1 Department of Nephrology, University Hospital Zürich, Zürich, Switzerland. 2 Department of Gastroenterology and Hepatology, University Hospital Zürich, Zürich, Switzerland. 3 Department of Internal Medicine, Cantonal Hospital Graubünden, Chur, Switzerland. 4 Department of Pulmonology, University Hospital Zürich, Zürich, Switzerland.
Transplantation. 2017 Jun;101(6):1455-1460. doi: 10.1097/TP.0000000000001376.
Chronic norovirus infection is an emerging challenge in the immunocompromised host, in whom it may be asymptomatic or present as chronic diarrhea. The mechanisms of diarrhea in chronic norovirus infection are not well understood, but in analogy to Gardia lamblia and rotavirus infections, secondary lactose maldigestion (LM) might be implicated.
Adult renal transplant recipients who had symptomatic chronic norovirus infection with diarrhea were asked to participate in this prospective parallel cohort study. Renal transplant recipients with otherwise unexplainable chronic diarrhea but absent infection served as control group. In both groups, a lactose hydrogen breath test and a lactose tolerance test were performed after exclusion of primary LM by a negative lactase gene test.
Of approximately 800 patients in the cohort of renal transplant recipients at our institution, 15 subjects were included in the present study. Of these, 7 had chronic symptomatic norovirus infection with diarrhea (noro group), and 8 had diarrhea in the absence of norovirus (control group). Lactose hydrogen breath test and lactose tolerance test were positive in all 7 patients (100%) in the noro group, whereas only 1 (12.5%) of 8 patients in the control group had a positive test. Thus, secondary LM was highly prevalent in the noro compared with the control group with an odds ratio of 75.0 (95% confidence interval, 2.6-2153, P = 0.01).
This is the first report showing a positive association of chronic norovirus infection and secondary LM. Further studies with larger patient numbers and longer follow-up are needed to test a causative relationship between both entities.
慢性诺如病毒感染是免疫功能低下宿主的一个新出现的挑战，在这些患者中，它可能无症状或表现为慢性腹泻。慢性诺如病毒感染导致腹泻的机制尚不清楚，但与蓝氏贾第鞭毛虫和轮状病毒感染类似，继发性乳糖酶不良消化（LM）可能与之相关。
患有有症状的慢性诺如病毒感染性腹泻的成年肾移植受者被要求参与这项前瞻性平行队列研究。患有原因不明的慢性腹泻但无感染的肾移植受者作为对照组。在两组中，在排除乳糖酶基因检测阴性的原发性 LM 后，均进行乳糖氢呼气试验和乳糖耐量试验。
在我们机构的约 800 例肾移植受者队列中，有 15 名受试者被纳入本研究。其中，7 名患有慢性有症状的诺如病毒感染性腹泻（诺如组），8 名患有腹泻而无诺如病毒（对照组）。诺如组的 7 名患者（100%）的乳糖氢呼气试验和乳糖耐量试验均为阳性，而对照组的 8 名患者中仅有 1 名（12.5%）的试验为阳性。因此，与对照组相比，诺如组的继发性 LM 更为普遍，其优势比为 75.0（95%置信区间，2.6-2153，P = 0.01）。
这是第一项报告表明慢性诺如病毒感染与继发性 LM 之间存在正相关的研究。需要进行更多的研究以确定两者之间的因果关系，包括更大的患者数量和更长的随访时间。
