STX2 and malignant hypertension: Importantly, all patients who presented with diarrhea had their stools examined for the presence of Shiga toxins STX1 and STX2, patients who were not tested for both serum ANA and anti-ENA antibody titers had no clinical evidence or histological signs (on their renal biopsies) of autoimmune disorders, and six of the patients who were diagnosed with severe or malignant hypertension were subjected to funduscopic examinations.