Changes in proteins and antibodies suggesting immune dysregulation may be detectable in serum years before clinical manifestation of complicated Crohn’s disease, shows a study recently published in Clinical Gastroenterology and Hepatology.
These preclinical signatures could one day play a role in screening for complicated Crohn’s disease (CD) and in mapping underlying disease pathways, potentially opening doors to new preventive approaches, wrote study authors who were led by Joseph A. Murray, MD, of the division of gastroenterology and hepatology at Mayo Clinic, Rochester, Minn.
“Mounting evidence suggests that the diagnosis of CD is preceded by a lengthy asymptomatic preclinical period,” investigators wrote. “Gaining insight into this phase may allow a better understanding of the primary events that lead to its development and offer potential strategies to predict and prevent the disease including its complications.”
The study, which was a nested case-control study based on the PREDICTS study, included 201 patients with CD who had serum samples archived 2, 4, and 6 years prior to diagnosis, as well as 201 healthy controls who provided serum samples for comparison. Serum samples were analyzed with a comprehensive panel of 1,129 proteomic markers and antimicrobial antibodies.
At time of diagnosis, 47 of the patients with CD (24%) had a complicated phenotype, including stricturing behavior, penetrating behavior, or need for early surgery.
“The unique availability of preclinical samples collected at multiple time points allowed us to examine the sequence of immunological changes and protein biomarkers that occurred before diagnosis,” the investigators wrote. “We also evaluated a wide array of protein biomarkers, utilizing a novel proteomic platform, and applied novel rigorous statistical approaches, which allowed us to discover the potential biomarkers and biologic pathways for the complicated phenotypes even before diagnosis.”
As early as 6 years before diagnosis, patients with complicated CD had significantly higher levels of antimicrobial antibodies than patients with noncomplicated CD, as well as elevations in 22 protein biomarkers indicating immune dysregulation.
Specifically, complicated CD was preceded by elevated anti–Saccharomyces cerevisiae antibodies (ASCA) IgA/IgG, anti-Flagellin antibodies, and other proteins linked with fibrosis, adaptive immunity, and innate immunity. Simultaneously, the same patients had reduced levels of protein biomarkers linked with protection against fibrosis and tissue damage. Network analysis added weight to these findings by demonstrating a significant correlation between ASCA IgA/IgG and protein biomarkers tied to innate immunity and lack of factors for tissue protection.
“Altogether, the hypothesis can be proposed that the combination of increasing levels of inflammatory cytokines, loss of anti-inflammatory proteins, and production of antimicrobial antibodies could accelerate and magnify tissue destruction and fibrosis driving complications at diagnosis in CD,” the investigators wrote. “These data support the concept that complicated CD may not always be the result of the progression of an uncontrolled inflammatory disease but may also be the consequence of a unique pathophysiological process.”
The findings deserve further investigation as they could lead to new clinical tools for screening and intervention. “The serological signature that we identified could help to further select subjects at risk of developing complicated CD who could be preferential candidates for preventative strategies,” investigators wrote.
The investigators disclosed relationships with Janssen, AbbVie, Galapagos, and others.
