Authors retract Nature Medicine cystic fibrosis paper after some results don’t hold up

The authors of a Nature Medicine study published online in September about the behavior of white blood cells in cystic fibrosis have retracted the paper, saying that further experiments suggested the original results were unreliable. According to the notice:

In the version of this article initially published, we reported that CXCL8 could efficiently induce neutrophil extracellular trap (NET) formation in vitro. When we followed up on the effect of recombinant CXCL8 (IL-8) on NET formation by comparing different cell culture conditions and extending our studies to neutrophils obtained from a larger number of healthy blood donors, we found that the CXCL8 effect was donor dependent and was less robust than we previously thought. In investigating the underlying factors, we observed that the CXCL8 effect that we initially observed was favored by our cell culture conditions (CXCL8-72aa (CXCL8 that is 72 amino acids in length) at 100 nM; RPMI-1640 medium; absence of albumin, buffers or serum; supplementation with L-glutamine; and precoating of culture plates with poly-D-lysine 30–70 kDa). We had initially chosen these conditions because we felt that they resembled the pulmonary microenvironment. On the basis of our recent observations, however, we conclude that these culture conditions are unstable and allow nonspecific neutrophil activation and autocrine/paracrine CXCL8 release.

In light of these results, we revise our conclusions to state that the effect of recombinant CXCL8 on NET formation is less efficient than we previously reported, donor dependent and less robust compared to the effect of phorbol 12-myristate 13-acetate. Thus, we wish to retract the paper.

As @biochembelle, who tipped us off to the retraction, noted,

This is the way to present retractions-transparent, detailed, and open to all. Well done, Nature Med (and authors)…

The paper has been cited nine times since it was published in September, according to Thomson Scientific’s Web of Knowledge.

The only questions we had for the authors were about the final paragraph of the retraction notice:

We did not use this in vitro methodology in the ex vivo and in vivo studies of human and mouse cystic fibrosis lung disease. Accordingly, we continue to endorse our NETosis studies in the context of cystic fibrosis lung disease.

Those studies were part of the paper now being retracted. So why retract the entire study, instead of just issuing a correction? Corresponding author Dominik Hartl tells Retraction Watch:

I felt that a partial retraction or a full retraction is the clearest way to go. Since NatMed does not do partial retraction, it took this road!

Indeed, the Committee on Publication Ethics recommends against partial retractions:

Partial retractions are not helpful because they make it difficult for readers to determine the status of the article and which parts may be relied upon.

We’d like to commend Hartl and his coauthors. Others would have hemmed and hawed, finding a reason to make this at most a correction. But the Tubingen team bent over backward to make it clear what happened, even if it meant a retraction on their CVs.