Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 3 complete abstracts (551 words), 9 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
The body fluid that circulates in the vascular system (blood vessels). Whole blood includes plasma and blood cells.
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Where it fits in the MeSH classification
- Broader topics
- Body Fluids; Hemic and Immune Systems
- Narrower topics
- Fetal Blood; Plasma; Serum; Blood Cells
- See also
- Hematopoiesis; Occult Blood
Related concepts
- Blood Vessels
- Plasma
- Blood Cells
Research landscape
PubMed indexes 1,270,289 records tagged with the MeSH heading “Blood” (counts retrieved 2026-10-31). 167,682 of them (13.2%) were published from 2020 onward, and the busiest period so far is through 1999 with 611,208 records.
Reviews account for 116,872 records (9.2%) and meta-analyses for 2,779. Randomized controlled trials number 15,147 (1.2%) as a share of all records on the topic. Randomized trials make up only a small share of this literature, so much of what is known comes from laboratory, observational or descriptive work.
Show the data
| Period | Records |
|---|---|
| through 1999 | 611,208 |
| 2000-2009 | 226,760 |
| 2010-2019 | 264,639 |
| 2020 onward | 167,682 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 116,872 | 9.2% |
| Meta-analyses | 2,779 | 0.2% |
| Randomized controlled trials | 15,147 | 1.2% |
Method: PubMed query "Blood"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-31.
Reading the evidence in anatomy and physiology
Anatomy describes how body structures are built and physiology describes how they normally work, so most findings here are descriptive or mechanistic rather than evidence about treatment. Much of what is known comes from dissection, imaging, tissue studies and experiments in animals, and measurements in healthy volunteers can differ from those in people with disease or at different ages. Normal ranges vary between individuals and populations. Check whether a result was measured in people or in another species, the age and health of the participants, and the method used.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| Innate immune imprints shape HIV-1 reservoir cell persistence during long-term antiretroviral therapy | 2026 | Research article Design not recorded in structured metadata | 2 | cc by PMID 42680897 · DOI · PMC13630574 |
| The HMG-CoA Reductase Inhibitor Fluvastatin Promotes Th2-Skewed Immune Responses by Modulating Dendritic Cell Differentiation | 2026 | Research article Design not recorded in structured metadata | 1 | cc by PMID 42680200 · DOI · PMC13533597 |
| Artery tertiary lymphoid organs encode a pathogenic high-affinity autoantibody-autoantigen pair in atherosclerosis | 2026 | Research article Design not recorded in structured metadata | 1 | cc by PMID 42706439 · DOI · PMC13561875 |
Innate immune imprints shape HIV-1 reservoir cell persistence during long-term antiretroviral therapy [1]
Abstract reading summary — source excerpts
- Opening excerpt
- Host immune responses that can target and eliminate HIV-1 reservoir cells during suppressive antiretroviral therapy are poorly understood.
- Closing excerpt
- These findings underscore the critical influence of host and viral genetic variation on reservoir persistence and highlight opportunities for leveraging innate immunity in HIV cure strategies.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (210 words)
Host immune responses that can target and eliminate HIV-1 reservoir cells during suppressive antiretroviral therapy are poorly understood. Here, analyzing over 6,000 proviral DNA amplicons from 104 individuals on long-term antiretroviral therapy, we found that carriers of HLA-C2 allotypes, which promote NK cell education via interactions with KIR2DL1, exhibited lower frequencies of intact proviruses. No protective effects of HLA-C2 alleles were observed during untreated infection, suggesting a selective vulnerability of reservoir cells to NK-cell-mediated immune activity under antiretroviral therapy. Supporting this, frequencies of KIR2DL1+ NK cells, particularly those coexpressing the activating HLA-E receptor NKG2C, were inversely correlated with frequencies of intact proviruses. Moreover, viral protein U variants that strongly downregulate HLA-C, increasing a missing-self response by KIR2DL1+ NK cells, were associated with smaller reservoirs in carriers of HLA-C2. Infected cells surviving long-term displayed elevated HLA-C expression, consistent with in vivo selection for resistance to KIR2DL1+ NK-cell-mediated immune clearance. Immune activity of KIR2DL1+ NK cells against viral reservoir cells was enhanced by NKG2C-HLA-E interactions, as sequence variants in HLA-E-restricted HIV-1 epitopes reduced NKG2C-dependent NK cell activation and were associated with higher frequencies of intact proviruses. These findings underscore the critical influence of host and viral genetic variation on reservoir persistence and highlight opportunities for leveraging innate immunity in HIV cure strategies.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42680897 · DOI · PMC13630574
The HMG-CoA Reductase Inhibitor Fluvastatin Promotes Th2-Skewed Immune Responses by Modulating Dendritic Cell Differentiation [2]
Abstract reading summary — source excerpts
- Opening excerpt
- Statins, inhibitors of HMG-CoA reductase, exert immunomodulatory effects beyond lipid lowering, yet how they regulate T helper (Th) cell differentiation remains poorly understood.
