Clinical efficacy of protein A immunoadsorption therapy on severe ANCA-associated vasculitis renal injury

The anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a group of diseases involving multiple systems, and kidney is one of the most commonly involved target organs. Some patients may rapidly progress to end-stage renal disease in a short time. Whereas some patients have poor remission and renal prognosis after standard induction therapy. As a selective blood purification therapy, protein a immunoadsorption (PAIA) has shown great advantages on treating of severe autoimmune diseases. This study aims to evaluate the short-term efficacy of PAIA therapy combined with glucocorticoids and immunosuppressants on treating of severe AAV renal injury.

A total of 10 AAV cases with severe kidney involvement in the Second Xiangya Hospital of Central South University from 2019 to 2020 were selected for this retrospective study. During the induction remission stage, each patient was treated with PAIA on the basis of standard therapy of glucocorticoids and immunosuppressive treatment. Before and after the initial treatment, 1 month and 3 months after treatment, clinical data including demographic characteristics, immunological indicators, and Birmingham Vasculitis Activity Score (BVAS) were compared. The related adverse reactions during treatment were recorded to evaluate the short-term efficacy.

In this study, all 10 patients were MPO positive, and 2 patients were PR3 positive (≥2.3 U/mL). There are 6 males and 4 females at (61.5±11.4) years old, with the median time from onset to admission to hospital at (2.8±1.8) months. Multisystem damage, especially kidney damage, can be seen with eGFR lower than 30 mL/(min·1.73 m²). During the 3-month follow-up, BVAS, erythrocyte sedimentation rate, and hemoglobin of 10 patients showed continuous improvement compared with the initial admission levels (all P<0.05). ANCA titer, serum creatinine and urine red blood cell were all decreased and eGFR levels were increased in 3 months after treatment (all P<0.05). Serum albumin, urinary protein, C-reactive protein and complement levels showed no significant changes after treatment (all P>0.05). One patient who had received renal replacement therapy was still dialysis dependent after PAIA treatment. One patient who had transient hypotension was corrected by routine treatment. The rest of the patients were all tolerant with PAIA during their treatments.

Treatment with PAIA combined with glucocorticoids and cyclophosphamide can rapidly lower serum ANCA level and improve disease activity in patients with AAV complicated with severe kidney damage, suggesting a good short-term renal prognosis and good overall safety.