Measurements of All-Particle Energy Spectrum and Mean Logarithmic Mass of Cosmic Rays from 0.3 to 30 PeV with LHAASO-KM2A.

We present the measurements of all-particle energy spectrum and mean logarithmic mass of cosmic rays in the energy range of 0.3-30 PeV using data collected from LHAASO-KM2A between September 2021 and December 2022, which is based on a nearly composition-independent energy reconstruction method, achieving unprecedented accuracy. Our analysis reveals the position of the knee at 3.67±0.05±0.15 PeV. Below the knee, the spectral index is found to be -2.7413±0.0004±0.0050, while above the knee, it is -3.128±0.005±0.027, with the sharpness of the transition measured with a statistical error of 2%. The mean logarithmic mass of cosmic rays is almost heavier than helium in the whole measured energy range. It decreases from 1.7 at 0.3 PeV to 1.3 at 3 PeV, representing a 24% decline following a power law with an index of -0.1200±0.0003±0.0341. This is equivalent to an increase in abundance of light components. Above the knee, the mean logarithmic mass exhibits a power law trend towards heavier components, which is reversal to the behavior observed in the all-particle energy spectrum. Additionally, the knee position and the change in power-law index are approximately the same. These findings suggest that the knee observed in the all-particle spectrum corresponds to the knee of the light component, rather than the medium-heavy components.

[Association between unhealthy lifestyles and hyperuricemia in occupational population and modification effect of hypertension and dyslipidemia].

Objective: To understand the relationship between unhealthy lifestyle and hyperuricemia, as well as the modification effects of hypertension and dyslipidemia in occupational population and provide a theoretical basis for the prevention of hyperuricemia. Methods: A cross-sectional survey design was adopted, based on baseline data from the Southwest Occupational Population Cohort from China Railway Chengdu Group Co., Ltd., which included the population in 28 prefectures from Sichuan Province and Guizhou Province, and 33 districts (counties) from Chongqing Municipality between October and December 2021. This study collected the information about the demographics characteristics, lifestyles, and prevalence of chronic non-communicable diseases of the study subjects through questionnaire, physical measurement and laboratory biochemical test. The unhealthy lifestyle score was scored based on smoking, alcohol consumption, dietary patterns, physical activity, and low weight or overweight, with higher scores being associated with more unhealthy lifestyles. The multivariate logistic regression model was used to analyze the relationship between unhealthy lifestyle score, smoking, alcohol consumption, other factors and hyperuricemia, and the stratified analysis was used to explore the modification effect of hypertension and other diseases on the relationship between unhealthy lifestyle and hyperuricemia. Results: A total of 11 748 participants were included in this study, the prevalence of hyperuricemia was 34.4%. Multivariate logistic regression model showed that current/previous smoking, current/previous alcohol consumption and BMI abnormality were risk factors for hyperuricemia, and the unhealthy lifestyle score showed a "cumulative" effect on the risk for hyperuricemia, with higher score increasing the risk of hyperuricemia, and the OR increased from 1.64 (95%CI: 1.34-2.00) to 2.89 (95%CI: 2.39-3.50). Stratified analysis showed that unhealthy lifestyles had a greater impact on the risk for hyperuricemia in people with hypertension and dyslipidemia. Conclusions: The coexistence of multiple unhealthy lifestyles might increase the risk of hyperuricemia, and this effect was stronger in participants with hypertension and dyslipidemia. Timely correction of unhealthy lifestyles, and control of hypertension and dyslipidemia might reduce the risk for hyperuricemia.

[Mediating effects of body mass index and lipid levels on the association between alcohol consumption and hypertension in occupational population].

