Phosphatidylserine and Tyro3-Axl-Mertk Receptor Tyrosine Kinase level detection in plasma and on plasma-derived extracellular vesicle surface in chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) is a chronic lymphoproliferative disorder characterized by monoclonal B cell proliferation. Studies carried out in recent years suggest that extracellular vesicles (EVs) may be a potential biomarker in cancer. Tyro3-Axl-Mertk (TAM) Receptor Tyrosine Kinases (RTKs) and Phosphatidylserine (PS) have crucial roles in macrophage-mediated immune response under normal conditions. In the tumor microenvironment, these molecules contribute to immunosuppressive signals and prevent the formation of local and systemic antitumor immune responses. Based on this, we aimed to evaluate the amount of PS and TAM RTK in plasma and on the surface of EVs in CLL patients and healthy volunteers in this study. In this study, 25 CLL (11 F/14 M) patients in the Rai (O-I) stage, newly diagnosed or followed up without treatment, and 15 healthy volunteers (11 F/4 M) as a control group were included. For all samples, PS and TAM RTK levels were examined first in the plasma and then in the EVs obtained from the plasma. We detected a significant decrease in plasma PS, and TAM RTK levels in CLL patients compared to the control. Besides, we determined a significant increase in TAM RTK levels on the EV surface in CLL, except for PS. In conclusion, these receptor levels measured by ELISA in plasma may not be effective for the preliminary detection of CLL. However, especially TAM RTKs on the surface of EVs may be good biomarkers and potential targets for CLL therapies.

Cross-sectional study of plasma Axl, ferritin, IGFBP4 and sTNFR2 as biomarkers of disease activity in childhood-onset SLE: A study of the Pediatric Nephrology Research Consortium.

OBJECTIVE: To evaluate the performance of 4 plasma protein markers for detecting disease activity in childhood-onset systemic lupus erythematosus (SLE) patients. METHODS: Eighty-three consecutive pediatric patients fulfilling ≥4 ACR criteria for SLE and twenty-five healthy controls were prospectively recruited for serological testing of 4 protein markers identified by antibody-coated microarray screen, namely Axl, ferritin, IGFBP4 and sTNFR2. SLE disease activity was assessed using SLEDAI-2000 score. Fifty-seven patients had clinically active SLE (SLEDAI score ≥4, or having a flare). RESULTS: The plasma concentrations of Axl and ferritin were significantly higher in patients with active SLE than inactive SLE. Plasma Axl levels were significantly higher in active renal versus active non-renal SLE patients. Levels of Axl, ferritin and IGFBP4 correlated significantly with SLEDAI scores. Levels of Axl, IFGBP4 and sTNFR2 inversely correlated with plasma complement C3 levels. Only plasma Axl and ferritin levels correlated with degree of proteinuria. These markers were more specific, but less sensitive, in detecting concurrent SLE activity than elevated anti-dsDNA antibody titer or decreased C3. Ferritin and IGFBP4 levels were more specific for concurrent active lupus nephritis than anti-dsDNA or C3. Plasma ferritin was the best monitor of global SLE activity, followed by C3 then Axl, while both Axl and C3 were best monitors of clinical lupus nephritis activity. CONCLUSION: In childhood-onset SLE patients, plasma ferritin and Axl perform better than traditional yardsticks in identifying disease activity, either global or renal. The performance of these plasma markers should be explored further in longitudinal cohorts of SLE patients.

Expression of Receptor Tyrosine Kinases on Peripheral Blood Mononuclear Cells and Tumor-Infiltrating Lymphocytes in Patients with Renal Cell Carcinoma and Healthy Donors.

