Socioeconomic and Other Risk Factors for Retear after Arthroscopic Surgery for Nontraumatic Rotator Cuff Tear.

Background and Objectives: Few studies have investigated the socioeconomic factors associated with retear after rotator cuff repair. This study aimed to identify the risk factors, including socioeconomic factors, for rotator cuff retear in patients who underwent arthroscopic rotator cuff repair. Materials and Methods: This retrospective study included 723 patients diagnosed with full-thickness rotator cuff tears who underwent arthroscopic rotator cuff repair from March 2010 to March 2021. The outcome variable was rotator cuff retear observed on postoperative magnetic resonance imaging or ultrasonography. Sex, age, obesity, diabetes, symptom duration, and tear size were the independent variables. Socioeconomic variables included occupation, educational level, type of medical insurance, and area of residence. We compared patients with and without retear and estimated the effects of the independent factors on retear risk. Results: The mean age of the patients, symptom duration, and tear size were 62.4 ± 8.0 years, 1.8 ± 1.7 years, and 21.8 ± 12.5 mm, respectively. The age, type of medical insurance, diabetes, tear size, and symptom duration differed significantly between patients with and without retearing (p < 0.05). Age, occupation, type of medical insurance, diabetes, initial tear size, and symptom duration significantly affected the risk of retear. Patients who performed manual labor had a significantly higher retear rate (p = 0.005; OR, 1.95; 95% CI, 1.23-3.11). The highest retear risk was seen in patients with Medicaid insurance (p < 0.001; OR, 4.34; 95% CI, 2.09-9.02). Conclusions: Age, initial tear size, and symptom duration significantly affect retear risk after arthroscopic rotator cuff repair. Occupation and type of medical insurance were also risk factors for retear. Socioeconomically vulnerable patients may be at a greater risk of retear. Proactive efforts are required to expand early access to medical care.

Screw only versus screw plus plate in isolated talonavicular arthrodesis.

BACKGROUND: We aimed to compare outcomes of treatment of isolated talonavicular arthrodesis (ITNA) with screw only or screw plus plate, respectively. METHODS: We retrospectively evaluated 40 consecutive cases of ITNA [two-screw fixation patients: Group 1 (23 cases); screw-plus-plate fixation patients: Group 2 (17 cases)]. Outcome measures included radiographic findings, Foot and Ankle Outcome Scores (FAOS), and visual analogue scale (VAS) scores. RESULTS: Nonunion occurred more frequently in group 1 (21.7%) than in group 2 (5.9%), but there was no statistical significance (p = 0.216). Although the preoperative FAOS and VAS score showed similar results between both groups, there were significantly better clinical outcomes in two of five FAOS domains and VAS scores at 3 months postoperative and final follow-up (p < 0.05). CONCLUSION: Although union rates were not significantly different, nonunion occurred more frequently in screw only group and we obtained more favorable clinical outcomes in screw plus plate group.

Spine-Hip Discordance and FRAX assessment Fracture Risk in Postmenopausal Women with Osteopenia from Concordant Diagnosis Between Lumbar Spine and Femoral Neck.

The diagnostic criteria proposed by the World Health Organization did not consider the discrepancy in diagnosis between lumbar spine (LS) and femoral neck (FN) and the clinical implications is unclear. Therefore, this retrospective study evaluated the probability of fracture risk in postmenopausal women with lumbar spine (LS)-femoral neck (FN) bone mineral density (BMD) discordance or not Patients included 1066 healthy postmenopausal women (median age 55.5 years) who visited our hospital for a health check-up between May 2013 and April 2017. Discordance was defined as a difference of one or two degrees between LS BMD and FN BMD. TBS was calculated from dual energy absorptiometry (DXA) images. Fracture risk was assessed using the Fracture Risk Assessment Tool (FRAX), including TBS-adjusted FRAX Seven hundred and two patients (65.9%) showed concordant LS and FN results, whereas 364 patients (34.1%) exhibited discordance. Normal BMD was found in 519 concordant patients (73.9%). Concordant patients showed significantly higher FRAX scores, including TBS-adjusted FRAX results, than discordant patients with low LS or FN. Furthermore, FRAX results in concordant osteopenia patients were similar to that of osteoporosis patients with osteopenia or a normal result at one site. FRAX and TBS-adjusted FRAX results in concordant osteopenia patients were comparable to that of discordant osteoporosis patients We concluded that patients with colncordant osteopenia in both the FN and LS should be managed in a similar way to patients with discordant osteoporosis.

