anti-CD74 Antibodies Research Articles

Potential protumor function of CD74 in clear cell renal cell carcinoma.

CD74 is a transmembrane protein that functions as a specialized chaperone of HLA class II and CD74 in tumor cells was suggested to be involved in cell proliferation in several kinds of malignant tumors. CD74 is also known to be expressed in macrophages, therefore, we investigated the CD74 expression in clear cell renal cell carcinoma (ccRCC). Immunohistochemistry of CD74 indicated that CD74 was expressed not only in cancer cells but also macrophages. CD74 was detected in surface membrane and cytoplasm of cancer cells in 92 of 94 cases (98%) and of 87 of 94 cases (93%). CD74 was expressed both in cancer cells and TAMs in 86 of 94 cases (91%). In vitro studies using cancer cell lines and monocyte-derived macrophages stimulated by anti-CD74 antibodies showed that CD74 signal accelerated cancer cell proliferation and macrophage activation. However, macrophage activation via CD74 signal did not influence macrophage-mediated cancer cell growth. RNA-sequence of macrophages stimulated by anti-CD74 antibodies indicated that CD74 signal was associated to inflammatory responses in macrophages. In conclusion, we examined the expression and functional significance of CD74 in ccRCC using tissue specimens and cell culture studies. The function of CD74 was suggested to be different in cancer cells and in macrophages, and further studies are necessary to clarify the functional significance of CD74 in ccRCC.

Year in Review in Axial Spondyloarthritis Clinical Research and Guidelines: SPARTAN 2023 Annual Meeting Proceedings.

To highlight high impact clinical publications in spondyloarthritis from May 2022 to April 2023 that were summarized and presented at the SPARTAN annual meeting in May 2023. Publications included updated guidelines on management of axial spondyloarthritis (axSpA) by ASAS-EULAR and development of a modified Juvenile Spondyloarthritis Disease Activity Index (JSpADA). Definitions were published for MRI lesions of the spine in axSpA and active and structural sacroiliac (SI) joint lesions in juvenile spondyloarthritis (JSpA). Anatomic variants of the sacroiliac joint were commonly detected using synthetic CT derived from pelvis MRI images. Anti-CD74 antibodies hold promise as a diagnostic biomarker for axSpA; however, the mechanism of such antibody development seems unrelated to gastrointestinal inflammation. High impact clinical publications in spondyloarthritis addressed lab-based and imaging biomarkers, outcome measures, and updated management guidelines.

The Level of IgA Antibodies to CD74 in Patients with Spondyloarthritis and Degenerative-Dystrophic Diseases of the Spine

Background. According to the scientific literature, anti-CD74 IgA antibodies (IgA anti-CD74) are considered as a possible marker for the diagnosis of axial spondyloarthritis (SpA). The level of IgA anti-CD74 in patients with back pain due to degenerative spine disease has not been studied. Therefore, it could be interesting to compare the serum levels of IgA anti-CD74 in patients with chronic back pain in various diseases. Aim: to compare the levels of IgA anti-CD74 in patients with SpA and degenerative spine diseases. Material and methods. A total of 87 SpA patients (55 male, mean age 41 [29; 49] years) fulfilling the Assessment of Spondyloarthritis International Society (2009) criteria for Axial SpA, and 39 patients (25 male, mean age 45 [34; 53] years) with neurologist-verified degenerative spine diseases (ICD 10 codes — M 51.1 and M 54.4) were enrolled to the study. The serum levels of IgA anti-CD74 were analyzed by enzyme-linked immunosorbent assay (ELISA) in all patients. Results. The median levels of IgA anti-CD74 in patients with SpA were 11.3 [5.4; 19.4] U/ml, in patients with degenerative spine disease — 6.9 [4.5; 13.7] U/ml (p=0.024). IgA anti-CD74 serum levels were above the cut-off value in 58 (66.7 %) patients with SpA and only in 11 (28.2 %) patients with degenerative spine disease (p<0,001). The elevated serum levels of IgA anti-CD74 were detected in 10 (40 %) of 25 male patients and in 1 (7.1 %) of 14 female patients (p = 0.029, χ2 = 4.785) with degenerative spine disease. Conclusion. Serum levels of I gA anti-CD74 were increased in two-thirds of patients with SpA. IgA anti-CD74 was significantly higher in SpA patients compared to patients with degenerative spine disease. >< 0,001). The elevated serum levels of IgA anti-CD74 were detected in 10 (40 %) of 25 male patients and in 1 (7.1 %) of 14 female patients (p = 0.029, χ2 = 4.785) with degenerative spine disease. Conclusion. Serum levels of I gA anti-CD74 were increased in two-thirds of patients with SpA. IgA anti-CD74 was significantly higher in SpA patients compared to patients with degenerative spine disease.