Objective: To investigate the association between alcohol consumption and hypertension and SBP, DBP and the mediating effects of body mass index (BMI) and lipid level in occupational population, and provide reference for the intervention and prevention of hypertension. Methods: Based on the data of Southwest Occupational Population Cohort from China Railway Chengdu Group Co., Ltd., the information about the demographic characteristics, behavior and lifestyle, blood pressure and lipids level of the participants were collected through questionnaire survey, physical examination and blood biochemical test. Logistic/linear regression was used to analyze the association between alcohol consumption and hypertension, SBP and DBP. The individual and joint mediating effects of BMI, HDL-C, LDL-C, TG, and TC were explored through causal mediating analysis. A network analysis was used to explore the correlation between alcohol consumption, BMI and lipid levels, and hypertension. Results: A total of 22 887 participants were included, in whom 1 825 had newly detected hypertension. Logistic regression analysis found that current/former drinkers had a 33% increase of risk for hypertension compared with never-drinkers (OR=1.33, 95%CI:1.19-1.48). Similarly, alcohol consumption could increase SBP (ß=1.05, 95%CI:0.69-1.40) and DBP (ß=1.10, 95%CI:0.83-1.38). Overall, BMI and lipid levels could mediate the associations between alcohol consumption and hypertension, SBP and DBP by 21.91%, 28.40% and 22.64%, respectively. BMI and TG were the main mediators, and they were also the two nodes with the highest edge weight and bridge strength centrality in the network of alcohol consumption, BMI, lipid levels and hypertension. Conclusions: Alcohol consumption was associated with increased risk for hypertension, and BMI and TG were important mediators and key nodes in the network. It is suggested that paying attention to the alcohol consumption, BMI and TG might help prevent hypertension in occupational population.

[Association between work environment noise perception and cardiovascular diseases, depressive symptoms, and their comorbidity in occupational population].

Objective: To explore the association between occupational noise perception and cardiovascular disease (CVD), depression symptoms, as well as their comorbidity in occupational population and provide evidence for the prevention and control of physical and mental illnesses. Methods: A cross-sectional survey design was adopted, based on baseline data in population in 28 prefectures in Sichuan Province and Guizhou Province, and 33 districts (counties) in Chongqing municipality from Southwest Occupational Population Cohort from China Railway Chengdu Group Co., Ltd. during October to December 2021. A questionnaire survey was conducted to collect information about noise perception, depressive symptoms, and the history of CVD. Latent profile analysis model was used to determine identify noise perception type, and multinomial logistic regression analysis was conducted to explore the relationship between different occupational noise perception types and CVD, depression symptoms and their comorbidity. Results: A total of 30 509 participants were included, the mean age was (36.6±10.5) years, and men accounted for 82.0%. The direct perception of occupational noise, psychological effects and hearing/sleep impact of occupational noise increased the risk for CVD, depressive symptoms, and their comorbidity. By using latent profile analysis, occupational noise perception was classified into four levels: low, medium, high, and very high. As the level of noise perception increased, the association with CVD, depressive symptoms, and their comorbidity increased. In fact, very high level occupational noise perception were found to increase the risk for CVD, depressive symptoms, and their comorbidity by 2.14 (95%CI: 1.73-2.65) times, 8.80 (95%CI: 7.91-9.78) times, and 17.02 (95%CI: 12.78-22.66) times respectively compared with low-level occupational noise perception. Conclusions: Different types of occupational noise perception are associated with CVD and depression symptom, especially in the form of CVD complicated with depression symptom. Furthermore, the intensity of occupational noise in the work environment should be reduced to lower the risk for physical and mental health.

[Association between unhealthy lifestyles and diabetic dyslipidemia in occupational population and network analysis].

Objective: To understand the influence of unhealthy lifestyle on diabetic dyslipidemia and the key influencing factors in occupational population and provided scientific evidence for the prevention of diabetic dyslipidemia. Methods: Based on baseline data and follow-up data of Southwest Occupational Population Cohort from China Railway Chengdu Group Co., Ltd. during 2021. Diabetic dyslipidemia was defined as diabetes plus one or more forms of dyslipidemia, and unhealthy lifestyle factors included smoking, alcohol consumption, unhealthy dietary patterns, low physical activity, and abnormal BMI. Multivariate logistic regression model was used to analyze the relationship between unhealthy lifestyle scores and diabetic dyslipidemia, network analysis was used to find and explore the key lifestyles influencing glycolipid metabolism. Results: A total of 25 631 subjects were included. People with unhealthy lifestyle score 2 and 3 were 1.93 (95%CI: 1.31-2.86) times and 2.37 (95%CI: 1.60-3.50) times more likely to have diabetes with ≥1 forms of dyslipidemia than those with scores of 0; People with unhealthy lifestyle score 1, 2 and 3 were 1.98 (95%CI: 1.08-3.61) times, 2.87 (95%CI: 1.60-5.14) times and 3.95 (95%CI: 2.22-7.06) times more likely to have diabetes with ≥2 forms of dyslipidemia than those with score 0. Network analysis found that abnormal BMI and HDL-C were the "bridge nodes" that link unhealthy lifestyles with diabetic dyslipidemia. Conclusion: The higher the score of unhealthy lifestyle, the higher the risk for diabetic dyslipidemia, abnormal BMI and HDL-C are key factors influencing the association between unhealthy lifestyle and diabetic dyslipidemia.

