LATE ONSET PRIMARY HEMOPHAGOCYTIC LYMPHOHISTIOCYTOSIS in AN INDIAN ADOLESCENT BOY during A PEAK of POST COVID-19 MULTISYSTEM INFLAMMATORY SYNDROME

Background: Familial Hemophagocytic lymphohistiocytosis (fHLH) categorized as FHL2 (PRF1), FHL3 (UNC13D), FHL4 (STX11), and FHL5 (STXBP2) encoding for Perforin, Munc13-4, Syntaxin11, and Syntaxin binding protein 2, respectively. There is limited information available about the clinical and mutational spectrum of FHL patients in Indian population. Objectives: To delineate clinical and laboratory features of late onset familial Hemophagocytic Lymphohistiocytosis. Methods: A 12-years-old well nourished sick looking boy, born to a non-consanguineous parents with normal birth, development and immunization history with uneventful past presented to us with 6 days history of high fever, cough, breathing difficulty and severe headache. He had occasional vomiting, abdominal pain, polyarthragia & chest pain from last 10 days. Mother also had given history of throat pain, backache & some non-specifc papular rashes over face before the onset of fever. His vitals were normal. Examination revealed faint diffuse fxed erythematous rash all over the body, pallor, icterus and hepatos-plenomegaly. Musculoskeletal examination was unremarkable. Lab evaluation revealed HB 8.9gm%, TLC 4700/cumm with neutrophils 40% and lymphocytes 56% with 8-9% activated lympocytes. Further evaluation showed low ESR 6mm/hr, fbrinogen 97mg% and albumin 2.2 gm% with elevated CRP 40mg/L, ferritin 2000ng/ml, LDH 658IU/L, SGPT 110IU/L, SGOT 221 IU/L, total bilirubin 6mg%, D-dimer 4355 ng:EFU/ml and Triglycerides 441mg%. His blood, urine, CSF and bone marrow cultures were sterile for endemic bacterial and viral infections in our area. His EBV PCR, CoVID RT PCR and CoVID antibody (Total & IgG) test were negative. His immunoglobulin leves were normal. HRCT Chest showed bilateral mild-moderate plural effusions, mild interstitial thickening in both the lower lobes, few fbrotic opacities & old areas of consolidation bilaterally. 2D echo showed mild pericardial effusion. Bone marrow examination showed Hypercellular marrow with iron depletion and occasional hemophagocytosis with CD8 T lymphocytes proliferation (55.2%) and double positive CD4 & CD8 (1.2%). He was initially commenced on supportive therapy, oxygen & intravenous antibiotics. In view of most probable non-infectious, non-malignant hemophagocytic lymphohistiocytosis, he was fnally given intravenous immunoglobulin (2gm/kg) and intravenous pulse methylprednisolone (30mg/kg). He responded well to above regimen within 3 days. He was discharged with tapering steroids over few weeks. Clinical exome by NGS revealed Homozygous Mutation in STXBP2 gene Intron 14, c.1280-1G>C (3' Splice Site) His parents has been counselled for hematopoietic stem cell transplantation and their decision is still pending. Results: We compared our patietnt with a reference to the largest Indian series of pediatric HLH1. Conclusion: Primary HLH type 5 can present frst time during childhood and adolescence. Any child presenting with unexplained HLH features should undergo genetic analysis irrespective of person's past and family history.

COVID-19 as part of the hyperferritinemic syndromes: the role of iron depletion therapy.

SARS-CoV-2 infection is characterized by a protean clinical picture that can range from asymptomatic patients to life-threatening conditions. Severe COVID-19 patients often display a severe pulmonary involvement and develop neutrophilia, lymphopenia, and strikingly elevated levels of IL-6. There is an over-exuberant cytokine release with hyperferritinemia leading to the idea that COVID-19 is part of the hyperferritinemic syndrome spectrum. Indeed, very high levels of ferritin can occur in other diseases including hemophagocytic lymphohistiocytosis, macrophage activation syndrome, adult-onset Still's disease, catastrophic antiphospholipid syndrome and septic shock. Numerous studies have demonstrated the immunomodulatory effects of ferritin and its association with mortality and sustained inflammatory process. High levels of free iron are harmful in tissues, especially through the redox damage that can lead to fibrosis. Iron chelation represents a pillar in the treatment of iron overload. In addition, it was proven to have an anti-viral and anti-fibrotic activity. Herein, we analyse the pathogenic role of ferritin and iron during SARS-CoV-2 infection and propose iron depletion therapy as a novel therapeutic approach in the COVID-19 pandemic.