EB病毒抗体和DNA联合检测可提高儿童传染性单核细胞增多症的诊断灵敏度

目的评估EB病毒抗体VCA-IgM、VCA-IgG、EA-IgG、EBNA-1-IgG及EBV-DNA载量检测在儿童传染性单核细胞增多症(传单)中的诊断意义。方法用ELISA方法检测70例传单患儿和25例健康儿童血清中EBV四种抗体及PCR荧光定量法检测外周血单个核细胞EBV-DNA载量。结果传单患儿组EBV-DNA的阳性率为87.14%(61/70),对照组阳性率为8.00%(2/25),传单组与对照组EBV-DNA的阳性率比较差异有统计学意义(P<0.01)。EBV抗体检测中,传单组的VCA-IgM阳性率最高,达91.43%(64/70),对照组VCA-IgM全部阴性。传单组EB病毒VCA-IgM和EBV-DNA联合检测的阳性率97.1%。结论 EBV抗体和EBV-DNA载量检测对儿童传单的诊断有极高的价值,尤其是VCA-IgM抗体和EBV-DNA联合检测,可提高儿童传单的临床诊断的敏感性。     

石家庄地区肺炎支原体感染的流行病学调查

目的:了解石家庄地区肺炎支原体感染的血清流行病学情况。方法:选择2011年3月~2012年2月我院住院和门诊收治的急性呼吸道感染患者1902例为研究对象,采用间接免疫荧光法(IFA)检测其血清肺炎支原体IgM抗体,并分析其流行病学资料。结果:1902例血清标本中,284例(14.93%)肺炎支原体IgM抗体阳性,男性和女性的阳性率无显著差异。肺炎支原体抗体阳性的患者主要分布于0~15岁年龄段,阳性检出率最高的年龄组为0~6岁,占21.26%(132/621)。各个季节均有肺炎支原体感染阳性患者,感染率无显著差异性,秋(80例)、冬(96例)两季的阳性感染率高于春(56例)、夏(52例)两季。患者100%出现发热症状,95.77%出现咳嗽。结论:石家庄地区肺炎支原体感染的主要人群为未成年人,无季节性和性别差异,以发热和咳嗽为最主要的临床症状。     

特发性急性横贯性脊髓炎临床及MRI特征分析

目的探讨特发性急性横贯性脊髓炎(IATM)的临床特征及MRI特点,提高对其诊断准确性。方法对41例首次发病并住院诊治的IATM患者的临床资料及MRI图像进行回顾性分析。结果 (1)临床症状:首发症状为肢体麻木无力共28例(68.29%);截瘫12例(29.27%),尿便障碍/失禁25例(60.98%)。查体所有患者均有感觉障碍并伴有明确的感觉平面,其中39例(95.12%)表现为痛觉减退,2例(4.88%)表现为痛觉过敏。(2)MRI特征:41例患者中38例(92.68%)MRI显示异常,表现为T2WI条片状高信号,其中颈髓11例(28.95%),胸髓22例(57.89%),颈胸髓1例(2.63%),胸髓及马尾4例(10.53%);脊髓肿胀11例(28.95%)。21例患者行增强扫描检查,13例(61.90%)轻-中度强化。结论肢体麻木无力、尿便障碍及确切感觉平面以下的痛觉减退为IATM较主要的临床表现。临床表现与MRI特征相结合,有利于IATM的诊断。     

基于三种试剂盒分析新型冠状病毒特异性抗体的动态变化

为了解新型冠状病毒肺炎(COVID-19)发病后血清中新型冠状病毒(SARS-CoV-2)特异性抗体的动态变化,本研究使用三种不同检测原理的SARS-CoV-2抗体检测试剂盒,对来自甘肃省33例核酸检测阳性的COVID-19确诊病例的58份血清标本,分别进行了病毒特异性抗体(IgM、IgG和总抗体)的检测。结果显示,COVID-19发病后IgM、IgG和总抗体阳性率随发病时间的推移而逐渐上升:发病早期3d以内,三种试剂盒检测病毒特异性抗体阳性率在13.6%～31.8%之间;发病4～7d时,阳性率在36.4%～45.5%之间;发病8～14d时,阳性率在55.6%～77.8%之间;而发病15d以上时,阳性率达到100%。此外,本研究使用三种试剂盒检测了健康人血清标本,检测特异性在99%～100%之间。统计学分析结果显示,三种检测试剂盒的检测结果差异无显著性(P0.05)。综上所述,三种SARS-CoV-2抗体检测试剂盒均具有较好的敏感性和特异性,可用于COVID-19疑似病例在核酸检测阴性时的辅助诊断;本研究初步获得的SARS-CoV-2特异性抗体动态变化特征可为COVID-19血清流行病学调查和无症状感染者研究提供重要的基础依据。     

