Neurologic Manifestations as Initial Clinical Presentation of Familial Hemophagocytic Lymphohistiocytosis Type2 Due to PRF1 Mutation in Chinese Pediatric Patients

PRF1 as a prognostic gene for lymphatic metastasis in skin melanoma

BACKGROUND

Melanoma is a highly aggressive tumor, predominantly found in the skin, recognized as skin cutaneous melanoma (SKCM). Lymph node metastasis is commonly used as the route of metastasis in SKCM, necessitating the discovery of prognostic genes associated with this process for improved prognosis.

METHODS

The prognostic significance of lymph node metastasis in SKCM was assessed through Kaplan-Meier analysis in SEER and TCGA-SKCM datasets. Prognostic genes were identified and a prognostic risk model was constructed Enrichment analysis and immune cell infiltration analysis were also carried out.Moreover, a validation in vitro and in vivo were conducted by CCK8,flow cytometry, transwell and animal study.

RESULTS

The Kaplan-Meier survival curve revealed that patients with lymph node metastasis had a worse prognosis compared to those without. FCGR3B and PRF1 were screened by TCGA analysis.Additionally, significant differences in nine immune cell types were observed between the two risk groups. Notably, a strong positive association with CD8 T cells and a negative relationship with M2 macrophages were exhibited by PRF1. The validation of our nomogram were conducted in vitro and in vivo, and the results showed the correlations between CD8+ T cell and PRF1.

CONCLUSION

In summary, two prognostic genes (FCGR3B and PRF1) were identified, and a prognostic risk model was developed for SKCM. These findings provide a novel approach for the diagnosis and treatment of SKCM.

Late Onset of Primary Hemophagocytic Lymphohistiocytosis (HLH) with a Novel Constellation of Compound Heterozygosity Involving Two Missense Variants in the PRF1 Gene

Hemophagocytic lymphohistiocytosis (HLH) is a rare but in most cases life-threatening immune-mediated disease of the hematopoietic system frequently associated with hematologic neoplasms. Here, we report on a case in which we detected a novel constellation of two missense variants affecting the PRF1 gene, leading to de novo primary HLH. Diagnostics included a comprehensive clinical work-up and standard methods of hematopathology as well as extended molecular genomics based on polymerase chain reaction (PCR) reactions and the calculation of three-dimensional molecule reconstructions of PRF1. Subsequently, a comprehensive review of the literature was performed, which showed that this compound heterozygosity has not been previously described. The patient was a 20-year-old female. Molecular diagnostics revealed two heterozygous missense variants in the PRF1 gene (A91V and R104C) on exon 2. Apart from the finding of two inconclusive genetic variants, all clinical criteria defined by the HLH study group of Histiocyte Society were met at initial presentation. The final diagnosis was made in cooperation with the Consortium of German HLH-reference centers. Here, chemotherapy did not lead to sufficient sustained disease control. Therefore, the decision for allogenic hematopoietic stem cell transplantation (alloHSCT) was made. Hitherto, the duration of response was 6 months. Due to severe and unmanageable hepatic graft-versus-host disease (GvHD), the patient died. We report on a novel constellation of a compound heterozygosity containing two missense variants on exon 2 of the PRF1 gene. To the authors' best knowledge, this is the first presentation of a primary HLH case harboring this genomic constellation with late-onset clinical manifestation.

