Cytophagic histiocytic panniculitis with fatal haemophagocytic lymphohistiocytosis in a paediatric patient with perforin gene mutation

Panniculitis: A Cardinal Sign of Autoinflammation

Panniculitis was first described in the nineteenth century and is characterized by inflammation of the subcutaneous fat. It may be categorized in septal or lobular subtypes, but other histopathological features (e.g., presence of vasculitis, nature of inflammatory infiltrates, characteristics of fat necrosis) are also important for diagnostic purposes. Clinically, panniculitis is characterized by the presence of subcutaneous nodules, and both ulcerative and nonulcerative clinical subtypes have been proposed. In this review, we aimed to describe the occurrence of panniculitis in autoinflammatory disorders (AIDs) and related diseases. Among monogenic AIDs, panniculitis is common in IFN-mediated disorders. Panniculitis is a distinctive feature in proteasome-associated autoinflammatory syndromes (PRAAS), including chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature (CANDLE) syndrome and Nakajo-Nishimura syndrome. On the other hand, erythema nodosum corresponds to the most common clinical form of panniculitis and is common in polygenic AIDs, such as Behçet's syndrome, inflammatory bowel disease, and sarcoidosis. Cytophagic histiocytic panniculitis, lipoatrophic panniculitis of children, and otulipenia are rare disorders that may also present with inflammation of the subcutaneous fat. Therefore, panniculitis can identify a specific subgroup of patients with AIDs and may potentially be regarded as a cardinal sign of autoinflammation.

[Ruxolitinib as an effective treatment for panniculitis associated hemophagocytic syndrome: A report of 2 cases and literature review]

Hemophagocytic syndrome (HPS) is a severe disease characterized by excessive release of inflammatory cytokines caused by abnormal activation of lymphocytes and macrophages, which can cause multiple organ damage and even death. Panniculitis is a disease characterized by inflammation of subcutaneous adipose tissue. We effectively treated 2 patients with panniculitis-associated HPS with ruxolitinib. Case 1: A 70-year-old male started with intermittent plantar swelling and pain, and then developed leukocytosis, mild anemia, multiple red maculopapules with painless subcutaneous nodules on the forehead, neck and bilateral lower legs. The patient was treated with prednisone and leflunomide for improvement. After that, repeated fever and rash occurred again. After admission to our hospital, we found his leukocyte and hemoglobin decreased, ferritin raised, fibrinogen and natural killer (NK) cell activity decreased, and hemophagocytic cells were found in bone marrow aspiration. The skin pathology was consistent with non-suppurative nodular panniculitis. He was diagnosed with nodular panniculitis associa-ted HPS. He was treated with glucocorticoid, cyclosporine, etoposide and gamma globule, but the disease was not completely controlled. After adjusting etoposide to ruxolitinib, his symptoms and abnormal laboratory findings returned to normal. After 2 months he stopped using ruxolitinib due to repeated infections. During the follow-up, though the prednisone dose was tapered, his condition was stable. Case 2: A 46-year-old female patient developed from intermittent fever, erythematous nodular rash with tenderness, leukopenia, and abnormal liver function. antibiotic therapy was ineffective. She improved after glucocorticoid treatment, and relapsed after glucocorticoid reduction. There were fever, limb nodules, erythema with ulcerative necrosis, intermittent abdominal pain when she came to our hospital. Blood examination showed that her white blood cells, red blood cells and platelets were decreased, fibrinogen was decreased, triglyceride was increased, ferritin and soluble interleukin-2 receptor(SIL-2R/sCD25) were significantly raised, and hemophagocytic cells were found in bone marrow aspiration. It was found that Epstein-Barr virus DNA was transiently positive, skin Staphylococcus aureus infection, and pulmonary Aspergillus flavus infection, but C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were normal, and no evidence of tumor and other infection was found. Skin pathology was considered panniculitis. The diagnosis was panniculitis, HPS and complicated infection. Antibiotic therapy and symptomatic blood transfusion were given first, but the disease was not controlled. Later, dexamethasone was given, and the condition improved, but the disease recurred after reducing the dose of dexamethasone. Due to the combination of multiple infections, the application of etoposide had a high risk of infection spread. Ruxolitinib, dexamethasone, and anti-infective therapy were given, and her condition remained stable after dexamethasone withdrawal. After 2 months of medication, she stopped using ruxolitinib. One week after stopping using ruxolitinib, she developed fever and died after 2 weeks of antibiotic therapy treatment in a local hospital. In conclusion, panniculitis and HPS are related in etiology, pathogenic mechanism and clinical manifestations. Abnormal activation of Janus-kinase and signal transduction activator of transcription pathway and abnormal release of inflammatory factors play an important role in the pathogenesis of the two diseases. The report suggests that ruxolitinib is effective and has broad prospects in the treatment of panniculitis associated HPS.

