Myeloperoxidase (MPO) antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) may develop after infection and regress after its resolution, according to data from a systematic review published in Clinical Immunology.
Although multiple autoantibodies may develop during infection, not all of them lead to vasculitis manifestations. However, previous studies have suggested that the production of anti-MPO-autoantibodies can lead to the development of vasculitis.
The objective of the current systematic review was to identify cases of MPO-AAV that occurred during or after the development of infection, and to describe their clinical characteristics and outcomes. The current analysis was based on uncontrolled studies, all of which were case reports.
The primary outcome was all-cause mortality, and secondary outcomes included identifying the types of pathogens associated with MPO-AAV, nonfatal outcomes of patients who developed MPO-AAV, rate of glomerulonephritis associated with MPO-AAV, treatments provided in these cases, and the rheumatologic diagnosis.
Of 658 articles identified in the PubMed database, 18 articles describing 23 patients (mean age, 50.5 years; 14 women) were included in the review. In the 13 reports with available data, the median time between the onset of infection and the development of vasculitis was 3 months (range, 3 weeks – 10 years). In approximately one-third of patients (n=7; 30.4%), the final rheumatologic diagnosis was microscopic polyangiitis.
A total of 5 fatalities (21.7%) were documented during follow-up, including 1 case of death due to missed diagnosis of infection, 1 that was secondary to vasculitis complication, 2 due to the disease despite treatment, and 1 due to self-discontinuation of treatment, which previously controlled the disease.
Renal involvement was the most frequent clinical manifestation (73.9%), with 14 patients (60.9%) with biopsy-proven glomerulonephritis. Bacteria was the most common pathogen associated with MPO-AAV during or after infection, including Staphylococcus aureus, S viridians, Enterococcus species, coagulase-negative Staphylococcus, S epidermidis, and Escherichia coli. In addition, Rickettsia rickettsii, Coccidioides species, and Mycobacterium species were also reported. Viruses, including Epstein-Barr virus, cytomegalovirus, and dengue virus infection, were documented in 6 cases.
A total of 18 of the 23 patients received immunosuppressive treatment, most commonly high-dose corticosteroids or cyclophosphamide. Type of infection, administration of immunosuppressive treatment, and development of glomerulonephritis had no significant effect on patient survival or treatment response and development of long-term complications.
The review had several limitations, including the small number of cases and the inclusion of only case reports as larger series were not available.
“Clinicians should be alert for the presence of an underlying infection in patients presenting with MPO-AAV, especially in cases that do not respond to aggressive immunosuppression,” the researchers concluded.
Kakoullis L, Parperis K, Papachristodoulou E, Panos G. Infection-induced myeloperoxidase specific antineutrophil cytoplasmic antibody (MPO-ANCA) associated vasculitis: a systematic review. Clin Immunol. Published online September 19, 2020. doi:10.1016/j.clim.2020.108595