MAUI, HAWAII – An underlying primary immunodeficiency is far more common among patients in rheumatologists’ offices than is generally appreciated, Anna Postolova, MD, said at the 2020 Rheumatology Winter Clinical Symposium.
Bruce Jancin/MDedge News
Dr. Anna Postolova
“Autoimmunity and immunodeficiency are often incorrectly thought to be mutually exclusive, but I hope to convey to you that they actually run together more than we think, and more than you realize. In the immunodeficiency community, we’re now realizing that autoimmunity can be the first presentation of an immunodeficiency disease,” according to Dr. Postolova, a dual rheumatologist and allergist/immunologist at Stanford (Calif.) University.
She cited a major retrospective study of 2,183 consecutive patients with primary immunodeficiencies (PIDs), mean age 25.8 years, enrolled in a French national PID registry. Of these patients, 26% had at least one autoimmune or inflammatory condition. The French investigators, all immunologists, categorized 12.8% of the PID patients as having rheumatologic disorders, but Dr. Postolova is convinced this figure would have been substantially higher had a rheumatologist been on the research team. That’s because vasculitis and inflammatory eye disorders weren’t included in the rheumatologic disease category, and psoriatic arthritis was probably present but undiagnosed in some psoriasis patients grouped in the skin disease category.
“Our results demonstrate that autoimmune and inflammatory diseases are much more frequent by a factor of at least 10 in patients with PIDs than in the general population,” the French investigators observed.
Indeed, the relative risks of vasculitis, inflammatory eye disease, and skin disease in patients with PID were increased 13-, 7-, and 10-fold, respectively. French children with PID were at 40-fold increased risk for rheumatoid arthritis and 80-fold elevated risk for inflammatory bowel disease.
Among the PID patients with at least one autoimmune or inflammatory condition, 31.6% had more than one. And therein lies a clue for rheumatologists.
“You might have some patients in your panel who have both arthritis and vasculitis, for example. It’s not that common for our patients to have two of our diseases, but those are the ones who might have an immune dysregulatory inborn error of metabolism mutation that’s driving their disease – and we’re now able to look into that,” Dr. Postolova explained.
At present, more than 300 identified single-gene inborn errors of immunity have been identified, some of which can manifest variously as systemic lupus erythematosus (SLE), arthritis, vasculitis, and/or cytopenias, she noted.
In the French study, onset of autoimmune or inflammatory manifestations of PID occurred across the age spectrum. The age of onset was earlier with T-cell and innate immunity deficiencies than in patients with B-cell deficiencies. The prevalence of an autoimmune or inflammatory disorder was greater than 40% in PID patients age 50 years or older.
“What I want to hammer home is these patients with PID are no longer succumbing to their infections. They’re being identified as having an immunodeficiency, they’re going on antibiotics, they’re strictly monitored, and they’re growing older. And as their aberrant immune system fights an infection, they have more and more time to dysregulate and develop one of our diseases. So in the coming years I think you’re going to see a lot more of these patients show up in your rheumatology clinic because they are getting older,” Dr. Postolova said.