Macrophage migration inhibitory factor (MIF) and IgA anti CD74 antibodies in Indian patients with enthesitis-related arthritis category of Juvenile idiopathic arthritis.

Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine and has been implicated in pathogenesis of ankylosing spondylitis (AS). CD 74 is the receptor for MIF and IgA antiCD74 autoantibodies have been described from different parts of the world in patients with AS. As enthesitis-related arthritis (ERA) is a form of juvenile spondyloarthropathy, we studied the serum and synovial fluid levels of MIF in ERA and looked for the IgA antiCD74 antibodies in patients with ERA in our population. Patients with JIA (ILAR classification) were studied. Serum MIF levels were measured by ELISA in 101 patients of ERA (synovial fluid also where available) and compared to 28 patients of other categories of JIA, 25 patients each of ankylosing spondylitis and rheumatoid arthritis, and 38 healthy controls. In addition, associationof MIF with disease activity was assessed. Ig A antiCD74 antibodies were measured in sera of ERA, AS and healthy controls. Median serum MIF levels were higher in ERA [2.50 (1.20-4.85) ng/ml] than in healthy controls [0.28 (0.16-0.48); p < 0.0001] and patients with RA [1.13 (0.44-2.45); p < 0.01] MIF levels in ERA were comparable to other categories of JIA [2.63 (1.70-4.05)] and patients with AS [3.62 (0.52-6.51)]. Synovial fluid MIF levels were higher than serum levels (p < 0.01). Serum MIF level had an association with the JSpADA score (r = 0.29, p < 0.01). Serum MIF levels had no association with presence of inflammatory markers, enthesitis, inflammatory back pain or sacroiliitis. IgA AntiCD74 antibody was positive only in 3/88 (3.41%) of ERA patients and was not detected in any patients of AS or healthy controls. Patients with ERA have high MIF levels that show modest correlation with disease activity. Higher synovial fluid MIF levelssuggest that it may play a role in synovitis seen in ERA. IgA antiCD74 antibodies are rarely seen in ERA.

Anti-CD74 IgA antibodies show diagnostic potential for axial spondyloarthritis but are not associated with microscopic gut inflammation.

