Inhibitory effect of bilirubin on complement-mediated hemolysis

We investigated the in vitro action of the bile pigments, unconjugated bilirubin (UB) and bilirubin monoglucuronide (BMG) on complement (C) cascade reaction. Both UB and BMG inhibited hemolysis in the classical pathway (CP) in a dose-dependent manner at low micromolar concentrations, UB showing a stronger effect than BMG. The analysis of the action of UB on the hemolytic activity of the C1, C4, C2 and C-EDTA components of the C cascade revealed that the C1 step was the most inhibited. An enzyme immunoassay was developed to evaluate the effect of UB on the binding of C1q, one of the subcomponents of C1, to human IgM and IgG. The study demonstrated that the unconjugated pigment interferes both the C1q-IgM and -IgG interactions, thus tentatively explaining the inhibitory action of UB on hemolytic activity of C1. We conclude that the anti-complement effect of UB is mainly exerted on the C1 component, the recognition unit of CP. The potential clinical implication of the reported effects in hyperbilirubinemia is discussed.

Medienart:

Artikel

Erscheinungsjahr:

1999

Erschienen:

1999

Enthalten in:

Zur Gesamtaufnahme - volume:1473

Enthalten in:

Biochimica et biophysica acta - 1473(1999), 2-3 vom: 27. Dez., Seite 329-36

Sprache:

Englisch

Beteiligte Personen:

Arriaga, S M [VerfasserIn]
Mottino, A D [VerfasserIn]
Almará, A M [VerfasserIn]

Themen:

27071-67-6
80295-33-6
9007-36-7
Bilirubin
Bilirubin glucuronate
Complement C1
Complement C1q
Complement Inactivator Proteins
Complement System Proteins
Immunoglobulin G
Immunoglobulin M
Journal Article
RFM9X3LJ49
Research Support, Non-U.S. Gov't

Anmerkungen:

Date Completed 14.02.2000

Date Revised 10.06.2019

published: Print

Citation Status MEDLINE

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM105241652