Jieduquyuziyin prescription enhances CD11a and CD70 DNA methylation of CD4+ T cells via miR-29b-sp1/DNMT1 pathway in MRL/lpr mice

ETHNOPHARMACOLOGICAL RELEVANCE

Jieduquyuziyin prescription (JP) is a traditional Chinese medicine utilized to treat systemic lupus erythematosus (SLE). Its efficacy has been confirmed through clinical trials and empirical evidence, leading to its authorized use in Chinese hospitals. The development of JP exemplifies the integration of traditional wisdom and scientific approaches, demonstrating the interdisciplinary essence of ethnopharmacology. These results emphasize the potential value of traditional medicine in addressing autoimmune disorders.

AIM OF THE STUDY

This study aims to address the effect of JP in MRL/lpr mice and elucidate the pharmacological mechanism by which JP targets CD11a and CD70 DNA methylation via the miR-29b-sp1/DNMT1 pathway.

MATERIALS AND METHODS

MRL/lpr mice were divided into three groups: the model group (received distilled water), the positive group (administered AAV/miR-29b-3p inhibitor), and the JP group (treated with JP decoction). C57BL/6 mice were constituted as a control group. Through ELISA assay, serum and urine samples were assessed for anti-dsDNA, TNF-α, TGF-β, IL-2, and UP. HE and Masson staining were conducted to reveal renal pathology. Genome DNA was extracted from CD4+ T cells of mice spleens to evaluate methylation level. The methylation of CD11a, CD70, and CD40L promoter regions was analyzed by targeted bisulfate sequencing. Their expression at the mRNA and protein levels was examined using quantitative real-time PCR, western blot analysis, immunohistochemistry, and immunofluorescence staining of kidney tissues. Furthermore, the molecular mechanisms underlying the regulation of the miR-29b-sp1/DNMT1 pathway by JP were explored with Jurkat cells transfected with miR-inhibitors or miR-mimics.

RESULTS

Mice treated with JP exhibited a significant decrease in anti-dsDNA, TNF-α, TGF-β, and UP, accompanied by a significant increase in IL-2. HE staining revealed JP effectively mitigated renal inflammatory response, while Masson staining indicated a reduction in collagen fiber content. In addition, JP exhibited a significant impact on the global hypomethylation of SLE, as evidenced by the induction of high methylation levels of CD11a and CD70 promoter regions, mediated through the miR-29b-sp1/DNMT1 pathway.

CONCLUSION

Our findings demonstrate JP exerts a protective effect against spontaneous SLE development, attenuates renal pathological changes, and functions as a miRNA inhibitor to enhance CD11a and CD70 DNA methylation through the modulation of the miR-29b-sp1/DNMT1 pathway.

CD11a regulates hematopoietic stem and progenitor cells

Integrin αLβ2 (CD11a/CD18, CD11a) is a critical leukocyte adhesion molecule in leukocyte arrest and immunological synapse formation. However, its role in the bone marrow has not been investigated in depth. Here we showed that CD11a was expressed on all subsets of hematopoietic stem and progenitor cells (HPSCs). CD11a deficiency enhanced HSPCs activity under lipopolysaccharide (LPS) stimulation as demonstrated by a higher HSPC cell count along with an increase in cell proliferation. However, our mixed chimera experiment did not support that this phenotype was driven in a cell-intrinsic manner. Rather we found that the production of IL-27, a major cytokine that drives HSPC proliferation, was significantly upregulated both in vivo and in vitro. This adds a novel role of CD11a biology.

Clinical and immunological characteristics of 69 leukocyte adhesion deficiency-I patients

BACKGROUND

In order to support the comprehensive classification of Leukocyte Adhesion Deficiency-I (LAD-I) severity by simultaneous screening of CD11a/CD18, this study assessed clinical, laboratory, and genetic findings along with outcomes of 69 LAD-I patients during the last 15 years.

