title: Shiga toxin-induced complement-mediated hemolysis and release of complement-coated red blood cell-derived microvesicles in hemolytic uremic syndrome.
abstract: Shiga toxin (Stx)-producing Escherichia coli (STEC) cause hemolytic uremic syndrome (HUS). This study investigated whether Stx2 induces hemolysis and whether complement is involved in the hemolytic process. RBCs and/or RBC-derived microvesicles from patients with STEC-HUS (n = 25) were investigated for the presence of C3 and C9 by flow cytometry. Patients exhibited increased C3 deposition on RBCs compared with controls (p < 0.001), as well as high levels of C3- and C9-bearing RBC-derived microvesicles during the acute phase, which decreased after recovery. Stx2 bound to P1 (k) and P2 (k) phenotype RBCs, expressing high levels of the P(k) Ag (globotriaosylceramide), the known Stx receptor. Stx2 induced the release of hemoglobin and lactate dehydrogenase in whole blood, indicating hemolysis. Stx2-induced hemolysis was not demonstrated in the absence of plasma and was inhibited by heat inactivation, as well as by the terminal complement pathway Ab eculizumab, the purinergic P2 receptor antagonist suramin, and EDTA. In the presence of whole blood or plasma/serum, Stx2 induced the release of RBC-derived microvesicles coated with C5b-9, a process that was inhibited by EDTA, in the absence of factor B, and by purinergic P2 receptor antagonists. Thus, complement-coated RBC-derived microvesicles are elevated in HUS patients and induced in vitro by incubation of RBCs with Stx2, which also induced hemolysis. The role of complement in Stx2-mediated hemolysis was demonstrated by its occurrence only in the presence of plasma and its abrogation by heat inactivation, EDTA, and eculizumab. Complement activation on RBCs could play a role in the hemolytic process occurring during STEC-HUS.
authors: Department of Pediatrics, Clinical Sciences Lund, Lund University, 22184 Lund, Sweden;
authors: Ida
authors: I
authors: Arvidsson
authors: Department of Pediatrics, Clinical Sciences Lund, Lund University, 22184 Lund, Sweden;
authors: Anne-Lie
authors: AL
authors: Ståhl
authors: Department of Pediatrics, Clinical Sciences Lund, Lund University, 22184 Lund, Sweden;
authors: Minola Manea
authors: MM
authors: Hedström
authors: Department of Pediatrics, Clinical Sciences Lund, Lund University, 22184 Lund, Sweden;
authors: Ann-Charlotte
authors: AC
authors: Kristoffersson
authors: Department of Anesthesia and Intensive Care, Sahlgrenska University Hospital, 41345 Gothenburg, Sweden; and.
authors: Christian
authors: C
authors: Rylander
authors: Department of Hematology and Transfusion Medicine, Lund University, 22184 Lund, Sweden.
authors: Julia S
authors: JS
authors: Westman
authors: Department of Hematology and Transfusion Medicine, Lund University, 22184 Lund, Sweden.
authors: Jill R
authors: JR
authors: Storry
authors: Department of Hematology and Transfusion Medicine, Lund University, 22184 Lund, Sweden.
authors: Martin L
authors: ML
authors: Olsson
authors: Department of Pediatrics, Clinical Sciences Lund, Lund University, 22184 Lund, Sweden; Diana.Karpman@med.lu.se.
authors: Diana
authors: D
authors: Karpman
mesh_terms: D000328:Adult; D000368:Aged; D061067:Antibodies, Monoclonal, Humanized / Q000494:pharmacology; D002648:Child; D002675:Child, Preschool; D018699:Coated Vesicles / Q000737:chemistry / Q000187:drug effects* / Q000276:immunology; D003167:Complement Activation / Q000187:drug effects; D003176:Complement C3 / Q000737:chemistry; D003186:Complement C9 / Q000737:chemistry; D015938:Complement Membrane Attack Complex / Q000737:chemistry; D004492:Edetic Acid / Q000494:pharmacology; D004912:Erythrocytes / Q000737:chemistry / Q000187:drug effects* / Q000276:immunology / Q000473:pathology; D004927:Escherichia coli Infections / Q000097:blood* / Q000276:immunology / Q000382:microbiology / Q000473:pathology; D019453:Escherichia coli O157 / Q000276:immunology / Q000378:metabolism / Q000472:pathogenicity*; D005260:Female; D015870:Gene Expression; D006461:Hemolysis / Q000187:drug effects; D006463:Hemolytic-Uremic Syndrome / Q000097:blood* / Q000276:immunology / Q000382:microbiology / Q000473:pathology; D006801:Humans; D007223:Infant; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D058919:Purinergic P2 Receptor Antagonists / Q000494:pharmacology; D018048:Receptors, Purinergic P2 / Q000235:genetics / Q000276:immunology; D022621:Shiga Toxin / Q000737:chemistry / Q000276:immunology / Q000633:toxicity*; D013498:Suramin / Q000494:pharmacology; D014281:Trihexosylceramides / Q000276:immunology
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D003176:Complement C3; D003186:Complement C9; D015938:Complement Membrane Attack Complex; D058919:Purinergic P2 Receptor Antagonists; D018048:Receptors, Purinergic P2; D014281:Trihexosylceramides; D013498:Suramin; C018549:globotriaosylceramide; D022621:Shiga Toxin; D004492:Edetic Acid; C481642:eculizumab; D007770:L-Lactate Dehydrogenase