Novel susceptibility loci for steroid-associated osteonecrosis of the femoral head in systemic lupus erythematosus.

Osteonecrosis of the femoral head (ONFH) involves necrosis of bone and bone marrow of the femoral head caused by ischemia with unknown etiology. Previous genetic studies on ONFH failed to produce consistent results, presumably because ONFH has various causes with different genetic backgrounds and the underlying diseases confounded the associations. Steroid-associated ONFH (S-ONFH) accounts for one-half of all ONFH, and systemic lupus erythematosus (SLE) is a representative disease underlying S-ONFH. We performed a genome-wide association study (GWAS) to identify genetic risk factors for S-ONFH in patients with SLE. We conducted a two-staged GWAS on 636 SLE patients with S-ONFH and 95 588 non-SLE controls. Among the novel loci identified, we determined S-ONFH-specific loci by comparing allele frequencies between SLE patients without S-ONFH and non-SLE controls. We also used Korean datasets comprising 148 S-ONFH cases and 37 015 controls to assess overall significance. We evaluated the functional annotations of significant variants by in silico analyses. The Japanese GWAS identified 4 significant loci together with 12 known SLE susceptibility loci. The four significant variants showed comparable effect sizes on S-ONFH compared with SLE controls and non-SLE controls. Three of the four loci, MIR4293/MIR1265 [odds ratio (OR) = 1.99, P-value = 1.1 × 10-9)], TRIM49/NAALAD2 (OR = 1.65, P-value = 4.8 × 10-8) and MYO16 (OR = 3.91, P-value = 4.9 × 10-10), showed significant associations in the meta-analysis with Korean datasets. Bioinformatics analyses identified MIR4293, NAALAD2 and MYO16 as candidate causal genes. MIR4293 regulates a PPARG-related adipogenesis pathway relevant to S-ONFH. We identified three novel susceptibility loci for S-ONFH in SLE.

Curvature-sensing peptide inhibits tumour-derived exosomes for enhanced cancer immunotherapy.

Tumour-derived exosomes (T-EXOs) impede immune checkpoint blockade therapies, motivating pharmacological efforts to inhibit them. Inspired by how antiviral curvature-sensing peptides disrupt membrane-enveloped virus particles in the exosome size range, we devised a broadly useful strategy that repurposes an engineered antiviral peptide to disrupt membrane-enveloped T-EXOs for synergistic cancer immunotherapy. The membrane-targeting peptide inhibits T-EXOs from various cancer types and exhibits pH-enhanced membrane disruption relevant to the tumour microenvironment. The combination of T-EXO-disrupting peptide and programmed cell death protein-1 antibody-based immune checkpoint blockade therapy improves treatment outcomes in tumour-bearing mice. Peptide-mediated disruption of T-EXOs not only reduces levels of circulating exosomal programmed death-ligand 1, but also restores CD8+ T cell effector function, prevents premetastatic niche formation and reshapes the tumour microenvironment in vivo. Our findings demonstrate that peptide-induced T-EXO depletion can enhance cancer immunotherapy and support the potential of peptide engineering for exosome-targeting applications.

Possible role of ß-hydroxybutyrate in inducing inflammation in alopecia areata.

Alopecia areata (AA) is an autoimmune inflammatory disease characterized by non-scarring hair loss due to an immune response that targets hair follicles. The current treatment approach for AA involves the use of immunosuppressants and immunomodulators to reduce cytokine levels around affected hair follicles. Sodium-glucose cotransporter 2 (SGLT2) inhibitors have emerged as potential anti-inflammatory agents with diverse beneficial effects in various medical conditions. This study investigates the role of beta-hydroxybutyrate (BHB), a ketone body produced during SGLT2 inhibition, in the pathogenesis of AA. Serum BHB levels were found to be significantly elevated in patients with AA compared with healthy controls, with higher levels correlating with severity of hair loss. BHB treatment increased inflammatory cytokine production in outer root sheath (ORS) cells, mimicking the inflammatory conditions seen in AA. The results suggest that elevated BHB levels may exacerbate the inflammatory immune response in AA patients and may be associated with chronic hair loss and resistance to treatment. Serum BHB levels may serve as a potential marker of poor prognosis in patients with severe AA. Further research is needed to elucidate the precise role of BHB in the pathogenesis of AA and its implications for disease management.

The crosstalk between PTEN-induced kinase 1-mediated mitophagy and the inflammasome in the pathogenesis of alopecia areata.