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.

A Young Boy With Hemophagocytic Lymphohistiocytosis Presenting With Vaccine-Related Granulomatous Dermatitis: A Case Report and Literature Review

ABSTRACT

Cutaneous eruptions associated with hemophagocytic lymphohistiocytosis (HLH) have been reported in 6%-63% of patients. Clinical findings of these skin lesions vary widely and include maculopapular rashes, ulcers, and violaceous nodules. Corresponding histologic findings are also variable and are considered nonspecific. We report the case of a 4-year-old boy who initially developed a widespread popular-pustular rash 2 weeks after his 12-month measles, mumps, and rubella vaccinations. These resolved with scarring then recurred following his 24-month vaccinations. Multiple skin biopsies were negative for infectious organisms and showed a granulomatous infiltrate with perforation and necrobiosis. The differential diagnosis included perforating granuloma annulare, infection, or rheumatoid nodules. At the age of 4, he developed fever, hepatosplenomegaly, pancytopenia and other laboratory abnormalities, requiring hospitalization. A number of studies were performed including biopsies of bone marrow and liver. Molecular testing revealed 2 mutations in UNC13D known to be associated with familial HLH. His prior cutaneous lesions were likely caused by immune dysregulation exacerbated by immunizations because of underlying familial HLH. This case illustrates the importance of recognizing an unusual cutaneous manifestation of a rare disease to arrive at an earlier diagnosis in a pediatric patient. Although cutaneous eruptions usually develop concurrently with other systemic symptoms of HLH, preceding unusual skin lesions may be the first indication of this rare disease.

Three Consecutive Cases of Familial Hemophagocytic Lymphohistiocytosis, Including a Case Due to Maternal Uniparental Disomy

We have experienced 3 consecutive cases of familial hemophagocytic lymphohistiocytosis (FHL). All affected infants had mutations in exon 3 of the perforin gene. The first had a homozygous mutation, c.1168C>T (p.R390*), caused by maternal uniparental isodisomy. The second and third had compound heterozygous mutations: c.781G>A (p.E261K) and c.1491T>A (p.C497*); c.1724G>T (p.C242G) and p.R390*, respectively. FHL is very rare in Northern Japan but should be suspected if infants exhibit prolonged fever. This is the first report of a relationship of p.R390* with FHL caused by uniparental isodisomy, and the second reported case of FHL type 2 with this form of inheritance.

Familial hemophagocytic lymphohistiocytosis: when rare diseases shed light on immune system functioning

The human immune system depends on the activity of cytotoxic T lymphocytes (CTL), natural killer (NK) cells, and NKT cells in order to fight off a viral infection. Understanding the molecular mechanisms during this process and the role of individual proteins was greatly improved by the study of familial hemophagocytic lymphohistiocytosis (FHL). Since 1999, genetic sequencing is the gold standard to classify patients into different subgroups of FHL. The diagnosis, once based on a clinical constellation of abnormalities, is now strongly supported by the results of a functional flow-cytometry screening, which directs the genetic study. A few additional congenital immune deficiencies can also cause a resembling or even identical clinical picture to FHL. As in many other rare human disorders, the collection and analysis of a relatively large number of cases in registries is crucial to draw a complete picture of the disease. The conduction of prospective therapeutic trials allows investigators to increase the awareness of the disease and to speed up the diagnostic process, but also provides important functional and genetic confirmations. Children with confirmed diagnosis may undergo hematopoietic stem cell transplantation, which is the only cure known to date. Moreover, detailed characterization of these rare patients helped to understand the function of individual proteins within the exocytic machinery of CTL, NK, and NKT cells. Moreover, identification of these genotypes also provides valuable information on variant phenotypes, other than FHL, associated with biallelic and monoallelic mutations in the FHL-related genes. In this review, we describe how detailed characterization of patients with genetic hemophagocytic lymphohistiocytosis has resulted in improvement in knowledge regarding contribution of individual proteins to the functional machinery of cytotoxic T- and NK-cells. The review also details how identification of these genotypes has provided valuable information on variant phenotypes.

