Chemokine CXCL1 as a potential marker of disease activity in systemic lupus erythematosus

Regulation of cell-mediated immune responses in dairy bulls via long non-coding RNAs from submandibular lymph nodes, peripheral blood, and the spleen

Cell-mediated immune responses (CMIRs) are critical to building a robust immune system and reducing disease susceptibility in cattle. Long non-coding RNAs (lncRNAs) regulate various biological processes. However, to the best of our knowledge, the characterization and functions of lncRNAs and their regulations on the bovine CMIR have not been investigated comprehensively. In this study, experimental bulls were immunized with heat-killed preparation of Candida albicans (HKCA) to induce delayed-type hypersensitivity (DTH). Three bulls were classified as high- CMIR responders and three were low-CMIR responders, based on their classical DTH skin reactions. LncRNAs were identified in the submandibular lymph nodes, peripheral blood, and spleen of high- and low-CMIR animals using strand-specific RNA sequencing. A total of 21,003 putative lncRNAs were identified across tissues, and 420, 468, and 599 lncRNAs were differentially expressed between the two groups in the submandibular lymph node, peripheral blood, and spleen tissues, respectively. Functional analysis of the differentially expressed lncRNA (DElncRNA) target genes showed that a number of immune-related Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were enriched, including immune response, cell adhesion, nucleosome, DNA packaging, antigen processing and presentation, and complement and coagulation cascades. Tissue specificity analysis indicated that lncRNA transcripts have stronger tissue specificity than mRNA. Furthermore, an interaction network was constructed based on DElncRNAs and DEGs, and 11, 14, and 11 promising lncRNAs were identified as potential candidate genes influencing immune response regulation in submandibular lymph nodes, peripheral blood, and spleen tissues, respectively. These results provide a foundation for further research into the biological functions of lncRNAs associated with bovine CMIR and identify candidate lncRNA markers for cell-mediated immune responses.

The Influence of Physical Training on Breast Cancer: The Role of Exercise-Induced Myokines in Regulating Breast Cancer Cell Growth and Survival

The beneficial impact of physical training in lowering cancer risk is well known. However, the precise mechanisms linking physical training and cancer are not fully understood. Skeletal muscle releases various myokines that seem to possess a direct anti-tumor effect. Although breast cancer (BC) is the prevalent form of cancer among women on a global scale, only limited data are available about the secretion of myokines following exercise in patients with BC. To study the effects of exercise on BC, the blood samples of patients with varied stages of BC were analyzed after 12 weeks of resistance training with whole-body electromyostimulation (WB-EMS). Following the training period, we observed that resistance training helps these patients to improve their physical characteristics and performance function by increasing skeletal muscle mass and strengthening their hand grip. Notably, the patient's serum was found to inhibit the growth and promote the apoptosis of BC cells in vitro. Moreover, the conditioned medium collected from in vitro stimulated human myotubes using electric pulse stimulation (EPS), an in vitro simulation of WB-EMS training, induced the cell death of BC cells. These results highlighted the direct cancer-protective effects of activated skeletal muscle. In line with our observed effects of serum from exercise-trained pancreatic and prostate cancer patients, the growth of BC cells was notably inhibited when supplemented directly with recombinant myokines C-X-C motif ligand 1 (CXCL1), Interleukin 10 (IL10), and C-C motif chemokine ligand 4 (CCL4). Notably, treatment with these myokines also increased the expression of caspase 3/7 (Casp3/7), resulting in enhanced BC cell death. Our data strongly suggest that physical exercise has a positive impact on skeletal muscle mass and hand grip strength in BC patients, along with a significant anti-tumor effect in BC cells. This shows promising potential for considering sports and physical training as supportive therapies for achieving more impactful cancer treatment.

D1-like dopamine receptors promote B-cell differentiation in systemic lupus erythematosus

BACKGROUND

Systemic lupus erythematosus (SLE) is an autoimmune disease that currently cannot be completely cured with a great health burden. Since the production of autoantibodies plays a key role in the pathogenesis of SLE, discovering the underlying immunoregulation mechanism of B cells will be helpful for developing promising immunotherapy for SLE. In recent studies, dopamine receptors (DRDs), G protein-coupled receptors that include D1-like and D2-like subtypes, are expressed on B cells and participate in various physiological processes, involving immune responses. However, the regulatory effect of DRDs on B cells has not been determined.

