Changes In Circulation Research Articles

Hydrochemical Characteristics and Evolution of Underground Brine in Lop Nur, Northwestern China

AbstractLop Nur is located at the eastmost end of the Tarim Basin in Xinjiang, Northwestern China. This study reviews the hydrochemical characteristics and evolution of underground brine in Lop Nur, based on analytical data from 429 water samples (mainly brine). It is found that in the NE–SW direction, from the periphery to the Luobei sub‐depression, while the hydrochemical type varies from the sodium sulfate subtype (S) to the magnesium sulfate subtype (M), the corresponding brine in the phase diagram transfers from the thenardite phase (Then) area, through the bloedite phase (Blo), epsomite phase (Eps), picromerite phase (Picro), finally reaching the sylvite phase (Syl) area. As for the degree of evolution, the sequence is the periphery < Luobei horizontally and the overlying glauberite brine < the underlying clastic brine vertically. It is concluded that the oxygen and hydrogen isotopic compositions of the brine have evidently been affected through the effects of evaporation and altitude, as well as the changes in local water circulation in recent years. Boron and chloride isotopic compositions show that the glauberite brine is formed under more arid conditions than the clastic one. The strontium isotopic composition indicates that the Lop Nur brine primarily originates from surface water; however, deep recharge may also be involved in the evolution of the brine, according to previous noble gas studies. It is confirmed that the brine in Lop Nur has become enriched with potassium prior to halite precipitation over the full course of the salt lake's evolution. Based on chemical compositions of brine from drillhole LDK01 and previous lithological studies, the evolution of the salt lake can be divided into three stages and it is inferred that the brine in Lop Nur may have undergone at least two significant concentration‐dilution periods.

Warm‐Season Drying Across Europe and Its Links to Atmospheric Circulation

AbstractWe study drying trends across the central latitude strip of Europe (47.5–52.5°N and 2.5–27.5°E) during 1980–2019 and their links to atmospheric circulation. Daily differences between potential evapotranspiration and precipitation (PET–P) calculated from the E–OBS data are used to characterize dryness, and atmospheric circulation is represented by circulation types classified using daily sea level pressure patterns from the NCEP/NCAR reanalysis. Circulation types favoring dry conditions in vegetation season (April–September) are identified based on daily PET–P, and their temporal changes, seasonal variations, and links to trends in dryness in individual European regions are analyzed. In the early vegetation season (AMJ), drying trends are observed mainly in Western and Central Europe while in the late vegetation season (JAS), they are located predominantly in Eastern Europe. The dry circulation types include all anticyclonic types in all regions, as well as northeast to south (southwest in Eastern Europe) directional types. Trends of the dry circulation types correspond to those of dryness: the largest increase is found during AMJ in Western and Central Europe but during JAS in Eastern Europe. The results show that trends in dryness in the central latitude strip of Europe in the warm half‐year were associated with changes in atmospheric circulation, as the largest increases in frequency of dry circulation types occurred in the regions and months affected by pronounced drying. The increasing frequency of anticyclonic types in AMJ and reduced inflow of moist air masses from the Atlantic are the key factors supporting intensification of dry conditions in European mid‐latitudes.

Primary Drivers of the Recent Changes Observed in Global Ocean Circulation Patterns in Mozambique

Purpose: The aim of the study was to examine the primary drivers of the recent changes observed in global ocean circulation patterns in Mozambique Methodology: This study adopted a desk methodology. A desk study research design is commonly known as secondary data collection. This is basically collecting data from existing resources preferably because of its low cost advantage as compared to a field research. Our current study looked into already published studies and reports as the data was easily accessed through online journals and libraries. Findings: The study revealed that primary drivers of the recent changes observed in global ocean circulation patterns are involving a combination of natural variability and anthropogenic influences. Key factors identified include global warming, alterations in wind patterns, sea surface temperature anomalies, and increased freshwater input from melting ice caps and glaciers. These elements interact in intricate ways to influence the dynamics of ocean currents, which are critical for regulating Earth's climate and supporting marine ecosystems. Unique Contribution to Theory, Practice and Policy: Bronfenbrenner's Ecological Systems Theory & Abraham Maslow's Hierarchy of Needs may be used to anchor future studies on primary drivers of the recent changes observed in global ocean circulation patterns in Mozambique. Increase investment in global ocean monitoring systems, such as Argo floats, satellite missions, and autonomous underwater vehicles, to collect high-resolution data on temperature, salinity, and currents. This data is crucial for validating models and understanding the current state and trends of ocean circulation. Strengthen international cooperation to address global warming, a primary driver of changes in ocean circulation. This includes adhering to and expanding commitments under the Paris Agreement to reduce greenhouse gas emissions.