BACKGROUND: Very little is known about receptor tyrosine kinase (RTK) expression on peripheral blood mononuclear cells (PBMC) in humans including renal cell carcinoma (RCC) patients. OBJECTIVES: The primary objective of this study was to evaluate expression levels of major RTKs on PBMC and tumor-infiltrating lymphocytes (TIL) isolated from RCC patients. The secondary aim was to compare levels of RTK expression in RCC patients before surgery and on the 180th day after surgery (lymphocyte lifetime) and to compare them with the expression in healthy donors. In addition, we compared RTK and PD-L1 expression in TIL. METHODS: Tumor and blood samples were obtained from 20 patients with primary RCC immediately after surgical resection. Blood samples were collected from 20 healthy donors. Tumors were harvested into RPMI 1640 medium (Gibco) and processed within 4 h. TIL isolation was performed using a modified protocol [Baldan et al. Br J Cancer. 2015;112:1510-18]. Expression of RTKs was evaluated with NovoExpress Software. Twenty tumors from the same patients were stained with PD-L1 IHC assay (clone SP142; Ventana). RESULTS: PBMC and TIL express RTKs in humans. The RTK expression level was significantly lower on peripheral blood cells in patients with RCC (mean 41%, range 27.1-62.6%) as compared with healthy donor PBMC (mean 77.1%, range 72.1-80.1%, all p < 0.05). Furthermore, RTK expression was significantly downregulated on intratumoral cells (mean 40%, range 23.2-52.3%) in comparison with healthy donor PBMC. There was no significant recovery of RTK expression on the 180th day except for VEGFR2. Five of 20 (25%) patients were PD-L1 positive. PD-L1 expression on TIL was strongly associated with downregulated expression of PDGFRα (p = 0.017) and PDGFRß (p = 0.024). CONCLUSIONS: PBMC and TIL had similar low RTK expression levels in RCC patients. PBMC of healthy humans had a significantly higher expression of RTK. PD-L1 and PDGFRα-ß expression could correlate. Comprehensive basic and clinical studies will be needed to define a biological role of RTKs on different lymphocyte subsets and correlations between clinical outcomes and expression levels.

Molecular-Recognition-Based DNA Nanodevices for Enhancing the Direct Visualization and Quantification of Single Vesicles of Tumor Exosomes in Plasma Microsamples.

Tumor exosomes (Exo) are presumed to expedite both the growth and metastasis of tumors by actively participating in nearly all aspects of cancer development. Tumor-derived Exos are thus proposed as a resource for diagnostic biomarkers in bodily fluids. However, most Exo assays require large samples and are time-consuming, complicated, and costly, and thus unsuited for practical applications. Herein, we show an ultrasensitive assay that can directly visualize and quantify tumor Exos in plasma microsamples (1 µL) at the single-vesicle level. The assay uses the specific binding of activatable aptamer probes (AAP) to target Exos captured by Exo-specific antibodies on the surface of a flow cell to produce activated fluorescence. Furthermore, the bound AAP triggers in situ assembly of a DNA nanodevice with enhanced fluorescence that improves the Exo-detection sensitivity. By identifying tyrosine-protein-kinase-like 7 (PTK7), a total-internal-reflection-fluorescence (TIRF) assay for PTK7-Exo distinguishes target tumors from control subjects. This assay is also informative in monitoring tumor progression and early responses to therapy. The developed assay can be readily adapted for diagnosis and monitoring of other disease-associated Exo biomarkers.

Muscle-Specific Kinase Autoimmune Myasthenia Gravis: Report of a Pediatric Case and Literature Review.

Myasthenia gravis (MG) with antibodies to the muscle-specific tyrosine kinase (MuSK-MG) receptor is a rare entity. It represents 5 to 8% of all MG patients. Few pediatric cases were reported. Clinical presentation is often atypical. It is characterized by predominant involvement of cranial, bulbar, and axial muscles and early respiratory crises. Myokymia and fasciculation are suggestive of MuSK-MG. The clinical course of patients with MuSK-MG is worse than other types of MG. Responses to standard therapies are variable. We report clinical, neurophysiological, serological, and outcome profile of a Tunisian child with MuSK-MG.

Soluble TAM receptor tyrosine kinases in rheumatoid arthritis: correlation with disease activity and bone destruction.

