Properties of Iron Primary Cosmic Rays: Results from the Alpha Magnetic Spectrometer

We report the observation of new properties of primary iron (Fe) cosmic rays in the rigidity range 2.65 GV to 3.0 TV with 0.62×10^{6} iron nuclei collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. Above 80.5 GV the rigidity dependence of the cosmic ray Fe flux is identical to the rigidity dependence of the primary cosmic ray He, C, and O fluxes, with the Fe/O flux ratio being constant at 0.155±0.006. This shows that unexpectedly Fe and He, C, and O belong to the same class of primary cosmic rays which is different from the primary cosmic rays Ne, Mg, and Si class.

Vertically stacked RGB LEDs with optimized distributed Bragg reflectors

The design and fabrication of a vertically stacked red-green-blue (RGB) light-emitting diode (LED) with novel, to the best of our knowledge, wavelength-selective distributed Bragg reflectors (DBRs) are demonstrated. The two DBRs are optimized to achieve selective reflectance in the RGB spectral region through theoretical calculations and simulation modeling. The insertion of optimal DBRs into the stack structure can effectively reflect downward emission from the upper chip without filtering the emission from the lower chips, thereby increasing the luminous efficiency for white emission with a color temperature range of 3000-8000 K by 1.6-7.4%. The optical performances of stacked devices with and without DBRs are thoroughly studied, verifying the effectiveness of the proposed wavelength-selective DBR structure.

Purification of Paclobutrazol-Free Steroidal Saponins and Flavonoids from the Fibrous Roots of Ophiopogon japonicas

In the current study, a convenient approach was developed to isolate and purify active ingredients, including total steroidal saponins and total flavonoids, while simultaneously removing the toxic component - paclobutrazol - from the fibrous root of Ophiopogon japonicas. The separation performance of eight macroporous resins (D101, AB-8, DM301, DA201, H103, HPD100, D3520, and HP20) were evaluated using static and dynamic experimentation. The results showed that the D101 resin had the optimal capacity of adsorption and desorption to total steroidal saponins and total flavonoids. The static adsorption of D101 resins to total steroidal saponins and total flavonoids conformed to the Langmuir isotherm model and pseudo-second-order kinetic model. Under optimal purification parameters, the recovery rates of total steroidal saponins and total flavonoids were 86.49% and 87.89%, respectively. The total steroidal saponins and total flavonoids's purities increased from 16.67% to 47.58%, and from 3.82% to 12.29%, respectively. Furthermore, paclobutrazol's content decreased from 16.902mg/kg to 1.106mg/kg with a removal rate of 93.45%.

Properties of Neon, Magnesium, and Silicon Primary Cosmic Rays Results from the Alpha Magnetic Spectrometer

We report the observation of new properties of primary cosmic rays, neon (Ne), magnesium (Mg), and silicon (Si), measured in the rigidity range 2.15 GV to 3.0 TV with 1.8×10^{6}  Ne, 2.2×10^{6}  Mg, and 1.6×10^{6}  Si nuclei collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. The Ne and Mg spectra have identical rigidity dependence above 3.65 GV. The three spectra have identical rigidity dependence above 86.5 GV, deviate from a single power law above 200 GV, and harden in an identical way. Unexpectedly, above 86.5 GV the rigidity dependence of primary cosmic rays Ne, Mg, and Si spectra is different from the rigidity dependence of primary cosmic rays He, C, and O. This shows that the Ne, Mg, and Si and He, C, and O are two different classes of primary cosmic rays.

0559 Association of Rapid Eye Movement Sleep with Insulin Resistance in Han Chinese Patients With Obstructive Sleep Apnea

Introduction

Obstructive sleep apnea (OSA) is increasingly associated with insulin resistance. The underlying pathophysiology remains unclear but rapid eye movement (REM) sleep has been hypothesized to play a key role. To investigate the associations of insulin resistance with respiratory events and sleep duration during REM sleep, 4,062 Han Chinese individuals with suspected OSA were screened and 2,899 were analyzed.

