Peripheral blood eosinophilia may identify IBD patients who fare worse

Last Updated: 2017-11-21

By Lorraine L. Janeczko

NEW YORK (Reuters Health) - Peripheral blood eosinophilia (PBE) may be a biomarker for a subgroup of IBD patients with a unique inflammatory signature and worse clinical outcomes, according to a longitudinal study.

"Elevated peripheral blood eosinophils identified from the white-blood-cell differential in a complete blood count identified a subgroup of patients with more severe disease over a six-year period," said senior author Dr. David G. Binion of the University of Pittsburgh School of Medicine in Pennsylvania.

"IBD - Crohn's disease, ulcerative colitis - is a heterogeneous syndrome of chronic inflammation in the gastrointestinal tract, with varying degrees of severity and potential to damage the affected tissues," he told Reuters Health by email. "At present, it is difficult to differentiate subgroups using routinely available biomarkers."

As reported online November 7 in the American Journal of Gastroenterology, Dr. Binion and colleagues analyzed data from an academic medical network's IBD patient registry for 2009 to 2014.

Of 2,066 adults with IBD in the registry, 396 (19.2%) developed PBE. PBE was significantly associated with ulcerative colitis, extensive colitis, and shorter disease duration.

During the six-year study period, patients with PBE were significantly more likely than non-PBE patients to have active IBD and concurrently elevated C-reactive protein levels; to be hospitalized and undergo IBD surgery; and to require aggressive medical treatment (prednisone, anti-TNF therapy).

UC patients with PBE also had a significantly shorter time to colectomy.

In multivariable analyses, PBE remained closely linked with hospitalization and surgery in Crohn's disease and UC. A new UC diagnosis in a patient with PBE was linked with significantly greater need for an increase in steroid or anti-TNF dosing.

The authors acknowledge that because patients with PBE were more often hospitalized, they probably received more tests and were observed more intensively. In addition, serologic testing was done only in patients with suspected active disease.

Although the study was observational, the authors believe it provided a "real-world view" of patterns in a large, heterogeneous IBD population.

Dr. Alyssa Parian of Johns Hopkins University, in Baltimore, said in an email, "These results are very important, as we are always searching for predictors of more severe disease in order to risk-stratify our patients." She was not involved in the current study.

"The next steps would be to determine which therapies are most and least effective in this population," she added. "The worse outcomes of hospitalization, colectomy and steroid use may be due to the fact that 'standard' ulcerative colitis medications are not effective in this subgroup of patients."

"These patients may be candidates for targeted therapy once the mechanism of eosinophil function is better understood," she explained. "Checking peripheral blood eosinophils is a cheap and easy test that may be a way to begin personalizing treatment in IBD patients."

Dr. Ashwin N. Ananthakrishnan of Massachusetts General Hospital in Boston, who also was not involved in the study, noted, "It is always important to get biomarkers that predict aggressive disease."

He cautioned, though, that "we don't know whether the eosinophilia was caused by other conditions or medications (many allergic responses lead to eosinophilia as do some medications). It is also not clear which came first: the severe disease or the eosinophilia."

"While this finding will not change my clinical practice at this time, it's good data to have nonetheless," he said. "We need to define the immunologic underpinnings of the IBD patients with or without peripheral eosinophilia and their differential responses to treatment modalities as a next step."

SOURCE: http://go.nature.com/2hHIPGx

Am J Gastroenterol 2017.