RESEARCH - Lactoferrin is a survival factor for neutrophils in rheumatoid synovial fluid

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Rheumatology Advance Access originally published online on November 23, 2008

Rheumatology 2009 48(1):39-44; doi:10.1093/rheumatology/ken412

Lactoferrin is a survival factor for neutrophils in rheumatoid synovial fluid

S. H. Wong1, N. Francis1, H. Chahal1, K. Raza1, M. Salmon1, D.

Scheel-Toellner1 and J. M. Lord1

1Rheumatology Research Group, MRC Centre for Immune Regulation,

Institute of Biomedical Research, Birmingham University, Birmingham,

UK.

Abstract

Objectives. Lactoferrin is an iron-binding protein that is released

from activated neutrophils at sites of inflammation and has

anti-microbial as well as anti-inflammatory properties. This study set

out to determine whether lactoferrin can delay neutrophil apoptosis

and could act as a survival factor for neutrophils in SF.

Methods. Human peripheral blood and SF neutrophils were incubated with

iron-free lactoferrin and apoptosis determined after 9 h. SF from

patients with RA was added to isolated neutrophils, with or without

immunodepletion of lactoferrin, and effects on neutrophil apoptosis

determined. Levels of lactoferrin in SF were assessed and related to

disease duration and markers of disease activity.

Results. Iron-free lactoferrin significantly delayed apoptosis of

peripheral blood neutrophils, in a concentration-dependent manner

after 9 h in culture (P < 0.04). Lactoferrin could also delay

apoptosis of neutrophils isolated from SF of patients with RA. SF from

patients with established RA delayed apoptosis of peripheral blood

neutrophils and this effect was significantly reduced by depletion of

lactoferrin (P < 0.03). Lactoferrin levels in SF from patients with

established RA did not correlate with disease severity, but did

correlate with markers of inflammation (CRP) and with the presence of

RF. SF from patients with arthritis of <12 weeks duration did not

contain significant levels of lactoferrin.

Conclusion. Lactoferrin contributes to extended neutrophil survival in

the rheumatoid joint in the established phase of RA but not in very

early arthritis.

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Read the full article here:

http://rheumatology.oxfordjournals.org/cgi/content/full/48/1/39

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