METHODS

Sixty-nine patients (40 females and 29 males) with a clinical phenotype suspected of LAD-I were referred to Immunology, Asthma, and Allergy research institute, Tehran, Iran between 2007 and 2022 for further advanced immunological screening and genetic evaluations as well as treatment, were enrolled in this study.

RESULTS

The diagnosis median age of the patients was 6 months. Delayed umbilical cord separation was found in 25 patients (36.2%). The median diagnostic delay time was 4 months (min-max: 0-82 months). Forty-six patients (66.7%) were categorized as severe (CD18 and/or CD11a: below 2%); while 23 children (33.3%) were in moderate category (CD18 and/or CD11a: 2%-30%). During the follow-ups, 55.1% of children were alive with a mortality rate of 44.9%. Skin ulcers (75.4%), omphalitis (65.2%), and gingivitis (37.7%) were the most frequent complaints. Genetic analysis of the patients revealed 14 previously reported and three novel pathogenic mutations in the ITGB2 gene. The overall survival of patients with and without hematopoietic stem cell transplantation was 79.3% and 55.6%, respectively.

CONCLUSION

Physicians' awareness of LAD-I considering delayed separation of umbilical cord marked neutrophilic leukocytosis, and variability in CD11 and CD18 expression levels, and genetic analysis leads to early diagnosis and defining disease severity. Moreover, the prenatal diagnosis would benefit families with a history of LAD-I.

PIMS-TS immunophenotype: description and comparison with healthy children, Kawasaki disease and severe viral and bacterial infections

BACKGROUND

A new clinical syndrome named Paediatric Inflammatory Multisystem Syndrome Temporally Associated with SARS-CoV-2 (PIMS-TS) has been described. This new disease is a leading cause of hospital and paediatric intensive care unit (PICU). It has been related to immunity dysregulation.

METHODS

Prospective-retrospective observational study to describe the innate cell signature and immunophenotype of children admitted to PICU because of PIMS-TS (from March 2020 to September 2020). The immunophenotype was done through the expression analysis of these proteins of mononuclear cells: CD64, CD18, CD11a and CD11b. They were compared with previous healthy controls and children admitted to PICU because of bacterial infection, viral infection and Kawasaki disease (KD). Two hundred and forty-seven children were studied: 183 healthy controls, 25 viral infections, 20 bacterial infections, 6 KD and 13 PIMS-TS.

RESULTS

PIMT-TS showed the lowest percentage of lymphocytes and monocytes with higher relative numbers of CD4+ (p = .000). Monocytes and neutrophils in PIMS-TS showed higher levels of CD64 expression (p = .000). Also, CD11a and CD11b were highly expressed (p =,000).

CONCLUSION

We observed a differential cell innate signature in PIMS-TS. These findings are consistent with a proinflammatory status (CD64 elevated expression) and lymphocyte trafficking to tissues (CD11a and CD11b). More studies should be carried out to confirm our results.

Possible Role of CD11a in Primary Immune Thrombocytopenia Patients on Immunosuppressive Therapy

Background and Objectives

Immune thrombocytopenia (ITP) is one of the autoimmune diseases that presented by thrombocytopenia and increased risk of bleeding. Etiology of immune thrombocytopenia (ITP) is very complex. Lymphocyte function associated antigen-1 (LFA-1) plays important role in ITP. The aim of this study was evaluation of expression of CD11a on lymphocytes to explore its possible role in primary ITP patients also, regarding severity and response to immunosuppressive treatment.

Patients and Methods

This is a cross-sectional case-control study. Forty adult patients aged (18:58) years, 29 females and 11 males were enrolled as newly diagnosed primary ITP. Forty age and sex matched control subjects were randomly selected. The expression of CD11a on lymphocyte subpopulations (CD3+ T cells, CD3+CD4+ T cells and CD19+ B cells) was analyzed by flowcytometry at the start of the study and after 6 months of follow-up.

