Preclinical evaluation of a TEX101 protein ELISA test for the differential diagnosis of male infertility.
TEX101 is a cell membrane protein exclusively expressed by testicular germ cells and shed into seminal plasma. We previously verified human TEX101 as a biomarker for the differential diagnosis of azoospermia, and developed a first-of-its-kind TEX101 ELISA. To demonstrate the clinical utility of TEX101, in this work we aimed at evaluating ELISA performance in a large population of fertile, subfertile, and infertile men.



Mass spectrometry, size-exclusion chromatography, ultracentrifugation, and immunohistochemistry were used to characterize TEX101 protein as an analyte in seminal plasma. Using the optimized protocol for seminal plasma pretreatment, TEX101 was measured by ELISA in 805 seminal plasma samples.



We demonstrated that TEX101 was present in seminal plasma mostly in a free soluble form and that its small fraction was associated with seminal microvesicles. TEX101 median values were estimated in healthy, fertile pre-vasectomy men (5436 ng/mL, N = 64) and in patients with unexplained infertility (4967 ng/mL, N = 277), oligospermia (450 ng/mL, N = 270), and azoospermia (0.5 ng/mL, N = 137). Fertile post-vasectomy men (N = 57) and patients with Sertoli cell-only syndrome (N = 13) and obstructive azoospermia (N = 36) had undetectable levels of TEX101 (≤0.5 ng/mL). A cut-off value of 0.9 ng/mL provided 100% sensitivity at 100% specificity for distinguishing pre- and post-vasectomy men. The combination of a concentration of TEX101 > 0.9 ng/mL and epididymis-specific protein ECM1 > 2.3 μg/mL provided 81% sensitivity at 100% specificity for differentiating between non-obstructive and obstructive azoospermia, thus eliminating the majority of diagnostic testicular biopsies. In addition, a cut-off value of ≥0.6 ng/mL provided 73% sensitivity at 64% specificity for predicting sperm or spermatid retrieval in patients with non-obstructive azoospermia.



We demonstrated the clinical utility of TEX101 ELISA as a test to evaluate vasectomy success, to stratify azoospermia forms, and to better select patients for sperm retrieval.
Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, M5T 3L9, Canada.|Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, M5T 3L9, Canada.
Dimitrios
D
Korbakis
Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, M5T 3L9, Canada.|Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, ON, M5T 3L9, Canada.
Christina
C
Schiza
Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, ON, M5T 3L9, Canada.
Davor
D
Brinc
Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, ON, M5T 3L9, Canada.
Antoninus
A
Soosaipillai
Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, M5T 3L9, Canada.|Department of Clinical Biochemistry, University Health Network, Toronto, Canada.
Theano D
TD
Karakosta
Centre de Recherche du Centre Hospitalier Universitaire (CHU) de Québec, Département d'Obstétrique, Gynécologie et Reproduction, Faculté de Medicine, Université Laval, Québec, Canada.
Christine
C
Légaré
Centre de Recherche du Centre Hospitalier Universitaire (CHU) de Québec, Département d'Obstétrique, Gynécologie et Reproduction, Faculté de Medicine, Université Laval, Québec, Canada.
Robert
R
Sullivan
Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, ON, M5T 3L9, Canada.
Brendan
B
Mullen
Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, M5T 3L9, Canada.|Division of Urology, Department of Surgery, Mount Sinai Hospital, Toronto, Canada.
Keith
K
Jarvi
Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, M5T 3L9, Canada. eleftherios.diamandis@sinaihealthsystem.ca.|Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, M5T 3L9, Canada. eleftherios.diamandis@sinaihealthsystem.ca.|Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, ON, M5T 3L9, Canada. eleftherios.diamandis@sinaihealthsystem.ca.|Department of Clinical Biochemistry, University Health Network, Toronto, Canada. eleftherios.diamandis@sinaihealthsystem.ca.
Eleftherios P
EP
Diamandis
Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, M5T 3L9, Canada. andrei.drabovich@utoronto.ca.|Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, ON, M5T 3L9, Canada. andrei.drabovich@utoronto.ca.|Department of Clinical Biochemistry, University Health Network, Toronto, Canada. andrei.drabovich@utoronto.ca.
Andrei P
AP
Drabovich
D000328:Adult; D015415:Biomarkers / Q000032:analysis; D003937:Diagnosis, Differential; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007248:Infertility, Male / Q000175:diagnosis*; D008297:Male; D008565:Membrane Proteins / Q000032:analysis*; D009845:Oligospermia / Q000175:diagnosis; D012661:Semen / Q000502:physiology*; D013048:Specimen Handling
D015415:Biomarkers; D008565:Membrane Proteins; C539319:TEX101 protein, human
Azoospermia; Immunoassay; Male infertility; Mass spectrometry; Oligospermia; Seminal microvesicles; Seminal plasma; TEX101; Testis-expressed sequence 101 protein