Contributions of changes in atmospheric circulation and thermodynamic factors to trends in spring gale events in northern China from 1973 to 2020

Contributions of changes in atmospheric circulation and thermodynamic factors to trends in spring gale events in northern China from 1973 to 2020

Abrupt increase in Greenland melt enhanced by atmospheric wave changes

Recent Greenland ice-sheet melt constitutes a considerable contribution to global sea-level rise. Observations indicate an approximate zero mass balance of the ice sheet until the late 1990s, after which a strong increase in melting occurred. This cannot be attributed linearly to gradually-increasing global warming. Instead the abrupt shift has been linked to atmospheric circulation changes, although causality is not fully understood. Here we show that changes of atmospheric waves over Greenland have significantly contributed to the shift into a strong melting state. This is evident after having applied a newly-developed methodology effectively decomposing atmospheric flow patterns into parts associated with waves of different scales such as Rossby waves and smaller perturbations. The onset of a westerly-flow reduction, consistent with anthropogenic Arctic warming, affected transports by atmospheric waves and led to a decrease in precipitation and an increase in surface warming, contributing to ice-sheet mass loss, in particular over the southwestern regions. As such, the Greenland ice-sheet melt is an example of a climate response non-linearly coupled to global warming.

Causes and multiyear predictability of the rapid acceleration of U.S. Southeast Sea level rise after 2010

The rate of sea level rise (SLR) along the Southeast Coast of the U.S. increased significantly after 2010. While anthropogenic radiative forcing causes an acceleration of global mean SLR, regional changes in the rate of SLR are strongly influenced by internal variability. Here we use observations and climate models to show that the rapid increase in the rate of SLR along the U.S. Southeast Coast after 2010 is due in part to multidecadal buoyancy-driven Atlantic meridional overturning circulation (AMOC) variations, along with heat transport convergence from wind-driven ocean circulation changes. We show that an initialized decadal prediction system can provide skillful regional SLR predictions induced by AMOC variations 5 years in advance, while wind-driven sea level variations are predictable 2 years in advance. Our results suggest that the rate of coastal SLR and its associated flooding risk along the U.S. southeastern seaboard are potentially predictable on multiyear timescales.

Recent wetting trend over Taklamakan and Gobi Desert dominated by internal variability

The Taklamakan and Gobi Desert (TGD) region has experienced a pronounced increase in summer precipitation, including high-impact extreme events, over recent decades. Despite identifying large-scale circulation changes as a key driver of the wetting trend, understanding the relative contributions of internal variability and external forcings remains limited. Here, we approach this problem by using a hierarchy of numerical simulations, complemented by diverse statistical analysis tools. Our results offer strong evidence that the atmospheric internal variations primarily drive this observed trend. Specifically, recent changes in the North Atlantic Oscillation have redirected the storm track, leading to increased extratropical storms entering TGD and subsequently more precipitation. A clustering analysis further demonstrates that these linkages predominantly operate at the synoptic scale, with larger contributions from large precipitation events. Our analysis highlights the crucial role of internal variability, in addition to anthropogenic forcing, when seeking a comprehensive understanding of future precipitation trends in TGD.

New characteristics of Meiyu precipitation changes in the middle and lower reaches of the Yangtze River since 2000

This study comprehensively analyzed the long-term changes of Meiyu in the middle and lower reaches of the Yangtze River with regard to precipitation, precipitation threshold, and interdecadal changes in atmospheric circulation. Results revealed obvious new features of Meiyu precipitation since 2000. (1) Meiyu precipitation shows a significant linear increase trend, with an average increment of 73.5 mm every 10 years. The increase in torrential rain is the most significant, accounting for 61% of the total precipitation increase, and its proportion has been increasing, while the proportions of light, moderate, and heavy rain in the total precipitation have been decreasing. (2) At the interdecadal scale, Meiyu precipitation and the local surface average temperature show opposite changes. Meiyu precipitation decreases by approximately 150 mm for every 1°C increase in the average temperature. This inverse correlation was not evident before 2000. (3) The saturated specific humidity in this area shows a significant increasing trend, indicating that precipitation in this area is caused by a higher threshold of atmospheric saturation and condensation, which may be a reason for the low Meiyu precipitation during high-temperature years. (4) The main atmospheric circulation in East Asia associated with Meiyu shows clear interdecadal changes, including the Western North Pacific Subtropical High and South Asian High having become significantly stronger and having extended westward and eastward, respectively, thereby facilitating the occurrence and persistence of Meiyu precipitation. The atmospheric circulation patterns associated with Meiyu, such as the Western North Pacific Subtropical High and South Asian High, have more significant impacts on Meiyu precipitation.