An A91V SNP in the perforin gene is frequently found in NK/T-cell lymphomas

NK/T-cell lymphoma (NKTCL) is the most frequent EBV-related NK/T-cell disease. Its clinical manifestations overlap with those of familial haemophagocytic lymphohistiocytosis (FHLH). Since PERFORIN (PRF1) mutations are present in FHLH, we analysed its role in a series of 12 nasal and 12 extranasal-NKTCLs. 12.5% of the tumours and 25% of the nasal-origin cases had the well-known g.272C>T(p.Ala91Val) pathogenic SNP, which confers a poor prognosis. Two of these cases had a double-CD4/CD8-positive immunophenotype, although no correlation was found with perforin protein expression. p53 was overexpressed in 20% of the tumoral samples, 80% of which were of extranasal origin, while none showed PRF1 SNVs. These results suggest that nasal and extranasal NKTCLs have different biological backgrounds, although this requires validation.

Clonal cytophagic histiocytic panniculitis in children may be cured by cyclosporine A

Cytophagic histiocytic panniculitis (CHP) is a rare panniculitis in childhood, associated either with nonmalignant conditions or with subcutaneous panniculitis-like T-cell lymphoma (SPTCL), and often also associated with macrophage activation syndrome (MAS). Discriminating between these 2 conditions is therapeutically important because nonmalignant CHP often improves under cyclosporine and prednisone, whereas most cases of SPLT may be best treated with more aggressive therapy. We report the cases of a 6-month-old boy and a 16-month-old girl who, after viral infection, developed multiple infiltrating skin nodules on the limbs and face, associated with MAS. Histopathologic findings for skin biopsy specimens revealed CHP associated with heavily cellular lobular panniculitis. Hemophagocytosis and immunohistochemical staining features were consistent with typical characteristics of in situ MAS in adipose tissue: the lymphocytes were mostly TCD8+ cells with an activated phenotype (human leukocyte antigen (HLA) -DR+) and expressed interferon-γ; CD68+ macrophages expressed tumor necrosis factor-α and interleukin-6. A monoclonal rearrangement of the T-cell receptor γ gene was present in skin tissue but not in peripheral blood or bone marrow lymphocytes. Cyclosporine A treatment resulted in the complete remission of cutaneous and systemic manifestations in both patients for 66 and 29 months, respectively. This report suggests that the diagnosis of a reactive T-cell lymphoproliferation should be the treatment of choice in young children with severe CHP, even if there is a SPTCL-like aspect with an in situ T-cell clonality. It also suggests that CSA is the optimal treatment of this condition and postulates the possible pathologic process underlying this efficacy.

Advances in understanding the pathogenesis of HLH

Haemophagocytic lymphohistiocytosis (HLH) is a hyperinflammatory disorder resulting from immune dysfunction reflecting either primary immune deficiency or acquired failure of normal immune homeostasis. Familial HLH includes autosomal recessive and X-linked disorders characterized by uncontrolled activation of T cells and macrophages and overproduction of inflammatory cytokines, secondary to defects in genes encoding proteins involved in granule-dependent cytolytic pathways. In older children and adults, HLH is associated more often with infections, malignancies, autoimmune diseases, and acquired immune deficiencies. HLH, macrophage activation syndrome, sepsis, and systemic inflammatory response syndrome are different clinical entities that probably represent a common immunopathological state, termed cytokine storm. These conditions may be clinically indistinguishable; all include massive inflammatory response, elevated serum cytokine levels, multi-organ involvement, haemophagocytic macrophages, and often death. Tissues of haematopoietic and lymphoid function are directly involved; other organs are secondarily damaged by circulating cytokines and chemokines. Haemophagocytic disorders are now increasingly diagnosed in the context of severe inflammatory reactions to viruses, malignancies and systemic connective tissue diseases. Many of these cases may reflect underlying genetic predispositions to HLH. The detection of gene defects has contributed considerably to our understanding of HLH, but the mechanisms leading to acquired HLH have yet to be fully determined.

