Artificial intelligence can be used in the identification and classification of shoulder osteoarthritis and avascular necrosis on plain radiographs: a training study of 7,139 radiograph sets.

BACKGROUND AND PURPOSE: Knowledge concerning the use AI models for the classification of glenohumeral osteoarthritis (GHOA) and avascular necrosis (AVN) of the humeral head is lacking. We aimed to analyze how a deep learning (DL) model trained to identify and grade GHOA on plain radiographs performs. Our secondary aim was to train a DL model to identify and grade AVN on plain radiographs. PATIENTS AND METHODS: A modified ResNet-type network was trained on a dataset of radiographic shoulder examinations from a large tertiary hospital. A total of 7,139 radiographs were included. The dataset included various projections of the shoulder, and the network was trained using stochastic gradient descent. Performance evaluation metrics, area under the receiver operating characteristic curve (AUC), sensitivity, and specificity were used to assess the network's performance for each outcome. RESULTS: The network demonstrated AUC values ranging from 0.73 to 0.93 for GHOA classification and > 0.90 for all AVN classification classes. The network exhibited lower AUC for mild cases compared with definitive cases of GHOA. When none and mild grades were combined, the AUC increased, suggesting difficulties in distinguishing between these 2 grades. CONCLUSION: We found that a DL model can be trained to identify and grade GHOA on plain radiographs. Furthermore, we show that a DL model can identify and grade AVN on plain radiographs. The network performed well, particularly for definitive cases of GHOA and any level of AVN. However, challenges remain in distinguishing between none and mild GHOA grades.

The Biophysical Properties of Microalgal Cell Surfaces Govern Their Interactions with an Amphiphilic Chitosan Derivative Used for Flocculation and Flotation.

Microalgae show great promise for producing valuable molecules like biofuels, but their large-scale production faces challenges, with harvesting being particularly expensive due to their low concentration in water, necessitating extensive treatment. While methods such as centrifugation and filtration have been proposed, their efficiency and cost-effectiveness are limited. Flotation, involving air-bubbles lifting microalgae to the surface, offers a viable alternative, yet the repulsive interaction between bubbles and cells can hinder its effectiveness. Previous research from our group proposed using an amphiphilic chitosan derivative, polyoctyl chitosan (PO-chitosan), to functionalize bubbles used in dissolved air flotation (DAF). Molecular-scale studies performed using atomic force microscopy (AFM) revealed that PO-chitosan's efficiency correlates with cell surface properties, particularly hydrophobic ones, raising the question of whether this molecule can in fact be used more generally to harvest different microalgae. Evaluating this, we used a different strain of Chlorella vulgaris and first characterized its surface properties using AFM. Results showed that cells were hydrophilic but could still interact with PO-chitosan on bubble surfaces through a different mechanism based on specific interactions. Although force levels were low, flotation resulted in 84% separation, which could be explained by the presence of AOM (algal organic matter) that also interacts with functionalized bubbles, enhancing the overall separation. Finally, flocculation was also shown to be efficient and pH-independent, demonstrating the potential of PO-chitosan for harvesting microalgae with different cell surface properties and thus for further sustainable large-scale applications.

Timing of Surgery for Proximal Humeral Fracture Treated with Shoulder Hemiarthroplasty, Best Results with Surgery Within 2 Weeks.

Background: Preoperative delay may affect the outcome of proximal humerus fractures treated with shoulder hemiarthroplasty. There is currently no consensus for the recommended preoperative time interval. The aim was to examine how the time to surgery with shoulder hemiarthroplasty after a proximal humerus fracture affected the patient-reported outcome. Methods: 380 patients with proximal humerus fractures treated with shoulder hemiarthroplasty recorded from the Swedish Shoulder Arthroplasty Registry were included. Three self-reporting outcome instruments were used at follow-up after 1-5 years: a shoulder-specific score, the Western Ontario Osteoarthritis of the Shoulder index (WOOS), the EuroQol-5 Dimension index (EQ-5D), and subjective patient satisfaction assessment. Results: The preoperative delay had a negative impact on the WOOS, EQ-5D, and patient satisfaction level (p < 0.01). The best result, measured with WOOS at a minimum 1-year follow-up, was found when surgery was performed 6-10 days after the reported date of fracture. WOOS% 8-14 days was 69.4% (± 24.2). A delay of more than 10 days was shown to be correlated with poorer outcomes. WOOS% 15-60 days was 55.8% (± 25.0) and continued to decrease. Conclusion: The current recommendation in Sweden to perform shoulder hemiarthroplasty within 2 weeks after sustaining a proximal humerus fracture is considered valid.