Measurement of Ultra-High-Energy Diffuse Gamma-Ray Emission of the Galactic Plane from 10 TeV to 1 PeV with LHAASO-KM2A.

The diffuse Galactic γ-ray emission, mainly produced via interactions between cosmic rays and the interstellar medium and/or radiation field, is a very important probe of the distribution, propagation, and interaction of cosmic rays in the Milky Way. In this Letter, we report the measurements of diffuse γ rays from the Galactic plane between 10 TeV and 1 PeV energies, with the square kilometer array of the Large High Altitude Air Shower Observatory (LHAASO). Diffuse emissions from the inner (15°10 TeV). The energy spectrum in the inner Galaxy regions can be described by a power-law function with an index of -2.99±0.04, which is different from the curved spectrum as expected from hadronic interactions between locally measured cosmic rays and the line-of-sight integrated gas content. Furthermore, the measured flux is higher by a factor of ∼3 than the prediction. A similar spectrum with an index of -2.99±0.07 is found in the outer Galaxy region, and the absolute flux for 10≲E≲60 TeV is again higher than the prediction for hadronic cosmic ray interactions. The latitude distributions of the diffuse emission are consistent with the gas distribution, while the longitude distributions show clear deviation from the gas distribution. The LHAASO measurements imply that either additional emission sources exist or cosmic ray intensities have spatial variations.

A tera-electron volt afterglow from a narrow jet in an extremely bright gamma-ray burst.

Some gamma-ray bursts (GRBs) have a tera-electron volt (TeV) afterglow, but the early onset of this has not been observed. We report observations with the Large High Altitude Air Shower Observatory (LHAASO) of the bright GRB 221009A, which serendipitously occurred within the instrument's field of view. More than 64,000 photons >0.2 TeV were detected within the first 3000 seconds. The TeV flux began several minutes after the GRB trigger and then rose to a peak ~10 seconds later. This was followed by a decay phase, which became more rapid ~650 seconds after the peak. We interpret the emission using a model of a relativistic jet with half-opening angle of ~0.8°. This is consistent with the core of a structured jet and could explain the high isotropic energy of this GRB.

Exploring Lorentz Invariance Violation from Ultrahigh-Energy γ Rays Observed by LHAASO.

Recently, the LHAASO Collaboration published the detection of 12 ultrahigh-energy γ-ray sources above 100 TeV, with the highest energy photon reaching 1.4 PeV. The first detection of PeV γ rays from astrophysical sources may provide a very sensitive probe of the effect of the Lorentz invariance violation (LIV), which results in decay of high-energy γ rays in the superluminal scenario and hence a sharp cutoff of the energy spectrum. Two highest energy sources are studied in this work. No signature of the existence of the LIV is found in their energy spectra, and the lower limits on the LIV energy scale are derived. Our results show that the first-order LIV energy scale should be higher than about 10^{5} times the Planck scale M_{Pl} and that the second-order LIV scale is >10^{-3}M_{Pl}. Both limits improve by at least one order of magnitude the previous results.

Constraints on Heavy Decaying Dark Matter from 570 Days of LHAASO Observations.

The kilometer square array (KM2A) of the large high altitude air shower observatory (LHAASO) aims at surveying the northern γ-ray sky at energies above 10 TeV with unprecedented sensitivity. γ-ray observations have long been one of the most powerful tools for dark matter searches, as, e.g., high-energy γ rays could be produced by the decays of heavy dark matter particles. In this Letter, we present the first dark matter analysis with LHAASO-KM2A, using the first 340 days of data from 1/2-KM2A and 230 days of data from 3/4-KM2A. Several regions of interest are used to search for a signal and account for the residual cosmic-ray background after γ/hadron separation. We find no excess of dark matter signals, and thus place some of the strongest γ-ray constraints on the lifetime of heavy dark matter particles with mass between 10^{5} and 10^{9} GeV. Our results with LHAASO are robust, and have important implications for dark matter interpretations of the diffuse astrophysical high-energy neutrino emission.

Peta-electron volt gamma-ray emission from the Crab Nebula.

