• PMID: 25205753
• Gene Name: ER-60
• Condition: Azoospermia, testicular inflammation
• Association: Associated
• Population size: 135
• Population details: 135 (20 normozoospermic men, 14 male blood donors, 14 men with impaired semen quality without symptoms of genital tract infection/inflammation, 26 men with impaired semen quality without symptoms of genital tract infection/inflammation, 16 azoospermic men
• Sex: Male
• Infertility type: Male infertility

Autoantibodies against protein disulfide isomerase ER-60 are a diagnostic marker for low-grade testicular inflammation

Fijak M, Zeller T, Huys T, Klug J, Wahle E, Linder M, Haidl G, Allam JP, Pilatz A, Weidner W, Schuppe HC, Meinhardt A.

STUDY QUESTION: Is there a non-invasive biomarker for the diagnosis of testicular inflammatory lesions? SUMMARY ANSWER: In sera from infertile azoospermic patients with histologically confirmed low-grade testicular inflammation, significantly elevated titers of autoantibodies against disulfide isomerase family A, member 3 (ER-60) were found. WHAT IS KNOWN ALREADY: Infection and inflammation of the genital tract are supposed to be responsible for up to 15% of cases among infertile males. However, specific seminal or serological markers are not available to assess subacute or chronic inflammatory conditions in the testis. STUDY DESIGN, SIZE, DURATION: This study consisted of the identification of autoantibodies for testicular antigens in sera of patients with low-grade testicular inflammation, validation of candidates, development of an ELISA for the most promising target antigen and measurement of autoantibodies titers in healthy normozoospermic men (n = 20); male blood donors (n = 14); men with impaired semen quality without (n = 14) or with (n = 26) symptoms of genital tract infection/inflammation; azoospermic men with histologically confirmed testicular inflammatory lesions (n = 16); men after pharmacotherapy of genital tract infection/inflammation (n = 15) and men with acute epididymo-orchitis (n = 30). PARTICIPANTS/MATERIALS, SETTING, METHODS: Proteins in lysates of normal testicular tissue were separated by high-resolution 2D gel electrophoresis and probed with sera of 13 patients with histologically confirmed chronic testicular inflammation. There were 14 proteins that immunoreacted with a majority of these sera and could be identified by mass spectrometry. Of these 14 proteins, disulfide isomerase family A, member 3 (ER-60), transferrin and chaperonin containing TCP1 complex, subunit 5 (epsilon) (CCT5) were considered as specific. Since ER-60 reacted with 92% of patient sera, an ER-60-autoantibody ELISA was developed. MAIN RESULTS AND THE ROLE OF CHANCE: The newly established ELISA detected significantly elevated titers of autoantibodies against ER-60 in the sera from infertile men with histologically confirmed chronic testicular inflammation (median 8.6; P < 0.01) compared with the control groups. Moreover, elevated levels of anti-ER-60 titers were detected in patients suffering from acute epididymo-orchitis (median 3.3; P < 0.05) as compared with healthy normozoospermic men (median 2.13; P < 0.001), male blood donors with unknown fertility status (median 2.72; P < 0.01), patients with impaired semen quality but no infection/inflammation (median 2.59; P < 0.001) and patients with symptoms of genital tract infections and/or inflammation (median 2.18; P < 0.001). Significantly lower levels of anti-ER-60 antibodies were measured in sera from patients after application of anti-inflammatory pharmacotherapy (median 1.9; P < 0.01) compared with those with histologically confirmed chronic testicular inflammation. The cut-off value of the assay was set to 6.6 U/ml based on a calculated sensitivity of 100% and a specificity of 81.2%. LIMITATIONS, REASONS FOR CAUTION: The results obtained in this study showed statistically significant elevated titers of ER-60 antibodies in sera from patients with histologically confirmed testicular inflammatory lesions and from a few patients with acute epididymo-orchitis. However, the number of serum samples tested was limited. Severe testicular damage seen in azoospermic patients could represent a bias towards ER-60 reactivity, while the assay does not allow for different etiologies of the lesions to be distinguished. Due to ethical reasons, the prevalence of testicular inflammatory lesions among controls and non-azoospermic men cannot be studied at the histological level. WIDER IMPLICATIONS OF THE FINDINGS: Measurement of ER-60 autoantibody titers in serum could be a novel non-invasive marker for the diagnosis of asymptomatic testicular inflammation causing male fertility disturbances. STUDY FUNDING/COMPETING INTERESTS: This study was supported by a grant of the Deutsche Forschungsgemeinschaft (ME 1323/4-4) and the Translational Science Fund (Wirtschafts-und Strukturbank Hessen-WI Bank). M.F., A.P., W.W., H.-C.S. and A.M. are supported by the LOEWE focus group 'MIBIE' (Male infertility during infection and inflammation). The ER-60 ELISA is protected by a patent to the Justus-Liebig-University of Giessen with A.M. and M.F. as inventors (patent no. DE 10 2008 053 503). T.Z. as employee of the DRG Company was responsible for the ELISA development. CI - © The Author 2014. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com. FAU - Fijak, Monika AU - Fijak M AD - Department of Anatomy and Cell Biology, Justus-Liebig University of Giessen, Aulweg 123, 35392 Giessen, Germany monika.fijak@anatomie.med.uni-giessen.de. FAU - Zeller, Thomas AU - Zeller T AD - DRG Instruments GmbH-R&D Department, 35037 Marburg, Germany. FAU - Huys, Tatjana AU - Huys T AD - Department of Anatomy and Cell Biology, Justus-Liebig University of Giessen, Aulweg 123, 35392 Giessen, Germany Clinic for Urology, Pediatric Urology and Andrology, Justus-Liebig-University Giessen, 35385 Giessen, Germany. FAU - Klug, Jörg AU - Klug J AD - Department of Anatomy and Cell Biology, Justus-Liebig University of Giessen, Aulweg 123, 35392 Giessen, Germany. FAU - Wahle, Eva AU - Wahle E AD - Department of Anatomy and Cell Biology, Justus-Liebig University of Giessen, Aulweg 123, 35392 Giessen, Germany. FAU - Linder, Monica AU - Linder M AD - Institute of Biochemistry, Faculty of Medicine, Justus-Liebig-University Giessen, 35385 Giessen, Germany. FAU - Haidl, Gerhard AU - Haidl G AD - Department of Dermatology, Andrology Unit, University of Bonn, 53127 Bonn, Germany. FAU - Allam, Jean-Pierre AU - Allam JP AD - Department of Dermatology, Andrology Unit, University of Bonn, 53127 Bonn, Germany. FAU - Pilatz, Adrian AU - Pilatz A AD - Clinic for Urology, Pediatric Urology and Andrology, Justus-Liebig-University Giessen, 35385 Giessen, Germany. FAU - Weidner, Wolfgang AU - Weidner W AD - Clinic for Urology, Pediatric Urology and Andrology, Justus-Liebig-University Giessen, 35385 Giessen, Germany. FAU - Schuppe, Hans-Christian AU - Schuppe HC AD - Clinic for Urology, Pediatric Urology and Andrology, Justus-Liebig-University Giessen, 35385 Giessen, Germany.