Rapid diagnosis of Streptococcus pneumoniae-induced haemolytic-uraemic syndrome.

Haemolytic-uraemic syndrome (HUS) is caused in many cases by an enteral infection with enterohaemorrhagic Escherichia coli (EHEC), Shigella dysenteriae type 1 or Citrobacter freundii producing Shiga-toxin, or by hereditary or acquired defects of the regulation of the complement cascade1–4. In rare cases infections with bacteria not producing Shiga-toxin, such as Streptococcus pneumoniae and Clostridium perfringens (e.g. in pneumonia, necrotising enterocolitis, sepsis or gas gangrene), can also cause life-threatening haemolysis, coagulation disorder, and acute renal failure5–9. Through the effect of the enzyme sialidase, these bacteria can unmask a normally hidden antigen on the red blood cell surface. This cryptic antigen, called T-antigen, was first described in vitro by Thomsen and Friedenreich10,11. The pathogenic part of a potential reaction of the corresponding antibody (of the IgM-class) in human plasma (anti-T) with the T-antigen in vivo is a source of controversy, since the optimal temperature of this antibody is lower than body temperature and other bacterial toxins (e.g. lecithinase in several Clostridium spp.) are also very strong haemolysins12,13. Independently of the pathogenic mechanism, detection of T-antigen activation on red blood cells can be of differential diagnostic value in acute haemolysis9. Here we report the case of life-threatening HUS in a child, in whom the combination of immunohaematological findings in the blood grouping laboratory and immunological detection of bacterial antigens in the patient’s body fluids led to the correct diagnosis of the underlying disease within only a few hours.