According to the results of examination for mycoplasma infection, positive IgM to M. pneumoniae were detected and it was decided to change the antibacterial drug to clarithromycin, an antibiotic from the macrolides group, despite the fact that M. pneumoniae DNA was not detected during the PCR examination of the oropharyngeal swab. Here, CD40LG is linked to Mycoplasmoides infection.