Alopecia areata (AA) is a T-cell-mediated autoimmune disease that causes chronic, relapsing hair loss; however, its precise pathogenesis remains to be elucidated. Recent studies have provided compelling evidence of crosstalk between inflammasomes and mitophagy-a process that contributes to the removal of damaged mitochondria. Our previous studies showed that the NLR family pyrin domain containing 3 (NLRP3) inflammasome is important for eliciting and progressing inflammation in AA. In this study, we detected mitochondrial DNA damage in AA-affected scalp tissues and IFNγ and poly(I:C) treated outer root sheath (ORS) cells. In addition, IFNγ and poly(I:C) treatment increased mitochondrial reactive oxygen species (ROS) levels in ORS cells. Moreover, we showed that mitophagy induction alleviates IFNγ and poly(I:C)-induced NLRP3 inflammasome activation in ORS cells. Lastly, PTEN-induced kinase 1 (PINK1) knockdown increased NLRP3 inflammasome activation, indicating that PINK1-mediated mitophagy plays a critical role in NLRP3 inflammasome activation in ORS cells. This study supports previous studies showing that oxidative stress disrupts immune privilege status and promotes autoimmunity in AA. The results emphasize the significance of crosstalk between mitophagy and inflammasomes in the pathogenesis of AA. Finally, mitophagy factors regulating mitochondrial dysfunction and inhibiting inflammasome activation could be novel therapeutic targets for AA.

Efficacy and safety of topical corticosteroid treatment under occlusion for severe alopecia areata in children: a single-centre retrospective analysis.

BACKGROUND: Alopecia areata (AA) has a poor clinical course in children. There are no reliable therapeutic options for children with severe AA, including alopecia totalis (AT) and alopecia universalis (AU). OBJECTIVES: We evaluated the efficacy and adverse effects of a potent topical corticosteroid (TCS) under occlusion in paediatric patients with severe AA. METHODS: We reviewed records of 23 patients under the age of 10 years with AT or AU treated with a potent TCS (0.05% clobetasol propionate or 0.3% diflucortolone valerate) for 8 h under occlusion with a plastic film. We used the Severity of Alopecia Tool (SALT) to measure clinical improvement. The primary endpoint was a SALT score of ≤ 20 at 6 months. We analysed the change in cortisol levels to identify the long-term safety of TCS therapy on the hypothalamus-pituitary-adrenal axis. RESULTS: Nineteen of the 23 patients (83%) reached SALT ≤ 20 at 6 months. Six patients relapsed over the 6-month follow-up period. Four patients were suspected of having adrenal insufficiency. However, the cortisol levels of the patients recovered to normal within 1 month of lowering the TCS potency or changing to nonsteroidal treatments. Limitations include the retrospective design and small sample size. CONCLUSIONS: This study shows that a potent TCS occlusion may be a safe treatment option in paediatric patients with severe AA. Further long-term studies are required to evaluate the safety and recurrence of TCS occlusion therapy for paediatric AA.

A preliminary study about the potential risks of the UV-weathered microplastic: The proteome-level changes in the brain in response to polystyrene derived weathered microplastics.

The growing use of plastic materials has resulted in a constant increase in the risk associated with microplastics (MPs). Ultra-violet (UV) light and wind break down modify MPs in the environment into smaller particles known as weathered MPs (WMPs) and these processes increase the risk of MP toxicity. The neurotoxicity of weathered polystyrene-MPs remains unclear. Therefore, it is important to understand the risks posed by WMPs. We evaluated the chemical changes of WMPs generated under laboratory-synchronized environmentally mimetic conditions and compared them with virgin MPs (VMPs). We found that WMP had a rough surface, slight yellow color, reduced molecular weight, and structural alteration compared with those of VMP. Next, 2 µg of ∼100 µm in size of WMP and VMP were orally administered once a day for one week to C57BL/6 male mice. Proteomic analysis revealed that the WMP group had significantly increased activation of immune and neurodegeneration-related pathways compared with that of the VMP group. Consistently, in in vitro experiments, the human brain-derived microglial cell line (HMC-3) also exhibited a more severe inflammatory response to WMP than to VMP. These results show that WMP is a more profound inflammatory factor than VMP. In summary, our findings demonstrate the toxicity of WMPs and provide theoretical insights into their potential risks to biological systems and even humans in the ecosystem.

Mechanistic Investigation of WWOX Function in NF-kB-Induced Skin Inflammation in Psoriasis.