Energetic particle precipitation influences global secondary ozone distribution

The secondary ozone layer is a global peak in ozone abundance in the upper mesosphere-lower thermosphere (UMLT) around 90-95 km. The effect of energetic particle precipitation (EPP) from geomagnetic processes on this UMLT ozone remains largely unexplored. In this research we investigated how the secondary ozone responds to EPP using satellite observations. In addition, the residual Mean Meridional Circulation (MMC) derived from model simulations and the atomic oxygen [O], atomic hydrogen [H], temperature measurements from satellite observations were used to characterise the residual circulation changes during EPP events. We report regions of secondary ozone enhancement or deficit across low, mid and high latitudes as a result of global circulation and transport changes induced by EPP. The results are supported by a sensitivity test using an empirical model.

Gastrointestinal Complications and Visceral Circulation Changes After Intentional Celiac Artery Embolization During Complex Endovascular Aortic Aneurysm Repair

Gastrointestinal Complications and Visceral Circulation Changes After Intentional Celiac Artery Embolization During Complex Endovascular Aortic Aneurysm Repair

Anthropogenic and atmospheric variability intensifies flash drought episodes in South Asia

Flash droughts are abrupt and rapid intensification of droughts that affect agriculture, water, and ecosystems and are commonplace in South Asia. Despite their potential impact, flash drought evolution characteristics and underlying mechanisms in South Asia remain underexplored. We use a multivariate approach to analyze the onset speed, frequency, severity, duration, and return period of flash droughts, and the role of atmospheric circulation and human-induced climate change. We find that flash droughts are more common and intense in the crop season, especially in central India, western Pakistan, and eastern Afghanistan. They are caused by persistent atmospheric patterns that block moisture transport to South Asia. Additionally, anthropogenic climate change has intensified flash droughts in the spring-summer season, with a median fraction of attributable risk of 60%, 80%, and 90% for Afghanistan, Pakistan, and India, respectively. Our results suggest that flash droughts will expand and worsen in the future, requiring adaptation measures for the water, agriculture, and energy sectors.

The Machine Learning Attribution of Quasi-Decadal Precipitation and Temperature Extremes in Southeastern Australia during the 1971–2022 Period

Much of eastern and southeastern Australia (SEAUS) suffered from historic flooding, heat waves, and drought during the quasi-decadal 2010–2022 period, similar to that experienced globally. During the double La Niña of the 2010–2012 period, SEAUS experienced record rainfall totals. Then, severe drought, heat waves, and associated bushfires from 2013 to 2019 affected most of SEAUS, briefly punctuated by record rainfall over parts of inland SEAUS in the late winter/spring of 2016, which was linked to a strong negative Indian Ocean Dipole. Finally, from 2020 to 2022 a rare triple La Niña generated widespread extreme rainfall and flooding in SEAUS, resulting in massive property and environmental damage. To identify the key drivers of the 2010–2022 period’s precipitation and temperature extremes due to accelerated global warming (GW), since the early 1990s, machine learning attribution has been applied to data at eight sites that are representative of SEAUS. Machine learning attribution detection was applied to the 52-year period of 1971–2022 and to the successive 26-year sub-periods of 1971–1996 and 1997–2022. The attributes for the 1997–2022 period, which includes the quasi-decadal period of 2010–2022, revealed key contributors to the extremes of the 2010–2022 period. Finally, some drivers of extreme precipitation and temperature events are linked to significant changes in both global and local tropospheric circulation.

Future changes in South Asian summer monsoon circulation under global warming: role of the Tibetan Plateau latent heating

The South Asian summer monsoon (SASM) is a significant monsoon system that exerts a profound impact on climate and human livelihoods. According to 38 models from the Coupled Model Intercomparison Project Phase 6, the SASM circulation is projected to weaken significantly under global warming as seen in the weakened low-level westerly wind over the northern tropical Indian Ocean; however, the associated climate dynamics is still under debate. Here, we identify that the weakened low-level westerly wind is closely related to the enhanced latent heating over the Tibetan Plateau (TP), which corresponds with increased summer precipitation in the future. The intensified TP latent heating triggers an anomalous meridional circulation with ascending motions over the plateau and descending motions to the south, leading to an anomalous low-level anticyclone over the northern tropical Indian Ocean. This anticyclone greatly weakens the prevailing low-level westerlies of the SASM through easterly anomalies at the anticyclone’s southern flank. Moisture budget analysis further reveals that increased atmospheric water vapor, rather than the vertical dynamic component, makes the largest contribution to the increased precipitation over the TP. This result confirms that the enhanced TP latent heating is a driver of atmospheric circulation change and contributes to weakening the SASM circulation.