神经梅毒的诊断与治疗（附23例分析）

观察神经梅毒的临床特点,以提高对神经梅毒的诊断与治疗水平。回顾性分析哈尔滨医科大学附属第一医院2005年1月至2010年12月收治的23例神经梅毒患者的临床资料。神经梅毒患者男17例（73.9%）,女6例（26.1%）,男女比约为2.8∶1;年龄27~71岁,平均年龄43.1岁。本组首发症状：麻痹性痴呆（7例）、精神异常（3例）、急性脑梗死（3例）、癫痫（2例）、脊髓病变（2例）、颅高压（2例）、周围神经损害（2例）、脑神经损害（1例）、无症状性神经梅毒（1例）。23例患者血清及脑脊液快速血浆反应素实验及梅毒螺旋体血凝试验均呈阳性反应。颅脑电子计算机断层扫描（CT）和/或磁共振成像（MRI）检查多表现为额叶、顶叶、颞叶、基底节等多发病变。本组患者经大剂量青霉素治疗后病情有显著改善20例,死亡1例,自动出院2例。神经梅毒的临床表现复杂多样,神经系统各部位均可受累,诊断依靠病史及临床表现、实验室血清及脑脊液梅毒抗体检测,误诊率高,应早期诊断,诊断后应进行规范治疗,早期治疗效果较好。     

类风湿性关节炎患者EBV感染情况分析

目的:检测类风湿性关节炎患者血清EBV(Epstein-Barr virus)衣壳抗原IgA抗体(VCA-IgA),分析EBV感染与类风湿性关节炎的相关性.方法:用酶联免疫吸附试验(ELISA)检测92例确诊为类风湿性关节炎患者和80例体检健康者血清VCA-IgA抗体,分析两组人群EBV VCA-IgA阳性率.结果:类风湿性关节炎患者VCA-IgA抗体阳性率为9.8％(9/92);健康对照组阳性率为2.4％ (2/85)(x2=4.038,P＜0.05).结论:类风湿性关节炎患者血清EBV VCA-IgA抗体检出率明显高于健康对照组,提示部分类风湿性关节炎患者发病与EBV感染有关.     

兰州地区健康体检者血脂水平分析

目的:通过检测兰州地区健康体检者空腹血脂水平了解本地区人群血脂水平现状及血脂异常情况,建立本地区血脂参考值。方法:采用全自动生化分析仪检测兰州市2328名健康体检者,血清胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)。比较不同年龄、性别血脂水平差异。结果:本地区2328名被检者,女性TC平均(4.54±0.94)mmol/L,TG中位数1.24mmol/L、HDL-C平均(1.34±0.26)mmol/L、LDL-C平均(2.61±0.76)mmol/L;男性TC平均(4.52±0.84)mmol/L、TG中位数1.56mmol/L mmol/L、HDL-C平均(1.20±0.23)mmol/L LDL-C平均(2.76±0.72)mmol/L,血脂水平随年龄增加逐渐升高(P<0.05)。血脂参考范围为女性TC:2.70~6.38 mmol/L、TG:0.52~3.66 mmol/L、HDL-C:0.83~1.85 mmol/L、LDL-C:1.12~4.10 mmol/L男性:TG:2.87~6.17 mmol/L、0.65~4.00 mmol/L、0.75~1.65 mmol/L、1.35~4.17 mmol/L。男性高TC、高TG、低HDL-C和高LDL-C患病率为18.2%、42.8%、19.6%和28%,女性高TC、高TG、低HDL和高LDL的患病率分别为22.1%、25.5%、2.7%和23.5%。结论:兰州地区血脂水平随年龄、性别、地区不同存在较大差异,临床上不能采用统一标准衡量,而应根据本地区建立的参考值诊断高脂血症。积极控制血脂水平、降低高脂血症患病率预防心脑血管疾病发生。     