The TAM receptor tyrosine kinases (TAM RTK) are a subfamily of receptor tyrosine kinases, the role of which in autoimmune diseases such as systemic lupus erythematosus has been well explored, while their functions in rheumatoid arthritis (RA) remain largely unknown. In this study, we investigated the role of soluble TAM receptor tyrosine kinases (sAxl/sMer/sTyro3) in patients with RA. A total of 306 RA patients, 100 osteoarthritis (OA) patients and 120 healthy controls (HCs) were enrolled into this study. The serum concentrations of sAxl/sMer/sTyro3 were measured by enzyme-linked immunosorbent assay (ELISA), then the associations between sAxl/sMer/sTyro3 levels and clinical features of RA patients were analysed. We also investigated whether sTyro3 could promote osteoclast differentiation in vitro in RA patients. The results showed that compared with healthy controls (HCs), sTyro3 levels in the serum of RA patients were elevated remarkably and sMer levels were decreased significantly, whereas there was no difference between HCs and RA patients on sAxl levels. The sTyro3 levels were correlated weakly but positively with white blood cells (WBC), immunoglobulin (Ig)M, rheumatoid factor (RF), swollen joint counts, tender joint counts, total sharp scores and joint erosion scores. Conversely, there were no significant correlations between sMer levels and the above indices. Moreover, RA patients with high disease activity also showed higher sTyro3 levels. In-vitro osteoclast differentiation assay showed further that tartrate-resistant acid phosphatase (TRAP)+ osteoclasts were increased significantly in the presence of sTyro3. Collectively, our study indicated that serum sTyro3 levels were elevated in RA patients and correlated positively with disease activity and bone destruction, which may serve as an important participant in RA pathogenesis.

Increased Circulating and Urinary Levels of Soluble TAM Receptors in Diabetic Nephropathy.

TAM receptors (Tyro3, Axl, and Mer) have been implicated in innate immunity. Circulating TAM receptor soluble forms (sTyro3, sAxl, sMer) are related to autoimmune disorders. We investigated TAM and their ligand protein S in patients with diabetes. Urinary and plasma levels of protein S, sTyro3, sAxl, and sMer were determined in 126 patients with diabetes assigned to a normoalbuminuric or macroalbuminuric (urinary albumin excretion <30 mg/24 hours and >300 mg/24 hours, respectively) study group and 18 healthy volunteers. TAM and protein S immunostaining was performed on kidney biopsy specimens from patients with diabetic nephropathy (n = 9) and controls (n = 6). TAM expression and shedding by tubular epithelial cells were investigated by PCR and enzyme-linked immunosorbent assay in an in vitro diabetes model. Patients with macroalbuminuria diabetes had higher circulating levels of sMer and more urinary sTyro3 and sMer than normoalbuminuric diabetics. Increased clearance of sTyro3 and sMer was associated with loss of tubular Tyro3 and Mer expression in diabetic nephropathy tissue and glomerular depositions of protein S. During in vitro diabetes, human kidney cells had down-regulation of Tyro3 and Mer mRNA and increased shedding of sTyro3 and sMer. Renal injury in diabetes is associated with elevated systemic and urine levels of sMer and sTyro3. This is the first study reporting excretion of sTAM receptors in urine, identifying the kidney as a source of sTAM.

Myasthenia gravis with muscle-specific tyrosine kinase antibodies: A narrative review.

Growing evidence provides new insights about myasthenia gravis (MG) with antibodies against muscle-specific tyrosine kinase (MuSK-MG), including its pathogenesis, clinical and electrophysiological manifestations, and treatment. Data now support the presence of both presynaptic and postsynaptic dysfunction in MuSK-MG. This is 1 of many key differences between MuSK-MG and acetylcholine receptor antibody-MG (AChR-MG), especially as it pertains to potential therapeutic implications. In comparison to AChR-MG, MuSK-MG is generally more refractory to treatment. However, because MuSK-MG is better understood and more readily recognized today, there are more reports of a relatively benign course. The most effective immunotherapies for MuSK-MG are corticosteroids, plasmapheresis, and rituximab. With appropriate therapy, most patients with MuSK-MG achieve minimal manifestation status or better on the postintervention status outlined by the Myasthenia Gravis Foundation of America. A minority of patients remain refractory to treatment, and optimal management for this group remains a considerable challenge. Muscle Nerve 58: 344-358, 2018.

Non-neuronal cholinergic activity is potentiated in myasthenia gravis.