Deep learning classification of shoulder fractures on plain radiographs of the humerus, scapula and clavicle.

In this study, we present a deep learning model for fracture classification on shoulder radiographs using a convolutional neural network (CNN). The primary aim was to evaluate the classification performance of the CNN for proximal humeral fractures (PHF) based on the AO/OTA classification system. Secondary objectives included evaluating the model's performance for diaphyseal humerus, clavicle, and scapula fractures. The training dataset consisted of 6,172 examinations, including 2-7 radiographs per examination. The overall area under the curve (AUC) for fracture classification was 0.89, indicating good performance. For PHF classification, 12 out of 16 classes achieved an AUC of 0.90 or greater. Additionally, the CNN model had excellent overall AUC for diaphyseal humerus fractures (0.97), clavicle fractures (0.96), and good AUC for scapula fractures (0.87). Despite the limitations of the study, such as the reliance on ground truth labels provided by students with limited radiographic assessment experience, our findings are in concordance with previous studies, further consolidating CNN as potent fracture classifiers in plain radiographs. The inclusion of multiple radiographs with different views from each examination, as well as the generally unselected nature of the sample, contributed to the overall generalizability of the study. This is the fifth study published by our group on AI in orthopaedic radiographs, which has consistently shown promising results. The next challenge for the orthopaedic research community will be to transfer these results from the research setting into clinical practice. External validation of the CNN model should be conducted in the future before it is considered for use in a clinical setting.

Western Ontario Osteoarthritis of the Shoulder Index (WOOS) - a validation for use in proximal humerus fractures treated with arthroplasty.

BACKGROUND: The Swedish shoulder and Arthroplasty Registry (SSAR) use the Western Ontario Osteoarthritis of the Shoulder Index (WOOS) as their shoulder-specific score in the follow-up. WOOS is not yet validated for use as the Patient Reported Outcome Measurement (PROM) for proximal humerus fractures (PHF) treated with shoulder hemiarthroplasty (SHA) in the Swedish registry. The aim of this study was to examine the validity, the reliability and the responsiveness of WOOS as a PROM for proximal humerus fractures treated with shoulder arthroplasty. METHODS: Data was collected from the SSAR from the 1st of January 2008 to the 31st of June 2011. A total of 72 subjects were identified with at least 1 year of follow-up. Of these 43 completed all the shoulder-specific PROM together with a clinical examination, including a WOOS retest and general health scores. A group of 29 did not undergo any clinical examination, but they completed all the questionnaires not requiring a clinical examination. The validity was assessed with WOOS compared to satisfaction level, and the Spearman rank coefficient was used for the correlation between WOOS and the shoulder-specific scores (Constant-Murley Score, Oxford Shoulder Score, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form and EQ-5D. For reliability, Intra Class Correlation (ICC) was used for the test-retest assessment and Cronbach´s alpha for the construct reliability. RESULTS: The validity for WOOS had an excellent correlation (> 0.75) with all the shoulder-specific scores and a good correlation (> 0.6) with EQ-5D. The reliability with the test-retest of the total WOOS score and the subgroups had an excellent correlation. Cronbach´s alpha also supports the construct of WOOS. There were no floor or ceiling effects. CONCLUSIONS: We found that WOOS is a reliable tool for evaluating patients with SHA after PHF. Based on our study, we recommend the continued use of WOOS in shoulder arthroplasty registries and observational studies.

Investigation of the role of cell hydrophobicity and EPS production in the aggregation of the marine diatom Cylindrotheca closterium under hypo-saline conditions.

