EGPA Symptoms More Pronounced in ANCA-positive Cases
Symptoms differ among people with the rare disorder eosinophilic granulomatosis with polyangiitis (EGPA), depending on whether they test positive or negative for antineutrophil cytoplasmic antibodies (ANCAs).
A recent case study revealed that ANCA-positive patients tended to have more blisters, body-wide inflammatory symptoms, and to receive higher doses of oral prednisolone and other immunosuppressive therapies.
The study, “Relevance of cutaneous manifestations and antineutrophil cytoplasmic antibody status in eosinophilic granulomatosis with polyangiitis,” was published in the Journal of Cutaneous Immunology and Allergy.
EGPA causes inflammation and the death of blood vessel-associated tissue in a wide variety of organs. A growing body of evidence suggests that EGPA symptoms differ based on whether a patient is positive for ANCAs.
Reports suggest that ANCA-positive cases involve the kidneys, peripheral nervous system (nerves outside the brain and spinal cord), and the skin. Approximately half of EGPA patients show skin involvement (cutaneous manifestations), which often associates with more severe symptoms spread across the body.
Skin lesions are easy to sample, which can help speed diagnosis. Much remains unknown, however, regarding the relationships between variations in the microscopic structure of skin samples and ANCA positivity.
To gain a better understanding of this relationship, researchers from the Tokyo Women’s Hospital in Japan reviewed the medical reports of nine EGPA cases diagnosed at their department of dermatology from 2005 to 2018.
Eight of the cases received diagnoses of definite EGPA, while one was classified as probable EGPA. Five tested positive for myeloperoxidase (MPO) — the most common ANCA found in EGPA cases.
Although skin symptoms occurred in both ANCA-positive and negative patients, blisters were most common in the ANCA-positive group (four cases, 80%) compared to the ANCA-negative group (one case, 25%).
Inflammation in the blood vessels running through muscles was present in two ANCA-negative patients and one ANCA-positive patient, whereas all patients displayed small vessel inflammation within the skin.
Furthermore, fever (two cases) and kidney involvement (one case) were observed only among ANCA-positive individuals. Other organs were affected at equivalent rates in ANCA-positive and ANCA-negative groups.
Microscopic examination of tissue samples (histopathology) also revealed some differences. Elevated levels of eosinophils, a type of disease-fighting white blood cell, and blisters occurred more often in ANCA-positive patients, whereas both groups had the same levels of neutrophils, another type of white blood cell. A type of chronic inflammation involving a mix of white blood cells was observed in one ANCA-positive patient.
ANCA-positive patients received higher doses of prednisolone than the ANCA-negative counterparts, a mean of 50 mg daily dose versus 36.25 mg. Only the ANCA-positive patients used other immunosuppressive medications.
The researchers also presented details of two patients as examples of the contrasting findings between ANCA-positive and negative individuals.
First, a 39-year-old female positive for MPO-ANCA had fever accompanying damaged small vessels in her lower leg. Doctors diagnosed her with eosinophilic pneumonia and histopathology revealed inflammation of small blood vessels in the dermis, which is the layer just below the outermost layer of skin.
Second, a 33-year-old, ANCA-negative male patient arrived at hospital with slightly red and hardened lower leg lesions and vocal cord paralysis. Histopathological examination revealed muscular-vessel inflammation just below the skin, in addition to inflamed small vessels within the dermis.
Overall, the data “indicate that ANCA-positive patients often present with blisters, systemic inflammatory symptoms, and are prone to receive a higher dose of oral prednisolone and additional immunosuppressive therapies,” the researchers wrote.
The team believes the “findings highlight the potential diagnostic importance of cutaneous manifestations and ANCA status in the evaluation and management of EGPA,” and suggest that “further studies are required to support our theory and improve the understanding of the pathogenic roles of ANCAs in EGPA.”