  We have observed a sample of 15 and 8 quasars with redshifts between 0.11 and
0.87 (mean value 0.38) in the J and K' bands respectively. Eleven of the
quasars were previously known to be associated with extended emission line
regions. After deconvolution of the image, substraction of the PSF when
possible, and identification of companions with the help of HST archive images
when available, extensions are seen for at least eleven quasars. However,
average profiles are different from that of the PSF in only four objects, for
which a good fit is obtained with an $r^{1/4}$ law, suggesting that the
underlying galaxies are ellipticals. Redshifts were available in the literature
for surrounding objects in five quasar fields. For these objects, one to five
companion galaxies were found. One quasar even belongs to a richness class 1
cluster. Most other quasars in our sample have nearby galaxies in projection
which may also be companions. Environmental effects are therefore probably
important to account for the properties of these objects.