Aggregation of diatoms is of global importance to understand settling of particulate organic carbon in aquatic systems. In this study, we investigate the aggregation of the marine diatom Cylindrotheca closterium during the exponential growth phase under hypo-saline conditions. The results of the flocculation/flotation experiments show that the aggregation of the diatom depends on the salinity. In favorable growth conditions for marine diatoms (salinity of 35), the highest aggregation is achieved. To explain these observations, we used a surface approach combining atomic force microscopy (AFM) and electrochemical methods to characterize both the cell surface properties and the structure of the extracellular polymeric substances (EPS) cell produce, and to quantify the amount of surface-active organic matter released. At a salinity of 35, the results showed that diatoms are soft, hydrophobic and release only small amounts of EPS organized into individual short fibrils. In contrast, diatoms adapt to a salinity of 5 by becoming much stiffer and more hydrophilic, producing larger amounts of EPS that structurally form an EPS network. Both adaptation responses of diatoms, the hydrophobic properties of diatoms and the release of EPS, appear to play an important role in diatom aggregation and explain the behavior observed at different salinities. This biophysical study provides important evidence allowing to get a deep insight into diatom interactions at the nanoscale, which may contribute to a better understanding of large-scale aggregation phenomena in aquatic systems.

Reconstructed membrane vesicles from the microalga Dunaliella as a potential drug delivery system.

The aim of this biophysical study is to characterize reconstructed membrane vesicles obtained from microalgae in terms of their morphology, properties, composition, and ability to transport a model drug. The reconstructed vesicles were either emptied or non-emptied and exhibited a non-uniform distribution of spherical surface structures that could be associated with surface coat proteins, while in between there were pore-like structures of up to 10 nm that could contribute to permeability. The reconstructed vesicles were very soft and hydrophilic, which could be attributed to their composition. The vesicles were rich in proteins and were mostly derived from the cytoplasm and chloroplasts. We demonstrated that all lipid classes of D. tertiolecta are involved in the formation of the reconstructed membrane vesicles, where they play fundamental role to maintain the vesicle structure. The vesicles appeared to be permeable to calcein, impermeable to FITC-ovalbumin, and semipermeable to FITC-concanavalin A, which may be due to a specific surface interaction with glucose/mannose units that could serve as a basis for the development of drug carriers. Finally, the reconstructed membrane vesicles could pave a new way as sustainable and environmentally friendly marine bioinspired carriers and serve for studies on microtransport of materials and membrane-related processes contributing to advances in life sciences and biotechnology.

The role of microplastics in microalgae cells aggregation: A study at the molecular scale using atomic force microscopy.

Plastic pollution has become a significant concern in aquatic ecosystems, where photosynthetic microorganisms such as microalgae represent a major point of entry in the food chain. For this reason an important challenge is to better understand the consequences of plastic pollution on microalgae and the mechanisms underlying the interaction between plastic particles and cell's interfaces. In this study, to answer such questions, we developed an interdisciplinary approach to investigate the role of plastic microparticles in the aggregation of a freshwater microalgae species, Chlorella vulgaris. First, the biophysical characterization, using atomic force microscopy, of the synthetic plastic microparticles used showed that they have in fact similar properties than the ones found in the environment, with a rough, irregular and hydrophobic surface, thereby making them a relevant model. Then a combination of optical imaging and separation experiments showed that the presence of plastic particles in microalgae cultures induced the production of exopolysaccharides (EPS) by the cells, responsible for their aggregation. However, cells that were not cultured with plastic particles could also form aggregates when exposed to the particles after culture. To understand this, advanced single-cell force spectroscopy experiments were performed to probe the interactions between cells and plastic microparticles; the results showed that cells could directly interact with plastic particles through hydrophobic interactions. In conclusion, our experimental approach allowed highlighting the two mechanisms by which plastic microparticles trigger cell aggregation; by direct contact or by inducing the production of EPS by the cells. Because these microalgae aggregates containing plastic are then consumed by bigger animals, these results are important to understand the consequences of plastic pollution on a large scale.

Reverse total shoulder arthroplasty provides better shoulder function than hemiarthroplasty for displaced 3- and 4-part proximal humeral fractures in patients aged 70 years or older: a multicenter randomized controlled trial.