Protein phosphatase magnesium-dependent 1A induces inflammation in rheumatoid arthritis.

Rheumatoid arthritis (RA) is a highly inflammatory autoimmune disease. Although proinflammatory cytokines, including tumor necrosis factor (TNF) and interleukin (IL)-6, play a key role in the pathogenesis of RA, the causes of chronic inflammation are not fully understood. Here, we report that protein phosphatase magnesium-dependent 1A (PPM1A) levels were increased in RA synovial fluid compared with osteoarthritis (OA) synovial fluid and positively correlated with TNF levels. In addition, PPM1A expression was increased in synovial tissue from RA patients and joint tissue from a mouse model of arthritis. Finally, extracellular PPM1A induced inflammation by stimulating macrophages to produce TNF through toll-like receptor 4 (TLR4) and myeloid differentiation primary response protein 88 (MyD88) signaling pathway. Our findings suggest that extracellular PPM1A may contribute to the pathogenesis of RA by functioning as a damage-associated molecular pattern (DAMP) to induce inflammation.

Prediction of Response to Tumor Necrosis Value-α Blocker Is Suggested by 18F-NaF SUVmax But Not by Quantitative Pharmacokinetic Analysis in Patients With Ankylosing Spondylitis.

OBJECTIVE. We aimed to evaluate the pharmacokinetics and maximum standardized uptake value (SUVmax) of 18F-NaF PET/CT for assessment of disease activity and prediction of response in patients with ankylosing spondylitis (AS). MATERIALS AND METHODS. Twenty-seven patients (age, interquartile range, 30.25-49.75 years) with AS who were receiving a tumor necrosis factor-α (TNF-α) blocker were included. All patients underwent dynamic PET of the pelvis followed by whole-body PET/CT. Quantitative analysis of kinetic data of the sacroiliac joints (SIJs) was performed, and the SUVmax of the SIJs and SUVmax of the spine were calculated. Clinical indexes related to AS disease activity (serum C-reactive protein level, Bath ankylosing spondylitis disease activity index [ BASDAI], and Bath ankylosing spondylitis functional index) were evaluated. Clinical response was defined as an improvement from the initial BASDAI score of 50% or more (BASDAI 50) within 2 years after baseline 18F-NaF PET/CT. RESULTS. The BASDAI score at 18F-NaF PET/CT was significantly different between the responders and nonresponders: 18F-NaF uptake at the spine was significantly higher in the responders than in the nonresponders. Only SUVmax of the spine had a significant positive correlation with BASDAI score at PET/CT (r = 0.38, p = 0.048). The BASDAI score at PET/CT (odds ratio [OR], 35.32; 95% CI, 2.09-57.84; p = 0.014) and SUVmax of the spine (OR, 14.69; 95% CI, 0.79-27.27; p = 0.027) were significantly associated with BASDAI 50 response prediction. CONCLUSION. The results of our study suggest that the SUVmax of the spine on whole-body 18F-NaF PET/CT is a reliable and noninvasive biomarker for predicting therapeutic response to TNF-α blocker and shows better performance for predicting response than quantitative pharmacokinetic parameters. Fluorine-18-labeled NaF PET/CT showed axial bone lesions with bone formation and can be used as a monitoring tool in patients with AS receiving anti-TNF-α drugs. However, these results need to be validated in a larger cohort.

A User-Friendly, Web-Based Integrative Tool (ESurv) for Survival Analysis: Development and Validation Study.

BACKGROUND: Prognostic genes or gene signatures have been widely used to predict patient survival and aid in making decisions pertaining to therapeutic actions. Although some web-based survival analysis tools have been developed, they have several limitations. OBJECTIVE: Taking these limitations into account, we developed ESurv (Easy, Effective, and Excellent Survival analysis tool), a web-based tool that can perform advanced survival analyses using user-derived data or data from The Cancer Genome Atlas (TCGA). Users can conduct univariate analyses and grouped variable selections using multiomics data from TCGA. METHODS: We used R to code survival analyses based on multiomics data from TCGA. To perform these analyses, we excluded patients and genes that had insufficient information. Clinical variables were classified as 0 and 1 when there were two categories (for example, chemotherapy: no or yes), and dummy variables were used where features had 3 or more outcomes (for example, with respect to laterality: right, left, or bilateral). RESULTS: Through univariate analyses, ESurv can identify the prognostic significance for single genes using the survival curve (median or optimal cutoff), area under the curve (AUC) with C statistics, and receiver operating characteristics (ROC). Users can obtain prognostic variable signatures based on multiomics data from clinical variables or grouped variable selections (lasso, elastic net regularization, and network-regularized high-dimensional Cox-regression) and select the same outputs as above. In addition, users can create custom gene signatures for specific cancers using various genes of interest. One of the most important functions of ESurv is that users can perform all survival analyses using their own data. CONCLUSIONS: Using advanced statistical techniques suitable for high-dimensional data, including genetic data, and integrated survival analysis, ESurv overcomes the limitations of previous web-based tools and will help biomedical researchers easily perform complex survival analyses.

