ESPN 51th Annual Meeting

ESPN 2018


 
Upgrade of serological diagnostics in STEC-HUS
KIOA WIJNSMA 2 SUSAN VEISSI 2 SHEILA VAN BOMMEL 2 ELENA VOLOKHINA 3 DIEGO COMERCI 1 JUAN UGALDE 1 NICOLE VAN DE KAR 2 BERT VAN DEN HEUVEL 3

1- INSTITUTO DE INVESTIGACIONES BIOTECNOLóGICAS DR. RODOLFO A. UGALDE, UNIVERSIDAD NACIONAL DE SAN MARTíN, BUENOS AIRES, ARGENTINA
2- DEPT. OF PEDIATRIC NEPHROLOGY, RADBOUDUMC AMALIA CHILDREN’S HOSPITAL, NIJMEGEN, THE NETHERLANDS
3- DEPT. OF LABORATORY MEDICINE, RADBOUD UNIVERSITY MEDICAL CENTER, NIJMEGEN, THE NETHERLAND
 
Introduction:

Differentiation between Shiga toxin producing E. coli (STEC) hemolytic uremic syndrome (HUS) and the rare atypical HUS remains a clinical conundrum. Atypical HUS is considered a diagnosis per exclusionem. Since the treatment of atypical HUS requires the highly expensive orphan drug eculizumab, a reliable method to detect STEC infection forms the basis for differentiation between both types of HUS. However, the current gold standard to detect STEC infection (i.e. fecal diagnostics) is not yet sufficient. Although serological detection of antibodies against the lipopolysaccharides (LPS) of STEC by ELISA has proven its incremental value, this assay has shown to have various drawbacks. Here we evaluate the diagnostic value of a new diagnostic technique: the indirect glycoprotein-based ELISA (glyco-iELISA).

Material and methods:

Combined retrospective single center study (n=51) and nationwide study (n=212) in which all patients with clinical suspicion of STEC-HUS, between 1990-2017, were included. LPS-ELISA and the glyco-iELISA were performed to detect IgM against STEC serotype O157 and compared with each other. Medical records were available of the single center patients and serological assay was compared with fecal diagnostics.

Results:

In the single center cohort, fecal diagnostics, LPS-ELISA, and glyco-iELISA identified STEC infection in 43%, 65%, and 78% of patients, respectively. Glyco-iELISA provided evidence of STEC infection in 7 (11%) and 20 (33%) additional patients when compared to LPS-ELISA or fecal diagnostics, respectively. Combining the glyco-iELISA with fecal diagnostics identified STEC infection in 89% of patients. In the nationwide study the glyco-iELISA yielded 12 additional positive STEC-HUS patients of which the majority was dubious positive with LPS-ELISA. Hence, the glyco-iELISA is highly sensitive and specific.

Conclusions:

Using glyco-iELISA STEC-infection could be detected in HUS patients, in which fecal diagnostics and serology based LPS-ELISA has failed to do so. Furthermore, STEC detection is increased by 36% when glyco-iELISA is combined with fecal diagnostics.