Immunological Characteristics of Chinese Adult Patients with Anti-Complement Factor H Autoantibodies-Associated...

Anti-complement factor H autoantibodies (FHAAs)-associated complement-mediated thrombotic microangiopathy (CM-TMA) is prevalent in pediatric patients and plays an important role in the pathogenesis of CM-TMA. The epitopes of FHAAs in adult CM-TMA patients remain to be explored.

A total of 114 adult patients with CM-TMA were enrolled. Their clinicopathological data as well as plasma samples were collected. Seven CFH fragments covering different short consensus repeats (SCRs) of factor H were expressed by HEK293 or ExpiCHO cells. The presence of FHAAs and the antigenic epitopes were detected by using enzyme-linked immunosorbent assay.

FHAAs were detected in 10 of the adult patients with CM-TMA. The main epitope of FHAAs was SCRs 15-20 (88.89%, 8/9). The prevalence of anti-SCRs 1-4, anti-SCRs 1-6, anti-SCRs 5-7, anti-SCR 7, anti-SCRs 11-14, and anti-SCRs 19-20 autoantibodies was 22.22% (2/9), 0% (0/9), 33.33% (3/9), 11.11% (1/9), 0% (0/9), and 44.44% (4/9), respectively. The levels of anti-SCRs 15-20 autoantibodies were significantly decreased in the remission phase compared with that in the active phase (107.49 ± 36.8 AU/mL vs. 181.52 ± 33.62 AU/mL, p = 0.04). Malignant hypertension was found in 60% (6/10) of patients with FHAA-associated CM-TMA. Eighty percent (8/10) of these patients had a poor prognosis, including 5 with end-stage kidney disease, 2 with renal transplantation, and 1 patient who died.

FHAAs were positive in 8.77% (10/114) of adult CM-TMA patients and SCRs 15-20 might be the main epitope of FHAAs in FHAA-associated CM-TMA.