Gut inflammation commonly occurs in axial SpA (axSpA), and is linked to disease activity and outcome. Given the role of IgA in mucosal immunity, we explored the association between anti-CD74 IgA antibodies, gut inflammation and axSpA. Anti-CD74 IgA was measured by ELISA in serum samples of axSpA patients, fulfilling the 2009 Assessment of SpondyloArthritis international Society classification criteria. A group of fibromyalgia (FM) and RA patients served as non-inflammatory and inflammatory controls. Newly diagnosed axSpA patients underwent ileocolonoscopy; mucosal biopsies were histopathologically assessed as normal, acute or chronically inflamed. Optimal anti-CD74 IgA cut-off values were determined with a receiver operating characteristics curve. axSpA patients (n = 281) showed higher anti-CD74 IgA levels [mean (s.d.) 18.8 (12.4) U/ml] compared with 100 FM patients [10.9 (5.0) U/ml, P < 0.001] and 34 RA patients [13.7 (9.6) U/ml, P = 0.02]. The area under the receiver operating characteristics curve for diagnosis (axSpA vs FM) was 0.70, providing a sensitivity of 60% and specificity of 87% (cut-off 15 U/ml). Antibody concentrations were not significantly different between axSpA patients with (n = 40) and without (n = 69) gut inflammation (P = 0.83), yielding an area under the receiver operating characteristics curve of 0.51. Anti-CD74 IgA levels were not associated with degree of bone marrow oedema on MRI of the sacroiliac joints, CRP or any other disease-specific feature such as the use of NSAIDs or biological treatment. Serum anti-CD74 IgA is a potentially useful diagnostic biomarker for axSpA. However, antibody levels do not correlate with any phenotypical feature, including microscopic gut inflammation, suggesting this to be a disease-specific rather than an inflammatory marker.

The association of anti-CD74 antibody with spondyloarthropathies.

The etiopathogenesis of spondyloarthropathies (SpA) is still unclear. Recently, anti-CD74 antibody has been suspected to play a role in SpA etiopathogenesis. This study aimed to examine the levels of anti-CD74 antibody in patients with SpA and investigate their association with disease activity. This study was conducted using data from patients who were treated at the departments of rheumatology and gastroenterology between June 2013 and November 2013. The demographic and clinical characteristics of the participants and their serum IgG-type antibodies against anti-CD74 were analyzed. We analyzed 111 patients with ankylosing spondylitis (AS), 108 patients with inflammatory bowel disease (IBD), and 101 healthy controls. The rate of human leukocyte antigen-B27 positivity was 86.5% in patients with AS and 21.3% in patients with IBD. The mean levels of anti-CD74 antibodies in the AS, IBD, and control groups were 6.99±3.24 ng/mL, 6.25±3.34 ng/mL, and 7.83±4.72 ng/mL, respectively. Anti-CD74 levels were higher in healthy controls than in patients with IBD (p=0.009). There was no significant difference in anti-CD74 levels between the AS and IBD groups and the AS and control groups. In addition, there was no correlation between anti-CD74 levels and disease activity. This study could not find an association between anti-CD74 levels and SpA in Turkish patients.

Macrophage migration inhibitory factor exerts pro-proliferative and anti-apoptotic effects via CD74 in murine hepatocellular carcinoma.

Macrophage migration inhibitory factor (MIF) is an inflammatory and chemokine-like protein expressed in different inflammatory diseases as well as solid tumours. CD74-as the cognate MIF receptor-was identified as an important target of MIF. We here analysed the role of MIF and CD74 in the progression of hepatocellular carcinoma (HCC) in vitro and in vivo. Multilocular HCC was induced using the diethylnitrosamine/carbon tetrachloride (DEN/CCl4 ) model in hepatocyte-specific Mif knockout (Mif Δhep ), Cd74-deficient, and control mice. Tumour burden was compared between the genotypes. MIF, CD74 and Ki67 expression were investigated in tumour and surrounding tissue. In vitro, the effects of the MIF/CD74 axis on the proliferative and apoptotic behaviour of hepatoma cells and respective signalling pathways were assessed after treatment with MIF and anti-CD74 antibodies. DEN/CCl4 treatment of Mif Δhep mice resulted in reduced tumour burden and diminished proliferation capacity within tumour tissue. In vitro, MIF stimulated proliferation of Hepa 1-6 and HepG2 cells, inhibited therapy-induced cell death and induced ERK activation. The investigated effects could be reversed using a neutralizing anti-CD74 antibody, and Cd74-/- mice developed fewer tumours associated with decreased proliferation rates. We identified a pro-tumorigenic role of MIF during proliferation and therapy-induced apoptosis of HCC cells. These effects were mediated via the MIF cognate receptor CD74. Thus, inhibition of the MIF/CD74 axis could represent a promising target with regard to new pharmacological therapies aimed at HCC.

