PhD defence R.C.A. (Ruben) de Groot

Below is a brief summary of the dissertation:

In this thesis we describe several studies on the host response to Mycoplasma pneumoniae. Mycoplasma pneumoniae is the most common bacteria to cause pneumonia in children. We showed that antibodies are very important during pneumonia caused by Mycoplasma pneumoniae. However, antibodies did not clear the upper airways of Mycoplasma pneumoniae. Furthermore, presence of Mycoplasma pneumoniae in the upper airways did not lead to the production of antibodies, whereas this is the case for other bacteria. The presence of Mycoplasma pneumoniae in the upper airways, or carriage, did lead to other responses, since we observed that Mycoplasma pneumoniae was cleared from the lungs faster if pneumonia occurred after Mycoplasma pneumoniae carriage. Surprisingly, we noted that accelerated Mycoplasma pneumoniae clearance also resulted in more lung damage. Children with recurrent respiratory infections more often carried Mycoplasma pneumoniae in the upper airways; together with other bacteria known for respiratory infections. We also observed that the cells that cover the airways did not produce as much inflammation compared to pneumococcal bacteria, which also cause pneumonia in children.