Methods

We screened 4,062 participants with suspected OSA who underwent polysomnography in our sleep center from 2009 to 2016. Polysomnographic variables, biochemical indicators, and physical measurements were collected. Logistic regression analyses were conducted to determine the odds ratios (ORs) and 95% confidence intervals (95% CIs) for insulin resistance as assessed by hyperinsulinemia, the homeostasis model assessment of insulin resistance (HOMA-IR), fasting insulin resistance index (FIRI), and Bennet’s insulin sensitivity index (ISI).

Results

The final analyses included 2,899 participants. After adjusting for age, gender, body mass index, waist circumference, mean arterial pressure, smoking status, alcohol consumption, and the apnea and hypopnea index during non-REM sleep (AHINREM), the results revealed that AHI during REM sleep (AHIREM) was independently associated with insulin resistance; across higher AHIREM quartiles, the ORs (95% CIs) for hyperinsulinemia were 1.340 (1.022, 1.757), 1.210 (0.882, 1.660), and 1.632 (1.103, 2.416); those for abnormal HOMA-IR were 1.287 (0.998, 1.661), 1.263 (0.933, 1.711), and 1.556 (1.056, 2.293); those for abnormal FIRI were 1.386 (1.048, 1.835), 1.317 (0.954, 1.818), and 1.888 (1.269, 2.807); and those for abnormal Bennet’s ISI were 1.297 (1.003, 1.678), 1.287 (0.949, 1.747), and 1.663 (1.127, 2.452) (P < 0.01 for all linear trends). Additionally, the results showed that for every 1-h increase in REM duration, the risk of hyperinsulinemia decreased by 22.3% (P < 0.05).

Conclusion

The present study demonstrated that AHIREM was independently associated with hyperinsulinemia and abnormal HOMA-IR, FIRI, and Bennet’s ISI. Additionally, REM sleep duration was independently associated with hyperinsulinemia.

Support

This study was supported by Grants-in-aid from Shanghai Municipal Commission of Science and Technology (No.18DZ2260200).

0713 Association Between Obesity Indices And Obstructive Sleep Apnea Is Modified By Age In A Sex-specific Manner

Introduction

The beneficial effects of weight loss on obstructive sleep apnea (OSA) are highly variable. Whether the variability is associated with the effects of age and sex remains unclear. This study examined this issue with large cross-sectional data.

Methods

A total of 4600 adult males and 1156 females with suspected OSA were included in the study. Anthropometric measurements, polysomnographic variables, biochemical indicators, and medical history were collected for each subject. Multivariable linear regression with interaction terms was used to estimate the modification effect of age on the associations between OSA severity (assessed by apnea-hypopnea index, AHI) with obesity indices (body mass index, BMI; neck circumference, NC; waist circumference, WC) in a sex-specific manner, and vice versa.

Results

BMI, NC, and WC were all positively correlated with AHI after adjusting for potential confounders in all populations. In males, these associations were much stronger and more significant in younger than older individuals (P for interaction < 0.001). For example, a 10% increase in BMI was independently associated with a 31.6% increase in AHI for males < 40 years old, whereas the corresponding increases were 20.8% and 16.7% for males 40-60 and >60 years old, respectively. By contrast, no modification effect of age was observed in females (P for interaction > 0.05). A 10% increase in BMI was associated with 25.6%, 26.8%, and 23.8% increases in AHI for females < 40, 40-60, and >60 years old, respectively.

Conclusion

Age modifies the associations between obesity indices and OSA severity in a sex-specific manner, and vice versa. These findings may broaden the understanding of age- and sex-related heterogeneities in the pathogenic role of obesity in OSA, and may be beneficial for individualized risk evaluation and treatment management for patients with OSA.

Support

This study was funded by Shanghai Municipal Commission of Science and Technology (grant number.18DZ2260200); the National Key R&D Program of China (grant number: 2017YFC0112500); Multi-Center Clinical Research Project from the School of Medicine, Shanghai Jiao Tong University (grant number: DLY201502); and the Shanghai Shen-Kang Hospital Management Center Project (grant number: SHDC12015101 and 16CR3103B).