METHODS

This study explored the expression of DRDs on B-cell subsets from SLE patients and healthy individuals. The effects of D1-like receptor on B-cell activation and differentiation were further explored using D1-like receptor agonists or antagonists. RNA-seq and bioinformatics analyses were used to identify specific molecular mechanisms involved.

RESULTS

The D1-like DRDs on B cells of SLE patients were highly expressed compared with those of healthy controls (HCs). D1-like receptor agonist treatment exacerbated lupus-like symptoms in pristane-induced lupus-like mice, while D1-like receptor antagonists alleviated the lupus-like phenotypes. Inhibition of D1-like receptor signals impeded B-cell differentiation, while activation of D1-like receptor signals could promote B cell differentiation. Further RNA-seq confirmed that PTGS2, a gene related to B-cell differentiation, was up-regulated once the D1-like receptor signals were activated, while BMP6 and IL-24 were up-regulated once the D1-like receptor signals were inhibited.

CONCLUSION

D1-like receptors probably promote B-cell differentiation through the PTGS2/PRDM1 pathway.

Osteogenic mechanism of deciduous teeth periodontal ligament stem cells in inflammatory environment

This study aimed to illustrate the biological behavior and changes in cell function during the progression of apical periodontitis in deciduous teeth and to explore the underlying molecular mechanism. Deciduous teeth periodontal ligament stem cells (DePDLSCs) were derived and their identity was confirmed. The viability, inflammation, and osteogenic ability of cells were tested by exposing them to various concentrations of lipopolysaccharide (LPS) (0-100 μg/mL) using the cell counting kit-8 (CCK-8) assay, reverse transcription polymerase chain reaction (real-time PCR), alkaline phosphatase (ALP) staining, and ALP activity assay. In addition, osteogenic-induced cells with and without 10 μg/mL LPS were harvested for high-throughput sequencing. Based on sequencing data, proinflammatory factors and ALP expression were measured after interference with the PI3K-AKT signaling pathway activator, 740Y-P. LPS biphasically affected the proliferation and osteogenesis of DePDLSCs. Low concentrations of LPS showed stimulatory effects, whereas inhibitory effects were observed at high concentrations. Sequencing analysis showed that the PI3K-AKT signaling pathway was significantly downregulated when DePDLSCs were treated with 10 μg/mL LPS. The LPS-induced inflammation and osteogenesis inhibition of DePDLSCs were partially rescued by 740Y-P treatment. In conclusion, LPS affected DePDLSCs proliferation and osteogenesis in a biphasic manner. Moderate activation of PI3K-AKT signaling pathway was beneficial for osteogenic differentiation and anti-inflammatory effect in DePDLSCs. This research may provide etiological probes for apical periodontitis and its treatment.

Immune-Mediated Inflammatory Diseases and Cancer - a dangerous liaison

Patients with Immune-Mediated Inflammatory Diseases (IMIDs) are known to have an elevated risk of developing cancer, but the exact causative factors remain subject to ongoing debate. This narrative review aims to present the available evidence concerning the intricate relationship between these two conditions. Environmental influences and genetic predisposition lead to a dysregulated immune response resulting in chronic inflammation, which is crucial in the pathogenesis of IMIDs and oncogenic processes. Mechanisms such as the inflammatory microenvironment, aberrant intercellular communication due to abnormal cytokine levels, excessive reparative responses, and pathological angiogenesis are involved. The chronic immunosuppression resulting from IMIDs treatments further adds to the complexity of the pathogenic scenario. In conclusion, this review highlights critical gaps in the current literature, suggesting potential avenues for future research. The intricate interplay between IMIDs and cancer necessitates more investigation to deepen our understanding and improve patient management.

Genetic insights into the association between serum cytokines and frozen shoulder risk: A bidirectional mendelian randomization study

BACKGROUND

Although existing studies have indicated a connection between chronic low-grade inflammation and the onset of frozen shoulder (FS), the precise causal relationship between distinct circulating inflammatory factors and FS has yet to be thoroughly evaluated. In this study, we employed a bidirectional two-sample Mendelian randomization (MR) analysis to investigate the potential causal relationship between systemic cytokines and FS.

METHODS

A genome-wide association dataset comprising 41 serum cytokines from 8,293 individuals of Finnish descent was utilized, along with FS data from the UK Biobank included 10,104 FS cases and 451,099 controls. The primary MR method was the inverse variance weighted approach, and four additional MR techniques (MR-Egger, weighted median, simple mode, and weighted mode) were also employed to support and validate the findings. Heterogeneity and horizontal pleiotropy assessments were assessed using Cochrane's Q and MR-Egger intercept tests. Moreover, a series of sensitivity analyses were conducted to strengthen the accuracy and credibility of these findings.

