Interleukin-6(IL-6)isamulti-functionalcytokinethatregulatesimmuneresponses,acutephasereactionsandhematopoiesisandmayplayacentralroleinhostdefensemechanisms.
IL-6isusuallynotproducedconstitutivelybynormalcells,butitsexpressionisreADIlyinducedbyavarietyofcytokines,lipopolysaccharideorviralinfections.IL-6isapleiotropiccytokineproducedbyavarietyofcells.Itactsonawiderangeoftissues,exertinggrowth-induction,growth-inhibition,anddifferentiationrespectively,dependingonthenatureofthetargetcells.

IL-6isinvolvedin

-theinductionofB-celldifferentiation
-theinductionofacutephaseproteinsinlivercells
-growthpromotionofmyeloma/plasmacytoma/hybridomacells
-inductionofIL-2andIL-2receptorexpression
-proliferationanddifferentiationofTcells
-inhibitionofcellgrowthofcertainmyeloidleukemiccelllinesandinductionoftheirdifferentiationtomacrophages
-enhancementofIL-3-inducedmultipotentialcolonycellformationinhematopoieticstemcellsandinductionofmaturationofmegakaryocytesasathrombopoieticfactor
-inductionofmesangialcellgrowth
-inductionofneuraldifferentiationofPC12cellsand
-inductionofkeratinocytegrowth

TheabnormalproductionofIL-6wasfirstsuggestedtoberelatedtopolyclonalB-cellactivationwithautoantibodyproductioninpatientswithcardiacmyxoma.Sincethen,IL-6hasbeensuggestedtobeinvolvedinthepathogenesisofavarietyofdiseases.MeasurementofIL-6levelsinserumandotherbodyfluidsthusprovidesmoredetailedinsightsintovariouspathologicalsituations.

Synonyms:Interferon-beta2,B-cellstimulatoryfactor2,HGF