Recent findings on the capacity of omeprazole to influence various leukocyt
e functions, in vitro, raises the question on the potential use of protonic
pump inhibitors, commonly used in the treatment of acid-secretion-related
disorders, as immunomodulators. The aim of this study was to evaluate the i
n vitro effect of lansoprazole on human natural killer (NK) cell cytotoxix
activity, chemotaxis and superoxide anion (02*(-)) generation exerted by po
lymorphonucleated cells (PMNs). NK cytotoxicity activity was assessed by a
Cr-51 release assay, PMN chemotaxis was determined by an under agarose meth
od and O2*(-) generation was analyzed on the basis of reduced cytochrome C.
Incubation times with lansoprazole was 30 min for PMNs and 1-4.5 hours for
NK cells, respectively. Lansoprazole induced significant dose dependent in
hibition of NK cell activity and PMN functions at concentrations ranging fr
om 100 to 1,000 mu M.
This study demonstrate that lansoprazole, like omeprazole, inhibits several
leukocyte functions, in vitro, then suggesting that protonic pump inhibito
rs are able to provoke these effects, at least at certain doses.