RESULTS

Based on the IVW method, genetically predicted increasing levels of growth regulated oncogene alpha (GROa) (OR=1.08, 95 % CI 1.02-1.13, P=0.005), interferon gamma-induced protein 10 (IP-10) (OR=1.09, 95 % CI 1.02-1.17, P=0.010), regulated on activation, C-C Motif Chemokine Ligand 5 (CCL5) (OR=1.11, 95 % CI 1.03-1.20, P=0.007) were suggestively associated with an increased risk of FS. Reverse MR analysis revealed no significant causal effect of FS on the 41 systemic inflammatory factors. No heterogeneity or horizontal pleiotropy was observed in our analysis.

CONCLUSION

This study established a causal association between 41 systemic inflammatory factors and FS, indicating that elevated levels of GROa, IP-10 and CCL5 were associated with a higher risk of FS. Further research is warranted to explore the potential of these biomarkers as early predictors and therapeutic targets for FS.

Increased Urine Excretion of Neutrophil Granule Cargo in Active Proliferative Lupus Nephritis

Key Points

Neutrophil degranulation participates in glomerular injury in proliferative lupus nephritis. Urine excretion of neutrophil granule proteins is a potential diagnostic for proliferative lupus nephritis.

Background

Lupus nephritis (LN) occurs in more than half of patients with systemic lupus erythematosus, but the cellular and molecular events that contribute to LN are not clearly defined. We reported previously that neutrophil degranulation participates in glomerular injury in mouse models of acute LN. This study tests the hypothesis that glomerular recruitment and subsequent activation of neutrophils result in urine excretion of neutrophil granule constituents that are predictive of glomerular inflammation in proliferative LN.

Methods

Urine and serum levels of 11 neutrophil granule proteins were measured by antibody-based array in patients with proliferative LN and healthy donors (HDs), and the results were confirmed by ELISA. Glomerular neutrophil accumulation was assessed in biopsies of patients with LN who contributed urine for granule cargo quantitation and normal kidney tissue by microscopy. Degranulation was measured by flow cytometry in neutrophils isolated from patients with LN and HD controls by cell surface granule markers CD63 (azurophilic), CC66b (specific), and CD35 (secretory). Nonparametric statistical analyses were performed and corrected for multiple comparisons.

Results

Eight granule proteins (myeloperoxidase, neutrophil elastase, azurocidin, olfactomedin-4, lactoferrin, alpha-1-acid glycoprotein 1, matrix metalloproteinase 9, and cathelicidin) were significantly elevated in urine from patients with active proliferative LN by array and/or ELISA, whereas only neutrophil elastase was increased in LN serum. Urine excretion of alpha-1-acid glycoprotein 1 declined in patients who achieved remission. The majority of LN glomeruli contained ≥3 neutrophils. Basal levels of specific granule markers were increased in neutrophils from patients with LN compared with HD controls. Serum from patients with active LN stimulated specific and secretory, but not azurophilic granule, release by HD neutrophils.

Conclusions

Circulating neutrophils in patients with LN are primed for enhanced degranulation. Glomerular recruitment of those primed neutrophils leads to release and urine excretion of neutrophil granule cargo that serves as a urine marker of active glomerular inflammation in proliferative LN.

Chemokine expression in sera of patients with microscopic polyangiitis and granulomatosis with polyangiitis

We evaluated chemokine expression and its correlation with disease activity in patients with microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA) (MPA/GPA). Serum CCL2, CCL4, CCL19, CXCL1, CXCL2, and CX3CL1 level in 80 patients were analysed using multiple enzyme-linked immunosorbent assays. Correlations between variables were investigated using Pearson's correlation analysis, and receiver operator curve analysis was performed to identify optimal CX3CL1 values in determining active disease. Multivariate logistic regression analysis was done to evaluate predictors of active disease. CCL4 (r = 0.251, p = 0.025), CXCL1 (r = 0.270, p = 0.015), and CX3CL1 (r = 0.295, p = 0.008) significantly correlated with BVAS, while CX3CL1 was associated with five-factor score (r =  - 0.290, p = 0.009). Correlations were revealed between CCL2 and CCL4 (r = 0.267, p = 0.017), CCL4 and CXCL1 (r = 0.368, p < 0.001), CCL4 and CXCL2 (r = 0.436, p < 0.001), and CXCL1 and CXCL2 (r = 0.518, p < 0.001). Multivariate analysis revealed serum CX3CL1 levels > 2408.92 pg/mL could predict active disease (odds ratio, 27.401, p < 0.001). Serum chemokine levels of CCL4, CXCL1, and CX3CL1 showed association with disease activity and especially, CX3CL1 > 2408.92 pg/mL showed potential in predicting active MPA/GPA.