Ankylosing spondylitis: an autoimmune or autoinflammatory disease?

Ankylosing spondylitis (AS) is a chronic inflammatory disorder of unknown aetiology. Unlike other systemic autoimmune diseases, in AS, the innate immune system has a dominant role characterized by aberrant activity of innate and innate-like immune cells, including γδ T cells, group 3 innate lymphoid cells, neutrophils, mucosal-associated invariant T cells and mast cells, at sites predisposed to the disease. The intestine is involved in disease manifestations, as it is at the forefront of the interaction between the mucosal-associated immune cells and the intestinal microbiota. Similarly, biomechanical factors, such as entheseal micro-trauma, might also be involved in the pathogenesis of the articular manifestation of AS, and sentinel immune cells located in the entheses could provide links between local damage, genetic predisposition and the development of chronic inflammation. Although these elements might support the autoinflammatory nature of AS, studies demonstrating the presence of autoantibodies (such as anti-CD74, anti-sclerostin and anti-noggin antibodies) and evidence of activation and clonal expansion of T cell populations support an autoimmune component to the disease. This Review presents the evidence for autoinflammation and the evidence for autoimmunity in AS and, by discussing the pathophysiological factors associated with each, aims to reconcile the two hypotheses.

Anti-CD74 IGA antibodies, genetic polymorphisms and inflammatory activity in ankylosing spondylitis

IgA anti-CD74 can be a promising marker for diagnosis, assessment of activity and prognosis for ankylosing spondylitis. The aim of the study was to determine the level of IgA anti-CD74 in patients with ankylosing spondylitis and to evaluate its relationships with ankylosing spondylitis activity and carriership of genetic alleles. Materials and methods . In 48 patients with a reliable diagnosis of ankylosing spondylitis, aged 18 to 69 years were measured the ASDAScrp, BASDAI, level of highly sensitive С-reactive protein, concentration of IgA anti-CD74. The polymorphisms of the genes interleukin (IL)-17A197 a/g, IL-17F7 histidine (His) / arginine (Arg), IL-17F11139 c/g, TNF-a-863, TNFα-308, TNFα-238, IL-1B-31, IL- 4-590, IL-6-174, IL-10-1082, IL-10-592, vascular endothelial growth factor (VEGF)-2578, VEGF-936, matrix metalloproteinase (MMP)2-1306, MMP3-5A6A, MMP9-1562, HLA-B27 were evaluated in their relationships with AS activity and IgA anti-CD74 levels. Results . The mean age of patients was 45.1±14.2 years, male - 72.9%, psoriasis - 10.4%, IBD - 2.1%, BASDAI -2.99±0.28, ASDAS - 2.29±0.16, CRP - 6.5±1.65 mg/L, IgA эпй-СВ74 - 18.6±1.73 U/mL (72.9% of the patients with &gt;12 U/mL). The relationship between an increase in concentration of IgA anti-CD74 and ASDAScrp, BASDAI activity indices, between an increase in the level of CRP and the presence of the IL-17A genotype heterozygous for the AA allele (r=0.965) was determined. CRP did not demonstrate the relationship with the BASDAI. An association of IL-17F-11139 СС and the presence of psoriasis (r=0.870) was established. 93.8% of patients with ankylosing spondylitis were carriers of the homozygous histidine allele IL-17F7 (his/his) and the TNF238 allele (GG). Conclusions . The increase in anti-CD74 IgA level was found in 72.9% of patients with ankylosing spondylitis receiving inhibitors of TNF-a and NSAIDs and associated with clinical and laboratory indicators of ankylosing spondylitis activity and with carriage of the homozygous histidine allele IL-17F7 (his/his) detected in 93.8% of patients. Carriage of TNF-238 GG; TNF-863 CC; HLA-B27; TNF-308 GG; IL-4-590 CC; IL-6-174 CG; MMP9-1562 CC; MMP9-1562 CC; VEGF- 936 CC alleles was not associated with an increase in concentration of IgA anti-CD74. CRP demonstrated an association with IL-17A-197 AA (r=0.965) detected in 29.2% of patients with no correlation with the clinical ankylosing spondylitis activity in patients receiving treatment with iTNF-α and NSAIDs.