BACKGROUND: Non-neuronal acetylcholine (ACh) restricts autoimmune responses and attenuates inflammation by cholinergic anti-inflammation pathway. To date, the implication of ACh in myasthenia gravis (MG) remained unexplored. This study aimed to investigate the possible relationship between ACh levels, anti-muscle-specific tyrosine kinase (MuSK) antibody titers, main clinical features and outcomes of MG patients. METHODS: We successfully measured ACh levels in human peripheral blood mononuclear cells (PBMCs) from 125 MG patients and 50 matched healthy controls by using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). We assessed the quantitative MG (QMG) scores for each patient and titered anti-MuSK antibody. RESULTS: We found that PBMC-derived ACh level was significantly higher in MG patients, especially in patients of class III, IV-V, compared with that in controls (0.142 ± 0.108 vs. 0.075 ± 0.014 ng/million cells, p = 0.0003) according to the Myasthenia Gravis Foundation of America clinical classification. Importantly, we also found that ACh levels were positively correlated with QMG scores (r = 0.83, p < 0.0001) and anti-MuSK Ab levels (r = 0.85, p < 0.0001). CONCLUSIONS: Our demonstration of elevated ACh levels in PBMCs of MG patients foreshadows potential new avenues for MG research and treatment.

Alectinib's activity against CNS metastases from ALK-positive non-small cell lung cancer: a single institution case series.

In the present study we assessed the activity of the next-generation anaplastic lymphoma kinase (ALK)-tyrosine kinase inhibitor (-TKI) alectinib, in patients with ALK-postive, advanced non-small cell lung cancer (NSCLC) and central nervous system (CNS) metastases. NSCLCs with ALK-positive disease, as assessed by fluorescence in situ hybridization, and CNS metastases were treated with alectinib 600 mg BID. Included patients were followed prospectively in order to evaluate the efficacy of the drug, with particular emphasis on activity in the CNS. Eleven consecutive patients were enrolled. The majority of them were pretreated with crizotinib (n = 10, 90.9 %), and cranial radiotherapy (n = 8, 72.7 %). Six of the seven patients with measurable CNS disease experienced a CNS response, including three patients who were naïve for cranial radiation. Median duration of response was 8 months. For the whole population, median CNS-progression-free survival (-PFS), systemic-PFS, overall-PFS, overall survival, and 1-year survival were 8, 11, 8, 13 months, and 31.1 %, respectively. Two patients experiencing a CNS response were assessed for alectinib's concentrations in serum and cerebro-spinal fluid (CSF), and showed a CSF-to-serum ratio ranging from 0.001 to 0.003 ng/mL. Alectinib is highly active against CNS metastases from ALK-positive NSCLCs, irrespective of prior treatment(s) with ALK-TKI(s) and/or cranial radiotherapy. The low CSF-to-serum ratio of alectinib suggests that measuring the concentrations of the drug in the CSF may not be a reliable surrogate of its distribution into the CNS.

Multicenter analysis of soluble Axl reveals diagnostic value for very early stage hepatocellular carcinoma.

If diagnosed at early stages, patients with hepatocellular carcinoma (HCC) can receive curative therapies, whereas therapeutic options at later stages are very limited. Here, we addressed the potential of soluble Axl (sAxl) as a biomarker of early HCC by analyzing levels of sAxl in 311 HCC and 237 control serum samples from centers in Europe and China. Serum concentrations of sAxl were significantly increased in HCC (18.575 ng/mL) as compared to healthy (13.388 ng/mL) or cirrhotic (12.169 ng/mL) controls. Receiver operating characteristic curve analysis of sAxl in very early stage HCC patients (BCLC 0) showed an area under the curve (AUC) of 0.848, with a sensitivity of 76.9% and a specificity of 69.2%. α-Fetoprotein (AFP)-negative HCC patients displayed an AUC of 0.803, with sensitivity and specificity of 73% and 70.8%. Combination of sAxl and AFP improved diagnostic accuracy to 0.936 in very early HCC patients and to 0.937 in all HCC. Differential diagnosis of very early HCC versus liver cirrhosis showed a combined performance for sAxl and AFP of 0.901 with a sensitivity of 88.5% and a specificity of 76.7%. Furthermore, sAxl levels failed to be elevated in primary ovarian, colorectal and breast carcinomas as well as in secondary hepatic malignancies derived from colon. In summary, sAxl outperforms AFP in detecting very early HCC as compared to healthy or cirrhotic controls and shows high diagnostic accuracy for AFP-negative patients. sAxl is specific for HCC and suggested as a biomarker for routine clinical use.

