CRP and tonsillitis: This would suggest that cef is also upregulated during invasive disease in the absence of SpeB and is further supported by evidence from a transcriptome study in S. pyogenes infected cynomolgus macaques which showed a strong correlation of spy0136/cef expression with peak levels of C-reactive protein, a sensitive serum marker of inflammation, and a negative correlation with the development of pharyngitis and tonsillitis [59].