Comment on: Diagnostic value of anti-CD74 antibodies in early and late axial spondyloarthritis and its relationship to disease activity.

Comment on: Diagnostic value of anti-CD74 antibodies in early and late axial spondyloarthritis and its relationship to disease activity.

Diagnostic value of anti-CD74 antibodies in early and late axial spondyloarthritis and its relationship to disease activity.

This study was designed to evaluate the role of anti-CD74 antibodies in diagnosis of axial spondyloarthritis (axSpA) and their relationship to disease duration and disease activity. Fifty patients with axSpA, 15 patients with RA and 15 healthy subjects were included in the study. Clinical examination and laboratory tests were done. The ESR, CRP level and ASDAS were measured as markers of the disease activity. Quantitative determination of human CD74 IgG antibodies was done. The mean age of the patients was 38.22 (S.D.12.20) years. The level of CD74 autoantibodies was significantly higher in axSpA in comparison to control groups. Most patients with positive articular and extra-articular manifestations were positive for CD74 autoantibodies. In patients with inactive disease, 33.3% were positive for CD74 autoantibodies, as were 83% with active disease. High percentages of patients with early and late axSPA were CD74 autoantibody positive. The majority of patients with positive disease activity in early and late axSpA were CD74 autoantibody positive. CD74 autoantibodies had 80% sensitivity vs both control groups with 87% specificity vs the healthy control group and 80% vs the RA control group in the diagnosis of axSpA. The frequency of positive anti-CD74 IgG antibodies was as high in patients with early axSpA as in those with late axSpA, with no significant differences. There was a significant difference in the frequency of positive anti-CD74 IgG antibodies between patients with positive and negative disease activity. Based on the sensitivity and specificity of anti-CD74 IgG, this is a promising diagnostic tool to support the clinical diagnosis of axSpA.