Sagittal spinopelvic alignment after spinal fusion in degenerative lumbar scoliosis: a meta-analysis.

Objective: This meta-analysis aimed to investigate the changes in sagittal spinopelvic alignment in degenerative lumbar scoliosis (DLS) from the preoperative state to the last follow-up.Methods: The MEDLINE via PubMed, Cochrane, Scopus, and Embase databases were searched for studies published between January 2010 and January 2019 evaluating radiological parameters including the coronal Cobb angle, sagittal vertical axis (SVA), thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), and pelvic tilt (PT) in DLS. Two authors performed data extraction independently. All discrepancies were resolved by consensus.Results: The 34 studies identified showed significant decreases in overall and subgroup Cobb angles from the preoperative state to the last follow-up. Both overall TK and LL were significantly increased from the preoperative state to the last follow-up. In subgroup analysis, LLs in the long fusion, combined approach, and posterior approach group were significantly increased at the final follow-up, but the LL increase in the short fusion group was not significant at the last follow-up. However, there was no significant change in SVA, PI, SS, and PT from the preoperative state to the last follow-up.Conclusions: A literature review identified 34 studies reporting preoperative and last follow-up data on spinal fusion in DLS. Despite heterogeneity, a limited meta-analysis showed significant improvement in the coronal Cobb angle, TK, and LL after spinal fusion in DLS. A large, randomized clinical trial would be necessary to validate our results.

Development of a risk scoring system for patients with papillary thyroid cancer.

As the importance of personalized therapeutics in aggressive papillary thyroid cancer (PTC) increases, accurate risk stratification is required. To develop a novel prognostic scoring system for patients with PTC (n = 455), we used mRNA expression and clinical data from The Cancer Genome Atlas. We performed variable selection using Network-Regularized high-dimensional Cox-regression with gene network from pathway databases. The risk score was calculated using a linear combination of regression coefficients and mRNA expressions. The risk score and clinical variables were assessed by several survival analyses. The risk score showed high discriminatory power for the prediction of event-free survival as well as the presence of metastasis. In multivariate analysis, the risk score and presence of metastasis were significant risk factors among the clinical variables that were examined together. In the current study, we developed a risk scoring system that will help to identify suitable therapeutic options for PTC.

Prognostic scoring system for osteosarcoma using network-regularized high-dimensional Cox-regression analysis and potential therapeutic targets.

With the recent emphasis on the importance of personalized genomic medicine, studies have performed prognostic stratification using gene signatures in cancers. However, these studies have not considered gene networks with clinical data. Therefore, this study aimed to develop a novel prognostic score using grouped variable selection for patients with osteosarcoma. We assessed messenger RNA (mRNA) expression and clinical data from Gene Expression Omnibus to develop a novel prognostic scoring system for patients with osteosarcoma. Variable selection using Network-Regularized high-dimensional Cox-regression analysis with information regarding gene networks obtained from six large pathway databases was performed. We determined the risk score on the linear combination of regression coefficients and mRNA expression values. Log-rank test, UNO's c-index, and area under the curve (AUC) values were determined to evaluate the discriminatory power between the low- and high-risk groups. A recently reported next-generation Connectivity Map was used to identify future therapeutic targets for osteosarcoma. Our novel model had significantly high discriminatory power in predicting overall survival. An optimal c-index of 0.967 was obtained and time-dependent receiver operating characteristic analysis revealed an acceptable predictive value of AUC between 0.953 and 1.000. Knockdown of BACE2 or ING2 and linifanib treatment may improve the prognosis of patients with osteosarcoma. Herein, this novel prognostic scoring system would not only facilitate a more accurate prediction of patient prognosis, but also contribute to the selection of suitable therapeutic alternatives for osteosarcoma patients.