广西柳州18～45岁女性人乳头瘤病毒16/18型中和抗体流行率及其与宫颈病变相关性的研究

阐明广西柳州地区自然人群中18~45岁女性人乳头瘤病毒(HPV)16/18型中和抗体和DNA流行情况,并探讨其与子宫颈癌癌前病变的相关性。2013年3月至7月在柳州市招募2 300名18~45岁女性,采集血清以假病毒中和试验(PBNA)法检测HPV16/18型中和抗体,同时采集宫颈脱落细胞进行液基细胞学诊断和HPV DNA检测,对细胞学异常者进行阴道镜检查,并对采集的组织学标本进行病理诊断。采用趋势性χ2检验分析不同年龄段HPV DNA阳性率及HPV中和抗体阳性率的差异,Logistic回归分析筛选宫颈癌前病变的影响因素。广西柳州地区18~45岁女性自然人群中,HPV16DNA或中和抗体阳性364例(15.8%,95%CI:14.4,17.4),HPV18DNA或中和抗体阳性164例(7.1%,95%CI:6.1,8.3)。CIN3在不同年龄组的卡方趋势检验有统计学意义(P=0.005),HPV16和HPV18型DNA阳性是CIN1+(宫颈上皮内瘤变1级及以上)、CIN2+(宫颈上皮内瘤变2级及以上)的主要危险因素,而自然感染产生的中和抗体与癌前病变未发现统计学相关性。HPV16/18型感染是宫颈癌癌前病变的主要危险因素,并未发现自然感染产生的中和抗体与其相关,表明接种疫苗仍是18~45岁女性预防HPV感染及癌前病变的主要方式。     

深圳市南山区健康人群百日咳抗体水平及疫苗免疫成功率监测

目的了解深圳市南山区健康人群百日咳免疫现状及疫苗免疫成功率。方法健康人群抗体水平监测按照<1岁、1岁~、2岁~、3岁~、4岁~、5岁~、10岁~、15岁~、≥20岁共9个年龄组,每个年龄组随机抽取50~60人共508人进行观察,采用ELISA检测其百日咳抗体水平,免疫成功率监测选定监测对象为50人,同一对象于基础免疫前和完成基础免疫后1个月进行抗体水平检测。结果健康人群百日咳抗体阳性率为44.3%,抗体几何平均浓度(GMC)为21.69 U/m L。免疫成功率的免疫前抗体检测结果为:阴性94.0%、临界4.0%、阳性2.0%,抗体GMC为3.39 U/m L;免疫后抗体检测结果:阴性38.0%、临界16.0%、阳性46.0%,抗体GMC为20.75 U/m L。结论深圳市南山区健康人群百日咳抗体阳性率和免疫成功率均不高,提示要提高百日咳疫苗的免疫成功率和接种率,必要时进行加强免疫。     

邯郸市女性人乳头瘤病毒中和抗体研究

目的了解邯郸市女性人群人乳头瘤病毒(human papilloma virus, HPV)中和抗体的研究,为当地制定适当的宫颈癌(uterine cervical carcinoma, UCC)防控策略和HPV疫苗接种提供依据。方法采用横断面的调查方法,以2019年9—12月河北工程大学附属医院就诊未接种过HPV疫苗的女性为调查对象,开展流行病学调查。采集血清样本,假病毒中和试验检测9种HPV基因型的血清中和抗体。结果 216份血清样本检出HPV阳性血清33份,阳性率15.28%。低危型血清13份,阳性率6.02%(95%CI:3.24%～10.07%);高危型血清27份,阳性率为12.50%(95%CI:8.4%～17.66%)。各基因型的中和抗体GMT为120～696。33份HPV阳性血清样本中,单一阳性血清样本22份,单一高危型阳性就有17份,占77.21%;多重阳性血清样本11份,均为多重高危型阳性样本。5个年龄组中,第1、2、3组的女性人群HPV阳性血清随着年龄的增长明显增加,而第4、5组则随着年龄的增长明显下降;第3组HPV检测出阳性血清最多,有12份,阳性率为25.00%;第5组HPV阳性血清检出最少,仅有3份,阳性率为15.00%,年龄组间阳性率差异无统计学意义(χ~2=4.957、P=0.292,P0.05)。乡镇和市区HPV阳性率分别为16.91%、12.50%;单一和多重HPV感染乡镇均高于城区,地区间阳性率差异无统计学意义(χ~2=0.757、P=0.384,P0.05)。中专及高中以上人群HPV阳性率最高,占20.27%,其单一阳性率高于其他人群,不同文化程度人群HPV阳性率差异无统计学意义(χ~2=3.152、P=0.207,P0.05)。结论邯郸市5个未接种过HPV疫苗年龄组均检出HPV抗体,自然感染产生的中和抗体滴度不高,阳性率处于全国较低水平。高危型血清样本阳性率很高,须及时采取主动干预措施,提高人群对HPV感染的认知,并在特定年龄段积极推广HPV多价疫苗的接种和提高接种率。     

