ABO and Rhesus blood groups and multiple health outcomes: an umbrella review of systematic reviews with meta-analyses of observational studies.

BACKGROUND: Numerous studies have been conducted to investigate the relationship between ABO and Rhesus (Rh) blood groups and various health outcomes. However, a comprehensive evaluation of the robustness of these associations is still lacking. METHODS: We searched PubMed, Web of Science, Embase, Scopus, Cochrane, and several regional databases from their inception until Feb 16, 2024, with the aim of identifying systematic reviews with meta-analyses of observational studies exploring associations between ABO and Rh blood groups and diverse health outcomes. For each association, we calculated the summary effect sizes, corresponding 95% confidence intervals, 95% prediction interval, heterogeneity, small-study effect, and evaluation of excess significance bias. The evidence was evaluated on a grading scale that ranged from convincing (Class I) to weak (Class IV). We assessed the certainty of evidence according to the Grading of Recommendations Assessment, Development, and Evaluation criteria (GRADE). We also evaluated the methodological quality of included studies using the A Measurement Tool to Assess Systematic Reviews (AMSTAR). AMSTAR contains 11 items, which were scored as high (8-11), moderate (4-7), and low (0-3) quality. We have gotten the registration for protocol on the PROSPERO database (CRD42023409547). RESULTS: The current umbrella review included 51 systematic reviews with meta-analysis articles with 270 associations. We re-calculated each association and found only one convincing evidence (Class I) for an association between blood group B and type 2 diabetes mellitus risk compared with the non-B blood group. It had a summary odds ratio of 1.28 (95% confidence interval: 1.17, 1.40), was supported by 6870 cases with small heterogeneity (I2 = 13%) and 95% prediction intervals excluding the null value, and without hints of small-study effects (P for Egger's test > 0.10, but the largest study effect was not more conservative than the summary effect size) or excess of significance (P < 0.10, but the value of observed less than expected). And the article was demonstrated with high methodological quality using AMSTAR (score = 9). According to AMSTAR, 18, 32, and 11 studies were categorized as high, moderate, and low quality, respectively. Nine statistically significant associations reached moderate quality based on GRADE. CONCLUSIONS: Our findings suggest a potential relationship between ABO and Rh blood groups and adverse health outcomes. Particularly the association between blood group B and type 2 diabetes mellitus risk.

Prostaglandin E2 restrains human Treg cell differentiation via E prostanoid receptor 2-protein kinase A signaling.

Regulatory T cells (Treg cells) belong to a class of immunosuppressive cells that control the pathological changes of autoimmunity and inflammation. Prostaglandin E2 (PGE2) is a potent lipid mediator of immune inflammation including rheumatoid arthritis (RA) that exerts its effects via four subtypes of G-protein-coupled receptors (EP1-4). The ability of PGE2 to regulate human Treg differentiation has not yet been reported. In the current study, we investigated the effects of PGE2 on the differentiation of naïve T cells from healthy and RA patients into Treg cells and the intracellular signaling involved in this process in vitro. Our data indicate that PGE2 negatively influenced the percentage of Treg cells and Foxp3 mRNA expression. The regulatory effects of PGE2 were associated with increased intracellular cAMP levels and PKA activity. EP2 receptors may mediate the inhibitory role of PGE2, since PGE2 actions were mimicked by EP2 agonist (Butaprost) and cAMP agonist (Sp-8-CPT-cAMPS) but were reversed by an EP2 antagonist (PF-04418948) and a PKA inhibitor (H-89). PGE2 negatively modulated the expression of cytotoxic T lymphocyte antigen-4 (CTLA-4) and glucocorticoid-induced tumor necrosis factor receptor-related protein (GITR), as well as the production of interleukin (IL)-10 by Treg cells via EP2 receptors and cAMP/PKA signaling. All these findings indicate that PGE2 can inhibit Treg differentiation mediated through the EP2-cAMP/PKA signaling pathway, and suggest novel immune-based therapies for use in RA treatment.

[Culture and Application of Entamoeba invadens Trophozoites from Snake].

The trophozoites of Entamoeba invadens from snake were seeded in liquid medium, incubated at 22 ℃ under constant temperature, and transferred weekly. The liquid medium which contained a large number of trophozoites was used for preparation of samples for microscopic observation. The cultured trophozoites of snake E. invadens displayed similar morphological changes, movement patterns, reproductive cycle and invasiveness with human E. histolytica. Therefore, the snake E. invadens trophozoites can be used as an alternative to the human E. histolytica trophozoites to facilitate students' observation of living amoeba trophozoites.

Cholecystokinin octapeptide regulates the differentiation and effector cytokine production of CD4(+) T cells in vitro.

Cholecystokinin octapeptide (CCK-8), an immunomodulatory peptide, can promote or suppress the development or function of specific CD4(+) T cell subsets by regulating antigen-presenting cell functions. In the current study, we investigated whether CCK-8 exerts a direct effect on T cells through influencing differentiation and cytokine production of distinct CD4(+) T cell subsets in vitro. Our results showed that CCK-8 differentially affects the development and function of CD4(+) T cell populations, with a negative influence on Th1 and Th17 cells and positive regulatory effect on inducible T regulatory cells (iTreg). Notably, CCK-8 suppressed Th1 while slightly enhancing Th2 development and cytokine production. Similarly, CCK-8 inhibited the differentiation of Th17 cells and promoted Foxp3 expression. L-364,718 and LY-288,513, selective antagonists of CCK1R and CCK2R, respectively, suppressed the effects of CCK-8 on CD4(+) T cell subset-specific transcription factors. Our findings strongly indicate that CCK-8 exerts a direct effect on T cells, which is dependent on CCKRs, particularly CCK2R. The collective results aid in further clarifying the mechanism underlying the anti-inflammatory and immunoregulatory effects of CCK-8.

Cholecystokinin octapeptide inhibits immunoglobulin G1 production of lipopolysaccharide-activated B cells.

Cholecystokinin octapeptide (CCK-8) is a typical brain-gut peptide that exerts a variety of physiological actions in both the peripheral and central nervous systems. Our laboratory has previously reported that CCK-8 produces immunoregulatory action through activating CCK receptor (CCK1R/CCK2R) expression on immune cell surfaces. In the present study, we investigated the effect of CCK-8 on immunoglobulin G1 (IgG1) production in lipopolysaccharide (LPS)-activated B cells in vitro. CCK-8 inhibited the proliferation and IgG1 mRNA expression of LPS-activated B cells and therefore inhibited IgG1 production. The mechanism may be associated with the regulation of CCK-8 on transcription factors Blimp1, Pax5, Xbp1 and Bcl6. CCK-8 inhibited the expression of Blimp1, while the effect on Pax5, Xbp1 and Bcl6 varied with time, suggesting that CCK-8 acted as a complex regulator of LPS-activated B cells. The inhibitory action of CCK-8 was mainly mediated through the CCK2R pathway. These studies indicate that CCK-8 attenuates humoral immune responses and acts as endogenous immune deactivators in autoimmune diseases.