Southern Ocean drives multidecadal atmospheric CO2 rise during Heinrich Stadials

The last glacial period was punctuated by cold intervals in the North Atlantic region that culminated in extensive iceberg discharge events. These cold intervals, known as Heinrich Stadials, are associated with abrupt climate shifts worldwide. Here, we present CO2 measurements from the West Antarctic Ice Sheet Divide ice core across Heinrich Stadials 2 to 5 at decadal-scale resolution. Our results reveal multi-decadal-scale jumps in atmospheric CO2 concentrations within each Heinrich Stadial. The largest magnitude of change (14.0 ± 0.8 ppm within 55 ± 10 y) occurred during Heinrich Stadial 4. Abrupt rises in atmospheric CO2 are concurrent with jumps in atmospheric CH4 and abrupt changes in the water isotopologs in multiple Antarctic ice cores, the latter of which suggest rapid warming of both Antarctica and Southern Ocean vapor source regions. The synchroneity of these rapid shifts points to wind-driven upwelling of relatively warm, carbon-rich waters in the Southern Ocean, likely linked to a poleward intensification of the Southern Hemisphere westerly winds. Using an isotope-enabled atmospheric circulation model, we show that observed changes in Antarctic water isotopologs can be explained by abrupt and widespread Southern Ocean warming. Our work presents evidence for a multi-decadal- to century-scale response of the Southern Ocean to changes in atmospheric circulation, demonstrating the potential for dynamic changes in Southern Ocean biogeochemistry and circulation on human timescales. Furthermore, it suggests that anthropogenic CO2 uptake in the Southern Ocean may weaken with poleward strengthening westerlies today and into the future.

Leeuwin current dynamics in the SE Indian Ocean and implications for regional surface hydrography since the latest Miocene: Results from ODP Site 763A

This study examines the relationship between the ocean circulation dynamics in the eastern Indian Ocean and climate variability in Northwest (NW) Australia over the last 6.1 million years. The vertical water column of the southeastern Indian Ocean was analyzed using planktic foraminifera assemblages, and oxygen and carbon isotope ratios of surface and subsurface dwelling foraminifera from Ocean Drilling Program (ODP) Site 763A. The X-ray fluorescence data of bulk sediment from ODP Site 763A was also used to understand variability in relative humidity and aridity in NW Australia associated with surface ocean warming. The findings suggest a pronounced change in surface oceanography and climate in the region from 5.4 to 5 Ma, indicating a weak Leeuwin Current (LC) and reduction in mixed layer thickness. Subsequently, between 5.0 and 3.6 Ma, a strongly stratified water column with a thick mixed layer and deep thermocline emerged owing to the intensified Indonesian Throughflow (ITF). This led to a strengthened LC and diminished surface productivity, corresponding to a wet phase in NW Australia. The closure of the Indonesian Seaway during the Middle Pliocene (3.6–3.2 Ma) restricted the flow of West Pacific Warm Water into the Indian Ocean, weakened the LC and intensified the dry phase in NW Australia. Significant shifts in planktic foraminifera abundances are observed in the early Pleistocene (2.6–1.2 Ma) perhaps linked to major changes in surface ocean circulation. During the Mid-Pleistocene Transition (1.2–0.6 Ma), the West Australian Current exerted a significant influence over Site 763A.

Dry and Wet Spells in Poland in the Period 1966–2023

The aim of this study is to present the spatial and temporal variability of the frequency of dry and wet days and dry and wet spells against the background of changes in precipitation and atmospheric circulation. The study is based on daily precipitation totals from 46 meteorological stations in Poland from 1966 to 2023. Additionally, seven circulation indices were used, namely GBI, NAO, AO, EA, EA/WR, SCAND, and AMO. Dry days are defined as days without precipitation. Wet days are days with at least 1 mm of precipitation. It was shown that dry spells are much more common than wet spells, are longer, and cover larger areas. Long-term changes in the annual characteristics of dry and wet days and spells are not statistically significant. Only the length of the most extended dry spell in the year increases. However, there are significant changes in their annual cycles. Spring is drier; in summer, precipitation decreases in the south and increases in the north; November and December, symbols of gloomy rainy weather, are increasingly drier; and rainy weather has shifted to January and February. The impact of circulation varies according to the season, with the NAO, AO, SCAND, and GBI indices having the greatest influence.