Autoantibody to MOG suggests two distinct clinical subtypes of NMOSD

We characterized a unique group of patients with neuromyelitis optica spectrum disorder(NMOSD) who carried autoantibodies of aquaporin-4(AQP4) and myelin-oligodendrocyte glycoprotein(MOG). Among the 125 NMOSD patients, 10(8.0%) were AQP4- and MOG-ab double positive, and 14(11.2%) were MOG-ab single positive. The double-positive patients had a multiphase disease course with a high annual relapse rate(P=0.0431), and severe residual disability(P0.0001). Of the double-positive patients, 70% had MS-like brain lesions, more severe edematous, multifocal regions on spinal magnetic resonance imaging(MRI), pronounced decreases of retinal nerve fiber layer thickness and atrophy of optic nerves. In contrast, patients with only MOG-ab had a higher ratio of monophasic disease course and mild residual disability. Spinal cord MRI illustrated multifocal cord lesions with mild edema, and brain MRIs showed more lesions around lateral ventricles. NMOSD patients carrying both autoantibodies to AQP4 and MOG existed and exhibited combined features of prototypic NMO and relapsing-remitting form of MS, whereas NMOSD with antibodies to MOG only exhibited an "intermediate" phenotype between NMOSD and MS. Our study suggests that antibodies against MOG might be pathogenic in NMOSD patients and that determination of anti-MOG antibodies maybe instructive for management of NMOSD patients.     

Aquaporin-4 antibodies are not related to HTLV-1 associated myelopathy

Introduction

The seroprevalence of human T-cell leukemia virus type 1 (HTLV-1) is very high among Brazilians (∼1∶200). HTLV-1 associated myelopathy or tropical spastic paraparesis (HAM/TSP) is the most common neurological complication of HTLV-1 infection. HAM/TSP can present with an acute/subacute form of longitudinally extensive myelitis, which can be confused with lesions seen in aquaporin-4 antibody (AQP4-Ab) positive neuromyelitis optica spectrum disorders (NMOSD) on MRI. Moreover, clinical attacks in patients with NMOSD have been shown to be preceded by viral infections in around 30% of cases.

Objective

To evaluate the frequency of AQP4-Ab in patients with HAM/TSP. To evaluate the frequency of HTLV-1 infection in patients with NMOSD.

Patients and Methods

23 Brazilian patients with HAM/TSP, 20 asymptomatic HTLV-1+ serostatus patients, and 34 with NMOSD were tested for AQP4-Ab using a standardized recombinant cell based assay. In addition, all patients were tested for HTLV-1 by ELISA and Western blotting.

Results

20/34 NMOSD patients were positive for AQP4-Ab but none of the HAM/TSP patients and none of the asymptomatic HTLV-1 infected individuals. Conversely, all AQP4-Ab-positive NMOSD patients were negative for HTLV-1 antibodies. One patient with HAM/TSP developed optic neuritis in addition to subacute LETM; this patient was AQP4-Ab negative as well. Patients were found to be predominantly female and of African descent both in the NMOSD and in the HAM/TSP group; Osame scale and expanded disability status scale scores did not differ significantly between the two groups.

Conclusions

Our results argue both against a role of antibodies to AQP4 in the pathogenesis of HAM/TSP and against an association between HTLV-1 infection and the development of AQP4-Ab. Moreover, the absence of HTLV-1 in all patients with NMOSD suggests that HTLV-1 is not a common trigger of acute attacks in patients with AQP4-Ab positive NMOSD in populations with high HTLV-1 seroprevalence.     

Immunobiology of neuromyelitis optica spectrum disorders

Neuromyelitis optica spectrum disorder (NMOSD) is a rare autoimmune inflammatory disease of the central nervous system. Most of the cases are positive for autoantibodies targeting the water channel aquaporin-4 (AQP4-IgG). Activated B and T cells, innate immunity cells, pro-inflammatory cytokines, and activated complement contribute to the formation of the NMOSD lesions. Optic neuritis, longitudinally extensive myelitis, and area postrema syndrome are core clinical manifestations. NMOSD diagnosis is based on clinical manifestations, magnetic resonance imaging findings, and AQP4-IgG positivity. Cell-based assays are the preferred method for the detection of AQP4-IgG. Acute relapses are treated with IV methylprednisolone or plasma exchange. Recent advances on the NMOSD immunobiology led to approved treatments such as eculizumab, satralizumab, and inebilizumab.     