The Crab Nebula is a bright source of gamma rays powered by the Crab Pulsar's rotational energy through the formation and termination of a relativistic electron-positron wind. We report the detection of gamma rays from this source with energies from 5 × 10-4 to 1.1 peta-electron volts with a spectrum showing gradual steepening over three energy decades. The ultrahigh-energy photons imply the presence of a peta-electron volt electron accelerator (a pevatron) in the nebula, with an acceleration rate exceeding 15% of the theoretical limit. We constrain the pevatron's size between 0.025 and 0.1 parsecs and the magnetic field to ≈110 microgauss. The production rate of peta-electron volt electrons, 2.5 × 1036 ergs per second, constitutes 0.5% of the pulsar spin-down luminosity, although we cannot exclude a contribution of peta-electron volt protons to the production of the highest-energy gamma rays.

Extended Very-High-Energy Gamma-Ray Emission Surrounding PSR J0622+3749 Observed by LHAASO-KM2A.

We report the discovery of an extended very-high-energy (VHE) gamma-ray source around the location of the middle-aged (207.8 kyr) pulsar PSR J0622+3749 with the Large High-Altitude Air Shower Observatory (LHAASO). The source is detected with a significance of 8.2σ for E>25 TeV assuming a Gaussian template. The best-fit location is (right ascension, declination) =(95.47°±0.11°,37.92°±0.09°), and the extension is 0.40°±0.07°. The energy spectrum can be described by a power-law spectrum with an index of -2.92±0.17_{stat}±0.02_{sys}. No clear extended multiwavelength counterpart of the LHAASO source has been found from the radio to sub-TeV bands. The LHAASO observations are consistent with the scenario that VHE electrons escaped from the pulsar, diffused in the interstellar medium, and scattered the interstellar radiation field. If interpreted as the pulsar halo scenario, the diffusion coefficient, inferred for electrons with median energies of ∼160 TeV, is consistent with those obtained from the extended halos around Geminga and Monogem and much smaller than that derived from cosmic ray secondaries. The LHAASO discovery of this source thus likely enriches the class of so-called pulsar halos and confirms that high-energy particles generally diffuse very slowly in the disturbed medium around pulsars.

Measurement of the Cosmic Ray Helium Energy Spectrum from 70 GeV to 80 TeV with the DAMPE Space Mission.

The measurement of the energy spectrum of cosmic ray helium nuclei from 70 GeV to 80 TeV using 4.5 years of data recorded by the Dark Matter Particle Explorer (DAMPE) is reported in this work. A hardening of the spectrum is observed at an energy of about 1.3 TeV, similar to previous observations. In addition, a spectral softening at about 34 TeV is revealed for the first time with large statistics and well controlled systematic uncertainties, with an overall significance of 4.3σ. The DAMPE spectral measurements of both cosmic protons and helium nuclei suggest a particle charge dependent softening energy, although with current uncertainties a dependence on the number of nucleons cannot be ruled out.

Ultrahigh-energy photons up to 1.4 petaelectronvolts from 12 γ-ray Galactic sources.

The extension of the cosmic-ray spectrum beyond 1 petaelectronvolt (PeV; 1015 electronvolts) indicates the existence of the so-called PeVatrons-cosmic-ray factories that accelerate particles to PeV energies. We need to locate and identify such objects to find the origin of Galactic cosmic rays1. The principal signature of both electron and proton PeVatrons is ultrahigh-energy (exceeding 100 TeV) γ radiation. Evidence of the presence of a proton PeVatron has been found in the Galactic Centre, according to the detection of a hard-spectrum radiation extending to 0.04 PeV (ref. 2). Although γ-rays with energies slightly higher than 0.1 PeV have been reported from a few objects in the Galactic plane3-6, unbiased identification and in-depth exploration of PeVatrons requires detection of γ-rays with energies well above 0.1 PeV. Here we report the detection of more than 530 photons at energies above 100 teraelectronvolts and up to 1.4 PeV from 12 ultrahigh-energy γ-ray sources with a statistical significance greater than seven standard deviations. Despite having several potential counterparts in their proximity, including pulsar wind nebulae, supernova remnants and star-forming regions, the PeVatrons responsible for the ultrahigh-energy γ-rays have not yet been firmly localized and identified (except for the Crab Nebula), leaving open the origin of these extreme accelerators.

Aerosol and environmental surface monitoring for SARS-CoV-2 RNA in a designated hospital for severe COVID-19 patients.