Changes in the pulmonary circulation due to gravitational loads in high altitude conditions.

The impact of gravity on the existence of all living things has long been of interest to scientists. The force of the Earth's gravity combined with hypoxia significantly affects blood circulation and blood accumulation in various parts of the human and animal body. To date, the relationship between body position and blood circulation in pulmonary circulation under hypobaric hypoxia has not been sufficiently studied. Therefore, the research aims to determine the possibility of changing the body position in space on the reactions in the pulmonary circulation in the plains and highlands. For this purpose, research was conducted on male Wistar rats, 44 of whom spent 150 days at an altitude of 3200 m above sea level, and 25 representatives of the control group - at an altitude of 164 m. The study revealed that gravitational redistribution of blood in mountainous conditions is less pronounced compared to the control group. This is explained by the remodeling of the vascular wall and an increase in its stiffness. It was found that a change in pulmonary artery pressure at the time of a change in body position was recorded both on the plains and in the highlands. On the plains, when the body position of rats was changed to passive orthostatic, a decrease in systolic and diastolic pulmonary artery pressure was noted, and when the body position was changed to passive anti-orthostatic, an increase in pulmonary artery pressure was observed. The increase in pulmonary artery pressure was a compensatory mechanism due to the increased stiffness of the pulmonary vasculature. The practical significance of this research is to expand the understanding of the pathogenesis of pulmonary hypertension in high-altitude hypoxia.

Influence of large-scale circulation and local feedbacks on extreme summer heat in Argentina in 2022/23

The summer of 2022/23 in Argentina set a record with ten heatwaves. Here, we compare the synoptic and thermodynamic conditions of the four heatwaves with the largest spatial extent using ERA5 reanalysis data. All heatwaves were associated with mid-level anticyclonic anomalies but with different characteristics: three were quasi-stationary high-pressure systems, while one was transient. We also find that enhanced surface fluxes strongly influenced the daily temperature evolution. Furthermore, we perform an attribution exercise using the analogue technique to measure the contributions of atmospheric circulation, soil moisture, and climate change. For quasi-stationary events, the main contribution came from the circulation (up to 2 °C relative to random flow in the present climate). Conversely, the transient heatwave showed a stronger association with extreme soil moisture deficits, with an estimated increase of ~+1 °C relative to wetter conditions. Climate change has also increased the intensity of heatwaves by +0.5 to +1.2 °C relative to previous decades.

A Holocene history of climate, fire, landscape evolution, and human activity in northeastern Iceland

Abstract. Paleoclimate reconstructions across Iceland provide a template for past changes in climate across the northern North Atlantic, a crucial region due to its position relative to the global northward heat transport system and its vulnerability to climate change. The roles of orbitally driven summer cooling, volcanism, and human impact as triggers of local environmental changes in the Holocene of Iceland remain debated. While there are indications that human impact may have reduced environmental resilience during late Holocene summer cooling, it is still difficult to resolve to what extent human and natural factors affected Iceland's late Holocene landscape instability. Here, we present a continuous Holocene fire record of northeastern Iceland from proxies archived in Stóra Viðarvatn sediment. We use pyrogenic polycyclic aromatic hydrocarbons (pyroPAHs) to trace shifts in fire regimes, paired with continuous biomarker and bulk geochemical records of soil erosion, lake productivity, and human presence. The molecular composition of pyroPAHs and a wind pattern reconstruction indicate a naturally driven fire signal that is mostly regional. Generally low fire frequency during most of the Holocene significantly increased at 3 ka and again after 1.5 ka BP before known human settlement in Iceland. We propose that shifts in vegetation type caused by cooling summers over the past 3 kyr, in addition to changes in atmospheric circulation, such as shifts in North Atlantic Oscillation (NAO) regime, led to increased aridity and biomass flammability. Our results show no evidence of faecal biomarkers associated with human activity during or after human colonisation in the 9th century CE. Instead, faecal biomarkers follow the pattern described by erosional proxies, pointing toward a negligible human presence and/or a diluted signal in the lake's catchment. However, low post-colonisation levels of pyroPAHs, in contrast to an increasing flux of erosional bulk proxies, suggest that farming and animal husbandry may have suppressed fire frequency by reducing the spread and flammability of fire-prone vegetation (e.g. heathlands). Overall, our results describe a fire frequency heavily influenced by long-term changes in climate through the Holocene. They also suggest that human colonisation had contrasting effects on the local environment by lowering its resilience to soil erosion while increasing its resilience to fire.