Results

The mean fluorescence intensity (MFI) of CD11a on CD3+ T and CD19+ B lymphocytes was significantly highly increased in ITP patients compared to healthy controls while MFI of CD11a on CD3+ CD4+Tclls was non-significant. MFI of CD11a on CD3+ and CD19+ B lymphocytes showed non-significant elevation with platelet count or bleeding score. MFI of CD11a on CD3+ showed significant highly increased level in refractory ITP compared with responder cases.

Conclusion

CD11a had possible role in the pathogenesis of ITP. Immunosuppressive therapy in ITP did not affect the level of CD11a expression on T and B lymphocytes. Levels of CD11a do not reflect the severity of ITP neither platelet count nor bleeding score. Increased MFI of CD11a in CD3+T lymphocytes of ITP patients may cause resistance to immunosuppressive therapy.

ADAP Promotes Degranulation and Migration of NK Cells Primed During in vivo Listeria monocytogenes Infection in Mice

The adhesion and degranulation-promoting adaptor protein (ADAP) serves as a multifunctional scaffold and is involved in the formation of immune signaling complexes. To date only limited and moreover conflicting data exist regarding the role of ADAP in NK cells. To extend existing knowledge we investigated ADAP-dependency of NK cells in the context of in vivo infection with the intracellular pathogen Listeria monocytogenes (Lm). Ex vivo analysis of infection-primed NK cells revealed impaired cytotoxic capacity in NK cells lacking ADAP as indicated by reduced CD107a surface expression and inefficient perforin production. However, ADAP-deficiency had no global effect on NK cell morphology or intracellular distribution of CD107a-containing vesicles. Proteomic definition of ADAPko and wild type NK cells did not uncover obvious differences in protein composition during the steady state and moreover, similar early response patterns were induced in NK cells upon infection independent of the genotype. In line with protein network analyses that suggested an altered migration phenotype in naïve ADAPko NK cells, in vitro migration assays uncovered significantly reduced migration of both naïve as well as infection-primed ADAPko NK cells compared to wild type NK cells. Notably, this migration defect was associated with a significantly reduced expression of the integrin CD11a on the surface of splenic ADAP-deficient NK cells 1 day post-Lm infection. We propose that ADAP-dependent alterations in integrin expression might account at least in part for the fact that during in vivo infection significantly lower numbers of ADAPko NK cells accumulate in the spleen i.e., the site of infection. In conclusion, we show here that during systemic Lm infection in mice ADAP is essential for efficient cytotoxic capacity and migration of NK cells.

CD11a expression distinguishes infiltrating myeloid cells from plaque-associated microglia in Alzheimer's disease

Alzheimer's disease (AD) is the leading cause of age-related neurodegeneration and is characterized neuropathologically by the accumulation of insoluble beta-amyloid (Aβ) peptides. In AD brains, plaque-associated myeloid (PAM) cells cluster around Aβ plaques but fail to effectively clear Aβ by phagocytosis. PAM cells were originally thought to be brain-resident microglia. However, several studies have also suggested that Aβ-induced inflammation causes peripheral monocytes to enter the otherwise immune-privileged brain. The relationship between AD progression and inflammation in the brain remains ambiguous because microglia and monocyte-derived macrophages are extremely difficult to distinguish from one another in an inflamed brain. Whether PAM cells are microglia, peripheral macrophages, or a mixture of both remains unclear. CD11a is a component of the β2 integrin LFA1. We have determined that CD11a is highly expressed on peripheral immune cells, including macrophages, but is not expressed by mouse microglia. These expression patterns remain consistent in LPS-treated inflamed mice, as well as in two mouse models of AD. Thus, CD11a can be used as a marker to distinguish murine microglia from infiltrating peripheral immune cells. Using CD11a, we show that PAM cells in AD transgenic brains are comprised entirely of microglia. We also demonstrate a novel fluorescence-assisted quantification technique (FAQT), which reveals a significant increase in T lymphocytes, especially in the brains of female AD mice. Our findings support the notion that microglia are the lead myeloid players in AD and that rejuvenating their phagocytic potential may be an important therapeutic strategy.