Serological Markers of Clinical Improvement in MuSK Myasthenia Gravis.

BACKGROUND AND OBJECTIVES: In this retrospective longitudinal study, we aimed at exploring the role of (a) MuSK-immunoglobulin G (IgG) levels, (b) predominant MuSK-IgG subclasses, and (c) antibody affinity as candidate biomarkers of severity and outcomes in MuSK-MG, using and comparing different antibody testing techniques. METHODS: Total MuSK-IgGs were quantified with radioimmunoassay (RIA), ELISA, flow cytometry, and cell-based assay (CBA) serial dilutions using HEK293 cells transfected with MuSK-eGFP. MuSK-IgG subclasses were measured by flow cytometry. SAffCon assay was used for determining MuSK-IgG affinity. RESULTS: Forty-three serum samples were obtained at different time points from 20 patients with MuSK-MG (median age at onset: 48 years, interquartile range = 27.5-72.5; women, 16/20), with 9 of 20 (45%) treated with rituximab. A strong correlation between MuSK-IgG levels measured by flow cytometry and RIA titers was found (rs = 0.74, 95% CI 0.41-0.89, p = 0.0003), as well as a moderate correlation between CBA end-point titers and RIA titers (rs = 0.47, 95% CI 0.01-0.77, p = 0.0414). A significant correlation was found between MuSK-IgG flow cytometry levels and disease severity (rs = 0.39, 95% CI 0.06-0.64, p = 0.0175; mixed-effects model estimate: 2.296e-06, std. error: 1.024e-06, t = 2.243, p = 0.032). In individual patients, clinical improvement was associated with decrease in MuSK-IgG levels, as measured by either flow cytometry or CBA end-point titration. In all samples, MuSK-IgG4 was the most frequent isotype (mean ± SD: 90.95% ± 13.89). A significant reduction of MuSK-IgG4 and, to a lesser extent, of MuSK-IgG2, was seen in patients with favorable clinical outcomes. A similar trend was confirmed in the subgroup of rituximab-treated patients. In a single patient, MuSK-IgG affinity increased during symptom exacerbation (KD values: 62 nM vs 0.6 nM) while total MuSK-IgG and IgG4 levels remained stable, suggesting that affinity maturation may be a driver of clinical worsening. DISCUSSION: Our data support the quantification of MuSK antibodies by flow cytometry. Through a multimodal investigational approach, we showed that total MuSK-IgG levels, MuSK-IgG4 and MuSK-IgG2 levels, and MuSK-IgG affinity may represent promising biomarkers of disease outcomes in MuSK-MG.

Gas6/TAM system as potential biomarker for multiple sclerosis prognosis.

Introduction: The protein growth arrest-specific 6 (Gas6) and its tyrosine kinase receptors Tyro-3, Axl, and Mer (TAM) are ubiquitous proteins involved in regulating inflammation and apoptotic body clearance. Multiple sclerosis (MS) is the most common inflammatory demyelinating disease of the central nervous system leading to progressive and irreversible disability if not diagnosed and treated promptly. Gas6 and TAM receptors have been associated with neuronal remyelination and stimulation of oligodendrocyte survival. However, few data are available regarding clinical correlation in MS patients. We aimed to evaluate soluble levels of these molecules in the cerebrospinal fluid (CSF) and serum at MS diagnosis and correlate them with short-term disease severity. Methods: In a prospective cohort study, we enrolled 64 patients with a diagnosis of clinical isolated syndrome (CIS), radiological isolated syndrome (RIS) and relapsing-remitting (RR) MS according to the McDonald 2017 Criteria. Before any treatment initiation, we sampled the serum and CSF, and collected clinical data: disease course, presence of gadolinium-enhancing lesions, and expanded disability status score (EDSS). At the last clinical follow-up, we assessed EDSS and calculated MS severity score (MSSS) and age-related MS severity (ARMSS). Gas6 and TAM receptors were determined using an ELISA kit (R&D Systems) and compared to neurofilament (NFLs) levels evaluated with SimplePlex™ fluorescence-based immunoassay. Results: At diagnosis, serum sAxl was higher in patients receiving none or low-efficacy disease-modifying treatments (DMTs) versus patients with high-efficacy DMTs (p = 0.04). Higher CSF Gas6 and serum sAXL were associated with an EDSS <3 at diagnosis (p = 0.04; p = 0.037). Serum Gas6 correlates to a lower MSSS (r2 = -0.32, p = 0.01). Serum and CSF NFLs were confirmed as disability biomarkers in our cohort according to EDSS (p = 0.005; p = 0.002) and MSSS (r2 = 0.27, p = 0.03; r2 = 0.39, p = 0.001). Results were corroborated using multivariate analysis. Conclusions: Our data suggest a protective role of Gas6 and its receptors in patients with MS and suitable severity disease biomarkers.

