Omalizumab use in a patient with asthma and hereditary spherocytosis

Biological drugs are becoming the standard of care in severe refractory allergic diseases. In the case of Omalizumab, it is indicated for severe asthma. Some biological drugs have unexpected effects related to hematotoxicity. Hereditary spherocytosis is a common cause of hereditary anemia, with heterogeneous manifestations influenced by multiple factors, as exposure to drugs. Our aim was to evaluate possible hematological effect of omalizumab in a case of hereditary spherocytosis. A 10-year-old boy with hereditary spherocytosis and severe asthma was started on Omalizumab due to several exacerbations and frequent need of oral corticosteroids, along with a decreased respiratory function. After six months, clinical improvement was observed. Simultaneously, there were no changes in hematological parameters. We report the first case of treatment with Omalizumab in a child with severe asthma and hereditary spherocytosis. In this study, this therapy appears to be safe in hemolytic anemia. Introduction Omalizumab is a recombinant DNA-derived humanized monoclonal antibody indicated in Step 5 treatment of asthma.1,2,3,4,5,6This biological drug has a specific connection to the constant region present on the surface of the molecule of Immunoglobulin E (IgE) Cɛ3, which will block the binding to its receptors (both high and low affinity), decreasing IgE levels in the bloodstream. This process will reduce the expression of the specific IgE receptors on inflammatory cells, such as mast cells and basophils, decreasing the release of inflammatory and allergic mediators. Omalizumab will act on dendritic cells as well, limiting the process of allergen presentation to T cells and, consequently, the cascade of the allergic reaction.1,2 Some biological therapies have shown unexpected effects related to hematotoxicity, such as thrombocytopenia, de novo immune hemolysis, or even the worsening of the previous anemia.7 Hereditary spherocytosis is a congenital, non-immune, hemolytic anemia, characterized by modifications of the red cell membrane. It is a common cause of hereditary anemia in children. Its clinical expression is heterogeneous, varying from silent chronic hemolysis to severe, transfusion-dependent forms. A broad range of factors can influence a worsening of the anemia, namely: infections, certain foods, deficiencies (vitamin B12, iron, folate) and oxidative drugs.8 There are no previous published data on the use of Omalizumab in patients with hemolytic hereditary anemias. This paper aimed to evaluate the possible effect of Omalizumab therapy, directed to the treatment of severe asthma, in a child with concomitant hereditary spherocytosis, and to ascertain any effects on hemolysis, given the underlying hemolytic anemia of the patient. For that, the authors collected clinical and laboratory data and compared them, before and after the periodic administration of Omalizumab. Case Report A ten-year-old boy (weight 30 kg, height 137 cm), with spherocytosis and asthma. His hemolytic anemia was previously stable, with compensated hemolysis, moderate reticulocytosis and slightly increased bilirubin, without significat anemia [Hemoglobin 12.8 g/ dL, hematocrit 35%, reticulocytes 239 000/uL (5.3%), total bilirubin 0.5 mg/dL, lactate dehydrogenase (LDH) 264 U/L, haptoglobin <10 mg/dL]. He did not have splenomegaly neither gallstones. By the age of nine, he had been diagnosed with severe asthma (stage 4), with persistent symptoms and multiple exacerbations, despite being medicated with high dose of inhaled corticosteroids therapy and long-acting beta-agonist combination (budesonide 160 ug/dose and formoterol 4.5ug/dose, twice daily), plus inhaled budesonide (200 ug/dose) twice daily Address for Correspondance: Sara Completo, Hospital Prof. Doutor Fernando Fonseca E.P.E . IC 19, 2720-276 Amadora. Email: completo.sara@gmail.com ©2021 Pediatric Oncall ARTICLE HISTORY Received 23 November 2021 Accepted 29 November 2021