0601 Use of The Epworth Sleepiness Scale, the NoSAS, and the STOP-BANG Questionnaire to Identify Patients with Moderate-to-Severe Obstructive Sleep Apnea

Introduction

A variety of scales and questionnaires regarding sleep and sleep-related disorders have been widely used in scientific research and clinical practice, as important tools for differential diagnosis and rapid screening of complex sleep disorders, especially obstructive sleep apnea (OSA). However, the diagnostic efficacy of different scales and questionnaires for patients with different severity of OSA and of different demographic characteristics has not been clearly described. In this study, we evaluated the ability of the most popular scales, including the Epworth Sleepiness Scale (ESS), the NoSAS, and the STOP-BANG questionnaire in predicting moderate-to-severe obstructive sleep apnea (OSA) by gender.

Methods

This cross-sectional study screened 2,031 consecutive subjects referred with suspected OSA from 2012 to 2016. Anthropometric measurements, polysomnographic data, ESS, NoSAS scores and STOP-BANG scores were recorded. Receiver operating characteristic curve analyses were performed, and the final predictive models were verified in a validation cohort.

Results

A total of 1,840 adults were finally included. The STOP-BANG questionnaire afforded a better diagnostic accuracy than did the ESS, with different cutoffs for the two genders: 3 in males and 1 in females. A predictive model based on STOP-BANG yielded an area under the curve (AUC) of 0.918 (0.897-0.935), a sensitivity of 79.89%, and a specificity of 89.19%, in males; and an AUC of 0.951 (0.914-0.975), a sensitivity of 80.52%, and a specificity of 95.92%, in females. In the validation cohort, the sensitivity and specificity were respectively 85.44 and 93.00% in males and respectively 83.02 and 87.60% in females.

Conclusion

The STOP-BANG questionnaire was moderately effective when used to screen for moderate-to-severe OSA. A STOP-BANG-based predictive model afforded excellent diagnostic efficacy, which could be applied in clinical practice. However, gender differences must be considered.

Support

This study was supported by Grants-in-aid from Shanghai Municipal Commission of Science and Technology (Grant No.18DZ2260200).

0565 Obstructive Sleep Apnea, But Not Short Sleep Duration, is Independently Associated with Insulin Resistance: A Large-Scale Cohort Study

Introduction

Both short sleep duration and obstructive sleep apnea (OSA) seem to be associated with insulin resistance. However, the majority of previous studies addressing the relationship between OSA and insulin resistance did not evaluate short sleep duration, and vice versa. In this study, we used a large-scale hospital-based cross-sectional dataset, including 5,447 participants, to examine 1) whether objectively measured short sleep duration and OSA are independently associated with insulin resistance, and 2) whether the presence of OSA modulates the association between sleep duration and insulin resistance.

Methods

Participants were consecutively enrolled from our sleep center during the period from 2007 to 2017. The index of homeostasis model assessment insulin resistance (HOMA-IR) was calculated from insulin and glucose. Sleep duration was determined by standard polysomnography. The associations between sleep duration and insulin resistance were estimated by logistic regression analyses.

Results

A total of 5,447 participants (4507 OSA and 940 primary snorers) were included in the study. In comparison to primary snorers, OSA combined with extremely short sleep duration (< 5 hours) increased the risk of insulin resistance by 34% (OR, 1.34; 95% CI, 1.01-1.77) after adjusting for confounding factors that are frequently associated with insulin resistance and OSA. In subgroup analysis stratified by sleep duration, the risk of insulin resistance in patients with a short sleep duration (5-6 hours or < 5 hours) was increased in those with OSA compared to primary snorers, but not in the other three sleep duration groups (6 - 7, 7 - 8, and > 8 hours).

