The blood protein hCAP‐18 in neutropenia: An 18‐month experience of a new ELISA for clinical use

• Published in: Scandinavian journal of immunology Vol. 94; no. 1; pp. e13037 - n/a
• Main Authors: Mortberg, A, Putsep, K, Hoglund, P
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.07.2021
• Subjects: Blood & organ donations; Blood donors; Differential diagnosis; ELISA; hCAP‐18; Leukocytes (neutrophilic); Medicin och hälsovetenskap; Neutropenia; Neutrophils; Proteins; pro‐LL‐37; neutropenia; pro-LL-37; ELISA; hCAP-18
• ISSN: 0300-9475; 1365-3083; 1365-3083
• DOI: 10.1111/sji.13037

Neutropenia as an isolated clinical finding may include aetiologies ranging from severe disease to a transient condition, and differential diagnosis may be challenging. Previous data and clinical experience suggest that low levels of the neutrophil‐derived protein human 18 kDa cathelicidin antimicrobial protein (hCAP‐18) in the blood are predictive of more severe forms of neutropenia. The objective of this study was to present the results from a newly developed ELISA method that has been used in clinical routine in Sweden since 2018 for quantification of hCAP‐18 in blood plasma. Using this method, we report that patients with severe disease analysed during the study period presented with low or undetectable levels of blood plasma hCAP‐18, validating its use as screening tool for severe neutropenia. Furthermore, neutropenic patients as a group displayed lower levels of hCAP‐18 as compared to blood donors. Within the group of neutropenic patients, those with neutrophil antibodies displayed significantly higher hCAP‐18 levels compared to patients with idiopathic neutropenia. By including an analysis of hCAP‐18 in the primary investigation of neutropenia, an increased accuracy in differential diagnosis is achieved, thus contributing to reduced costs of neutropenia management.