Histone demethylase JMJD3 regulates CD11a expression through changes in histone H3K27 tri-methylation levels in CD4+ T cells of patients with systemic lupus erythematosus

Aberrant CD11a overexpression in CD4+ T cells induces T cell auto-reactivity, which is an important factor for systemic lupus erythematosus (SLE) pathogenesis. Although many studies have focused on CD11a epigenetic regulation, little is known about histone methylation. JMJD3, as a histone demethylase, is capable of specifically removing the trimethyl group from the H3K27 lysine residue, triggering target gene activation. Here, we examined the expression and function of JMJD3 in CD4+ T cells from SLE patients. Significantly decreased H3K27me3 levels and increased JMJD3 binding were detected within the ITGAL (CD11a) promoter locus in SLE CD4+ T cells compared with those in healthy CD4+ T cells. Moreover, overexpressing JMJD3 through the transfection of pcDNA3.1-JMJD3 into healthy donor CD4+ T cells increased JMJD3 enrichment and decreased H3K27me3 enrichment within the ITGAL (CD11a) promoter and up-regulated CD11a expression, leading to T and B cell hyperactivity. Inhibition of JMJD3 via JMJD3-siRNA in SLE CD4+ T cells showed the opposite effects. These results demonstrated that histone demethylase JMJD3 regulates CD11a expression in lupus T cells by affecting the H3K27me3 levels in the ITGAL (CD11a) promoter region, and JMJD3 might thereby serve as a potential therapeutic target for SLE.

Pathogenic Bacterium Acinetobacter baumannii Inhibits the Formation of Neutrophil Extracellular Traps by Suppressing Neutrophil Adhesion

Hospital-acquired infections caused by Acinetobacter baumannii have become problematic because of high rates of drug resistance. A. baumannii is usually harmless, but it may cause infectious diseases in an immunocompromised host. Although neutrophils are the key players of the initial immune response against bacterial infection, their interactions with A. baumannii remain largely unknown. A new biological defense mechanism, termed neutrophil extracellular traps (NETs), has been attracting attention. NETs play a critical role in bacterial killing by bacterial trapping and inactivation. Many pathogenic bacteria have been reported to induce NET formation, while an inhibitory effect on NET formation is rarely reported. In the present study, to assess the inhibition of NET formation by A. baumannii, bacteria and human neutrophils were cocultured in the presence of phorbol 12-myristate 13-acetate (PMA), and NET formation was evaluated. NETs were rarely observed during the coculture despite neutrophil PMA stimulation. Furthermore, A. baumannii prolonged the lifespan of neutrophils by inhibiting NET formation. The inhibition of NET formation by other bacteria was also investigated. The inhibitory effect was only apparent with live A. baumannii cells. Finally, to elucidate the mechanism of this inhibition, neutrophil adhesion was examined. A. baumannii suppressed the adhesion ability of neutrophils, thereby inhibiting PMA-induced NET formation. This suppression of cell adhesion was partly due to suppression of the surface expression of CD11a in neutrophils. The current study constitutes the first report on the inhibition of NET formation by a pathogenic bacterium, A. baumannii, and prolonging the neutrophil lifespan. This novel pathogenicity to inhibit NET formation, thereby escaping host immune responses might contribute to a development of new treatment strategies for A. baumannii infections.