A cell-adapted SARS-CoV-2 mutant, showing a deletion in the spike protein spanning the furin cleavage site, has reduced virulence at the lung level in K18-hACE2 mice

Here we investigated the virulence properties of a unique cell-adapted SARS-CoV-2 mutant showing a ten-amino acid deletion encompassing the furin cleavage site of the spike protein (Δ680SPRAARSVAS689; Δ680-689-B.1) in comparison to its parental strain (wt-B.1) and two Delta variants (AY.122 and AY.21) of concern. After intranasal inoculation, transgenic K18-hACE2 mice were monitored for 14 days for weight change, lethality, and clinical score; oral swabs were daily collected and tested for the presence of N protein subgenomic RNA. At 3 and 7 dpi mice were also sacrificed and organs collected for molecular, histopathological, and immune response profile investigations. The Δ680-689-B.1-infected mice exhibited reduced shedding, lower virulence at the lung level, and milder pulmonary lesions. In the lung, infection with Δ680-689-B.1 was associated with a significant lower expression of some cytokines at 3 dpi (IL-4, IL-27, and IL-28) and 7 dpi (IL-4, IL-27, IL-28, IFN-γ and IL-1α).

Tlr5 deficiency exacerbates lupus-like disease in the MRL/lpr mouse model

Introduction

Leaky gut has been linked to autoimmune disorders including lupus. We previously reported upregulation of anti-flagellin antibodies in the blood of lupus patients and lupus-prone mice, which led to our hypothesis that a leaky gut drives lupus through bacterial flagellin-mediated activation of toll-like receptor 5 (TLR5).

Methods

We created MRL/lpr mice with global Tlr5 deletion through CRISPR/Cas9 and investigated lupus-like disease in these mice.

Result

Contrary to our hypothesis that the deletion of Tlr5 would attenuate lupus, our results showed exacerbation of lupus with Tlr5 deficiency in female MRL/lpr mice. Remarkably higher levels of proteinuria were observed in Tlr5 -/- MRL/lpr mice suggesting aggravated glomerulonephritis. Histopathological analysis confirmed this result, and Tlr5 deletion significantly increased the deposition of IgG and complement C3 in the glomeruli. In addition, Tlr5 deficiency significantly increased renal infiltration of Th17 and activated cDC1 cells. Splenomegaly and lymphadenopathy were also aggravated in Tlr5-/- MRL/lpr mice suggesting impact on lymphoproliferation. In the spleen, significant decreased frequencies of regulatory lymphocytes and increased germinal centers were observed with Tlr5 deletion. Notably, Tlr5 deficiency did not change host metabolism or the existing leaky gut; however, it significantly reshaped the fecal microbiota.

Conclusion

Global deletion of Tlr5 exacerbates lupus-like disease in MRL/lpr mice. Future studies will elucidate the underlying mechanisms by which Tlr5 deficiency modulates host-microbiota interactions to exacerbate lupus.

Cytokine fluctuation during acute stress is correlated to life trauma

BACKGROUND

Multiple studies have demonstrated that human neurobiology and behavior are inextricably linked to the activity of our immune systems. Trauma is associated with a multitude of immune system changes; reflecting this, posttraumatic stress disorder (PTSD) is often comorbid with immune-related conditions such as autoimmune disorders. To further investigate this phenomenon, we tested our hypothesis that cytokine fluctuations during and after an acute stress response correlates with experienced life trauma.

METHODS

Using a prospective observational approach, this cohort study measured biomarker profiles in firefighter participants (n = 63), with 9 participants having prior PTSD diagnoses and 54 without prior PTSD diagnoses. In addition, life trauma scores were determined from all participants using the Life Events Checklist 5 (LEC-5) survey. Baseline salivary biomarker concentrations were determined, along with levels immediately before, immediately after, and 1 hour following a standardized stressful training event. Biomarkers measured using these salivary samples included 42 cytokines and 6 steroid and thyroid hormones. The concentrations of these markers were then correlated, using Pearson correlation coefficients, with the participants' LEC-5 scores. t Tests were also performed to compare cytokine values between the populations with and without prior PTSD diagnosis.