Case Report: Chronic inflammatory demyelinating polyradiculoneuropathy rather than hemophagocytic lymphohistiocytosis-the initial phenotype of PRF1 gene mutation

Perforin is essentially involved in the granule-dependent killing activities of cytotoxic T lymphocytes and NK cells. Monoallelic PRF1 mutation increases the risk of autoimmune diseases, and biallelic PRF1 mutation causes familial hemophagocytic lymphohistiocytosis-2. Here, we report a case of a 12-year-old girl with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), followed by a rapidly progressive onset of hemophagocytic lymphohistiocytosis (HLH) 9 months later, alongside manifestations of demyelinating encephalopathy. Genetic sequencing revealed a heterozygous nonsense mutation in the PRF1 gene (c.984G>A; p.W328*) and a heterozygous missense mutation in the PRF1 gene (c.1349C>T; p.T450M). Eventually, she died because of no suitable allogeneic hematopoietic stem cell available in time. Our observations suggest that CIPD might represent the initial phenotype of biallelic PRF1 mutation and could serve as an early sign of subsequent HLH. A comprehensive understanding of this condition is paramount for timely diagnosis, treatment, and ultimately improved patient outcomes.

Hemophagocytic lymphohistiocytosis with a hemizygous PRF1 c.674G>A mutation

Hemophagocytic lymphohistiocytosis(HLH) is a rare highly-fatal disease presenting with fever, hepatosplenomegaly, and pancytopenia and has a poor prognosis. Homozygous or semi-zygous or complex heterozygous variants can cause familial HLH and heterozygous carriers are frequently seen in secondary HLH. A 42-year-old male patient was admitted to the hospital for persistent fever, fatigue, and splenomegaly. Investigations revealed hypertriglyceridemia, hyperlactatemia dehydrogenaseemia, hyperferritinemia, and elevated levels of soluble cluster of differentiation 25. We found a heterozygous mutation of PRF1: c.674G>A (p.R225Q) through next-generation sequencing technology of hemophagocytic-lymphohistiocytosis-related genes. After a brief remission with dexamethasone and etoposide-based therapy, the disease relapsed quickly, and an allogeneic hematopoietic stem cell transplant was performed to achieve complete remission. To date, the patient's condition was in complete remission. Our study detected a rare missense mutation in the PRF1 gene in a patient with HLH disease and the c.674G>A mutation may be rated as a possible pathogenic variant.

Familial hemophagocytic phohistiocytosis induced by PRF1 mutation with neurologic manifestations as the initial clinical presentations: A case report

BACKGROUND

To investigate the clinical characteristics of familial hemophagocytic phohistiocytosis (FHL) induced by PRF1 gene mutation and with central nervous injury as the initial presentation.

CASE PRESENTATION

Herein, we presented 2 cases of a familial hemophagocytic syndrome caused by PRF1 gene mutation in 1 family with central nervous injury as the first symptom and searched relevant literature for clinical analysis of its pathogenic characteristics. Two children from 1 family were included in this study, both of whom had complex heterozygous mutations of C. 1189_1190dupTG (p.H398Afs*23) and C. 394G>A (p.G132R). Literature search further revealed 20 cases of PRF1 gene mutation-induced familial FHL with central nervous injury as the initial presentation. The main neurological symptoms included cranial nerve injury (81.8%), convulsion (77.3%), ataxia (63.6%), encephalopathy (59.1%), and limb paralysis (40.9%). Cranial imaging findings were dominated by the cerebral hemisphere (100%), cerebellar hemisphere (85%), brainstem (55%), and periventricular white matter (40%), and 73.7% of cases had elevated white blood cell count in CSF. Most cases were confirmed by differential diagnosis and gene sequencing, which suggested that C. 673C>T (P.r225W), C. 394G>A (P.G132r), C. 666C>A (p.H222Q), C. 1349C>T (p.T450M), C. 1349C>T (p.T450M), and C. 443C>C (p.A148G) could be focal mutations of this disease.

CONCLUSION

Lesions involving the cerebellum and brainstem in children with ataxia and cranial nerve damage could be indicative of primary FHL; thus, the inherent immune test and gene test should be timely performed to help confirm the diagnosis, guide the treatment, and improve the prognosis.

