STUDY QUESTION Should testicular sperm extraction (TESE) in non-mosaic 47,XXY Klinefelter syndrome (KS) patients be performed soon after puberty or could it be delayed until adulthood? SUMMARY ANSWER The difference in sperm retrieval rate (SRR) in TESE was not significant between the 'Young' (15-22 years old) cohort and the 'Adult' (23-43 years old) cohort of non-mosaic KS patients recruited prospectively in parallel. WHAT IS KNOWN ALREADY Several studies have tried to define predictive factors for TESE outcome in non-mosaic KS patients, with very heterogeneous results. Some authors have found that age was a pejorative factor and recommended performing TESE soon after puberty. To date, no predictive factors have been unanimously recognized to guide clinicians in deciding to perform TESE in azoospermic KS patients. STUDY DESIGN, SIZE, DURATION Two cohorts (Young: 15-22 years old; Adult: 23-43 years old) were included prospectively in parallel. A total of 157 non-mosaic 47,XXY KS patients were included between 2010 and 2020 in the reproductive medicine department of the University Hospital of Lyon, France. However 31 patients gave up before TESE, four had cryptozoospermia and three did not have a valid hormone assessment; these were excluded from this study. PARTICIPANTS/MATERIALS, SETTING, METHODS Data for 119 patients (61 Young and 58 Adult) were analyzed. All of these patients had clinical, hormonal and seminal evaluation before conventional TESE (c-TESE). MAIN RESULTS AND THE ROLE OF CHANCE The global SRR was 45.4%. SRRs were not significantly different between the two age groups: Young SRR=49.2%, Adult SRR = 41.4%; P = 0.393. Anti-Müllerian hormone (AMH) and inhibin B were significantly higher in the Young group (AMH: P = 0.001, Inhibin B: P < 0.001), and also higher in patients with a positive TESE than in those with a negative TESE (AMH: P = 0.001, Inhibin B: P = 0.036). The other factors did not differ between age groups or according to TESE outcome. AMH had a better predictive value than inhibin B. SRRs were significantly higher in the upper quartile of AMH plasma levels than in the lower quartile (or in cases with AMH plasma level below the quantification limit): 67.7% versus 28.9% in the whole population (P = 0.001), 60% versus 20% in the Young group (P = 0.025) and 71.4% versus 33.3% in the Adult group (P = 0.018). LIMITATIONS, REASONS FOR CAUTION c-TESE was performed in the whole study; we cannot rule out the possibility of different results if microsurgical TESE had been performed. Because of the limited sensitivity of inhibin B and AMH assays, a large number of patients had values lower than the quantification limits, preventing the definition a threshold below which negative TESE can be predicted. WIDER IMPLICATIONS OF THE FINDINGS In contrast to some studies, age did not appear as a pejorative factor when comparing patients 15-22 and 23-44 years of age. Improved accuracy of inhibin B and AMH assays in the future might still allow discrimination of patients with persistent foci of spermatogenesis and guide clinician decision-making and patient information. STUDY FUNDING/COMPETING INTEREST(S) The study was supported by a grant from the French Ministry of Health D50621 (Programme Hospitalier de Recherche Clinical Régional 2008). The authors have no conflicts of interest to disclose. TRIAL REGISTRATION NUMBER NCT01918280.

中文翻译：

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延迟 47,XXY Klinefelter 患者的睾丸精子提取不会影响精子提取率，并且当 TESE 呈阳性时 AMH 水平更高。

研究问题 非马赛克 47,XXY 克氏综合征 (KS) 患者的睾丸精子提取 (TESE) 应该在青春期后立即进行还是可以推迟到成年期进行？答案总结 前瞻性招募的非马赛克 KS 患者的“年轻”（15-22 岁）队列和“成人”（23-43 岁）队列之间的 TESE 精子回收率 (SRR) 差异不显着在平行下。已知信息 几项研究试图确定非马赛克 KS 患者 TESE 结果的预测因素，结果非常不同。一些作者发现年龄是一个贬义因素，并建议在青春期后尽快进行 TESE。迄今为止，还没有一致认可的预测因素来指导临床医生决定对无精子症 KS 患者进行 TESE。学习规划，规模、持续时间前瞻性地平行纳入两个队列（年轻人：15-22 岁；成人：23-43 岁）。2010 年至 2020 年间，法国里昂大学医院生殖医学科共纳入 157 名非镶嵌 47,XXY KS 患者。然而，有 31 名患者在 TESE 之前放弃，四名患有隐精子症，三名没有进行有效的激素评估；这些被排除在本研究之外。参与者/材料、环境、方法 分析了 119 名患者（61 名年轻人和 58 名成人）的数据。所有这些患者在常规 TESE (c-TESE) 之前都进行了临床、激素和精液评估。主要结果和机会的作用 全球 SRR 为 45.4%。两个年龄组的 SRR 没有显着差异：青年 SRR = 49.2%，成人 SRR = 41.4%；P = 0.393。抗苗勒管激素 (AMH) 和抑制素 B 在年轻组中显着更高 (AMH：P = 0.001，抑制素 B：P < 0.001)，并且在 TESE 阳性患者中也高于 TESE 阴性患者 (AMH ：P = 0.001，抑制素 B：P = 0.036）。其他因素在年龄组之间或根据 TESE 结果没有差异。AMH 比抑制素 B 具有更好的预测价值。AMH 血浆水平上四分位数的 SRR 显着高于下四分位数（或 AMH 血浆水平低于定量限的病例）：67.7% 对整个人群的 28.9% (P = 0.001)，青年组分别为 60% 和 20% (P = 0.025)，成人组分别为 71.4% 和 33.3% (P = 0.018)。局限性、谨慎的原因 在整个研究中进行了 c-TESE；如果进行了显微外科 TESE，我们不能排除不同结果的可能性。由于抑制素 B 和 AMH 检测的灵敏度有限，大量患者的值低于量化限值，因此无法定义一个阈值，低于该阈值可以预测 TESE 为阴性。研究结果的更广泛意义 与一些研究相反，在比较 15-22 岁和 23-44 岁的患者时，年龄似乎不是贬义因素。未来提高抑制素 B 和 AMH 检测的准确性可能仍然可以区分具有持续精子发生灶的患者，并指导临床医生决策和患者信息。研究资金/竞争利益 该研究得到了法国卫生部 D50621 的资助（Programme Hospitalier de Recherche Clinical Régional 2008）。作者没有要披露的利益冲突。试用注册号 NCT01918280。