BRAF-positive multifocal and unifocal papillary thyroid cancer show different messenger RNA expressions.

OBJECTIVE: Thyroid cancer is the most common malignant endocrine tumour, and its incidence has continuously increased worldwide over the past three decades. We focused on the association of multifocal papillary thyroid carcinoma (PTC) with messenger RNA (mRNA) expression to characterize how molecular and histopathologic features relate to multifocality. DESIGN: A retrospective cohort study. PATIENTS: The primary and processed data were downloaded from The Cancer Genome Atlas. A total of 490 patients were included in this study. METHODS: The statistical significance of differences in sex, age, histology, LN metastasis and recurrence were analysed using chi-squared test. To identify differentially expressed genes between BRAF (+) multifocal and unifocal PTCs and between BRAF (-) multifocal and unifocal PTCs, we used the Significance Analysis of Microarray. Over-representation analysis is conducted using CPDB. RESULTS: A total of 237 patients had BRAF (+) PTCs, whereas 253 had BRAF (-) PTCs. There were 110 patients with multifocal PTCs and 127 with unifocal PTCs in the BRAF (+) group and 116 patients with multifocal PTCs and 137 with unifocal PTCs in the BRAF (-) group. In BRAF (+) group, multifocal PTCs had increased expression of 158 mRNAs as compared to that in unifocal PTCs. Ten mRNAs were involved in Wnt-related pathways, and seven mRNAs were included in pluripotency-related pathways. CONCLUSION: Multifocal PTCs have higher expression of mRNAs in Wnt- and pluripotency-related pathways when BRAF mutation is present. This might be the mechanism that accounts for the difference between multifocal and unifocal PTCs.

Radiologic parameters of ankylosing spondylitis patients treated with anti-TNF-α versus nonsteroidal anti-inflammatory drugs and sulfasalazine.

PURPOSE: Limited data are available on the relationship between treatment agents and sagittal balance in ankylosing spondylitis (AS). We investigated radiological features related to treatment agents and compared sagittal balance between patients treated with anti-tumor necrosis factor-α (anti-TNF-α) and those treated with nonsteroidal anti-inflammatory drugs (NSAIDs) and sulfasalazine (SSZ). METHODS: We prospectively enrolled 133 consecutive AS patients. Patients were eligible for the trial if they were under medical treatment with the same treatment agents for at least 1 year. All patients were treated initially with NSAIDs and SSZ. Sixty-nine patients achieved an excellent pain control outcome with these agents (group A). Sixty-four patients who reported of intractable low back pain were switched to anti-TNF-α treatment (group B). Twelve radiographic parameters were measured. Clinical outcome was assessed with the Bath AS Disease Activity Index (BASDAI), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP). All parameters were measured at enrolment, upon changing treatment agents, and every 6 months during follow-up. RESULTS: The mean ESR, CRP, BASDAI, and thoracic kyphosis at baseline were significantly higher in group B. After treatment, group B had significantly higher lumbar lordosis (LL) and significantly better clinical outcomes. Correlation analysis revealed significant relationships between radiologic parameters and BASDAI. On multiple regression analysis, LL was a significant predictor of BASDAI. CONCLUSIONS: This study demonstrated a clear association between treatment agents and radiologic parameters in AS. Anti-TNF-α treatment improved LL with improvement in clinical outcomes. Lumbar lordosis was a significant predictor of clinical outcome in AS patients treated with anti-TNF-α. These slides can be retrieved under Electronic Supplementary Material.

Interleukin 6 gene polymorphism in patients with degenerative lumbar scoliosis: a cohort study.

PURPOSE: Low bone mass and a female gender increase susceptibility to the development of degenerative lumbar scoliosis (DLS), which suggests the potential involvement of an osteoporosis-related gene in the pathogenesis of DLS. In the present study, the authors studied the relations between polymorphisms of interleukin 6 (IL-6) gene and DLS in a patient cohort. METHODS: In 184 patients with a diagnosis of DLS, the authors determined the presence of the -597 G/A, -572 G/C, and -174 G/C polymorphisms, measured bone mineral densities at the lumbar spine (LSBMD) and femoral neck (FNBMD), assessed radiological findings including lumbar scoliosis and lateral listhesis, investigated biochemical markers of bone turnover, and compared these results obtained with those of 220 healthy normal controls. RESULTS: Genotype frequencies in the DLS patients and controls revealed a significant difference for the IL6-572 G/C polymorphism (P = 0.0168). Mean LSBMD was lower in DLS patients than in controls, but no significant difference was found between these two groups with respect to FNBMD, biochemical markers, or radiological findings. A significant association was found between the IL6-572 G/C polymorphism and LSBMD. LSBMD in DLS with the CC genotype was found to be significantly higher than in DLS with the GC (P < 0.05) or GG (P < 0.05) genotypes. CONCLUSION: The results of this study suggest that the IL6-572 G/C polymorphism influences LSBMD in Korean DLS patients and the prevalence of the disease.