BACKGROUND: The most appropriate treatment for displaced multiple-fragment proximal humeral fractures in elderly patients is currently unclear. Reverse total shoulder arthroplasty (rTSA) is a promising treatment option that is being used increasingly. The purpose of this study was to compare the outcome of rTSA vs. hemiarthroplasty (HA) for the treatment of displaced 3- and 4-part fractures in elderly patients. METHODS: This was a multicenter randomized controlled trial. We included patients aged ≥ 70 years with displaced 3- or 4-part proximal humeral fractures between September 2013 and May 2016. The minimum follow-up period was 2 years, with outcome measures including the Constant score (primary outcome), Western Ontario Osteoarthritis of the Shoulder index, EQ-5D (EuroQol 5 Dimensions) index, and range of motion, as well as pain and shoulder satisfaction assessed on a visual analog scale. RESULTS: We randomized 99 patients to rTSA (48 patients) or HA (51 patients). Fifteen patients were lost to follow-up, leaving 41 rTSA and 43 HA patients for analysis. The mean age was 79.5 years, and there were 76 women (90%). The rTSA group had a mean Constant score of 58.7 points compared with 47.7 points in the HA group, with a mean difference of 11.1 points (95% CI, 3.0-18.9 points; P = .007). Compared with HA patients, rTSA patients had greater mean satisfaction with the shoulder (79 mm vs. 63 mm, P = .011), flexion (125° vs. 90°, P < .001), and abduction (112° vs. 83°, P < .001), but there was no difference in Western Ontario Osteoarthritis of the Shoulder index, pain, or EQ-5D index scores. We identified 3 and 4 adverse events in the rTSA and HA groups, respectively. Among patients aged ≥ 80 years (n = 38), there was no difference between rTSA treatment and HA treatment in pain (17 mm vs. 9 mm, P = .17) or shoulder satisfaction (77 mm vs. 74 mm, P = .73). CONCLUSION: We found that rTSA provides better shoulder function than HA as measured with the Constant score, further emphasized by rTSA patients being more satisfied with their shoulder function. The difference appears to be mainly a result of better range of motion (abduction and flexion) in the rTSA group. The results also indicate that patients aged ≥ 80 years benefit less from rTSA than patients aged 70-79 years.

Low arthroplasty survival after treatment for proximal humerus fracture sequelae: 3,245 shoulder replacements from the Nordic Arthroplasty Register Association.

Background and purpose - Proximal humerus fractures (PHF) may result in sequelae indicating arthroplasty. We report cumulative survival rates and reasons for revision after arthroplasty for proximal humerus fracture sequelae (PHFS).Patients and methods - Data were derived from the Nordic Arthroplasty Register Association. The Kaplan-Meier method was used to illustrate survival rates. A scaled Schoenfeld residual plot was used to report the risk of revision for men relative to women in patients who were treated with reverse shoulder arthroplasty (RSA). Revision was defined as removal or exchange of any component or the addition of a glenoid component.Results - 30,190 primary arthroplasties were reported from 2004 to 2016, of which 3,245 were for PHFS. The estimated 1-, 5-, and 10-year cumulative survival rates (95% CI) were 96% (95-97), 90% (89-92), and 86% (83-88) for stemmed hemiarthroplasty and 94% (92-95), 89% (87-91), and 86% (82-90) for RSA with a median time to revision of 18 months (IQR 9-44) and 3 months (IQR 0-17). The risk of revision for men relative to women in patients who were treated with RSA was 3.2 (1.9-5.1) 0-1 year after surgery and 1.9 (0.9-4.1) 1-8 years after surgery. The estimated 1-, 5-, and 10-year cumulative survival rates (95% CI) were 94% (92-96), 88% (85-90), and 80% (75-86) for men and 95% (94-96), 86% (84-89), and 81% (77-84) for young patients.Interpretation - Shoulder arthroplasty for PHFS was associated with lower survival rates, compared with previously published results of shoulder arthroplasty for acute PHF. The low arthroplasty survival rates for men and young patients especially are worrying.

Revision after shoulder replacement for acute fracture of the proximal humerus.

Background and purpose - For more than half a century, stemmed hemiarthroplasty (SHA) has been used in the treatment of comminuted and displaced fractures of the proximal humerus. Reverse shoulder arthroplasty (RSA) has been increasingly popular in cases where it is difficult to obtain satisfactory fixation of the tuberosities. We report revision rates and reasons for revision after shoulder arthroplasty for acute fractures of the proximal humerus. Patients and methods - This study was based on a common dataset from the Nordic Arthroplasty Register Association (NARA), which includes data reported to the national shoulder arthroplasty registries in Denmark, Sweden, and Norway. We included 6,756 shoulder arthroplasties performed for acute fractures between 2004 and 2013. Results - There were 6,112 SHAs (90%) and 565 RSAs (8.4%). The cumulative arthroplasty survival rate after 5 years was 0.96 for both SHA and RSA. The relative risk of revision of RSA was 1.4 (95% CI: 0.9-2.2) with SHA as reference. For both types of arthroplasty, the most common reason for revision was infection (SHA 0.8%, RSA 2.1%). The relative risk of revision due to infection was 3.1 (95% CI: 1.6-5.9) for RSA with SHA as reference. The relative risk of revision for patients who were less than 75 years of age was 2.8 (95% CI: 2.0-3.8) compared to older patients. Interpretation - Revision after shoulder arthroplasty for acute fractures was rare. Survival rates were similar between SHA and RSA, but RSA had a statistically significant and clinically relevant higher risk of revision because of infection.