Abstract PO2-03-11: A novel peripheral CD4+ T cell immune network associated with response to PD-1 inhibitor in early-stage triple negative breast cancer

Abstract A novel peripheral CD4+ T cell immune network associated with response to PD-1 inhibitor in early-stage triple negative breast cancer Background: Immunotherapy has showed benefits in early-stage triple-negative breast cancer (eTNBC). However, there is an urgent need to identify novel biomarkers that can guide stratification for immunotherapy in eTNBC. Anti-tumor immunity is a systemic response that encompasses the mobilization of dendritic cells, lymphocytes, and myeloid cells involving the tumor, blood, and lymph nodes. The activation of anti-tumor immune responses via immunotherapy is expected to reflect in the subset change of circulation. Combined with advantage of dynamic monitoring by liquid biopsy, we detected peripheral blood in the eTNBC patients under immunotherapy to explore potential immune therapeutic predictive subsets. Methods: Single-cell (sc) RNA sequencing was utilized to determine the transcriptomics of immune cells in the peripheral blood. Meanwhile scTCR sequencing was used to trace the dynamic changes of clonetypes under multi-therapy. Nanostring analysis of primary tumor and in vivo models were used to validate the mechanism of immune crosstalk. Prediction index was built based on the proportion of immune subsets at each time point and change of tumor size in each patient. Results: 12 eTNBC patients who participated in neoadjuvant chemotherapy in combination with PD-1 inhibitor (Toripalimab) clinical trial were included in this study. The clinical trial consists of two stages. All eligible patients received four cycles of EC (cyclophosphamide plus epirubicin) regimen and followed four cycles of nab-paclitaxel plus PD-1 inhibitor. Among the 12 patients, 5 patients achieved pCR, while the remaining 7 patients were non-pCR. Peripheral blood samples were collected at baseline, after chemotherapy induction, and on PD-1 inhibitor treatment for scRNA- and scTCR-sequencing. Through prediction index, a novel predictive pattern based on ratio of memory T cells (central memory T and resident memory T) to effective T cells in the peripheral was vividly defined, by which the patients could be classified into C-type (memory T cells dominated) and E-type (effective T cells dominated). The C-type indicated better efficacy of immunotherapy combination therapy, while the E-type suggested better efficacy of chemotherapy alone. Meanwhile, a novel peripheral CD4+Trm (resident-memory-like) subset that possessed both strong differentiation potential and memory function was higher in pCR group at baseline. TCR-tracing analysis revealed that the new clones induced by chemotherapy mainly belong to the CD4+ Trm and CD8+ CD161+ Tcm (central memory) subsets, and the upregulation of CD8+ CD161+ Tcm during therapy was a dynamic predictor for immunotherapy benefits. Besides, most of CD4+Trm transitioned into CD4+Th1-like cells as an activated status, which considered CD4+Trm as a group of reservoirs with polyclonality and differentiation potential for tumor-killing. Meanwhile, the increase in CD5+ cDC2 (type 2 conventional dendritic cell) after chemotherapy was associated with enhanced antigen-presenting function and cell communication and co-stimulation with CD4+ Trm cells which helped the activated transition from CD4+Trm into CD4+Th1-like cells in lymph nodes. Moreover, CD4+Th1-like cells increased secretion of Th1 cytokines thus leading to promote CD8+CD161+ Tcm upregulation and tumor-infiltration after immunotherapy. Conclusions: A novel peripheral pattern based on subsets of T cells as C-type and E-type was established as potential predictors for immunotherapy stratification in eTNBC patients. Meanwhile, a novel peripheral CD4+Trm immune network was identified, in which CD5+cDC2 activated the transition of CD4+Trm into CD4+Th1-like subset leading to activation and tumor-infiltration of CD8+CD161+Tcm. All the above provided potential therapeutic targets for enhancing immunotherapy. Citation Format: Zehao Wang, Zhibo Shao, Bingqiu Xiu, Jiong Wu. A novel peripheral CD4+ T cell immune network associated with response to PD-1 inhibitor in early-stage triple negative breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-03-11.