Full endoscopic lumbar interbody fusion (FELIF): technical note.

PURPOSE: Interbody fusion by open discectomy is the usual treatment for degenerative lumbar disease but requires a relatively long recovery period. Prevalent several interbody fusion methods have shown limitations by its own character. Full endoscopic lumbar interbody fusion (FELIF) has advantages in direct decompression of pathology with minimal invasive technique. We report novel technique of endoscopic fusion method through full guided with endoscopic view monitoring system. METHODS: The authors provide an introduction of FELIF technique followed by a description of the technical steps with discussion on its indications and advantages. In particular, tips to shorten operation time, simplify technical steps, and avoid complications are also presented. CONCLUSIONS: FELIF is a safe and effective interbody fusion option to decompress the lumbar exiting nerve root and ventral side of dura directly with minimal invasive situation. These slides can be retrieved under Electronic Supplementary Material.

Minimally invasive percutaneous endoscopic treatment for acute pyogenic spondylodiscitis following vertebroplasty.

INTRODUCTION: Acute pyogenic spondylodiscitis caused by percutaneous vertebroplasty is a rare complication. We present the first report of minimally invasive endoscopic treatment for acute spondylodiscitis caused by vertebroplasty. CASE PRESENTATION: A 60-year-old female was transferred with the symptom of right hip flexion weakness for 1 day. The patient underwent a vertebroplasty procedure because of L3 osteoporotic compression fracture at other hospital 6 weeks ago. Physical examination, laboratory finding and magnetic resonance imaging revealed an acute pyogenic spondylodiscitis with right L2 nerve root palsy caused by compression of bone and cement after L3 body collapse. Percutaneous endoscopic procedures including needle biopsy, debridement, root decompression and drainage were performed. One week after endoscopic treatment, her symptoms of back pain and nerve palsy improved significantly. After endoscopic treatment, the patient underwent conservative treatment with appropriate antibiotics according to the bacterial culture test results. Six weeks postoperatively, she was pain free with no neurological deficits or signs of infection. Five months later, spontaneous fusion between L2 and L3 body was observed. CONCLUSION: We report a case treated with endoscopic procedure without open surgery for acute pyogenic spondylodiscitis following vertebroplasty.

Iatrogenic dural tear in endoscopic lumbar spinal surgery: full endoscopic dural suture repair (Youn's technique).

BACKGROUND: With the advancement of minimally invasive spinal surgery, endoscopic lumbar decompression has been widely used for the treatment of degenerative lumbar spinal diseases. Iatrogenic dural tear is a relatively common complication in endoscopic lumbar spinal surgery. The golden standard of treatment for iatrogenic dural tear is immediate open conversion and direct repair under microscopic visualization. Recently, most of endoscopic spinal surgery is performed under local anesthesia. So, conversion to open surgery is very embarrassing situation because of the need of additional general anesthesia. But, direct endoscopic dural repair is very difficult procedure due to the limitation of manipulation. No report showed direct dural suture under full endoscopic situation. PURPOSE: The purpose of this surgical technique is to provide a method of full endoscopic dural suture repair without conversion to open surgery.

Correlation between body image perception and spinopelvic parameters in ankylosing spondylitis.