MP28-13 ACTIVATION OF INTRAVESICAL MACROPHAGE MIGRATION INHIBITORY FACTOR (MIF) RECEPTORS MEDIATES BLADDER PAIN

You have accessJournal of UrologyBladder & Urethra: Anatomy, Physiology & Pharmacology I (MP28)1 Apr 2020MP28-13 ACTIVATION OF INTRAVESICAL MACROPHAGE MIGRATION INHIBITORY FACTOR (MIF) RECEPTORS MEDIATES BLADDER PAIN Shaojing Ye, Fei Ma, Katherine Meyer-Siegler, Lin Leng, Richard Bucala, and Pedro Vera* Shaojing YeShaojing Ye More articles by this author , Fei MaFei Ma More articles by this author , Katherine Meyer-SieglerKatherine Meyer-Siegler More articles by this author , Lin LengLin Leng More articles by this author , Richard BucalaRichard Bucala More articles by this author , and Pedro Vera*Pedro Vera* More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000000867.013AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Activation of intravesical protease activated receptor-4 (PAR4) releases urothelial MIF to mediate release of urothelial high mobility group box1 (HMGB1) and mediate bladder pain. MIF receptors (CD74, CXCR2 OR CXCR4) are all localized within the urothelium and their role in bladder pain remains to be determined. We hypothesized that MIF mediates bladder pain by interacting with urothelial MIF receptors. Therefore, we tested whether intravesical antagonism of MIF reduces or prevents bladder pain. METHODS: PAR4 (100 µM; 1hr) was intravesically infused in female C57BL/6 mice under isoflurane anesthesia. Bladder pain (50% mechanical threshold on lower abdomen by von Frey (VF) stimulation) was measured before (baseline) and 24 hr post-PAR4 infusion. Scrambled PAR4 peptide (Scramb) was used as control. Intravesical pre-treatment (10 min prior to PAR4) with PBS, isotype control antibodies, neutralizing anti-MIF or anti-CD74 monoclonal antibodies, AMD-3100 (CXCR4 antagonist) and SB225002 (CXCR2 antagonist) tested the effect of specific MIF receptor antagonism on PAR4-induced bladder pain. Voided volume and frequency were also measured at 24 hr. At the end of experiments, bladders were collected for histology. ANOVA with Tukey post-hoc tests was used. RESULTS: Intravesical scrambled peptide did not produce bladder pain while intravesical PAR4 induced bladder pain. Pre-treatment with neutralizing anti-MIF or anti-CD74 antibodies, or CXCR4 antagonist prevented PAR4-induced bladder pain (Figure 1). Pretreatment with CXCR2 antagonist was not effective. No significant effects were noted on micturition volume while anti-CD74 pretreatment increased frequency slightly (Table 1). CONCLUSIONS: Intravesical MIF receptors (CD74 and CXCR4, but not CXCR2) mediate bladder pain. Future experiments will examine how intravesical antagonism of MIF or its receptors contributes to downstream mechanisms (e.g. release of urothelial HMGB1) that mediate bladder pain. Source of Funding: DK121695 (PLV); AR049610 (RB) © 2020 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 203Issue Supplement 4April 2020Page: e425-e425 Advertisement Copyright & Permissions© 2020 by American Urological Association Education and Research, Inc.MetricsAuthor Information Shaojing Ye More articles by this author Fei Ma More articles by this author Katherine Meyer-Siegler More articles by this author Lin Leng More articles by this author Richard Bucala More articles by this author Pedro Vera* More articles by this author Expand All Advertisement PDF downloadLoading ...

CD74 Signaling Links Inflammation to Intestinal Epithelial Cell Regeneration and Promotes Mucosal Healing.

Background & AimsThe inflammatory response to intestinal damage promotes healing through mechanisms that are incompletely understood. Gene expression of cluster of differentiation 74 (CD74), the receptor for cytokine macrophage migration inhibitory factor, is increased in patients with inflammatory bowel disease (IBD), however, the role of CD74 signaling in intestinal inflammation remains poorly understood. The aim of this study was to determine the functional role of CD74 signaling in intestinal inflammation.MethodsWe studied the characteristics of CD74 protein expression in human IBD and experimental colitis. The functional role of CD74 signaling in the intestine was investigated using cellular models; wild-type, CD74-/-, and bone marrow chimera mice; neutralizing anti-CD74 antibodies; flow cytometry; immunohistochemistry; immunofluorescence; immunoblotting; and clustered regularly interspaced short palindromic repeats and associated protein 9 technology.ResultsIn IBD patients and experimental colitis, CD74-receptor protein expression was increased in inflamed intestinal tissue, prominently in the crypt epithelial cells. By using distinct but complementary chemical and non–chemically induced mouse models of colitis with genetic and antibody neutralization approaches, we found that CD74 signaling was necessary for gut repair. Mechanistically, we found that the macrophage migration inhibitory factor cytokine, which also is increased in colitis, stimulated the CD74 receptor, enhancing intestinal epithelial cell proliferation through activation of the protein kinase B and the extracellular signal-regulated kinase pathways. Our data also suggest that CD74 signaling in immune cells was not essential for mucosal healing.ConclusionsCD74 signaling is strongly activated during intestinal inflammation and protects the host by promoting epithelial cell regeneration, healing, and maintaining mucosal barrier integrity. Enhancing the CD74 pathway may represent a unique therapeutic strategy for promoting healing in IBD.

Added Value of Anti-CD74 Autoantibodies in Axial SpondyloArthritis in a Population With Low HLA-B27 Prevalence.