Glycogen storage disease type Ib neutrophils exhibit impaired cell adhesion and migration

Glycogen storage disease type Ib (GSD-Ib), characterized by impaired glucose homeostasis, neutropenia, and neutrophil dysfunction, is an inherited autosomal recessive disorder caused by a deficiency in the glucose-6-phosphate transporter (G6PT). Neutrophils play an essential role in the defense against invading pathogens. The recruitment of neutrophils towards the inflammation sites in response to inflammatory stimuli is a tightly regulated process involving rolling, adhesion, and transmigration. In this study, we investigated the role of G6PT in neutrophil adhesion and migration using in vivo and in vitro models. We showed that the GSD-Ib (G6pt^-/-) mice manifested severe neutropenia in both blood and bone marrow, and treating G6pt^-/- mice with granulocyte colony-stimulating factor (G-CSF) corrected neutropenia. However, upon thioglycolate challenge, neutrophils from both untreated and G-CSF-treated G6pt^-/-mice exhibited decreased ability to migrate to the peritoneal cavity. In vitro migration and cell adhesion of G6PT-deficient neutrophils were also significantly impaired. Defects in cell migration were not due to enhanced apoptosis or altered fMLP receptor expression. Remarkably, the expression of the β2 integrins CD11a and CD11b, which are critical for cell adhesion, was greatly decreased in G6PT-deficient neutrophils. This study suggests that deficiencies in G6PT cause impairment in neutrophil adhesion and migration via aberrant expression of β2 integrins, and our finding should facilitate the development of novel therapies for GSD-Ib.

Expression of CD11a in lymphocyte subpopulation in immune thrombocytopenia

Recent research demonstrates that the underlying mechanism in immune thrombocytopenia (ITP) is very complex. Lymphocyte function associated antigen-1 (LFA-1) plays important roles in autoimmune diseases. The purpose of this study was to investigate the expression of CD11a on lymphocytes and explore its possible role in ITP. The expression of CD11a on lymphocyte subpopulations (CD3(+) T cells, CD3(+)CD4(+) T cells, CD3(+)CD4(-) T cells, CD4(+)Foxp3(+) T regulatory cells and CD19(+) B cells) were analyzed by flow cytometry. Specific anti-platelet GPIIb/IIIa and/or GPIb/IX autoantibodies were assayed by modified monoclonal antibody specific immobilization of platelet antigens (MAIPA). The mean fluorescence intensity of CD11a on CD3(+) T, CD3(+)CD4(-) T and CD19(+) B lymphocytes were increased in ITP patients compared to healthy controls. No significant difference of CD11a expression on CD3(+)CD4(+) T cells or CD4(+)Foxp3(+) T regulatory cells was found between ITP patients and controls. Our data indicates the possible role of CD11a in the pathogenesis of ITP.

Hypomethylation and overexpression of ITGAL (CD11a) in CD4(+) T cells in systemic sclerosis

Background

The pathogenesis and etiology of systemic sclerosis (SSc) are complex and poorly understood. To date, several studies have demonstrated that the activation of the immune system undoubtedly plays a pivotal role in SSc pathogenesis. Activated immune effector T cells contribute to the release of various pro-inflammatory cytokines and drive the SSc-specific autoantibody responses. This, and a profibrotic environment, are all-important components of abnormal active immune responses that can lead to pathological disorders of SSc. CD11a is essential to inflammatory and immune responses, regulating adhesive and co-stimulatory interactions between CD4⁺ T cells and other cells. Although CD11a is overexpressed in SSc patients, the mechanisms leading to this overexpression and its consequences remain unclear. DNA methylation, a main epigenetic modification, plays an important role in the regulation of gene expression and is involved in the pathogenesis of autoimmune diseases. This work aims to investigate the effect of DNA demethylation on CD11a expression in SSc CD4⁺ T cells and to determine its functional significance. CD11a expression was measured using RT-PCR and flow cytometry. Bisulfite sequencing was used to determine the methylation status of the CD11a regulatory region. CD4⁺ T cells were co-cultured with antigen-presenting cells, B cells, or fibroblasts with and without anti-CD11a, and proliferation of CD4⁺ T cells, IgG production by B cells, and expression levels of COL1A2 mRNA by fibroblasts were evaluated.