Screening the PRF1, UNC13D, STX11, SH2D1A, XIAP, and ITK gene mutations in Chinese children with Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis

BACKGROUND

This study aimed to investigate the prevalence of mutations in the PRF1, UNC13D, STX11, SH2D1A, XIAP, and ITK in Chinese pediatric patients with EBV-HLH.

METHODS

Sixty-seven pediatric patients diagnosed with EBV-HLH in Beijing Children's Hospital were recruited. Nucleotide sequences of all exons and their flanking intronic sequences of PRF1, UNC13D, STX11, SH2D1A, XIAP, and ITK were amplified by PCR followed by direct sequencing.

RESULTS

Eight patients were identified with heterozygous, compound heterozygous, or homozygous mutations in PFR1, UNC13D, and XIAP. Three missense mutations (c.83G>A, c.503G>A, c.632C>T) were found in PRF1 of two males and two females. Compound heterozygous c.93C>G and c.1066C>T were found in PRF1 of a 2.5-year-old female. Four different mutations were found in UNC13D of two patients: compound nonsense heterozygous mutations c.766C>T and c.1215C>G were found in one male and two splicing mutations c.1596+1G>C and c.2709+1G>A were found in another male. A heterozygous mutation c.1099+2T>C in XIAP was found in a 4-year-old male. No detrimental mutations were identified in STX11, SH2D1A, or ITK. NK cell activity did not differ between the eight FHL patients and the remaining patients. There was no statistical difference in clinical features and laboratory data for these two subgroups with biallelic and heterozygous mutations.

CONCLUSIONS

Seven novel mutations in PRF1, UNC13D, and XIAP were identified in EBV-HLH patients. Only a fraction of the Chinese children with EBV-HLH have genetic defects in PRF1, UNC13D, and XIAP. There were no gene mutations of PRF1/UNC13D/STX11/SH2D1A/XIAP/ITK in the majority of Chinese child patients with EBV-HLH.

Clinical aspects, immunologic assessment, and genetic analysis in Taiwanese children with hemophagocytic lymphohistiocytosis

BACKGROUND

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening syndrome characterized by immune disturbance associated with certain genetic defects. This study aimed to define the clinical spectrum, immunology, and candidate genes in HLH in Taiwanese patients.

PATIENTS AND METHODS

The medical records of children who met the updated diagnostic criteria and had confirmed hemophagocytosis by bone marrow aspiration between 1992 and 2007 were retrospectively evaluated. The clinical course and prognosis were analyzed. Quantitative immunoglobulin, lymphocyte subsets, cytotoxicity to K562 cells, intracellular natural killer perforin expression, and candidate genes including SH2D1A, PFR1, Mun13-4, and STX11 genes were also investigated.

RESULTS

Thirty-two patients (16 male) were evaluated during the 15-year period. The underlying diseases were acute lymphoblastic leukemia, systemic lupus erythematosus, natural killer malignancy, juvenile idiopathic arthritis, and Chediak-Higashi syndrome. Epstein-Barr virus (EBV)-associated HLH was present in 12 patients, 6 of whom died, while 12 of 20 non-EBV-associated patients died despite aggressive polychemotherapy. Extreme immunoglobulin values occurred in 3 fatal cases. There was decreasing percentage of CD4, CD1656, and B-memory cells and increasing CD8, activated lymphocyte, and T-memory cells among the patients. Cytotoxicity in 14 patients and intracellular perforin expression in 13 were diminished but restored to borderline normal range during the convalescent stage. None of the mutations of SH2D1A, PFR1, Mun13-4, and STX11 genes were found.

CONCLUSIONS

In the treatment of Taiwanese HLH patients, aggressive chemotherapy in EBV-associated patients and stem cell transplantation in non-EBV-associated patients are recommended to improve survival. Individualized immune dysregulation instead of the well-known candidate genetic mutations can explain the genetic variation in our cohort.