Serum GAS6, sAXL, IL-10, NO, and BCL-2 levels are decreased in patients with Behçet's disease.

PURPOSE: Behçet's disease (BD) is an autoimmune chronic systemic inflammatory disease characterized by a versatile clinical spectrum. Growth arrest specific protein 6 (GAS6)/soluble AXL (sAXL) signaling pathway draws attention in the resolution of inflammation, and its deficiency is associated with chronic inflammatory, autoimmune diseases, as well as clearance of apoptotic cells by phagocytes - efferocytosis. In this study, it was aimed to investigate whether GAS6/sAXL, interleukin (IL)-10, nitric oxide (NO), and BCL-2 levels were associated with inflammation and efferocytosis contributes to the pathogenesis of BD. METHODS: A total of 37 Behçet patients with ocular involvement and 30 healthy control subjects were included in this study. GAS6, sAXL, IL-10, NO, and BCL-2 levels were quantified using enzyme-linked immunosorbent assay (ELISA) method. RESULTS: Serum GAS6, sAXL, IL-10, NO, and BCL-2 levels were significantly lower in patients with BD compared to the controls (P < 0.005, P < 0.001, P < 0.001, P < 0.001, and P < 0.001, respectively). In correlation analysis, research parameters decreased in patients with BD was significantly correlated with each other: GAS6-IL-10 (r = 0.585, P < 0.001), GAS6-BCL-2 (r = 0.541, P < 0.001), sAXL-BCL-2 (r = 0.696, P < 0.001), IL-10-NO (r = 0.717, P < 0.001), IL-10-BCL-2 (r = 0.759, P < 0.001), and NO-BCL-2 (r = 0.541, P < 0.001). CONCLUSION: In conclusion, decreased serum BCL-2 level may be an indicator of increased apoptosis in these patients and decreased levels of GAS6/sAXL, IL-10, and NO may indicate insufficient clearance of apoptotic bodies released as a result of increased apoptosis in BD patients.

Serum AXL is a potential molecular marker for predicting COVID-19 progression.

Background: The severity, symptoms, and outcome of COVID-19 is thought to be closely linked to how the virus enters host cells. This process involves the key roles of angiotensin-converting enzyme 2 (ACE2) and the Tyrosine protein kinase receptor UFO (AXL) receptors. However, there is limited research on the circulating levels of ACE2 and AXL and their implications in COVID-19. Methods: A control group of 71 uninfected individuals was also included in the study. According to the Guidance for Corona Virus Disease 2019 (10th edition), a cohort of 358 COVID-19 patients were categorized into non-severe and severe cases. Serum ACE2/AXL levels in COVID-19 patients were detected by enzyme-linked immunosorbent assay (ELISA) at different time points post-COVID-19 infection, including days 0-7, 8-15, 31-179 and >180 days. Serum SARS-CoV-2 IgG/IgM antibodies in COVID-19 patients at the same intervals were assessed by using an iFlash 3000 Chemiluminescence Immunoassay Analyzer. The receiver operating characteristic (ROC) curves were used to assess the diagnostic value of the biological markers, and the association between laboratory parameters and illness progression were explored. Results: Compared with the uninfected group, the levels of ACE2 and AXL in the COVID-19 group were decreased, and the SARS-COV-2 IgG level was increased. AXL (AUC = 0.774) demonstrated a stronger predictive ability for COVID-19 than ACE2. In the first week after infection, only the level of AXL was statistically different between severe group and non-severe group. After first week, the levels of ACE2 and AXL were different in two groups. Moreover, in severe COVID-19 cases, the serum ACE2, AXL, and SARS-COV-2 IgM levels reached a peak during days 8-15 before declining, whereas serum SARS-COV-2 IgG levels continued to rise, reaching a peak at day 31-180 days before decreasing. In addition, the AXL level continued to decrease and the SARS-COV-2 IgG level continued to increase in the infected group after 180 days compared to the uninfected group. Conclusions: The levels of serum ACE2 and AXL correlate with COVID-19 severity. However, AXL can also provide early warning of clinical deterioration in the first week after infection. AXL appears to be a superior potential molecular marker for predicting COVID-19 progression.