RESULTS

Included in the cytokine panel were interleukin (IL)-8, IL-10, IL-1B, GCSF, IL1-Ra, Groα, IFNa2, PDGFAA, and VEGF, all of which demonstrated positive correlation at various time points in individuals with increased severity of LEC-5 scores (and thus increased experienced life trauma). Concentrations of Groα, PDGFAA, IL1-Ra, IL-1a, Mip1a, IL-1a, IL-6, Mip1b, TNFα, and TGFα were also found to be significantly altered at various time points in participants with prior PTSD diagnoses, demonstrating some overlap with the LEC-5 Pearson correlations.

CONCLUSION

The results support our hypothesis and demonstrate that LEC-5 scores are indeed significantly correlated to cytokine concentrations and fluctuations surrounding a stress test.

LEVEL OF EVIDENCE

Diagnostic Tests or Criteria; Level IV.

FKN secreted by kidney epithelial cells regulates macrophage activation in lupus nephritis via the Hippo signaling pathway

BACKGROUND

Lupus nephritis (LN) is a serious complication of systemic lupus erythematosus (SLE), and its pathogenesis is not fully understood. Previously, we showed that fractalkine (FKN) expression was positively correlated with the severity of LN. Here, we aimed to study the role of the Hippo signaling pathway (HSP) and its interaction with FKN in LN in an attempt to provide novel strategies for LN treatment.

METHODS

In this study, lipopolysaccharide (LPS)/interferon-γ (IFN-γ)-stimulated THP-1 cells were co-cultured with FKN up-regulated or down-regulated kidney epithelial cells Hkb20. FKN-knockout (KO-FKN) mice were used to construct LN model. Flow cytometric analysis, quantitative real-time polymerase chain reaction (qRT-PCR), enzyme-linked immunosorbent assay (ELISA), pathological staining, Western blot, and immunofluorescence (IF) staining were employed to investigate the role of FKN and its interaction with the Hippo signaling pathway (HSP) in LN.

RESULTS

Up-regulation of FKN in kidney epithelial cells was associated with increased macrophage activation. FKN overexpression in kidney epithelial cells suppressed apoptosis, inflammation levels, and M1 polarization of THP-1 cells and inhibited the HSP. Oppositely, FKN knockdown in kidney epithelial cells increased apoptosis, inflammation, and M1 polarization and activated the HSP. HSP inhibitor reversed the effect of FKN knockdown on THP-1 cells. In LN mice, FKN knockout and YAP inhibitor decreased the levels of renal function markers, alleviated kidney injury induced by LN, and inhibited macrophage activation in LN mice.

CONCLUSIONS

FKN down-regulation reduced the activation of macrophages in renal tissue and alleviated kidney damage by activating HSP. The regulatory effect of FKN on HSP should be confirmed in patients with LN, and the mechanism of FKN in LN should be further explored.

Assessment of anti-nucleosome antibody (ANuA) isotypes for the diagnosis and prediction of systemic lupus erythematosus and lupus nephritis activity

Our study aims to investigate the serum levels of anti-nucleosome antibody (ANuA) isotypes in patients with systemic lupus erythematosus (SLE) and clarify ANuA isotypes that may diagnose and predict SLE. We detected anti-nucleosome antibodies (ANuA) in the serum from 120 patients with SLE, 99 patients suffering from other autoimmune diseases (OAD), and 50 healthy controls by performing IgG-, IgA-, and IgM-specific ELISAs. The serum levels of total anti-nuclear antibodies (ANA IgG), ANuA IgG subclasses (IgG1, IgG2, IgG3, and IgG4), anti-dsDNA antibodies, and the avidities of ANA IgG were also analysed using ELISAs. The levels of three ANuA isotypes (IgG, IgA, and IgM) were significantly higher in patients with SLE than in patients with OAD and healthy controls (p < 0.05). Moreover, the concentrations of ANuA isotypes increased in the active SLE and lupus nephritis (LN) groups and in patients with SLE presenting high-avidity IgG ANA (p < 0.05). Furthermore, ANuA isotype levels decreased significantly with drug therapy, while anti-dsDNA IgG levels decreased with the same trend. Additionally, ANuA isotypes were positively related to the SLEDAI (SLE Disease Activity Index) score, RAI (relative avidity index) of high-avidity IgG ANAs, and serum anti-dsDNA IgG levels. Last, the sensitivity and specificity values for SLE were 83.33 and 96.67% for ANuA IgG, 85.83 and 93.33% for ANuA IgA, and83.33 and 86.67% for ANuA IgM, respectively. The sensitivity and specificity values for LN were 61.67 and 96.67% for ANuA IgG, 49.17 and 96.67% for ANuA IgA, and 52.50 and 96.67% for ANuA IgM, respectively. In conclusion, we evaluated whether ANuA isotypes represent a diagnostic tool to predict SLE activity and define subsets of patients with LN.

