IMMUNOFLUORESCENCE (IF) STAINING FOR DETECTION OF PML-RAR𝛂 ONCOPROTEIN AS A RAPID DIAGNOSTIC TEST FOR ACUTE PROMYELOCYTIC LEUKEMIA (APL)

MARONI G; OJEDA M; WILLIAMS GM; MISAÑA M; SCHOEPF MARÍA; RAVIOLA M; DETARSIO G; PRATTI A

Rosario

Congreso; XXI Congress-XXXIX Annual Meeting of Rosario Biology Society; 2022

SOCIEDAD DE BIOLOGÍA DE ROSARIO

APL is a highly aggressive subtype of acute myeloid leukemia (AML) that, however, can be cured with targetedtherapies. APL is characterized by fusion of the PML (promyelocytic leukemia) and RARα (retinoic acid receptor-α)genes [t(15;17)], leading to expression of PML-RARα oncoprotein. Clinically, APL represents a hematologicalemergency since it registers high early mortality due to the risk of hemorrhage, disseminated intravascularcoagulation or primary fibrinolysis if the diagnosis is delayed, so the rapid detection of PML-RARα is of crucialimportance for the diagnosis and prognosis of the disease. Detection methods include conventional cytogeneticanalysis (CTG), FISH, nested polymerase chain reaction (PCR), and IF staining for PML protein. CTG can detect thet(15;17)(q24;q21) and other chromosomal abnormalities, although the process time may take several days. NestedPCR allows the qualitative detection of the fusion transcript and the isoform (bcr 1, 2 or 3), which is essential for themonitoring of minimal residual disease (MRD). IF allows the detection of the oncoprotein in a period of 2 to 4 h. Weperformed IF and nested PCR to analyze bone marrow or peripheral blood samples from 20 patients withmorphological suspicion of APL. The smears were fixed with methanol, and a primary mouse monoclonal antibody(PG-M3) and a secondary antibody (anti-mouse) conjugated to FITC were used. The samples were analyzed on a Zeizz® Axio A.1 microscope. 46.7% of the patients were positive with both methods. We can conclude that IF is asimple, rapid, and sensitive technique for the detection of the PML-RARα oncoprotein. Although it could not replacethe nested PCR, IF is a rapid diagnostic test for patients with morphological and clinical suspicion of APL.