Conclusion

OSA, but not short sleep duration, was independently associated with insulin resistance. It is worth noting that OSA combined with extremely short sleep duration showed a greater detrimental effect than OSA itself with regard to insulin resistance.

Support

This study was supported by grants-in-aid from Shanghai Municipal Commission of Science and Technology (Grant No.18DZ2260200).

Effects of acute heat stress on intestinal microbiota in grow-finishing pigs, and associations with feed intake and serum profile

AIMS

This study was conducted to assess the effects of acute heat stress (HS) on intestinal microbiota, and the associations with the changes in feed intake (FI) and serum profile.

METHODS AND RESULTS

Twenty four individually housed pigs (Duroc × Large White × Landrace, 30 ± 1 kg body weight) were randomly assigned to receive one of three treatments (8 pigs/treatment): (i) thermal neutral (TN) conditions (25 ± 1°C), (ii) HS conditions (35 ± 1°C), (iii) pair-feeding (PF) with HS under TN conditions. After 24-h treatment, pigs were monitored to assess FI, and samples of serum and faeces were collected to investigate serum profile, microbial composition and short chain fatty acids (SCFAs). The results showed that HS decreased (P < 0·05) FI compared with the TN group. Compared with TN group, HS changed the serum profile by affecting biochemical parameters and hormones related with energy metabolism and stress response; immune indicators were also altered in HS group. Most of changes in serum profile were independent of FI reduction. Additionally, HS shifted the diversity and composition of faecal microbial community by increasing (P < 0·05) Proteobacteria and decreasing (P < 0·05) Bacteroidetes. Moreover, HS decreased (P < 0·05) the concentrations of propionate, butyrate, valerate, iso-valerate and total SCFAs in faeces in an FI-independent manner. Furthermore, the Spearman correlation analysis implied that changes of serum profile have potential correlation with alterations of faecal microbiota and their SCFAs metabolites in acute HS-treated grow-finishing pigs.

CONCLUSIONS

Metabolism disorders caused by 24-h acute HS associated with changes of faecal microbiota and their SCFAs metabolites in an FI-independent manner in grow-finishing pigs.

SIGNIFICANCE AND IMPACT OF THE STUDY

These results give us a new insight of the intestinal damage caused by acute HS and the underlying mechanisms.

Properties of Cosmic Helium Isotopes Measured by the Alpha Magnetic Spectrometer

Precision measurements by the Alpha Magnetic Spectrometer (AMS) on the International Space Station of ^{3}He and ^{4}He fluxes are presented. The measurements are based on 100 million ^{4}He nuclei in the rigidity range from 2.1 to 21 GV and 18 million ^{3}He from 1.9 to 15 GV collected from May 2011 to November 2017. We observed that the ^{3}He and ^{4}He fluxes exhibit nearly identical variations with time. The relative magnitude of the variations decreases with increasing rigidity. The rigidity dependence of the ^{3}He/^{4}He flux ratio is measured for the first time. Below 4 GV, the ^{3}He/^{4}He flux ratio was found to have a significant long-term time dependence. Above 4 GV, the ^{3}He/^{4}He flux ratio was found to be time independent, and its rigidity dependence is well described by a single power law ∝R^{Δ} with Δ=-0.294±0.004. Unexpectedly, this value is in agreement with the B/O and B/C spectral indices at high energies.

The stomatal flexoskeleton: how the biomechanics of guard cell walls animate an elastic pressure vessel

In plants, stomatal guard cells are one of the most dynamic cell types, rapidly changing their shape and size in response to environmental and intrinsic signals to control gas exchange at the plant surface. Quantitative and systematic knowledge of the biomechanical underpinnings of stomatal dynamics will enable strategies to optimize stomatal responsiveness and improve plant productivity by enhancing the efficiency of photosynthesis and water use. Recent developments in microscopy, mechanical measurements, and computational modeling have revealed new insights into the biomechanics of stomatal regulation and the genetic, biochemical, and structural origins of how plants achieve rapid and reliable stomatal function by tuning the mechanical properties of their guard cell walls. This review compares historical and recent experimental and modeling studies of the biomechanics of stomatal complexes, highlighting commonalities and contrasts between older and newer studies. Key gaps in our understanding of stomatal functionality are also presented, along with assessments of potential methods that could bridge those gaps.

