identify the underlying disease, we performed exome sequencing, which showed an unreported frameshift mutation in the XIAP gene.

Conclusion

We present eosinophilic colitis as the initial manifestation of XIAP deficiency for the first time in this article, which expands the mutation spectrum and phenotype of this disease.