Psoriasis is a chronic inflammatory skin disease characterized by epidermal hyperproliferation, aberrant differentiation of keratinocytes, and dysregulated immune responses. WW domain-containing oxidoreductase (WWOX) is a non-classical tumor suppressor gene that regulates multiple cellular processes, including proliferation, apoptosis, and migration. This study aimed to explore the possible role of WWOX in the pathogenesis of psoriasis. Immunohistochemical analysis showed that the expression of WWOX was increased in epidermal keratinocytes of both human psoriatic lesions and imiquimod-induced mice psoriatic model. Immortalized human epidermal keratinocytes were transduced with a recombinant adenovirus expressing microRNA specific for WWOX to downregulate its expression. Inflammatory responses were detected using Western blotting, real-time quantitative reverse transcription polymerase chain reaction (PCR), and enzyme-linked immunosorbent assay. In human epidermal keratinocytes, WWOX knockdown reduced nuclear factor-kappa B signaling and levels of proinflammatory cytokines induced by polyinosinic: polycytidylic acid [(poly(I:C)] in vitro. Furthermore, calcium chelator and protein kinase C (PKC) inhibitors significantly reduced poly(I:C)-induced inflammatory reactions. WWOX plays a role in the inflammatory reaction of epidermal keratinocytes by regulating calcium and PKC signaling. Targeting WWOX could be a novel therapeutic approach for psoriasis in the future.

Biological insights into systemic lupus erythematosus through an immune cell-specific transcriptome-wide association study.

OBJECTIVE: Genome-wide association studies (GWAS) have identified >100 risk loci for systemic lupus erythematosus (SLE), but the disease genes at most loci remain unclear, hampering translation of these genetic discoveries. We aimed to prioritise genes underlying the 110 SLE loci that were identified in the latest East Asian GWAS meta-analysis. METHODS: We built gene expression predictive models in blood B cells, CD4+ and CD8+ T cells, monocytes, natural killer cells and peripheral blood cells of 105 Japanese individuals. We performed a transcriptome-wide association study (TWAS) using data from the latest genome-wide association meta-analysis of 208 370 East Asians and searched for candidate genes using TWAS and three data-driven computational approaches. RESULTS: TWAS identified 171 genes for SLE (p<1.0×10-5); 114 (66.7%) showed significance only in a single cell type; 127 (74.3%) were in SLE GWAS loci. TWAS identified a strong association between CD83 and SLE (p<7.7×10-8). Meta-analysis of genetic associations in the existing 208 370 East Asian and additional 1498 cases and 3330 controls found a novel single-variant association at rs72836542 (OR=1.11, p=4.5×10-9) around CD83. For the 110 SLE loci, we identified 276 gene candidates, including 104 genes at recently-identified SLE novel loci. We demonstrated in vitro that putative causal variant rs61759532 exhibited an allele-specific regulatory effect on ACAP1, and that presence of the SLE risk allele decreased ACAP1 expression. CONCLUSIONS: Cell-level TWAS in six types of immune cells complemented SLE gene discovery and guided the identification of novel genetic associations. The gene findings shed biological insights into SLE genetic associations.

Meta-analysis of 208370 East Asians identifies 113 susceptibility loci for systemic lupus erythematosus.

OBJECTIVE: Systemic lupus erythematosus (SLE), an autoimmune disorder, has been associated with nearly 100 susceptibility loci. Nevertheless, these loci only partially explain SLE heritability and their putative causal variants are rarely prioritised, which make challenging to elucidate disease biology. To detect new SLE loci and causal variants, we performed the largest genome-wide meta-analysis for SLE in East Asian populations. METHODS: We newly genotyped 10 029 SLE cases and 180 167 controls and subsequently meta-analysed them jointly with 3348 SLE cases and 14 826 controls from published studies in East Asians. We further applied a Bayesian statistical approach to localise the putative causal variants for SLE associations. RESULTS: We identified 113 genetic regions including 46 novel loci at genome-wide significance (p<5×10-8). Conditional analysis detected 233 association signals within these loci, which suggest widespread allelic heterogeneity. We detected genome-wide associations at six new missense variants. Bayesian statistical fine-mapping analysis prioritised the putative causal variants to a small set of variants (95% credible set size ≤10) for 28 association signals. We identified 110 putative causal variants with posterior probabilities ≥0.1 for 57 SLE loci, among which we prioritised 10 most likely putative causal variants (posterior probability ≥0.8). Linkage disequilibrium score regression detected genetic correlations for SLE with albumin/globulin ratio (rg=-0.242) and non-albumin protein (rg=0.238). CONCLUSION: This study reiterates the power of large-scale genome-wide meta-analysis for novel genetic discovery. These findings shed light on genetic and biological understandings of SLE.

