Thomsen-Friedenreich antigen exposure as a cause of Streptococcus pyogenes-associated hemolytic-uremic syndrome.

Infection with Streptococcus pyogenes, a Group A beta-hemolytic streptococcus (GAS), is a rare cause of hemolyticuremic syndrome (HUS). Invasive infections with Streptococcus pneumoniae that produce neuraminidase are a well-recognized cause of HUS without diarrhea. The Thomsen- Friedenreich antigen (T antigen) plays a role in the pathophysiology of pneumococcal HUS. We describe the case of a 3-year-old boy with GAS-associated HUS and show how T-antigen exposure was implicated in this case. He had no diarrhea and cultures for blood, urine, and stool were negative. The urinary pneumococcal antigen was negative; his direct Coombs test was positive. Glomerular capillary loops, tubular epithelium on his renal biopsy specimen, and red blood cells in his blood smear showed positive fluorescence with anti-T lectin. Although the pathogenesis of GAS-associated HUS is not well understood, T-antigen exposure may be implicated in some cases with GAS-associated HUS.