AML-192: Enhancer of Zeste Homolog 2 (EZH2) in COVID-19-Positive Acute Myeloid Leukemia

Abstract

<h3>Background:</h3> Enhancer of Zeste Homolog 2 (EZH2) is the catalytic subunit of the chromatin-modifying enzyme polycomb group (PRC)2. This complex selectively trimethylates histone H3 at lysine 27. EZH2 is strongly upregulated in septic patients. EZH2 blockage suppresses the activation of inflammatory cells and release of cytokines in circulation and infections sites, replenishes circulating neutrophil and monocyte pools from the bone marrow, and suppresses the progression of lung injury. <h3>Objective:</h3> This study aimed to determine the relationship between the expression levels of <i>EZH2,</i> CT lung findings, and treatment outcomes in adult newly diagnosed with acute myeloid leukemia (AML) and COVID-19 disease. <h3>Materials and Methods:</h3> The present study included 5 <i>de novo</i> AML cases. The following was performed for all patients: complete blood count, bone marrow examination, cytochemical and immunophenotyping studies, and conventional cytogenetic, hepatic, and renal function tests. Detection of <i>EZH2</i> expression level was achieved by real-time quantitative polymerase chain reaction (RT-qPCR). COVID-19 diagnosis was based on lung CT and VIASURE SARS-CoV Real-Time PCR of nasopharyngeal swabs (CerTestBiotec, Spain). <h3>Results:</h3> The median age of our patients was 35 years (60%); 3 patients were male. (40%), and 2 patients were female (60%). Three patients were M5. Cytogenetic studies revealed presence of normal cytogenetics in (60%) 3 patients. One case had intermediate/severe disease, while 4 cases were ICU admitted and later died. Lung CT changes were present in all cases. Unexpectedly, <i>EZH2</i> expression was lower in patients with CT findings consistent with micronodule infiltration and consolidation (2 patients) than patients with ground glass appearance (3 patients). This means that lower <i>EZH2</i> levels are present in patients with a higher degree of lung injury or perhaps presence of other coexisting infections modifying the results. <h3>Conclusions:</h3> Low <i>EZH2</i> is not protective against progression of lung injury induced by COVID-19.