Adverse Events in Healthcare Workers after the First Dose of ChAdOx1 nCoV-19 or BNT162b2 mRNA COVID-19 Vaccination: a Single Center Experience.

Coronavirus disease 2019 vaccinations for healthcare workers (HCWs) have begun in South Korea. To investigate adverse events (AEs) of the first dose of each vaccine, any symptom was collected daily for seven days after vaccination in a tertiary hospital. We found that 1,301 of 1,403 ChAdOx1 nCoV-19 recipients and 38 of 80 BNT162b2 recipients reported AEs respectively (90.9% vs. 52.5%): injection-site pain (77.7% vs. 51.2%), myalgia (60.5% vs. 11.2%), fatigue (50.7% vs. 7.5%), headache (47.4% vs. 7.5%), and fever (36.1% vs. 5%; P < 0.001 for all). Young HCWs reported more AEs with ChAdOx1 nCoV-19 than with BNT162b2. No incidences of anaphylaxis were observed. Only one serious AE required hospitalization for serious vomiting, and completely recovered. In conclusion, reported AEs were more common in recipients with ChAdOx1 nCoV-19 than in those with BNT162b2. However, most of the reported AEs were mild to moderate in severity. Sufficient explanation and preparation for expected AEs required to promote widespread vaccination.

Genome-wide association study in a Korean population identifies six novel susceptibility loci for rheumatoid arthritis.

OBJECTIVE: Genome-wide association studies (GWAS) in rheumatoid arthritis (RA) have discovered over 100 RA loci, explaining patient-relevant RA pathogenesis but showing a large fraction of missing heritability. As a continuous effort, we conducted GWAS in a large Korean RA case-control population. METHODS: We newly generated genome-wide variant data in two independent Korean cohorts comprising 4068 RA cases and 36 487 controls, followed by a whole-genome imputation and a meta-analysis of the disease association results in the two cohorts. By integrating publicly available omics data with the GWAS results, a series of bioinformatic analyses were conducted to prioritise the RA-risk genes in RA loci and to dissect biological mechanisms underlying disease associations. RESULTS: We identified six new RA-risk loci (SLAMF6, CXCL13, SWAP70, NFKBIA, ZFP36L1 and LINC00158) with pmeta<5×10-8 and consistent disease effect sizes in the two cohorts. A total of 122 genes were prioritised from the 6 novel and 13 replicated RA loci based on physical distance, regulatory variants and chromatin interaction. Bioinformatics analyses highlighted potentially RA-relevant tissues (including immune tissues, lung and small intestine) with tissue-specific expression of RA-associated genes and suggested the immune-related gene sets (such as CD40 pathway, IL-21-mediated pathway and citrullination) and the risk-allele sharing with other diseases. CONCLUSION: This study identified six new RA-associated loci that contributed to better understanding of the genetic aetiology and biology in RA.

Discrepancy of alignment in different weight bearing conditions before and after high tibial osteotomy.

PURPOSE: To evaluate the differences in the amount of varus malalignment and valgus (over) correction in relation to three different weight bearing conditions from whole leg AP radiographs (single-limb (SL) stance, double-limb (DL) stance, supine position (S)) before and after high tibial osteotomy (HTO), and to evaluate which alignment parameters affect the changes for patients in three different weight bearing conditions. METHODS: A total of 40 consecutive patients (43 knees) with varus osteoarthritis underwent navigation assisted open wedge HTO. Mechanical axis angle (MA) was measured before and after surgery from hip-to-ankle radiographs taken with patients in three different weight bearing conditions. To find significant factors that affect the alignment differences, several variables including patient demographics, soft tissue laxity, pelvic obliquity, and ground mechanical axis deviation of tibia (calculated by the angle between two lines, tibial anatomical axis and weight-bearing line) were evaluated. RESULTS: Pre-operatively, mean MA measured on SL stance radiographs was significantly more varus than on DL stance (10.1° ± 2.4° and 8.0° ± 2.6°, respectively, p < 0.001), which was significantly more varus than on supine position (6.6° ± 2.6°, p < 0.001). Meanwhile, in patients with post-operatively valgus corrected knee, MA did not show the same pattern of change as with pre-operative varus knee. Mean MA measured on DL stance radiographs was more valgus than in supine position (-3.0o ± 2.4o and -2.6o ± 3.1o, p = 0.455), while mean MA on SL stance radiographs (-2.0o ± 2.1o) was significantly less valgus than on DL stance (p = 0.002). The ground mechanical axis deviation of tibia showed a significant correlation with MA difference between SL and DL stance radiographs before (ß = -0.341, p = 0.045) and after surgery (ß = -0.536, p = 0.001). CONCLUSION: In pre-operative varus knee, the mean MA on SL stance was changed to more varus than on DL stance, which changed to less valgus in post-operative valgus knee. The understanding in discrepancy of alignment in different weight bearing conditions before and after HTO should be considered for the appropriate realignment of the limb. STUDY DESIGN: Level II Prospective comparative study.