Multiplex analysis of cytokines and chemokines in persons aging with or without HIV

People with HIV (PWH) on combined antiretroviral therapy (cART) are living longer lives due to modern cART advances and increased routine medical care. The full landscape of aging with HIV is unclear; given that HIV emerged relatively recently in human history and initially had a high mortality rate, there has not been a substantially aged population to evaluate. In the present study, we set out to perform high throughput plasma analyte profiling by multiplex analysis, focusing on various T helper (Th)-related cytokines, chemokines, and pro- and anti-inflammatory cytokines. The primary goals being to provide reference ranges of these analytes for aging PWH cohorts, as well as testing the utility of high throughput multiplex plasma assays. The cohort used in this study was comprised of age-matched healthy donors (aged 32.6-73.5), PWH on cART (aged 26.7-60.2), and viremic PWH (aged 27.5-59.4). The patients in each group were then stratified across the age span to examine age-related impacts of these plasma biomarkers. Our results largely indicate feasibility of plasma analyte monitoring by multiplex and demonstrate a high degree of person-to-person variability regardless of age and HIV status. Nonetheless, we find multiple associations with age, duration of known infection, and viral load, all of which appear to be driven by either prolonged HIV disease progression or long-term use of cART.

Serum C-X-C Chemokine Ligand 1 Levels in Patients with Systemic Sclerosis: Relationship of Clinical and Laboratory Observations to Anti-CD20 Monoclonal Antibody Administration

Objectives: To determine whether C-X-C chemokine ligand 1 (CXCL1), which is a potent neutrophil chemoattractant and activator that plays important role in inflammation, is elevated in patients with systemic sclerosis (SSc) and whether it is associated with the clinical features and disease activity of patients with SSc. In addition, to determine whether the changes in serum CXCL1 levels before and after treatment correlate with changes in disease activity in SSc patients who received an anti-CD20 monoclonal antibody drug. Patients and method: We examined patient serum collected in the DesiReS trial, which was a double-blind, parallel-group, randomized, placebo-controlled, multicenter, phase II clinical trial. In the trial, patients were randomly allocated to the drug or placebo group and received 375 mg/m2 of an anti-CD20 antibody, rituximab, or placebo once a week for four weeks. We obtained serum samples from 47 patients administered at our hospital, including 3 males and 44 females, the median age of 48 years, range 27−71 years, with 42 diffuse cutaneous SSc and 5 with limited cutaneous SSc. Serum CXCL1 levels were measured using multiplex immunoassay in patient serum before and 24 weeks after administration and also in serum from 33 healthy controls. Results: Serum CXCL1 levels were significantly higher in SSc patients (mean 25.70 ng/mL; 95% confidence interval (CI) 18.35−33.05 ng/mL) than in the healthy controls (15.61 ng/mL; 95% CI 9.73−21.51 ng/mL). In addition, SSc patients with elevated CXCL1 levels had a significantly higher percentage of area occupied with interstitial shadows (p < 0.05), increased serum levels of surfactant protein (SP)-A (p < 0.05), SP-D (p < 0.05), Krebs von den Lungen-6 (p < 0.01), and C-reactive protein (p < 0.05) compared to those with normal levels. Furthermore, defining Δ as the value after rituximab administration minus the value before rituximab administration, baseline serum CXCL1 levels correlated with Δ percent predicted diffusing capacity for carbon monoxide (p < 0.01). In addition, ΔCXCL1 correlated with ΔSP-A (p < 0.05). Similarly, serum CXCL1 levels after rituximab administration correlated with percent predicted forced vital capacity (p < 0.05) and serum SP-D levels (p < 0.05) after rituximab. Conclusions: Our results suggest that serum CXCL1 is associated with the disease activity of SSc-ILD, and high serum CXCL1 levels are one of the predictors of improvement in SSc-ILD with rituximab.