Synergistic Pectin Degradation and Guard Cell Pressurization Underlie Stomatal Pore Formation

Stomatal pores are vital for the diffusion of gasses into and out of land plants and are, therefore, gatekeepers for photosynthesis and transpiration. Although much published literature has described the intercellular signaling and transcriptional regulators involved in early stomatal development, little is known about the cellular details of the local separation between sister guard cells that give rise to the stomatal pore or how formation of this pore is achieved. Using three-dimensional (3D) time-lapse imaging, we found that stomatal pore formation in Arabidopsis (Arabidopsis thaliana) is a highly dynamic process involving pore initiation and enlargement and traverses a set of morphological milestones in 3D. Confocal imaging data revealed an enrichment of exocytic machinery, de-methyl-esterified pectic homogalacturonan (HG), and an HG-degrading enzyme at future pore sites, suggesting that both localized HG deposition and degradation might function in pore formation. By manipulating HG modification via enzymatic, chemical, and genetic perturbations in seedling cotyledons, we found that augmenting HG modification promotes pore formation, whereas preventing HG de-methyl-esterification delays pore initiation and inhibits pore enlargement. Through mechanical modeling and experimentation, we tested whether pore formation is an outcome of sister guard cells being pulled away from each other upon turgor increase. Osmotic treatment to reduce turgor pressure did not prevent pore initiation but did lessen pore enlargement. Together, these data provide evidence that HG delivery and modification, and guard cell pressurization, make functional contributions to stomatal pore initiation and enlargement.

Towards Understanding the Origin of Cosmic-Ray Electrons

Precision results on cosmic-ray electrons are presented in the energy range from 0.5 GeV to 1.4 TeV based on 28.1×10^{6} electrons collected by the Alpha Magnetic Spectrometer on the International Space Station. In the entire energy range the electron and positron spectra have distinctly different magnitudes and energy dependences. The electron flux exhibits a significant excess starting from 42.1_{-5.2}^{+5.4}  GeV compared to the lower energy trends, but the nature of this excess is different from the positron flux excess above 25.2±1.8  GeV. Contrary to the positron flux, which has an exponential energy cutoff of 810_{-180}^{+310}  GeV, at the 5σ level the electron flux does not have an energy cutoff below 1.9 TeV. In the entire energy range the electron flux is well described by the sum of two power law components. The different behavior of the cosmic-ray electrons and positrons measured by the Alpha Magnetic Spectrometer is clear evidence that most high energy electrons originate from different sources than high energy positrons.

Towards Understanding the Origin of Cosmic-Ray Positrons

Precision measurements of cosmic ray positrons are presented up to 1 TeV based on 1.9 million positrons collected by the Alpha Magnetic Spectrometer on the International Space Station. The positron flux exhibits complex energy dependence. Its distinctive properties are (a) a significant excess starting from 25.2±1.8  GeV compared to the lower-energy, power-law trend, (b) a sharp dropoff above 284_{-64}^{+91}  GeV, (c) in the entire energy range the positron flux is well described by the sum of a term associated with the positrons produced in the collision of cosmic rays, which dominates at low energies, and a new source term of positrons, which dominates at high energies, and (d) a finite energy cutoff of the source term of E_{s}=810_{-180}^{+310}  GeV is established with a significance of more than 4σ. These experimental data on cosmic ray positrons show that, at high energies, they predominantly originate either from dark matter annihilation or from other astrophysical sources.

Immunogenicity and safety of an accelerated hepatitis E vaccination schedule in healthy adults: a randomized, controlled, open-label, phase IV trial

OBJECTIVES

This study aimed to evaluate the immunogenicity and safety of a hepatitis E (HE) vaccine using an accelerated vaccination schedule (vaccine doses at 0, 7 and 21 days).