Case report: Ruxolitinib plus dexamethasone as first-line therapy in haemophagocytic lymphohistiocytosis

Haemophagocytic lymphohistiocytosis (HLH) is a cytokine-driven inflammatory syndrome caused by uncontrolled hypersecretion of inflammatory cytokines. Conventional first-line treatment for HLH included HLH-94 and HLH-2004 regimens. However, quite a few patients do not respond to treatment or cannot tolerate intensive chemotherapy. We reported two cases of HLH, one caused by natural killer (NK)/T-cell lymphoma and another associated with missense variants in the perforin 1 gene. They both received the ruxolitinib plus dexamethasone protocol and had a rapid response to treatment without obvious adverse effects. Our report indicates that treatment with ruxolitinib plus dexamethasone might be a potential option for HLH, and clinical trials warrant further investigation. In addition, the detection of HLH-related genes is necessary for the identification of late-onset familial HLH in certain settings.

A Toddler With New Seizures, Progressive White Matter Lesions, and Multifocal Microhemorrhages

A 16-month-old, previously healthy male is hospitalized for new onset seizures. Initial investigation is significant for enterovirus/rhinovirus respiratory infection, abnormal T2 signal predominantly in the white matter and scattered microhemorrhages on brain MRI, transaminitis, and thrombocytopenia. His symptoms initially improve on steroid therapy and he is discharged from the hospital. During the ensuing month with the tapering of the steroids, he develops new motor deficits for which he is rehospitalized. His laboratory investigation on readmission is unremarkable. However, there is significant progression of white matter lesions and microhemorrhages on repeat MRI. While in the hospital, he becomes febrile and has seizure recurrence and worsening neurologic symptoms, including cerebral salt wasting and encephalopathy. Subsequent neuroimaging demonstrates cerebral edema and diffuse brain injury. A high index of suspicion for a rare condition ultimately leads us to perform the specialized testing that confirms the diagnosis. We will discuss the diagnostic challenges that arise from an atypical presentation of an uncommon condition, and from the disease progression that is modified by previous interventions.

Misdiagnosis of adult primary hemophagocytic lymphohistiocytosis as NK/T-cell lymphoma: A case report

We reported a case of a 19-year-old male patient with central nervous system symptoms as the main clinical manifestations, and multiple intracranial and abdominal occupying lesions visualized by imaging examinations, who was initially misdiagnosed as NK/T-cell lymphoma but poorly responsive to the treatment. Finally, he was diagnosed as familial hemophagocytic lymphohistiocytosis type-2 by genome sequencing, perforin test and pedigree study. The patient survived well after allogeneic hematopoietic stem cell transplantation. Central nervous system symptoms could be the main clinical manifestations in patients with primary hemophagocytic lymphohistiocytosis , whose early-stage manifestations of blood system were usually atypical, easily leading to misdiagnosis. In clinical practice, primary hemophagocytic lymphohistiocytosis should be considered in patients with central nervous system symptoms and unknown causes. The combination of rapid immunological function test and genome sequencing contributes to the diagnosis of primary hemophagocytic lymphohistiocytosis.

Neuroinflammation Associated With Inborn Errors of Immunity

The advent of high-throughput sequencing has facilitated genotype-phenotype correlations in congenital diseases. This has provided molecular diagnosis and benefited patient management but has also revealed substantial phenotypic heterogeneity. Although distinct neuroinflammatory diseases are scarce among the several thousands of established congenital diseases, elements of neuroinflammation are increasingly recognized in a substantial proportion of inborn errors of immunity, where it may even dominate the clinical picture at initial presentation. Although each disease entity is rare, they collectively can constitute a significant proportion of neuropediatric patients in tertiary care and may occasionally also explain adult neurology patients. We focus this review on the signs and symptoms of neuroinflammation that have been reported in association with established pathogenic variants in immune genes and suggest the following subdivision based on proposed underlying mechanisms: autoinflammatory disorders, tolerance defects, and immunodeficiency disorders. The large group of autoinflammatory disorders is further subdivided into IL-1β-mediated disorders, NF-κB dysregulation, type I interferonopathies, and hemophagocytic syndromes. We delineate emerging pathogenic themes underlying neuroinflammation in monogenic diseases and describe the breadth of the clinical spectrum to support decisions to screen for a genetic diagnosis and encourage further research on a neglected phenomenon.