There is limited information concerning the viral load of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in aerosols deposited on environmental surfaces and the effectiveness of infection prevention and control procedures on eliminating SARS-CoV-2 contamination in hospital settings. We examined the concentration of SARS-CoV-2 in aerosol samples and on environmental surfaces in a hospital designated for treating severe COVID-19 patients. Aerosol samples were collected by a microbial air sampler, and environmental surfaces were sampled using sterile premoistened swabs at multiple sites. Ninety surface swabs and 135 aerosol samples were collected. Only two swabs, sampled from the inside of a patient's mask, were positive for SARS-CoV-2 RNA. All other swabs and aerosol samples were negative for the virus. Our study indicated that strict implementation of infection prevention and control procedures was highly effective in eliminating aerosol and environmental borne SARS-CoV-2 RNA thereby reducing the risk of cross-infection in hospitals.

An office building outbreak: the changing epidemiology of tuberculosis in Shenzhen, China.

Tuberculosis (TB) is generally considered a disease that principally afflicts the low-income segments of a population. In the Nanshan District of Shenzhen, China, with the economic transformation and a new Headquarters Economy (HE) emerging, there are now more cases in office workers than in manufacturing workers. To illustrate this trend, we describe a small TB outbreak in an office building located in the centre of the rapidly growing HE district. Two active pulmonary tuberculosis cases were found in workers who shared an office, and whole genome sequencing showed that the genetic distance between the strains of the two cases was just one single nucleotide polymorphism, consistent with intra-office transmission. Investigation of 30 other workers in the same or adjacent offices with interviews, interferon-gamma release assays (IGRAs) and chest X-rays, identified one new TB case and latent tuberculosis infection (LTBI) in 40.0% (12/30) of the contacts. The offices were under-ventilated. None of the IGRA positive, asymptomatic contacts agreed to receive treatment for LTBI, presumably due to TB stigma, and over the next 2 years 69.0% (20/29) of the contacts were lost to follow-up. Treatment for LTBI and stigma of TB remain challenges here. Office workers in the HE of rapidly economic developing areas should be targeted with increased vigilance by TB control programmes.

Measurement of the cosmic ray proton spectrum from 40 GeV to 100 TeV with the DAMPE satellite.

The precise measurement of the spectrum of protons, the most abundant component of the cosmic radiation, is necessary to understand the source and acceleration of cosmic rays in the Milky Way. This work reports the measurement of the cosmic ray proton fluxes with kinetic energies from 40 GeV to 100 TeV, with 2 1/2 years of data recorded by the DArk Matter Particle Explorer (DAMPE). This is the first time that an experiment directly measures the cosmic ray protons up to ~100 TeV with high statistics. The measured spectrum confirms the spectral hardening at ~300 GeV found by previous experiments and reveals a softening at ~13.6 TeV, with the spectral index changing from ~2.60 to ~2.85. Our result suggests the existence of a new spectral feature of cosmic rays at energies lower than the so-called knee and sheds new light on the origin of Galactic cosmic rays.

Effect of lncRNA MALAT1 on rats with myocardial infarction through regulating ERK/MAPK signaling pathway.

OBJECTIVE: To explore the effect of the long non-coding ribonucleic acid (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) on rats with myocardial infarction (MI) by regulating the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) signaling pathway. MATERIALS AND METHODS: The Sprague- Dawley (SD) rat model of MI was established, and lncRNA MALAT1 was overexpressed using pcDNA-MALAT1 plasmids (MALAT1 group, n=10) and silenced using RNA interference technique (siMALAT1 group, n=10). The Sham group (n=10) was also set up. The transfection efficiency of lncRNA MALAT1 in rats was detected via Reverse Transcription-Polymerase Chain Reaction (RT-PCR). 2 weeks after the successful modeling, the cardiac function indexes were measured through magnetic resonance imaging (MRI) and echocardiography (ECG). The myocardial tissue injury was observed via hematoxylin-eosin (HE) staining, and the apoptosis of myocardial tissues was detected via terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. Moreover, the levels of the serum inflammatory factors were detected via enzyme-linked immunosorbent assay (ELISA), the messenger RNA (mRNA) expressions of Collagen I and III, the apoptosis, the and pathway genes were detected via RT-PCR. The expressions of ERK/MAPK pathway-related proteins in myocardial tissues were detected via Western blotting. RESULTS: The expression of lncRNA MALAT1 was remarkably increased in the MALAT1 group but evidently declined in the siMALAT1 group (p<0.05), indicating the successful transfection. The fractional shortening (FS, %) and ejection fraction (EF, %) were significantly restored in siMALAT1 group (p<0.05), suggesting that the silence of MALAT1 can improve the cardiac function after acute MI. The results of the HE staining and TUNEL assay manifested that siMALAT1 group had milder myocardial injury and decreased apoptosis compared with MALAT1 group. In the MALAT1 group, the mRNA expressions of Collagen I and III, Caspase3, ERK2, and MAPK were remarkably increased (p<0.05), while the mRNA expression of Bcl-2 was remarkably decreased (p<0.05). The above expressions had the opposite trends in siMALAT1 group. Besides, the protein expressions of ERK2 and MAPK in MALAT1 group were significantly increased (p<0.05). CONCLUSIONS: The downregulation of lncRNA MALAT1 can significantly improve the cardiac function after MI in SD rats mainly by inhibiting the ERK/MAPK pathway.