Decreased soluble TGF-ß1, Tie-2, and angiopoietins serum levels in bone marrow after treating healthy donors with granulocyte colony-stimulating factor.

The goal of this study was to investigate the effect of granulocyte colony-stimulating factor (G-CSF) on Tie-2, angiopoietins, VEGF, and TGF-ß1 in bone marrow (BM) of healthy donors. Soluble Tie-2, angiopoietins, VEGF, and TGF-ß1 levels in the BM were determined via ELISA in 25 healthy donors before and after G-CSF treatment. The results showed that treating healthy donors with G-CSF significantly decrease serum levels of Tie-2, angiopoietin-1, angiopoietin-2, and TGF-ß1. In contrast, median VEGF level in the G-CSF-primed BM was significantly higher than steady-state BM. Our results suggest that decreased soluble TGF-ß1, Tie-2, and angiopoietins levels in the BM could be related to stem cell mobilization.

Up-regulated serum levels of TAM receptor tyrosine kinases in a group of Egyptian autistic children.

TAM receptor family belongs to receptor tyrosine kinases (TAMRTKs). It includes three receptors; Tyro-3, Axl and Mer. TAMRTKs has a great role in resolution of inflammation due to their role in clearance of apoptotic cells by macrophages. Dysregulated TAM signaling pathways are associated with many autoimmune diseases and chronic inflammatory disorders. Autism may be an autoimmune disease in some patients. This work was the first study that investigated serum levels of the soluble ectodomain shed TAMRTKs in a group of autistic children. Serum levels of TAMRTKs were measured by ELISA in 30 autistic children aged between 3.5 and 11 years and 30 age and sex-matched healthy control children. Serum levels of TAMRTKs were significantly higher in autistic children than healthy control children (P < 0.001). Patients with severe autism had significantly higher serum levels of TAMRTKs than patients with mild to moderate autism (P < 0.01). In addition, there were significant positive correlations between scores of the Childhood Autism Rating Scale (CARS) and serum levels of TAMRTKs in autistic patients, (P < 0.01). In conclusions, serum levels of TAMRTKs were up-regulated in autistic children with significant positive correlations with the degree of the disease severity. This initial report requires further studies to investigate the relationship between TAMRTKs and autism.

Increased serum AXL is associated with radiographic knee osteoarthritis severity.

OBJECTIVE: To investigate the expression and clinical significance of serum soluble AXL in patients with radiographic knee osteoarthritis (KOA). METHODS: There were 183 patients with KOA who were selected and divided based on the Kellgren-Lawrence (KL) score into KL 0 subgroups (n = 42), KL I-II subgroups (n = 90), and KL III-IV subgroups (n = 51). Healthy volunteers (n = 170) in our hospital were selected with matched age and gender as the control group. AXL level in serum was detected by enzyme-linked immunosorbent assay. The correlation between serum AXL with severity and clinical indicators of osteoarthritis was analyzed. RESULTS: The level of serum AXL was significantly higher in the osteoarthritis group than that in the control group (P < .05). In the osteoarthritis patients, serum AXL level was increased with the increase of KL score. Serum AXL level was positively correlated with age, body mass index, erythrocyte sedimentation rate, serum C-reactive protein, cartilage oligomeric protein, matrix metalloproteinase-13, and transforming growth factor-ß1 levels. The cut-off value for serum AXL was determined as 33.375 ng/mL by receiver operating curve analysis. CONCLUSION: The level of serum AXL in patients with osteoarthritis is significantly higher than in healthy controls, and is closely related to the severity of radiographic osteoarthritis.