Low Levels of Vitamin D in Neuromyelitis Optica Spectrum Disorder: Association with Disease Disability

Patients with autoimmune disorders often have low levels of 25-hydroxyvitamin D [25(OH)D₃], which correlates with disability or disease activity. Vitamin D may play a role in neuromyelitis optica (NMO) or NMO spectrum disorder (NMOSD), as an important factor involved in immunological pathways. We investigated the relationship between vitamin D levels and disease related disability and clinical activity in patients with NMOSD. Blood samples from 51 patients with NMOSD who were positive for anti-aquaporin4-antibody (AQP4-ab) and 204 healthy controls were collected for 25(OH)D₃ measurement. Clinical parameters, including expanded disability status scale (EDSS) score, annualized relapse rate (ARR) and time of blood sampling relative to attack, were determined in patients with NMOSD. We found that 25(OH)D₃ levels were significantly lower in patients with NMOSD compared to healthy controls. There was no difference between 25(OH)D3 levels in blood samples taken at relapse or remission, and no association between 25(OH)D3 levels and ARR, but there was an inverse correlation between 25(OH)D3 levels and EDSS scores in patients with NMOSD. It remains to be determined whether low vitamin D levels predispose to NMO and/or modify disease severity, or are secondary to neurological disability. In either case the results could also be of relevance to other neurological diseases such as multiple sclerosis as well as NMO.     

A Longitudinal Brain Magnetic Resonance Imaging Study of Neuromyelitis Optica Spectrum Disorder

Brain involvement is commonly seen in patients with neuromyelitis optica spectrum disorder (NMOSD). However, little is known about the chronic changes of acute brain lesions on MRI over time. Here, our objective was to evaluate how acute brain MRI lesions in NMOSD changed on follow-up MRI. We reviewed the MRIs of 63 patients with NMOSD who had acute brain lesions and follow-up MRI over an interval of at least 3 months. Of the 211 acute brain lesions, 24% of lesions disappeared completely on T2-weighed images (WI) and a decrease in size ≥50% on T2-WI was observed in 58% of lesions on follow-up MRI. However, 47% of lesions revealed focal T1-hypointensity and, in particular, 18% showed focal cystic changes. Cystic changes were observed most commonly in corticospinal tract and corpus callosal lesions whereas the vast majority of lesions in the cerebellum, basal ganglia and temporal white matter resolved completely. MRI remission on T2-WI occurred in 82% of lesions, while approximately half of the lesions presented foci of T1-hypointensity, which may be considered a severe tissue injury over time. The extent of brain injury following an acute brain lesion in NMOSD may depend on the location of the lesion.     

Pathogenic antibodies to AQP4: Neuromyelitis optica spectrum disorder (NMOSD)

NMOSD is a rare but severe relapsing remitting demyelinating disease that affects both adults and children. Most patients have pathogenic antibodies that target the central nervous system AQP4 protein. This review provides an update on our current understanding of the disease pathophysiology and describes the clinical, paraclinical features and therapeutic management of the disease.     

Aquaporin-4 gene disruption in mice reduces brain swelling and mortality in pneumococcal meningitis

The astroglial water channel aquaporin-4 (AQP4) facilitates water movement into and out of brain parenchyma. To investigate the role of AQP4 in meningitis-induced brain edema, Streptococcus pneumoniae was injected into cerebrospinal fluid (CSF) in wild type and AQP4 null mice. AQP4-deficient mice had remarkably lower intracranial pressure (9 +/- 1 versus 25 +/- 5 cm H2O) and brain water accumulation (2 +/- 1 versus 9 +/- 1 microl) at 30 h, and improved survival (80 versus 0% survival) at 60 h, through comparable CSF bacterial and white cell counts. Meningitis produced marked astrocyte foot process swelling in wild type but not AQP4 null mice, and slowed diffusion of an inert macromolecule in brain extracellular space. AQP4 protein was strongly up-regulated in meningitis, resulting in a approximately 5-fold higher water permeability (P(f)) across the blood-brain barrier compared with non-infected wild type mice. Mathematical modeling using measured P(f) and CSF dynamics accurately simulated the elevated lower intracranial pressure and brain water produced by meningitis and predicted a beneficial effect of prevention of AQP4 upregulation. Our findings provide a novel molecular mechanism for the pathogenesis of brain edema in acute bacterial meningitis, and suggest that inhibition of AQP4 function or up-regulation may dramatically improve clinical outcome.     

