  Much effort has been done in order to better understand the active galactic
nuclei mechanisms behind the relativistic jets observed in radio-loud sources.
These phenomena are commonly seen in luminous objects with intermediate/high
redshift such as quasars, so that the analysis of the spectroscopic properties
of these sources may be a way to clarify this issue. Measurements are presented
and contextualized taking advantage of the set of correlations associated with
the quasar Main Sequence (MS), a parameter space that allows to connect
observed properties to the relative relevance of radiative and gravitational
forces. In the redshift range we consider, the low-ionization HI Balmer line
H\b{eta} is shifted into the near infrared. Here we present first results of a
sample of 22 high-luminosity quasars with redshift between 1.4 and 3.8.
Observations covering the H\b{eta} spectral region were collected with the IR
spectrometer ISAAC at ESO-VLT. Additional data were collected from SDSS in
order to cover the UV region of our sources. The comparison between the strong
C IV {\lambda}1549 high-ionization line and H\b{eta} in terms of line widths
and shifts with respect to the rest-frame leads to an evaluation of the role of
radiative forces in driving an accretion disk wind. While for non-jetted
quasars the wind properties have been extensively characterized as a function
of luminosity and other physical parameters, the situation is by far less clear
for jetted sources. The overarching issue is the effect of the relativistic
jets on the wind, and on the structure of the emitting region in general. We
present results from our analysis of the optical and UV line profiles aimed to
identifying the wind contribution to the line emission.

Astrophysics of Galaxies