- Closing excerpt
- These findings indicate that continuous fluvastatin exposure during DC differentiation is associated with an altered DC phenotype and enhanced Th2-polarizing capacity.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (178 words)
Statins, inhibitors of HMG-CoA reductase, exert immunomodulatory effects beyond lipid lowering, yet how they regulate T helper (Th) cell differentiation remains poorly understood. We show that fluvastatin administration to C57BL/6 mice for 7 days suppressed interferon-γ and elevated interleukin-4 production by splenic CD4+ T cells, shifting the immune balance toward Th2 without altering splenocyte numbers or major immune cell subset proportions. This effect was not shared by rosuvastatin, suggesting that lipophilicity-dependent cellular uptake influences immunomodulatory potency. In vitro experiments confirmed a direct Th2-promoting action of fluvastatin on CD4+ T cells. Basophils were excluded as mediating cells, as fluvastatin suppressed rather than enhanced basophil interleukin-4 production. Continuous fluvastatin exposure during granulocyte-macrophage colony-stimulating factor (GM-CSF)-driven dendritic cell (DC) differentiation altered the phenotype of the resulting DCs and markedly enhanced their Th2-polarizing capacity in co-cultures with antigen-specific CD4+ T cells. These functional changes were accompanied by alterations in DC surface molecule expression, although their causal contribution remains to be established. These findings indicate that continuous fluvastatin exposure during DC differentiation is associated with an altered DC phenotype and enhanced Th2-polarizing capacity.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42680200 · DOI · PMC13533597
Artery tertiary lymphoid organs encode a pathogenic high-affinity autoantibody-autoantigen pair in atherosclerosis [3]
Abstract reading summary — source excerpts
- Opening excerpt
- Artery tertiary lymphoid organs (ATLOs) emerge in atherosclerosis, which is a chronic inflammatory artery disease with an autoimmune component.
- Closing excerpt
- We suggest that ATLOs harbor a dysregulated immune tolerance environment permissive for autoreactive B cells that express pathogenic autoantibodies promoting atherosclerosis.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (163 words)
Artery tertiary lymphoid organs (ATLOs) emerge in atherosclerosis, which is a chronic inflammatory artery disease with an autoimmune component. However, whether disease-relevant autoimmune B cells emerge in ATLOs remains unknown. In this study, we isolate germinal center (GC) B cells from ATLOs and lymph nodes from healthy and atherosclerosis-burdened mice, expression clone 60 autoantibodies and screen them for arterial wall reactivity. ATLO GC B cell-derived autoantibodies skew to atherosclerosis-relevant autoantigens versus their counterparts in lymph nodes of both genotypes. One ATLO GC B cell-derived autoantibody (termed A6) binds to histone 2B (H2B) with high affinity. Both vaccination with H2B and adoptive transfer of A6 accelerate atherosclerosis, revealing a pathogenic autoantibody-autoantigen pair. Mechanistically, ATLOs specifically show both distorted B cell activation and immune tolerance checkpoint-regulating gene expression profiles. In a human cohort, circulating anti-H2B antibody titers positively correlate with aortic calcification in humans. We suggest that ATLOs harbor a dysregulated immune tolerance environment permissive for autoreactive B cells that express pathogenic autoantibodies promoting atherosclerosis.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42706439 · DOI · PMC13561875