[Influence of data quality on early warning sensitivity of syndromic surveillance system based on medical institutions].

Objective: To evaluate the influence of data quality on the sensitivity of early warning syndromic surveillance system based on medical institutions in Qianjiang, Hubei province and explore the relationship between data quality and sensitivity of early warning of the system. Methods: The delay reporting rate and underreporting rate were calculated for the evaluation of the data quality. Data obtained from semi-synthetic simulated outbreak and area under the curve (AUC) were used in combination to test the sensitivity of early warning of various models and select the optimal model. Time-series generalized additive model (GAM) was used to analyze the curve fitting and threshold effect between data quality and early warning sensitivity of the system. Results: A total of 179 905 cases were reported from April 1, 2012 to January 31, 2014, in which 8 744 were not reported timely (16.45%). Averagely 416 reporting were delayed in each month. There were 2 566 cases which were underreported (4.83%). Compared with other early warning models, i.e. Cumulative Sum (CUSUM), Shewhart, Exponentially Weighted Moving Average (EWMA), Early Aberration Reporting System (EARS-3C), the MA model had the maximum area under the curve (AUC=0.93), and the difference was significant (P<0.001). The early warning sensitivity ranged from 84.89% to 97.25% during the operation period of the syndromic surveillance system. Underreporting had influence on early warning sensitivity, when underreporting rate was over 2.78%, the sensitivity would decrease obviously. No obvious associations were observed between the delay reporting rate and early warning sensitivity of the system. Conclusion: The data quality had influence on the early warning sensitivity of the syndromic surveillance system based on medical institution in Qianjiang. In the context of this study, underreporting had the main influence on the sensitivity of early warning.

The value of decreased plasma gelsolin levels in patients with systemic lupus erythematosus and rheumatoid arthritis in diagnosis and disease activity evaluation.

Plasma gelsolin, the extracellular gelsolin isoform, circulates in the blood of healthy individuals at a concentration of 200 ± 50 mg/l and plays important roles in the extracellular actin-scavenging system during tissue damage. Decreased plasma gelsolin levels have been observed in many inflammatory diseases. In the present study, the variation and potential clinical application of plasma gelsolin levels in patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) were analysed. Plasma samples and clinical data were collected from informed and consenting participants: 47 SLE patients, 60 RA patients and 50 age- and gender-matched healthy individuals. Semiquantitative western blotting was used for measuring plasma gelsolin levels. The plasma gelsolin levels in patients with SLE and RA were significantly decreased compared with healthy controls (145.3 ± 40.4 versus 182.7 ± 38.3 mg/l and 100.8 ± 36 versus 182.7 ± 38.3 mg/l, p < 0.001), and plasma gelsolin levels were especially lower in RA than in SLE patients (100.8 ± 36 versus 145.3 ± 40.4 mg/L, p < 0.001). An analysis of the clinical data showed a significant negative correlation between plasma gelsolin levels and SLE Disease Activity Index (SLEDAI) scores (r = 0.659, p < 0.001) but no correlation between plasma gelsolin levels and RA disease activity score 28 (DAS28) (r = 0.076, p = 0.569). Different clinical characteristics were also observed in SLE and RA patients with normal and decreased plasma gelsolin levels.This study found significantly lower plasma gelsolin levels in patients with SLE and RA compared with healthy controls and documented a significant negative correlation between plasma gelsolin levels and SLEDAI, which suggested the potential clinical application of plasma gelsolin in SLE diagnosis and disease activity evaluation. The different clinical characteristics in SLE and RA patients with normal and decreased plasma gelsolin levels indicate differences in the basis of the diseases.