Case report: EBV-related eye orbits and sinuses lymphohistiocytic infiltration responsive to rituximab in a patient with X lymphoproliferative syndrome type 1.

Background and aims: X lymphoproliferative syndrome type 1 (XLP1) is a rare inborn error of immunity due to mutations of SH2D1A, encoding for slam-associated protein (SAP). The clinical phenotype includes severe mononucleosis, hemophagocytic lymphohistiocytosis (HLH), and B-cell lymphomas. Methods: We report the case of a child affected with XLP1 who presented with an incomplete HLH, triggered by Epstein-Barr virus (EBV) and treated with rituximab, involving orbits and paranasal sinuses. Results: The lesion was indistinguishable from lymphoma, complicating diagnosis and treatment. In addition, considering the high incidence of lymphoma in patients with XLP1, histology helped define its nature, driving therapeutic choices. Conclusion: We described an unusual presentation of incomplete HLH in a patient affected with XLP1: an EBV-driven infiltration of the orbits and paranasal sinuses. This led us to a challenging differential diagnosis of lymphoma-associated hemophagocytic syndrome, which can be frequently observed in patients with XLP1. Considering the extremely poor prognosis of this clinical finding, we sought for a prompt diagnosis and managed to obtain it and to immediately establish the right treatment on the basis of the pathological finding.

Outcome of primary hemophagocytic lymphohistiocytosis: a report on 143 patients from the Italian Registry.

Primary hemophagocytic lymphohistiocytosis (pHLH) is a severe, life-threatening hyperinflammatory syndrome caused by defects in genes of the granule-dependent cytotoxic pathway. Here we investigated the clinical presentation and outcome in a large cohort of 143 patients with pHLH diagnosed in the last 15 years and enrolled in the Italian registry. The median age at diagnosis was 12 months (IQR 2-81), and ninety-two patients (64%) fulfilled the HLH-2004 criteria. Out of 111 patients who received first-line combined therapy (HLH-94, HLH-2004, Euro-HIT protocols), 65 (59%) achieved complete response (CR) and 21 (19%) partial response (PR). Thereafter, 33 patients (30%) reactivated, and 92 (64%) received HSCT, 78 of whom (85%) survived and were alive at a median follow-up from diagnosis of 67 months. Thirty-six patients (25%) died before HSCT and 14 (10%) after. Overall, 93 patients (65%) were alive after a median follow-up of 30 months. Unadjusted predictors of non-response were age.

Integrated imaging of systemic Langerhans cell histiocytosis in an infant.

Langerhans cell histiocytosis (LCH) is a myeloid neoplasm characterized by a clonal proliferation of CD1a+/CD207+ dendritic cells. Although individuals of any age can be affected, the disease is most common in infants younger than 5 years of age, especially males. A wide range of manifestations, from asymptomatic to aggressive, have been described, along with multiorgan involvement. Even though the majority of bone lesions are observed, skin, lymph nodes, brain and lungs can also be involved. The involvement of hematopoietic system, including bone marrow, liver and spleen, is less frequent yet associated with worse prognosis, due to a worse treatment response. Diagnosis of LCH is based on the integration of clinical, laboratory, and radiological data; however, only histopathological examination might confirm it. As far as the spleen involvement is concerned, according to literature, it has been reported in about 15% patients with multisystem involvement, nonetheless only a few cases show parenchymal lesions. The present study reports the case of an infant with LCH with multisystem involvement, including bone, skin, liver, and spleen, with evidence of parenchymal lesions.

Musculoskeletal manifestations of childhood cancer and differential diagnosis with juvenile idiopathic arthritis (ONCOREUM): a multicentre, cross-sectional study.