A phase I clinical and pharmacokinetic study (LIPOTEC - GP PHARM/DOXO 01) of a new liposomal doxorubicin given as 3-week schedule in patients with solid tumors

As a dose-finding phase I study of a new liposomal formulation of doxorubicin (LipD), patients (n?=?39; median age: 60 years; range, 41–75; median ECOG performance status, 1; range, 0–2) with refractory cancer had a starting dose of LipD administered at 30?mg/m² as a 1-hour iintravenous infusion. Cycle duration was 21 days. At the recommended dose (RD), patients received a first cycle of nonliposomal doxorubicin (non-LipD) to evaluate intrapatient pharmacokinetic differences between non-LipD and LipD. The most frequent diagnosis was head and neck tumor (7 patients). Tolerance and safety of dose levels of 30, 40, 50, 60, 70, 80, and 90?mg/m² were evaluated. A total of 131 cycles were administered (median per patient, 3; range, 1–6). Of the 39 patients, 8 completed the planned six cycles. Febrile neutropenia was dose limiting and defined the toxic dose of LipD as 70?mg/m². Other significant toxicities included asthenia (G2: 31%; G3: 8%), neutropenia (G3: 35%; G4: 29%), thrombopenia (G3: 15%; G4: 2%), anemia (G1–G2: 67%; G3–G4: 5%), mucositis (G1–G2: 32%, G3: 4%), and acute allergic reactions (G1–G2: 36%). Comparison of pharmacokinetic profiles of non-LipD and LipD showed that higher exposure was achieved with LipD. Stable disease was observed in 14 patients. We conclude that the LipD regimen, given as a 1-hour infusion every 3 weeks, is well tolerated and has a favorable pharmacokinetic profile. The recommended dose is 70?mg/m² with prophylactic antihistamines and corticoids to preempt allergic reaction.     

Is CSF cytology a useful diagnostic procedure in staging paediatric CNS tumours?

Objectives:  To evaluate whether there are any factors that predict malignant cells being found in paediatric cerebrospinal fluid (CSF) samples. To determine whether CSF provides useful staging information not provided by magnetic resonance imaging (MRI) in paediatric patients with primary central nervous system (CNS) malignancy.
Methods:  We compared the CSF cytology and spinal MRI staging results in paediatric patients with primary CNS malignancy at a UK tertiary referral centre, over a decade.
Results:  Of 159 CSF samples, 72 samples were from 72 patients with primary CNS malignancy with spinal MRI available for comparison. Eight of these 72 had positive cytology (seven malignant and one suspicious). All had a high clinical suspicion of tumour at the time of sampling. Of the 72 patients, only two had evidence of CSF spread on MRI spinal staging and CSF cytology; ten had MRI without cytological evidence and six had cytological without MRI evidence.
Conclusions:  In paediatric patients with primary CNS tumours, CSF cytology provides useful staging information. Spinal MRI alone may miss some patients with CSF spread who would be identified with CSF cytology.     

Light inactivation of water transport and protein-protein interactions of aquaporin-Killer Red chimeras

Aquaporins (AQPs) have a broad range of cellular and organ functions; however, nontoxic inhibitors of AQP water transport are not available. Here, we applied chromophore-assisted light inactivation (CALI) to inhibit the water permeability of AQP1, and of two AQP4 isoforms (M1 and M23), one of which (M23) forms aggregates at the cell plasma membrane. Chimeras containing Killer Red (KR) and AQPs were generated with linkers of different lengths. Osmotic water permeability of cells expressing KR/AQP chimeras was measured from osmotic swelling-induced dilution of cytoplasmic chloride, which was detected using a genetically encoded chloride-sensing fluorescent protein. KR-AQP1 red fluorescence was bleached rapidly (~10% per second) by wide-field epifluorescence microscopy. After KR bleaching, KR-AQP1 water permeability was reduced by up to 80% for the chimera with the shortest linker. Remarkably, CALI-induced reduction in AQP4-KR water permeability was approximately twice as efficient for the aggregate-forming M23 isoform; this suggests intermolecular CALI, which was confirmed by native gel electrophoresis on cells coexpressing M23-AQP4-KR and myc-tagged M23-AQP4. CALI also disrupted the interaction of AQP4 with a neuromyelitis optica autoantibody directed against an extracellular epitope on AQP4. CALI thus permits rapid, spatially targeted and irreversible reduction in AQP water permeability and interactions in live cells. Our data also support the utility of CALI to study protein-protein interactions as well as other membrane transporters and receptors.