Safety of simultaneous bilateral total knee arthroplasty using an extramedullary referencing system: results from 2098 consecutive patients.

INTRODUCTION: Simultaneous bilateral total knee arthroplasty (TKA) has been associated with a high risk of morbidity and mortality. The orthopedic surgeon must, therefore, decide whether bilateral simultaneous TKA is a safe operation to perform and endeavor to decrease the risk of serious complications or even death. METHODS: This retrospective review included 2098 consecutive patients who underwent bilateral simultaneous TKAs by the protocol used in our institution, including the use of extramedullary instruments to minimize medullary canal invasion and overlapping procedures for both knees to decrease operation time. RESULTS: The incidence rate of occurred complications was 0.33 % for symptomatic pulmonary embolism, 0.62 % for deep surgical infection requiring revision surgery, 0.05 % for 14-day mortality, 1.14 % for adverse cardiac events, and 0.76 % for postsurgical delirium within the 1-year follow-up. CONCLUSIONS: Our protocols, including the use of an extramedullary referencing system and overlapping procedures for both knees, may be considered to decrease the perioperative short-term morbidity and 14-day mortality rates in simultaneous bilateral TKA.

Inhibitory effect of cucurbitacin B on imiquimod-induced skin inflammation.

Psoriasis is a common skin disease, of which pathogenesis involves the increase of inflammatory reaction in epidermal cells. In an attempt to find therapeutics for psoriasis, we found that cucurbitacin B has an inhibitory potential on imiquimod-induced inflammation of keratinocytes. Cucurbitacin B significantly inhibited imiquimod-induced expression of crucial psoriatic cytokines, such as IL-8 and CCL20, via down-regulation of NF-κB and STAT3 signaling pathway in human keratinocytes. In addition, keratinocyte proliferation was markedly inhibited by cucurbitacin B. The potential beneficial effect of cucurbitacin B on psoriasis was further validated in imiquimod-induced psoriasiform dermatitis of experimental animal. Topical application of cucurbitacin B resulted in significant reduction of epidermal hyperplasia and inflammatory cytokines production, and ameliorated the psoriatic symptom. Taken together, these results suggest that cucurbitacin B may be a potential candidate for the treatment of psoriasis.

Identification of a possible susceptibility locus for UVB-induced skin tanning phenotype in Korean females using genomewide association study.

A two-stage genomewide association (GWA) analysis was conducted to investigate the genetic factors influencing ultraviolet (UV)-induced skin pigmentation in Korean females after UV exposure. Previously, a GWA study evaluating ~500 000 single nucleotide polymorphisms (SNPs) in 99 Korean females identified eight SNPs that were highly associated with tanning ability. To confirm these associations, we genotyped the SNPs in an independent replication study (112 Korean females). We found that a novel SNP in the intron of the WW domain-containing oxidoreductase (WWOX) gene yielded significant replicated associations with skin tanning ability (P-value = 1.16 × 10(-4) ). To understand the functional consequences of this locus located in the non-coding region, we investigated the role of WWOX in human melanocytes using a recombinant adenovirus expressing a microRNA specific for WWOX. Inhibition of WWOX expression significantly increased the expression and activity of tyrosinase in human melanocytes. Taken together, our results suggest that genetic variants in the intronic region of WWOX could be determinants in the UV-induced tanning ability of Korean females. WWOX represents a new candidate gene to evaluate the molecular basis of the UV-induced tanning ability in individuals.

Clinical significance of serum high-mobility group box 1 level in alopecia areata.