Loss of offset after pertrochanteric hip fractures affects hip function one year after surgery with a short intramedullary nail. A prospective cohort study.

PURPOSE: We hypothesised that protruding collum screws in intramedullary nails used for pertrochanteric fractures cause lateral pain/discomfort and that loss of offset relates to poorer hip function. METHODS: Seventy-six patients with an acute pertrochanteric femoral fracture AO types A1 and A2 were operated upon using a short intramedullary nail and were included in a prospective observational cohort study and followed-up for one year. The main outcome variables were lateral pain and hip function as evaluated with the Harris Hip Score. The main exposure was compression along the collum screw and lateral protrusion measured by anteroposterior X-ray images. Perioperative images were compared to images at the follow-up visit. Outcome variables were adjusted in regression models for reduction, fracture type, body mass index, sex and age. RESULTS: A total of 28 (36 %) patients experienced lateral pain at one year. We found a correlation between lateral protrusion and lateral pain, adjusted OR 4.5 per protruding centimetre (95 % CI, 1.1-17.5). Collum compression correlated with a poorer outcome with Harris Hip Score -14.2 per compressed centimetre (95 % CI, -21.8 to -6.7). CONCLUSIONS: In patients with type A1 and A2 pertrochanteric fractures operated on using intramedullary nailing, a large compression and lateral protrusion of the collum screw are associated with poorer hip function and lateral pain. New technical improvements for implants should focus on these factors to improve functional outcome after surgery.

Factors affecting the tuberculosis risk in patients receiving anti-tumor necrosis factor-α treatment.

BACKGROUND: Tumor necrosis factor (TNF)-α inhibitors are known to increase the risk of tuberculosis (TB). OBJECTIVES: To examine the factors associated with an increased risk of TB in patients receiving anti-TNF-α treatment (aTNF-α-T). METHOD: Of 3,094 patients who received aTNF-α-T between 2003 and 2013, a total of 1,964 subjects with a follow-up time longer than 6 months were identified and included in this retrospective analysis. Potential risk factors for the development of TB in patients receiving aTNF-α-T were evaluated. RESULTS: Of the 1,964 patients, 1,009 (51%) were male and 955 (49%) were female, with a mean age of 39.7 ± 13.9 years. The primary conditions requiring aTNF-α-T included ankylosing spondylitis (n = 875), rheumatoid arthritis (n = 711), Behçet's disease (n = 83), and others (n = 295). Sixteen patients [8 (50%) males and 8 (50%) females; 5 (31.2%) with pulmonary TB and 11 (68.8%) with extrapulmonary TB] developed TB, with a corresponding TB incidence of 466/100,000. No significant associations were found between age, gender, smoking history, pack-years of smoking, isoniazid (INH) chemoprophylaxis, type of anti-TNF-α agent, use of other immunosuppressive drugs, and the risk of TB (p > 0.05). Multivariate logistic regression analysis showed a significantly higher risk of TB in patients diagnosed with Behçet's disease, and a significantly lower risk of TB in patients with a tuberculin skin test wheal ≥10 mm in diameter (p < 0.05). CONCLUSION: aTNF-α-T is associated with an increased risk of pulmonary or extrapulmonary TB, even when follow-up protocols and INH chemoprophylaxis are implemented, and TB often develops in the later stages of treatment. The risk of TB was higher in patients with Behçet's disease and lower in patients who had a strong tuberculin skin test reaction.

Antigen location contributes to the pathological features of a transplanted heart graft.