Results

Elevated CD11a expression levels were observed in CD4⁺ T cells from SSc patients; these levels were found to be positively correlated with disease activity. The methylation levels of the CD11a regulatory sequences were lower in SSc patients than in controls and inversely correlated with CD11a mRNA expression. Treatment of CD4⁺ T cells with 5-azacytidine (5-azaC) decreased CD11a promoter methylation and caused CD11a overexpression. SSc CD4⁺ T cells and 5-azaC-treated CD4⁺ T cells showed increased proliferation of CD4⁺ T cells, increased production of IgG by co-cultured B cells, and induced expression of COL1A2 mRNA by co-cultured fibroblasts. These stimulatory effects were abrogated by anti-CD11a.

Conclusions

Demethylation of CD11a regulatory elements and subsequent CD11a overexpression in CD4⁺ T cells may mediate immunological abnormalities and fibrotic processes in SSc.

Expressions of CD11a, CD11b, and CD11c integrin proteins in rats with myocardial hypertrophy

OBJECTIVES

To examine the expressions of CD11a, CD11b, and CD11c integrins in the myocardial tissues of rats with isoproterenol-induced myocardial hypertrophy. This study also provided morphological data to investigate the signal transduction mechanisms of myocardial hypertrophy and reverse it.

MATERIALS AND METHODS

A myocardial hypertrophy model was established by subcutaneously injecting isoprenaline in healthy adult Sprague-Dawley rats. Myocardial tissues were obtained, embedded in conventional paraffin, sectioned, and stained with hematoxylin. Pathological changes in myocardial tissues were then observed. The expressions and distributions of CD11a, CD11b, and CD11c integrins were detected by immunohistochemistry. Changes in the mRNA expressions of CD11a, CD11b, and CD11c in the myocardial tissues of rats were detected by RT-PCR. Image analysis software was used to determine the expressions of CD11a, CD11b, and CD11c integrins quantitatively.

RESULTS

Immunohistochemical results showed that the positive expressions of CD11a, CD11b, and CD11c integrins increased significantly in the experimental group compared with those in the control group. The mRNA expressions of CD11a, CD11b, and CD11c in the myocardial tissues of rats were consistent with the immunohistochemical results.

CONCLUSION

The increase in the protein expressions of CD11a, CD11b, and CD11c integrins may have an important role in the occurrence and development of myocardial hypertrophy.

Expression and targeting of lymphocyte function-associated antigen 1 (LFA-1) on white blood cells for treatment of allergic asthma

Allergic asthma is a chronic respiratory disease that results from an exaggerated inflammatory response in the airways. Environment stimuli, such as pollen and HDM, cause activation and migration of inflammatory WBCs into the respiratory tract, where they cause lung damage. Migration of these WBCs is dependent on the active configuration of the β2 integrin LFA-1. The experimental therapeutic agent LtxA specifically targets active LFA-1 and causes cell death. We investigated the association between LFA-1 and allergic asthma and hypothesized that targeting LFA-1 with LtxA could be an attractive strategy for treatment of the condition. We examined LFA-1 (CD11a) levels on PBMCs from patients with allergic asthma compared with healthy controls. Patients exhibited a significantly higher percentage of PBMCs expressing LFA-1 than healthy controls. Furthermore, the level of LFA-1 expression on patient PBMCs was greater than on healthy PBMCs. We identified a unique cellular population in patients that consisted of CD4(-) CD11a(hi) cells. We also evaluated LtxA in a HDM extract-induced mouse model for allergic asthma. LtxA caused resolution of disease in mice, as demonstrated by a decrease in BALF WBCs, a reduction in pulmonary inflammation and tissue remodeling, and a decrease in proinflammatory cytokines IL-4, IL-5, IL-9, IL-17F, and IL-23α in lung tissue. LFA-1 may serve as an important marker in allergic asthma, and the elimination of activated WBCs by use of LtxA could be a viable therapeutic strategy for treating patients with this condition.

