Doctors need to better understand IgG4 pancreatitis, study says
Researchers note 'insidious onset' of condition, urge early diagnosis
As IgG4-related pancreatitis, or pancreas inflammation, becomes increasingly recognized as a manifestation of IgG4-related disease (IgG4-RD), physicians need to better understand how to recognize and treat it, according to a review study giving a comprehensive overview of the clinical features associated with IgG4-related pancreatitis (IRP) and how it should be diagnosed and treated.
The authors noted a need for more research that will advance patient care.
“Early diagnosis of IRP and the optimization of personalized treatment strategies will be key focuses of future research,” the scientists wrote. “Additionally, long-term follow-up and disease management mechanisms need further refinement.”
The study, “A comprehensive review of IgG4-related pancreatitis: pathogenesis, diagnosis, and therapeutic advances,” was published in Frontiers in Immunology.
In IgG4-RD, immune cells — particularly ones that secrete an antibody called IgG4 — infiltrate tissues, leading to inflammation, scarring, and the formation of tumor-like masses. IgG4-RD symptoms vary, depending on which organs are affected and to what degree.
Misdiagnosis common, researchers say
While IgG4-RD can cause problems in virtually any part of the body, among its most common clinical profiles is pancreato-hepatobiliary disease, which affects the pancreas, liver, and bile ducts (the tubes that transport the digestive fluid bile out of the liver).
People with this clinical profile often develop IRP. That corresponds to type 1 autoimmune pancreatitis, where the body’s immune system wrongly attacks the pancreas, causing inflammation and scarring.
IgG4-RD has become recognized as a distinct clinical condition in recent decades. Clinicians still have a limited understanding of the disease and its manifestations, and may often misdiagnose IRP as other forms of pancreatitis, pancreatic cysts, or cancer, according to the authors.
The team of scientists in China said they aimed to “provide a reference for clinical diagnosis and treatment practices of IRP” and “enhance comprehensive knowledge and accurate diagnostic capabilities for this disease, and avoid misdiagnosis that could delay treatment and affect patients’ quality of life.”
IRP is most commonly seen in middle-aged men, the researchers noted. The frequency of this form of pancreatitis is highest in Japan, and lower in Europe and the U.S.
“However, with advancements in diagnostic techniques and increased awareness worldwide, the detection rate of this disease has been gradually rising,” the scientists wrote.
To accurately diagnose the condition, physicians must consider clinical symptoms, results from blood tests and tissue analyses, the pattern of organ involvement outside the pancreas, and whether a person responds to glucocorticoids, the standard IgG4-RD treatment.
The pancreas has two essential functions: It produces enzymes to aid in digestion and hormones to regulate blood sugar. The symptoms of IRP are signs that these processes aren’t working as they should.
To reach a diagnosis of IgG4-RD, physicians should look for symptoms such as abdominal pain, bloating, weight loss, indigestion, fatty stool, and blood sugar changes, the researchers said. Itchy skin and jaundice, or a yellowing of the skin and whites of the eyes, are also common if the liver and bile ducts (which work closely with the pancreas in the digestive system) are affected.
These symptoms may come and go. However, in most cases IRP has an “insidious onset” and show no symptoms, according to the authors.
Many people with IRP will also have signs of IgG4-RD involvement in at least one other tissue or organ. Other diagnostic indicators include elevated blood levels of IgG4, an enlarged pancreas on imaging tests, and distinct cellular features when pancreatic tissue is examined under a microscope.
Doctors use the combination of these tests to identify hallmarks of IgG4-RD and to rule out differential diagnoses such as cancer or other forms of pancreatitis.
The standard treatment is a course of glucocorticoids, a class of potent anti-inflammatory and immunosuppressive medications. Most people respond to this treatment, although the disease can recur, or relapse.
Other immunosuppressive medications or more targeted therapies may be considered in difficult-to-treat cases or when glucocorticoids are poorly tolerated. Less often, surgery may be done to manage complications or in cases where the disease did not respond to first-line medications.
The scientists said future research should focus on identifying blood biomarkers of IgG4-related pancreatitis that will make it easier to diagnose and monitor. With more research will come better target therapeutics to improve long-term outcomes, they said.
“More targeted therapeutic agents are expected to emerge, improving patient prognosis,” the researchers wrote.
While several such therapies are in development, “the efficacy and safety of these drugs require further validation through larger-scale, multicenter [appropriately controlled] controlled trials,” the team concluded.
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