Organ-specific injury after transplantation presents with a variety of clinical and pathological phenotypes, yet the factors influencing development of each outcome are poorly understood. Because primed T lymphocytes must re-encounter their antigen within the target organ to engage effector functions, we postulated that the cellular location of antigen within that organ could significantly impact the induced pathology. We challenged female Marilyn CD4 T-cell receptor transgenic mice, in which all T cells are specific for the male minor transplantation antigen, with male heart transplants expressing the relevant peptide: major histocompatibility complex on either graft parenchymal/vascular cells or alternatively, on graft-infiltrating mononuclear cells. The two different graft donors led to equivalent activation of recipient T cells as assessed by frequency, cell surface marker expression, cytokine production, and the ability to traffic to the graft. Nonetheless, if the target antigen was expressed on graft vascular and/or parenchymal cells, the outcome was acute graft destruction. In contrast, if the antigen was expressed only on graft-infiltrating mononuclear cells the same effector T-cell repertoire caused chronic rejection and vasculopathy. This unique result, that target antigen location can influence pathological outcome, has significant implications for understanding the pathogenesis of chronic allograft injury in humans.

Effects of green tea polyphenols on murine transplant-reactive T cell immunity.

Green tea polyphenols (GrTP), the active ingredient of green tea, may have immunosuppressive properties, but whether and how GrTP affect transplant-reactive T cells is unknown. To address this, we tested the effects of GrTP on in vitro and in vivo transplant-reactive T cell immunity. GrTP inhibited IFNgamma secretion by cultured monoclonal T cells and by alloreactive T cells in mixed lymphocyte reactions. Oral GrTP significantly prolonged minor antigen-disparate skin graft survival and decreased the frequency of donor-reactive interferon gamma-producing T cells in recipient secondary lymphoid organs compared to controls. In contrast to other hypothesized actions, oral GrTP did not alter dendritic cell trafficking to lymph nodes or affect metalloproteinase activity in the graft. This is the first report of an immunosuppressive effect of GrTP on transplant-reactive T cell immunity. The results suggest that oral intake of green tea could act as an adjunctive therapy for prevention of transplant rejection in humans.

The male minor transplantation antigen preferentially activates recipient CD4+ T cells through the indirect presentation pathway in vivo.

To evaluate the priming and trafficking of male Ag-reactive CD4(+) T cells in vivo, we developed an adoptive transfer model, using Marilyn (Mar) TCR transgenic T cells that are specific for the H-Y minor transplantation Ag plus I-A(b). By manipulating donor and recipient strain combinations, we permitted the Mar CD4(+) T cells to respond to the H-Y Ag after processing and presentation by recipient APCs (indirect pathway), or to the male Ag as expressed on donor APCs (direct pathway). Mar CD4(+) T cells responding through the indirect pathway specifically proliferated and expressed activation markers between days 2 and 4 posttransplant, migrated to the graft 2-3 days before cessation of graft heartbeat, and were detected in close proximity to transplant-infiltrating recipient APCs. Intriguingly, adoptively transferred Mar T cells did not respond to male heart or skin grafts placed onto syngeneic MHC class II-deficient female recipients, demonstrating that activation of Mar T cell preferentially occurs through cognate interactions with processed male Ag expressed on recipient APCs. The data highlight the potency of indirect processing and presentation pathways in vivo and underscore the importance of indirectly primed CD4(+) T cells as relevant participants in both the priming and effector phases of acute graft rejection.

Cardiac allograft rejection in the absence of macrophage migration inhibitory factor.

BACKGROUND: Macrophage migration inhibitory factor (MIF) is a secreted proinflammatory lymphokine essential for elicitation of delayed-type hypersensitivity (DTH) reactions in vivo. We tested whether MIF blockade-absence affected acute or chronic murine cardiac allograft rejection. METHODS: Wild-type (WT) C57BL/6 (B6) mice underwent transplantation with BALB/c hearts with or without blocking anti-MIF antibody, and MIF knockout (KO) B6 mice underwent transplantation with MIF KO BALB/c hearts. Chronic immune injury was induced in WT and KO recipients using donor-specific transfusion and anti-CD40L antibody. RESULTS: Unexpectedly, the blockade or genetic absence of MIF did not prolong graft survival even if recipient T-cell cytotoxicity was additionally impaired. The histologic manifestations of acute and chronic immune injury to the allograft were similar between groups. CONCLUSIONS: MIF is not required for acute or chronic allograft rejection in mice. The findings raise questions about the role of DTH as an important mediator of cardiac allograft injury.