CD11a, CD11c, and CD18 gene polymorphisms and susceptibility to Behçet's disease in Koreans

Lesions of Behçet's disease (BD) show vascular infiltrates of immune cells expressing integrins. β2 integrins (CD11/CD18) play a major role in cell migration to the inflammatory lesion and also induce cytokine production. Thus, genetic polymorphisms of CD11/CD18 may be associated with the pathogenesis of BD. In this study, nine single nucleotide polymorphisms (SNPs) of the CD11a, CD11c, and CD18 were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and haplotype analysis in 305 BD patients and 266 healthy controls. The frequencies of genotype rs11574944 CC and haplotype rs11574944C-rs2230433G-rs8058823A in CD11a were significantly lower in BD patients. The frequencies of genotype rs2230429 CC, rs2929 GG, and haplotype rs2230429C-rs2929G in CD11c were higher in BD patients. The frequencies of genotype rs235326CC and haplotype rs2070946A-rs235326C-rs760456G-rs684G in CD18 were significantly higher in the BD patients than in the controls. Other SNPs in CD11a, CD11c, and CD18 gene were not significantly different. Therefore, the major genotype and haplotype of CD11a/CD18 may play a role in decreasing the susceptibility of BD, whereas the major genotype and haplotype of CD11c/CD18 may play a role in increasing the susceptibility of BD.

Natalizumab treatment alters the expression of T-cell trafficking marker LFA-1 α-chain (CD11a) in MS patients

OBJECTIVE

To determine the long-term effect of natalizumab (NTZ) treatment on the expression of integrins and chemokine receptors involved in the migration of T cells towards the central nervous system (CNS).

METHODS

We drew the blood of 23 patients just before starting NTZ therapy and every 12 months thereafter, for up to 48 months of treatment. We assessed the ex-vivo expression of phenotype markers (CCR7 and CD45RA), CNS-addressing integrins (CD11a, CD49d and CD29) and chemokine receptors (CXCR3 and CCR6) in CD4+ or CD8+ T-cell subsets by flow cytometry.

RESULTS

As compared to the pre-NTZ values, there was a marked increase in central memory (CCR7+/CD45RA-) CD4+ T cells and in effector memory (CCR7-/CD45RA-) CD8+ T cells at 12 and 24 months. In addition to an expected downregulation of both VLA-4 subunits (CD49d/CD29), we also found decreased T-cell expression of CXCR3 at 12 months, and of CD11a (LFA-1 αL subunit) at 12 months, but mostly at 24 months of NTZ treatment.

CONCLUSION

Our data show a nadir of CD11a expression at 2 years of NTZ treatment, at the peak of incidence of progressive multifocal leukoencephalopathy (PML), indirectly suggesting that a lack of these molecules may play a role in the onset of PML in NTZ-treated patients.

Endogenous tumor-reactive CD8+ T cells are differentiated effector cells expressing high levels of CD11a and PD-1 but are unable to control tumor growth

Immunotherapies aimed at enhancing natural or endogenous antitumor T-cell immunity in patients affected by advanced malignancies are currently being implemented in the clinic with promising results. In order to optimize therapeutic protocols and monitor the effectiveness of such therapies, reliable biomarkers are needed. We used CD11a, an integrin that is upregulated on the surface of effector and memory CD8⁺ T cells, and PD-1, an immunoregulatory receptor expressed by activated T cells, as biomarkers to identify, quantify and monitor endogenous tumor-reactive cytotoxic T lymphocytes (CTLs) in two mouse tumor models and in the peripheral blood of 12 patients affected by Stage IV melanoma. High expression levels of CD11a and PD-1 were detected among CD8⁺ T cells residing within primary and metastatic murine tumor sites, as well as in spontaneous murine breast cancer tissues. In the peripheral blood of melanoma patients, tumor antigen-specific CD8⁺ T cells were associated with a population of CD11a^high CD8⁺ T cells that co-expressed high levels of PD-1. Healthy donors exhibited a comparatively much lower frequency of such PD-1⁺CD11a^highCD8⁺ T cells. Phenotypic analyses demonstrated that CD11a^highCD8⁺ T cells are proliferating (Ki67⁺) and activated (CD62L^-CD69⁺). Increased CD11a^highCD8⁺ T cells and delayed tumor growth were observed in PD-1 deficient mice, suggesting that the antitumor effector functions of CD8⁺ T cells is compromised by an elevated expression of PD-1. The CD11a^highCD8⁺ T-cell population expresses high levels of PD-1 and presumably constitutes the cellular target of PD-1 blockade therapy. The expression level of CD11a and PD-1 by CD8⁺ T cells may therefore represent a novel biomarker to identify and monitor endogenous tumor-reactive CTLs. This may not only provide an immunological readout for evaluating the efficacy of immunotherapy but also contribute to the selection of cancer patients who are likely to benefit from anti-PD-1 therapy.

