University Children's Hospital, Würzburg, Germany.
Children's Hospital of the University of Würzburg, Josef-Schneider Str. 2, 97080, Würzburg, Germany.
BMC Pulm Med. 2018 Jan 16;18(1):8. doi: 10.1186/s12890-018-0580-1.
Recurrent airway infections are common in patients with Down's syndrome (DS). Hence, ruling out Cystic Fibrosis (CF) in these patients is often required. In the past, the value of sweat testing - the gold standard to diagnose CF - has been questioned in DS as false positive results have been reported. However, these reports are based on measurements of sweat osmolality or sodium concentrations, not chloride concentrations. This study analyses sweat secretion rate and chloride concentration in sweat samples of patients with DS in comparison to healthy controls.
We assessed sweat samples in 16 patients with DS and 16 healthy controls regarding sweat secretion rate (SSR) and sweat chloride concentration.
All measured chloride concentrations were within the normal range. The chloride concentrations were slightly, but not significantly lower in patients with DS (15,54 mmol/l (±4,47)) compared to healthy controls (18,31 mmol/l (±10,12)). While no gender gap in chloride concentration could be found, chloride concentration increased with age in both groups. Insufficient sweat was collected in 2 females with DS (12.5% of the study group) but not in an individual of the control group. A significant lower sweat secretion rate was found in the DS group (27,6 μl/30 min (± 12,18)) compared to the control group (42,7 μl/30 min (± 21,22)). In a sub-analysis, female patients produced significantly less sweat (20,8 ± 10,6 μl/30 min) than male patients with DS (36,4 ± 7,8 μl/30 min), which accounts for the difference between patients and controls. Furthermore, while the sweating secretion rate increased with age in the control group, it did not do so in the DS group. Once again this was due to female patients with DS, who did not show a significant increase of sweat secretion rate with age.
Sweat chloride concentrations were within the normal range in patients with DS and therefore seem to be a reliable tool for testing for CF in these patients. Interestingly, we found a reduced sweat secretion rate in the DS group. Whether the last one has a functional and clinical counterpart, possibly due to a disturbed thermoregulation in DS patients, requires further investigation.
唐氏综合征（Down's syndrome，DS）患者常发生复发性呼吸道感染，因此常需要排除囊性纤维化（cystic fibrosis，CF）。过去，汗液检测（诊断 CF 的金标准）在 DS 患者中的价值受到质疑，因为曾有假阳性结果的报道。然而，这些报告基于汗液渗透压或钠离子浓度的测量，而不是氯离子浓度。本研究分析了 DS 患者与健康对照者的汗液分泌率（sweat secretion rate，SSR）和汗液氯离子浓度。
我们评估了 16 例 DS 患者和 16 例健康对照者的汗液样本，检测 SSR 和汗液氯离子浓度。
所有测量的氯离子浓度均在正常范围内。DS 患者的氯离子浓度稍低，但无统计学意义（15.54mmol/L（±4.47）），低于健康对照组（18.31mmol/L（±10.12））。虽然在 DS 患者中未发现性别差异，但两组的氯离子浓度均随年龄增长而增加。有 2 例 DS 女性患者（占研究组的 12.5%）采集的汗液量不足，但对照组中没有。DS 组的 SSR 明显较低（27.6μl/30min（±12.18）），低于对照组（42.7μl/30min（±21.22））。在亚分析中，女性 DS 患者的汗液分泌量明显较少（20.8±10.6μl/30min），低于男性 DS 患者（36.4±7.8μl/30min），这是患者与对照组之间的差异。此外，尽管对照组的 SSR 随年龄增长而增加，但 DS 组则没有。这同样是由于 DS 女性患者的 SSR 随年龄增长没有明显增加。
DS 患者的汗液氯离子浓度在正常范围内，因此似乎是这些患者 CF 检测的可靠工具。有趣的是，我们发现 DS 组的 SSR 降低。这是否与 DS 患者的体温调节障碍有关，需要进一步研究。
