  It has been suggested that some radio-loud narrow-line Seyfert 1 contain
relativistic jets, on the basis of their flat-spectrum radio nuclei and studies
on variability. We present preliminary results of an ongoing investigation of
the X-ray and multiwavelength properties of 5 radio-loud NLS1 based on archival
data from Swift and XMM-Newton. Some sources present interesting
characteristics, very uncharacteristic for a radio-quiet narrow-line Seyfert 1,
such as very hard X-ray spectra, and correlated optical and ultraviolet
variability. However, none of the studied sources show conclusive evidence for
relativistic jets. gamma-ray observations with Fermi are strongly recommended
to definitely decide on the presence or not of relativistic jets.