CD11a polymorphisms regulate TH2 cell homing and TH2-related disease

BACKGROUND

TH2-dependent diseases vary in severity according to genotype, but relevant gene polymorphisms remain largely unknown. The integrin CD11a is a critical determinant of allergic responses, and allelic variants of this gene might influence allergic phenotypes.

OBJECTIVE

We sought to determine major CD11a allelic variants in mice and human subjects and their importance to allergic disease expression.

METHODS

We sequenced mouse CD11a alleles from C57BL/6 and BALB/c strains to identify major polymorphisms; human CD11a single nucleotide polymorphisms were compared with allergic disease phenotypes as part of the international HapMap project. Mice on a BALB/c or C57BL/6 background and congenic for the other strain's CD11a allele were created to determine the importance of mouse CD11a polymorphisms in vivo and in vitro.

RESULTS

Compared with the C57BL/6 allele, the BALB/c CD11a allele contained a nonsynonymous change from asparagine to aspartic acid within the metal ion binding domain. In general, the BALB/c CD11a allele enhanced and the C57BL/6 CD11a allele suppressed TH2 cell-dependent disease caused by the parasite Leishmania major and allergic lung disease caused by the fungus Aspergillus niger. Relative to the C57BL/6 CD11a allele, the BALB/c CD11a allele conferred both greater T-cell adhesion to CD54 in vitro and enhanced TH2 cell homing to lungs in vivo. We further identified a human CD11a polymorphism that significantly associated with atopic disease and relevant allergic indices.

CONCLUSIONS

Polymorphisms in CD11a critically influence TH2 cell homing and diverse TH2-dependent immunopathologic states in mice and potentially influence the expression of human allergic disease.

Blast cell deficiency of CD11a as a marker of acute megakaryoblastic leukemia and transient myeloproliferative disease in children with and without Down syndrome

BACKGROUND

The classification of acute myeloid leukemia (AML) FAB subtype M7 relies on immunophenotypic assessment. CD41 is expressed throughout all stages of maturation of megakaryocytes and has therefore been described as a specific blast cell marker in AML M7 as well as in transient myeloproliferative disease (TMD) of patients with Down syndrome (DS). However, technical difficulties underlie the need for new markers for these entities.

METHODS

We evaluated the expression of human lymphocyte function-associated antigen 1 (CD11a) in a large cohort of pediatric AML and TMD patients (n = 91) of the Austrian AML-BFM 98 and 2004 studies.

RESULTS

We found a consistent deficiency of CD11a as assessed by mean fluorescence intensity in all patients with non-DS AML M7 (n = 8) and M6 (n = 1), all cases of classical DS-AML (n = 12) as well as TMD (n = 15) that was statistically significant in comparison to non-DS AML M0-M5 patients (n = 55; P < 0.001, sensitivity 100%). Only three of 55 Non-DS M0-5 patients were CD11a deficient (specificity 95%). Monocytic leukemias (M4/5) and normal monocytes typically showed a high CD11a expression, FAB types M1/2 and normal neutrophils an intermediate expression level, while all M3 leukemias were rather low in CD11a expression.

CONCLUSIONS

We conclude, that deficiency of CD11a expression should be added to the diagnostic criteria of AML-M7, classical DS-AML and TMD.