Conformation-dependent anti-Aβ monoclonal antibody signatures of disease status and severity in urine of women with preeclampsia.

Prior research has shown that urine of women with preeclampsia (PE) contains amyloid-like aggregates that are congophilic (exhibit affinity for the amyloidophilic dye Congo red) and immunoreactive with A11, a polyclonal serum against prefibrillar β-amyloid oligomers, thereby supporting pathogenic similarity between PE and protein conformational disorders such as Alzheimer's and prion disease. The objective of this study was to interrogate PE urine using monoclonal antibodies with previously characterized A11-like epitopes. Over 100 conformation-dependent monoclonals were screened and three (mA11-09, mA11-89, and mA11-205) selected for further confirmation in 196 urine samples grouped as follows: severe features PE (sPE, n = 114), PE without severe features (mPE, n = 30), chronic hypertension (crHTN, n = 14) and normotensive pregnant control (P-CRL, n = 38). We showed that the selected conformation-specific monoclonals distinguished among patients with varying severities of PE from P-CRL and patients with crHTN. By use of latent class analysis (LCA) we identified three classes of subjects: Class 1 (n = 94) comprised patients whose urine was both congophilic and reactive with the monoclonals. These women were more likely diagnosed with early-onset sPE and had severe hypertension and proteinuria; Class 2 patients (n = 55) were negative for congophilia and against the antibodies. These were predominantly P-CRL and crHTN patients. Lastly, Class 3 patients (n = 48) were positive for urine congophilia, albeit at lower intensity, but negative for monoclonal immunoreactivities. These women were diagnosed primarily as mPE or late-onset sPE. Collectively, our study validates conformation-dependent Aβ imunoreactivity of PE urine which in conjunction to urine congophilia may represent an additional indicator of disease severity.