BACKGROUND: Alopecia areata (AA), a chronic, relapsing hair-loss disorder, is considered to be a T-cell-mediated autoimmune disease. High-mobility group box 1 (HMGB1), released by necrotic cells and in response to various inflammatory stimuli, is currently considered to be a significant target antigen in diverse autoimmune diseases. OBJECTIVE: We sought to investigate the clinical significance of serum HMGB1 levels in AA. METHODS: We compared levels of HMGB1 in scalp specimens from 7 patients with AA and 8 healthy control subjects and in blood samples from 45 patients with AA and 10 healthy control subjects. Moreover, we evaluated the correlation between HMGB1 level and clinical severity. RESULTS: Immunohistochemical staining of scalp tissues from patients with AA revealed higher HMGB1 levels than in healthy control subjects. In addition, serum HMGB1 levels in the AA group were generally higher, and showed concordance with the patients' clinical characteristics, including onset, hair-pull test results, and treatment response. LIMITATIONS: The number of patients and healthy control subjects evaluated was small. CONCLUSION: These results suggest that HMGB1 plays a significant role in the pathogenesis of AA, and that it is a promising predictor of prognosis and treatment response. Moreover, this study identifies a new potential therapeutic target for the treatment of AA.

Higher Genetic Risk Loads Confer More Diverse Manifestations and Higher Risk of Lupus Nephritis in Systemic Lupus Erythematosus.

OBJECTIVE: Systemic lupus erythematosus (SLE) is a highly heritable complex disorder with heterogeneous clinical manifestations. In this study, we aimed to identify the genetic risk load using clinical and serological manifestations in SLE patients. METHODS: We genotyped a total of 1,655 Korean patients with SLE (n = 1,243 as a discovery set and n = 412 as a replication set) using a customized genome-wide single-nucleotide polymorphism (SNP) array, KoreanChip. A weighted genetic risk score (wGRS) for an individual was calculated from 112 well-validated non-HLA SNPs and HLA haplotypes of SLE-risk loci. We analyzed associations between individual wGRS and clinical SLE subphenotypes and autoantibodies using multivariable linear or logistic regression adjusted by onset age, sex, and disease duration. RESULTS: Childhood-onset SLE (<16 years) conferred the highest genetic risk compared with adult-onset (16-50 years) or late-onset (>50 years) SLE (P = 6.8 × 10-6 ). High wGRS significantly increased associations with SLE manifestations, regardless of onset age, sex, and disease duration. Individual wGRS significantly correlated positively with more clinical American College of Rheumatology criteria (ß = 0.143, P = 1.8 × 10-6 ). Subphenotype analysis revealed significant associations between the highest and lowest wGRS quartile with risk of renal disorder (hazard ratio [HR] 1.74, P = 2.2 × 10-8 ) and anti-Sm antibody production (HR 1.85, P = 2.8 × 10-5 ). Higher wGRS markedly modulated the pathogenesis of proliferative and membranous lupus nephritis class III or IV (HR 1.98, P = 1.6 × 10-5 ) and class V (HR 2.79, P = 1.0 × 10-3 ), but especially lupus nephritis class V in anti-Sm-positive SLE (area under the curve 0.68, P = 1.8 × 10-4 ). CONCLUSION: Patients with SLE and high wGRS tended to have earlier age of SLE onset, higher anti-Sm antibody positivity, and more diverse clinical phenotypes. Genetic profiling may predict high risk for lupus nephritis and a diverse clinical course in SLE patients.

Disease-microenvironment modulation by bare- or engineered-exosome for rheumatoid arthritis treatment.

BACKGROUND: Exosomes are extracellular vesicles secreted by eukaryotic cells and have been extensively studied for their surface markers and internal cargo with unique functions. A deeper understanding of exosomes has allowed their application in various research areas, particularly in diagnostics and therapy. MAIN BODY: Exosomes have great potential as biomarkers and delivery vehicles for encapsulating therapeutic cargo. However, the limitations of bare exosomes, such as rapid phagocytic clearance and non-specific biodistribution after injection, pose significant challenges to their application as drug delivery systems. This review focuses on exosome-based drug delivery for treating rheumatoid arthritis, emphasizing pre/post-engineering approaches to overcome these challenges. CONCLUSION: This review will serve as an essential resource for future studies to develop novel exosome-based therapeutic approaches for rheumatoid arthritis. Overall, the review highlights the potential of exosomes as a promising therapeutic approach for rheumatoid arthritis treatment.