METHODS

A total of 126 participants aged ≥18 years were randomly assigned to receive the hepatitis E virus vaccine in either the accelerated group (0, 7 and 21 days) or the routine group (0, 1 and 6 months). Serology samples were obtained at 0, 21, 28 and 51 days, and 7 months in the accelerated group, or 0, 1, 2 and 7 months in the routine group after the first vaccine injection. Adverse events (AEs) reported during the whole study were analysed.

RESULTS

A total of 126 participants were randomized, 63 for each group. Sixty-two participants in the accelerated group and 63 in the routine group received at least one dose of vaccine; 57 and 63 participants received all three doses and were included in per-protocol set, respectively. In the per-protocol population, at 1 month after the last dose (accelerated group at 51 days versus routine group at 7 months), the seropositive rates were both 100% (57/57 and 63/63, respectively), and the geometric mean concentrations (GMCs) were 8.51 WHO units/mL (95% CI 6.73-10.76) in the accelerated group and 9.67 WHO units/mL (95% CI 7.67-12.20) in the routine group. The ratio of the accelerated group GMC to the routine group GMC was 0.88 (95% CI 0.61-2.17, lower limit of 95% CI > 0.5), indicating that the accelerated vaccination schedule was non-inferior to the routine one. The overall incidence rates of solicited AEs in the accelerated and routine groups were 32.26% (20/62) and 30.16% (19/63), respectively (p 0.800). Most AEs were moderate.

CONCLUSIONS

An accelerated schedule is safe and provides protective antibodies in a shorter time compared with the routine schedule. The accelerated schedule should be recommended to adults who are travelling on short notice to an HE-endemic area or during an HE outbreak (Clinical Trial Registration. NCT03168412).

Balancing Strength and Flexibility: How the Synthesis, Organization, and Modification of Guard Cell Walls Govern Stomatal Development and Dynamics

Guard cells are pairs of epidermal cells that control gas diffusion by regulating the opening and closure of stomatal pores. Guard cells, like other types of plant cells, are surrounded by a three-dimensional, extracellular network of polysaccharide-based wall polymers. In contrast to the walls of diffusely growing cells, guard cell walls have been hypothesized to be uniquely strong and elastic to meet the functional requirements of withstanding high turgor and allowing for reversible stomatal movements. Although the walls of guard cells were long underexplored as compared to extensive studies of stomatal development and guard cell signaling, recent research has provided new genetic, cytological, and physiological data demonstrating that guard cell walls function centrally in stomatal development and dynamics. In this review, we highlight and discuss the latest evidence for how wall polysaccharides are synthesized, deposited, reorganized, modified, and degraded in guard cells, and how these processes influence stomatal form and function. We also raise open questions and provide a perspective on experimental approaches that could be used in the future to shed light on the composition and architecture of guard cell walls.

Observation of Complex Time Structures in the Cosmic-Ray Electron and Positron Fluxes with the Alpha Magnetic Spectrometer on the International Space Station

We present high-statistics, precision measurements of the detailed time and energy dependence of the primary cosmic-ray electron flux and positron flux over 79 Bartels rotations from May 2011 to May 2017 in the energy range from 1 to 50 GeV. For the first time, the charge-sign dependent modulation during solar maximum has been investigated in detail by leptons alone. Based on 23.5×10^{6} events, we report the observation of short-term structures on the timescale of months coincident in both the electron flux and the positron flux. These structures are not visible in the e^{+}/e^{-} flux ratio. The precision measurements across the solar polarity reversal show that the ratio exhibits a smooth transition over 830±30 days from one value to another. The midpoint of the transition shows an energy dependent delay relative to the reversal and changes by 260±30 days from 1 to 6 GeV.