BACKGROUND: Presenting symptoms of childhood cancers might mimic those of rheumatic diseases. However, the evidence available to guide differential diagnosis remains scarce. Preventing wrong or delayed diagnosis is therefore important to avoid incorrect administration of glucocorticoid or immunosuppressive therapy and worsening of prognosis. As such, we aimed to assess the prevalence and characteristics of presenting musculoskeletal manifestations in patients at cancer onset and to identify the factors that differentiate childhood malignancies with arthropathy from juvenile idiopathic arthritis. METHODS: We did a multicentre, cross-sectional study at 25 paediatric haemato-oncology centres and 22 paediatric rheumatology centres in Italy. We prospectively recruited patients who were younger than 16 years that were newly diagnosed with cancer or juvenile idiopathic arthritis. We excluded patients with glucocorticoid pre-treatment (>1 mg/kg per day of oral prednisone or equivalent for ≥2 consecutive weeks). We collected data for patients with a new diagnosis of cancer or juvenile idiopathic arthritis using an electronic case report form on a web-based platform powered by the Cineca Interuniversity Consortium. The primary outcome was to describe the frequency and characteristics of musculoskeletal manifestations at cancer onset; and the secondary outcome was to identify factors that could discriminate malignancies presenting with arthropathy, with or without other musculoskeletal symptoms, from juvenile idiopathic arthritis using multivariable logistic regression analysis. FINDINGS: Between May 1, 2015, and May 31, 2018, 1957 patients were eligible, of which 1277 (65%) had cancer and 680 (35%) had juvenile idiopathic arthritis. Musculoskeletal symptoms occurred in 324 (25% [95% CI 23·0-27·8]) of 1277 patients with cancer, of whom 207 had arthropathy. Patients with malignant bone tumours had the highest frequency of musculoskeletal symptoms (53 [80%] of 66), followed by patients with Langerhans histiocytosis (16 [47%] of 34), leukaemia (189 [32%] of 582), soft-tissue sarcomas (16 [24%] of 68), and neuroblastoma (21 [19%] of 109). In the 324 patients with cancer and musculoskeletal symptoms, the most common complaints were joint pain (199 [61%]), followed by limb bone pain (112 [35%]). Joint involvement had a prevalent monoarticular pattern (100 [48%] of 207) and oligoarticular pattern (86 [42%] had 2-4 joints involved and 20 [10%] had >4 joints involved), with the most frequently involved joints being the hip (88 [43%] of 207) and knee (81 [39%]). On multivariable analysis, limb bone pain was the independent variable most strongly associated with cancer (odds ratio [OR] 87·80 [95% CI 18·89-408·12]), followed by weight loss (59·88 [6·34-565·53]), thrombocytopenia (12·67 [2·40-66·92]), monoarticular involvement (11·30 [4·09-31·19]), hip involvement (3·30 [1·13-9·61]), and male sex (2·40 [1·03-5·58]). Factors independently associated with juvenile idiopathic arthritis were morning stiffness (OR 0·04 [95% CI 0·01-0·20]), joint swelling (0·03 [0·01-0·09]), and involvement of the small hand joints (0·02 [0-1·05]). INTERPRETATION: Our study provides detailed information about presenting musculoskeletal manifestations of childhood cancers and highlights the clinical and laboratory features that are most helpful in the differential diagnosis with juvenile idiopathic arthritis. FUNDING: Associazione Lorenzo Risolo.

A single amino acid change, A91V, leads to conformational changes that can impair processing to the active form of perforin.

Mutations in the perforin gene have been found in patients with hemophagocytic lymphohistiocytosis (HLH), a rare autosomal recessive disease. We describe a patient expressing perforin with amino acid changes A91V and W374X. The ability of cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells to lyse target cells is greatly reduced. Here we demonstrate that perforin from this patient is not recognized using an antibody raised against native perforin (deltaG9), but is readily detected using an antibody raised against a peptide epitope (2d4), suggesting that the epitope recognized by deltaG9 is destroyed by the change at A91V. Immunoblotting reveals no protein corresponding to the truncated transcript encoded by W374X, revealing that only perforin with the A91V change is expressed in CTLs from the patient. Patient CTLs show bands corresponding to the immature and intermediate forms of perforin, but the mature active form of perforin is absent or barely detectable. The conformational changes and impaired cleavage of A91V perforin are likely to explain the reduced cytotoxicity in CTLs and NK cells from this patient and are likely to contribute to the pathogenesis of HLH.

Use of the minimum spanning tree model for molecular epidemiological investigation of a nosocomial outbreak of hepatitis C virus infection.

The minimum spanning tree (MST) model was applied to identify the history of transmission of hepatitis C virus (HCV) infection in an outbreak involving five children attending a pediatric oncology-hematology outpatient ward between 1992 and 2000. We collected blood samples from all children attending since 1992, all household contacts, and one health care worker positive for antibody to HCV (anti-HCV). HCV RNA detection was performed with these samples and with smears of routinely collected bone marrow samples. For all isolates, we performed sequence analysis and phylogenetic tree analysis of hypervariable region 1 of the E2 gene. The MST model was applied to clinical-epidemiological and molecular data. No additional cases were detected. All children, but not the health care worker, showed genotype 3a. On six occasions, all but one child had shared the medication room with another patient who later seroconverted. HCV RNA detection in bone marrow smears revealed, in some cases, a delay of several months in anti-HCV responses. Sequence analysis and phylogenetic tree analysis revealed a high identity among the isolates. The MST model applied to molecular data, together with the clinical-epidemiological data, allowed us to identify the source of the outbreak and the most probable patient-to-patient chain of transmission. The management of central venous catheters was suspected to be the probable route of transmission. In conclusion, the MST model, supported by an exhaustive clinical-epidemiological investigation, appears to be a useful tool in tracing the history of transmission in outbreaks of HCV infection.