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article Prognostic value of inflammatory markers NLR, PLR, and LMR in gastric cancer patients treated with immune checkpoint inhibitors: a meta-analysis and systematic review [4]
- Research article PRP Injections for the Treatment of Knee Osteoarthritis: The Improvement Is Clinically Significant and Influenced by Platelet Concentration: A Meta-analysis of Randomized Controlled Trials [5]
- Research article Efficacy and safety of corticosteroids, hyaluronic acid, and PRP and combination therapy for knee osteoarthritis: a systematic review and network meta-analysis [6]
- Research article Neutrophil to lymphocyte ratio (NLR) prognostic effects on heart failure; a systematic review and meta-analysis [7]
- Research article The association between immune cells and breast cancer: insights from Mendelian randomization and meta-analysis [8]
- Research article Prognostic value of inflammatory markers NLR, PLR, LMR, dNLR, ANC in melanoma patients treated with immune checkpoint inhibitors: a meta-analysis and systematic review [9]
References
- Tan TS, Sun W, Gao C, Viard M, Walters LC, Lancien M, et al.. Innate immune imprints shape HIV-1 reservoir cell persistence during long-term antiretroviral therapy. . 2026. PMID 42680897 · DOI · PMC13630574
- Ishikawa S, Mizuno H, Murase K, Sasano K, Ogawa I, Itoh Y, et al.. The HMG-CoA Reductase Inhibitor Fluvastatin Promotes Th2-Skewed Immune Responses by Modulating Dendritic Cell Differentiation. . 2026. PMID 42680200 · DOI · PMC13533597
- Zhang C, Zhang X, Ran Y, Wang Z, Li L, Wang S, et al.. Artery tertiary lymphoid organs encode a pathogenic high-affinity autoantibody-autoantigen pair in atherosclerosis. . 2026. PMID 42706439 · DOI · PMC13561875
- Tan S, Zheng Q, Zhang W, Zhou M, Xia C, Feng W. Prognostic value of inflammatory markers NLR, PLR, and LMR in gastric cancer patients treated with immune checkpoint inhibitors: a meta-analysis and systematic review. Front Immunol. 2024. PMID 39050856 · DOI · PMC11266030
- Bensa A, Previtali D, Sangiorgio A, Boffa A, Salerno M, Filardo G. PRP Injections for the Treatment of Knee Osteoarthritis: The Improvement Is Clinically Significant and Influenced by Platelet Concentration: A Meta-analysis of Randomized Controlled Trials. Am J Sports Med. 2025. PMID 39751394 · DOI · PMC11874499
- Qiao X, Yan L, Feng Y, Li X, Zhang K, Lv Z, et al.. Efficacy and safety of corticosteroids, hyaluronic acid, and PRP and combination therapy for knee osteoarthritis: a systematic review and network meta-analysis. BMC Musculoskelet Disord. 2023. PMID 38037038 · DOI · PMC10687893
- Vakhshoori M, Nemati S, Sabouhi S, Yavari B, Shakarami M, Bondariyan N, et al.. Neutrophil to lymphocyte ratio (NLR) prognostic effects on heart failure; a systematic review and meta-analysis. BMC Cardiovasc Disord. 2023. PMID 37957565 · DOI · PMC10644447
- Xu W, Zhang T, Zhu Z, Yang Y. The association between immune cells and breast cancer: insights from Mendelian randomization and meta-analysis. Int J Surg. 2025. PMID 38935111 · DOI · PMC11745723
- Ou Y, Liang S, Gao Q, Shang Y, Liang J, Zhang W, et al.. Prognostic value of inflammatory markers NLR, PLR, LMR, dNLR, ANC in melanoma patients treated with immune checkpoint inhibitors: a meta-analysis and systematic review. Front Immunol. 2024. PMID 39493767 · DOI · PMC11527641
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-10-31; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-10-31.
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Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.