OBJECTIVE: To identify relationships between spinopelvic parameters and body image perception in ankylosing spondylitis (AS). METHODS: The study and control groups comprised 107 AS patients (18 women and 89 men) and 40 controls. All underwent anteroposterior and lateral radiography of whole spine, including hip joints, and completed clinical questionnaires. The radiographic parameters examined were sagittal vertical axis, sacral slope, pelvic tilt, pelvic incidence, lumbar lordosis, thoracic kyphosis, spinosacral angle (SSA), and spinopelvic angle (SPA). The Trunk appearance scale (TAPS), and the Scoliosis Research Society 22 appearance questionnaire (SRSapp) were administered to evaluate body image perception. RESULTS: The patient and control groups were found to differ significantly in terms of sagittal vertical axis, sacral slope, pelvic tilt, pelvic incidence, lumbar lordosis, SSA, and SPA. However, no significant intergroup difference was observed for thoracic kyphosis (p > .05). Correlation analysis revealed significant relationships between radiographic parameters and body image perception. Multiple regression analysis was performed to identify predictors of body image perception scores, and the results obtained revealed age, SSA, and SPA significantly predicted SRSapp scores and that age and SSA predicted TAPS scores. CONCLUSIONS: AS patients and normal controls were found to differ significantly in terms of sagittal spinopelvic parameters. Correlation analysis revealed significant relationships between radiographic parameters and body image perception. In particular, age, SSA, and SPA were found to be significant predictors of body image perception scores in AS patients.

Validation of the Korean version of the Brace Questionnaire.

OBJECTIVE: To evaluate the reliability and validity of an adapted Korean version of the Brace Questionnaire (K-BrQ). METHODS: The Greek version of the BrQ was translated/retranslated, and all steps of the cross-cultural adaptation process were performed. The K-BrQ and the previously validated Korean version of the Scoliosis Research Society-22 Outcomes questionnaire (K-SRS-22) were mailed to 120 patients with adolescent idiopathic scoliosis (AIS). Reliability assessments were conducted using kappa statistics to assess item agreements, and intraclass correlation coefficients (ICC) and Cronbach's α values were calculated. Convergent validity was evaluated by comparing the K-BrQ and K-SRS-22 scores and discriminant validity by analyzing relationships between the K-BrQ scores and patient characteristics. RESULTS: 103 patients filled in questionnaires twice. All items of the K-BrQ had kappa values of agreement of >0.6. The K-BrQ showed an excellent test/re-test reliability with an ICC of 0.913. The internal consistency of the K-BrQ was found to be very good (α = 0.872). The convergent validity testing demonstrated a strong correlation between the K-BrQ and K-SRS-22 (r = 712). The correlation between the K-BrQ and major curve magnitude was significant (r = -0.302). CONCLUSION: The adapted K-BrQ showed satisfactory reliability and validity and is thus considered suitable for monitoring the quality of life of Korean-speaking patients with AIS during brace treatment.

New insights of common gamma chain in hematological malignancies.

The common gamma chain (γc) receptor family of cytokines including interleukin-2 (IL-2), IL-4, IL-7, IL-9, IL-15, and IL-21 has the common feature of sharing γc signaling subunit of their receptors. The γc cytokines have unique biological effects that regulate differentiation, survival and activation of multiple lymphocyte lineages and control proliferation of malignant cell by influencing tumor environment. It has been also described that different types of lymphoid leukemia and lymphoma exhibit expression of divergent γc cytokines and their receptors, as they may promote malignant transformation of lymphoid cells or on the contrary lead to tumor regression by inducing cell-cycle arrest. Therefore, cytokine-based or cytokine-directed blockade in cancer immunotherapy has currently revolutionized the development of cancer treatment. In this review, we will discuss about the role of γc cytokines and their signaling pathways in hematological malignancies and also propose a novel alternative approach that regulates γc cytokine responsiveness by γc in hematological malignancies.

IL-7 Induces an Epitope Masking of γc Protein in IL-7 Receptor Signaling Complex.

IL-7 signaling via IL-7Rα and common γ-chain (γc) is necessary for the development and homeostasis of T cells. Although the delicate mechanism in which IL-7Rα downregulation allows the homeostasis of T cell with limited IL-7 has been well known, the exact mechanism behind the interaction between IL-7Rα and γc in the absence or presence of IL-7 remains unclear. Additionally, we are still uncertain as to how only IL-7Rα is separately downregulated by the binding of IL-7 from the IL-7Rα/γc complex. We demonstrate here that 4G3, TUGm2, and 3E12 epitope masking of γc protein are induced in the presence of IL-7, indicating that the epitope alteration is induced by IL-7 binding to the preassembled receptor core. Moreover, the epitope masking of γc protein is inversely correlated with the expression of IL-7Rα upon IL-7 binding, implying that the structural alteration of γc might be involved in the regulation of IL-7Rα expression. The conformational change in γc upon IL-7 binding may contribute not only to forming the functional IL-7 signaling complex but also to optimally regulating the expression of IL-7Rα.