Multiple organ involvement more common in older IgG4-RD patients
Study: Disease predominantly affects a single organ in people 25 or younger
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Most adults ages 50 and older with immunoglobulin G4-related disease (IgG4-RD) have multiple organ involvement, whereas the disease predominantly affects a single organ in patients ages 25 years or younger, according to a study in Argentina.
Data also showed that older patients had more pronounced involvement of lymph nodes (immune structures throughout the body), salivary glands located below the jaw, and lungs. Younger patients showed a trend toward more frequent unilateral eye involvement.
“It is crucial to review the existing literature and present our data on IgG4-RD in children, adolescents and young adults, as this condition is often overlooked by pediatricians,” researchers wrote. “This fact, as in adult cases, could help prevent unnecessary surgeries and irreversible organ damage.”
The study, “Comparison of IgG4 related disease in patients aged ≤ 25 years (pediatric, adolescent, and young adult) and those aged ≥ 50 years,” was published in the journal Reumatología Clínica.
Researchers compared older adults with IgG4-RD to those under 25
IgG4-RD occurs when immune cells, particularly B-cells that produce a type of antibody called IgG4, infiltrate tissues. This results in inflammation and tumor-like masses or enlargements that can damage tissue, leading to a wide range of symptoms depending on which organs are affected.
“Several studies have been published on the differences in this disease between elderly patients and children, particularly in terms of gender distribution, the number of affected organs and the types of organs involved — internal organs in adults versus superficial organs in children,” the researchers wrote.
To learn more, researchers at two hospitals in Argentina conducted a retrospective study comparing IgG4-RD characteristics in children, adolescents, and young adults with those in older adults.
Of the 64 IgG4-RD patients followed at the researchers’ hospitals, seven (11%) were 25 years or younger, and 35 (54.7%) were 50 years or older. These 42 patients were included in the analysis.
Most were female (85.7% in the younger group and 57% in the older group), with a mean age of 21.3 years in the younger group and 60 years in the older group. Blood IgG4 levels were elevated in 42.9% of younger patients and 75.8% of older patients.
Nonspecific body-wide symptoms more common in older group
Single-organ involvement was significantly more common in the younger group (71.4% vs. 17.1%), while the older group was significantly more likely to have multiple organ involvement (82.9% vs. 28.6%).
Nonspecific body-wide symptoms were more common in the older group (62.9% vs. 28.6%), but this difference did not reach statistical significance. Still, feelings of generalized physical or mental weakness, fatigue, or loss of energy were reported significantly more often among older patients (57.1% vs. 14.3%).
The older group was significantly more likely to have swollen lymph nodes (57.1% vs. 14.3%), and swelling of the salivary glands below the jaw (54.3%) and lung involvement (51.4%) were present only in this group.
Eye involvement was more frequent in younger patients (57.1% vs. 31.4%), but this difference was not statistically significant. Still, eye involvement predominantly affected only one eye in younger patients, and both eyes in patients older than 50, with group differences reaching statistical significance.
No significant group differences were detected regarding laboratory data. However, older patients tended to show higher levels of inflammation markers and higher rates of very high IgG4 levels (54.5% vs. 14.3%).
Imaging studies are essential to rule out [body-wide] involvement, and biopsy of the affected organ is of particular importance to evaluate [tissue] findings in patients with these characteristics.
Data from biopsies of affected organs, where a small piece of tissue is collected for analysis under a microscope, showed that most younger patients (87.5%) and all older patients had tissue infiltration with immune cells, including antibody-producing B-cells.
Rates of infiltration with eosinophils, another type of immune cell sometimes found at higher levels in IgG4-RD patients, were numerically higher in older patients (76.5% vs. 42.9%).
Dense, irregular tissue scarring, called non-storiform fibrosis, was present in almost half of older patients (47.1%), but absent in younger patients. Storiform fibrosis, an IgG4-RD hallmark characterized by scarring in a swirling or “cartwheel” pattern, was found at comparable rates between groups.
“In patients aged [25 years and younger], organ involvement was predominantly single-organ and mainly unilateral,” and “most of these patients presented with normal [blood] IgG4 levels,” the researchers wrote. “Consequently, imaging studies are essential to rule out [body-wide] involvement, and biopsy of the affected organ is of particular importance to evaluate [tissue] findings in patients with these characteristics.”