Multiple-Organ Involvement in Familial Hemophagocytic Lymphohistiocytosis Type 2 Shown on FDG PET/CT

ABSTRACT

FDG PET/CT in an 18-year-old man with known familial hemophagocytic lymphohistiocytosis (HLH) type 2 demonstrated abnormally in the brain, liver, and lymph nodes. Pathology showed no sign of lymphoproliferative disease. The patient underwent the chemotherapy of HLH. Six months after chemotherapy, a follow-up FDG PET/CT did not show any abnormal 18F-FDG activity, suggesting a complete response. The present case shows FDG PET/CT might not only be useful in staging the familial HLH but also able to evaluate the therapy response.

Familial hemophagocytic lymphohistiocytosis type 2 in a female Chinese neonate: A case report and review of the literature

BACKGROUND

Familial hemophagocytic lymphohistiocytosis type 2 (FHL2) is a rare genetic disorder presenting with fever, hepatosplenomegaly, and pancytopenia secondary to perforin-1 (PRF1) mutation. FLH2 has been described in Chinese but usually presents after 1 year old. We describe a female Chinese neonate with FHL2 secondary to compound heterozygous PRF1 mutation with symptom onset before 1 mo old. We review Chinese FHL2 patients in the literature for comparison.

CASE SUMMARY

A 15-d-old female neonate was referred to our hospital for persistent fever and thrombocytopenia with diffuse petechiae. She was born to a G5P3 mother at 39 wk and 4 d via cesarean section secondary to breech presentation. No resuscitation was required at birth. She was described to be very sleepy with poor appetite since birth. She developed a fever up to 39.5°C at 7 d of life. Leukocytosis, anemia, and thrombocytopenia were detected at a local medical facility

CONCLUSION

A literature review identified 75 Chinese FHL2 patients, with only five presenting in the first year of life. Missense and frameshift mutations are the most common PRF1 mutations in Chinese, with 24.8% having c.1349C>T followed by 11.6% having c.65delC. The c.658G>C mutation has only been reported once in the literature and our case suggests it can be pathogenic, at least in the presence of another pathogenic mutation such as c.1066C>T.

Adult onset type 2 familial hemophagocytic lymphohistiocytosis with PRF1 c.65delC/c.163C>T compound heterozygous mutations: A case report

BACKGROUND

Familial hemophagocytic lymphohistiocytosis (FHL) is a primary immunodefici-ency disease caused by gene defects. The onset of FHL in adolescents and adults may lead clinicians to ignore or even misdiagnose the disease. To the best of our knowledge, this is the first report to detail the clinical features of type 2 FHL (FHL2) with compound heterozygous perforin (PRF1) defects involving the c.163C>T mutation, in addition to correlation analysis and a literature review.

CASE SUMMARY

We report a case of a 27-year-old male patient with FHL2, who was admitted with a persistent fever and pancytopenia. Through next-generation sequencing technology of hemophagocytic lymphohistiocytosis (HLH)-related genes, we found compound heterozygous mutations of PRF1: c.65delC (p.Pro22Argfs*29) (frameshift mutation, paternal) and c.163C>T (p.Arg55Cys) (missense mutation, maternal). Although he did not receive hematopoietic stem cell transplantation, the patient achieved complete remission after receiving HLH-2004 treatment protocol. To date, the patient has stopped taking drugs for 15 mo, is in a stable condition, and is under follow-up observation.

CONCLUSION

The delayed onset of FHL2 may be related to the PRF1 mutation type, pathogenic variation pattern, triggering factors, and the temperature sensitivity of some PRF1 mutations. For individual, the detailed reason for the delay in the onset of FHL warrants further investigation.