MICROVESICLES CARRYING SHIGA TOXIN TYPE 2 (MVS-STX2) AS A NEW CLINICAL BIOMARKER FOR THE RAPID DIAGNOSIS OF PATIENTS AT RISK OF DEVELOP- ING HEMOLYTIC UREMIC SYNDROME (HUS)

FERNANDO DANIEL GOMEZ; FLAVIA SACERDOTI; CLAUDIO DANIEL GIRÓN REYES; CARLA PASCUALE; TOMÁS LOMBARDO ; ROXANE MARIA FONTES PIAZZA; LAURA ALCONCHER; MARIA MARTA AMARAL

Mar del Plata

Congreso; Reunion Anual de Sociedades de Investigación Clinica; 2023

Sociedad de Investigación clinica

In Argentina, Hemolytic Uremic Syndrome (HUS) caused by Shigatoxin (Stx)-producing Escherichia coli (STEC-HUS) infection is an endemic disease and one of the most common causes of acute kid-ney injury in children. Negligible amounts of free toxin are present inthe circulation during HUS, and it circulates mainly bound to bloodcells and microvesicles (MVs). Platelets and leukocytes derivedMVs were detected in the plasma of STEC-HUS patients. In this sense, preliminary, we successfully identified circulating MVs car-rying Stx2 (MVs-Stx2) in two STEC-HUS patients. In this study, our objective was to analyze the presence of MVs-Stx2 in blood sam-ples of six STEC-HUS patients, between 3 and 17 years old, that were admitted to the Hospital Penna-Bahía Blanca. Blood sampleswere collected and underwent sequential ultracentrifugation to ob-tain a suspension enriched with MVs. Then, MVs were labeled withAnnexin V-FITC and MVs-Stx2 were detected by a monoclonal an-ti-Stx2 antibody and a secondary antibody conjugated to Alexa Fluor647. Finally, MVs were analyzed by flow cytometry. Data are ex-pressed as the percentage of positives MVs-Stx2. Ten age-matchedhealthy controls were also recruited and a cut-off point for MVs-Stx2was established. Medical history of patients indicated that to the dayof hospitalization, three of them exhibited aqueous diarrhea, twoshowed bloody mucous diarrhea and the other had no diarrhea. ForStx2 PCR analysis, 50% of them were positive. Anti-LPS antibod-ies were positive for O145 IgM/IgG in three patients and for O157 IgG in one of them. All patients showed a significant percentageof MVs-Stx2 in circulation compared to controls (3.4%, 7%, 13.7%,6%, 3.6% and 13.8% vs 1.76 ± 0.74 %, n=10, (p