Precision Measurement of Cosmic-Ray Nitrogen and its Primary and Secondary Components with the Alpha Magnetic Spectrometer on the International Space Station

A precision measurement of the nitrogen flux with rigidity (momentum per unit charge) from 2.2 GV to 3.3 TV based on 2.2×10^{6} events is presented. The detailed rigidity dependence of the nitrogen flux spectral index is presented for the first time. The spectral index rapidly hardens at high rigidities and becomes identical to the spectral indices of primary He, C, and O cosmic rays above ∼700  GV. We observed that the nitrogen flux Φ_{N} can be presented as the sum of its primary component Φ_{N}^{P} and secondary component Φ_{N}^{S}, Φ_{N}=Φ_{N}^{P}+Φ_{N}^{S}, and we found Φ_{N} is well described by the weighted sum of the oxygen flux Φ_{O} (primary cosmic rays) and the boron flux Φ_{B} (secondary cosmic rays), with Φ_{N}^{P}=(0.090±0.002)×Φ_{O} and Φ_{N}^{S}=(0.62±0.02)×Φ_{B} over the entire rigidity range. This corresponds to a change of the contribution of the secondary cosmic ray component in the nitrogen flux from 70% at a few GV to <30% above 1 TV.

Observation of Fine Time Structures in the Cosmic Proton and Helium Fluxes with the Alpha Magnetic Spectrometer on the International Space Station

We present the precision measurement from May 2011 to May 2017 (79 Bartels rotations) of the proton fluxes at rigidities from 1 to 60 GV and the helium fluxes from 1.9 to 60 GV based on a total of 1×10^{9} events collected with the Alpha Magnetic Spectrometer aboard the International Space Station. This measurement is in solar cycle 24, which has the solar maximum in April 2014. We observed that, below 40 GV, the proton flux and the helium flux show nearly identical fine structures in both time and relative amplitude. The amplitudes of the flux structures decrease with increasing rigidity and vanish above 40 GV. The amplitudes of the structures are reduced during the time period, which started one year after solar maximum, when the proton and helium fluxes steadily increase. Above ∼3  GV the p/He flux ratio is time independent. We observed that below ∼3  GV the ratio has a long-term decrease coinciding with the period during which the fluxes start to rise.

Patients affected by a new variant of endemic pemphigus foliaceus have autoantibodies colocalizing with MYZAP, p0071, desmoplakins 1-2 and ARVCF, causing renal damage

BACKGROUND

We have previously reported that about 30% of patients affected by a new variant of endemic pemphigus foliaceus (EPF) in El Bagre, Colombia (termed El Bagre-EPF or pemphigus Abreu-Manu) have systemic compromise. In the current study, we focused on studying autoreactivity to the kidney and its pathological correlations.

AIM

To investigate patients with El Bagre-EPF for renal compromise.

METHODS

We performed a case-control study, enrolling 57 patients with El Bagre-EPF and 57 controls from the endemic area, matched by age, sex, race, work activity, demographics and comorbidities. We took skin and renal biopsies; performed direct and indirect immunofluorescence, immunohistochemistry (IHC), confocal microscopy, immunoblotting, direct and indirect immune electron microscopy; and tested kidney function in all living patients. We also used IHC to study seven kidney autopsy samples.

RESULTS

Of the 57 patients, 19 had autoantibodies to kidney, with polyclonal reactivity (P < 0.01). Most cases were positive along the basement membrane of the proximal tubules, but in some cases there was also positivity against the glomeruli and/or mixed patterns. Fifteen patients had increases in serum urea and creatinine compared with controls (P < 0.01). The autoantibodies colocalized with commercial antibodies to desmoplakins I and II, p0071, armadillo repeat gene deleted in velo-cardio-facial syndrome (ARCVF) and myocardium-enriched zonula occludens-1-associated protein (MYZAP) (P < 0.01). All of the kidney disease autopsies showed alterations, mostly in the vessels.

CONCLUSION

We demonstrate for the first time that one-third of patients with El Bagre-EPF have polyclonal autoantibodies to kidney. The kidneys showed a mixed histological pattern resembling lupus nephritis, with a diffuse proliferative Class IV (G) global diffuse pattern in active lesions, and additional interposition of membranoproliferative glomerulonephritis.