Axial spondyloarthritis (axSpA) is often diagnosed late due to the non-specific nature of its main symptom [chronic back pain (CBP)] and to the paucity of diagnostic markers, particularly in regions with low HLA-B27 prevalence, such as the Middle-East. We tested the performance of IgG4 and IgA anti-CD74 antibodies as an early diagnostic marker for axSpA, compared with the performance of HLA-B27, in Lebanon. Sera of axSpA patients diagnosed by the rheumatologist and also fulfilling the imaging arm of the ASAS criteria (patients) and of blood donors (BD) (controls) were analyzed for HLA-B27, IgG4 and IgA anti-CD74, blinded to clinical characteristics. Receiver Operating Characteristic curves were constructed to identify an optimal cut-off point for anti-CD74 antibodies. Diagnostic properties were calculated (sensitivity, specificity, positive, and positive predictive values (PPV, NPV), Likelihood ratios) for each marker. Forty-nine axSpA patients and 102 BD were included in the final analysis. IgA anti-CD74 correlated poorly with axSpA (Area Under the Curve (AUC) 0.657), whereas IgG4 anti-CD74 had a good discriminative value (AUC 0.837). Respectively, for HLA-B27, IgG4 anti-CD74, and the combination of both, we found a sensitivity of 33-92-33%, specificity of 96-79-98%, PPV 80-68-89%, NPV 75-95-75%, and LR+ 8.2-4.4-16.5. IgG4 anti-CD 74 were positive in 88% of HLA-B27 negative axSpA patients, and correlated with BASDAI. In this first study in a population with low HLA-B27 prevalence, IgG4 anti-CD74 antibodies combined with HLA-B27 showed higher diagnostic value than HLA-B27 alone for early axSpA. IgG4 anti-CD74 should be considered for further evaluation as an early axSpA diagnostic marker in future dedicated research, particularly in patients with CBP.

Anti-CD74 antibodies have no diagnostic value in early axial spondyloarthritis: data from the spondyloarthritis caught early (SPACE) cohort

BackgroundAnti-CD74 IgG antibodies are reported to be elevated in patients with axial spondyloarthritis (axSpA). This study assessed the diagnostic value of anti-CD74 antibodies in patients with early axSpA.MethodsAnti-CD74 IgG and IgA antibodies were first measured in an exploratory cohort of patients with radiographic axSpA (138 patients with ankylosing spondyloarthritis (AS)) and 57 healthy controls and then were measured in patients with early axSpA (n = 274) and with non-SpA chronic back pain (CBP) (n = 319), participating in the spondyloarthritis caught early (SPACE) prospective cohort study of patients under 45 years old with early back pain (for ≥ 3 months, but ≤ 2 years).ResultsIn the exploratory cohort, anti-CD74 IgG antibodies were present in 79.7% of patients with AS vs. 43.9% of healthy controls (p < 0.001). Anti-CD74 IgA antibodies were present in 28.5% of patients with AS vs. 5.3% of healthy controls (p < 0.001). In the SPACE cohort, anti-CD74 IgG antibody levels were present in 46.4% of the patients with axSpA vs. 47.9% of the patients with CBP (p = 0.71). Anti-CD74 IgA antibodies were present in 54.7% of the patients with axSpA and 37.0% of the patients with CBP (p < 0.001). This resulted in a positive predictive value of 58.8% (compared to a prior probability of 46.2%) and a negative predictive value of 59.1% (compared to a prior probability of 53.8%). In a regression model, total serum IgA was associated with axSpA odds ratio (OR) 1.19, p < 0.001) whereas anti-CD74 IgA was not (OR) 1.01, p = 0.33). Furthermore, anti-CD74 IgA was associated with sacroiliitis on magnetic resonance imaging (MRI) (OR) = 2.50, p = 0.005) and heel enthesitis (OR) = 2.56, p = 0.002).ConclusionsAlbeit anti-CD74 IgA is elevated in patients with early axSpA, this elevation is not sufficiently specific to yield significant diagnostic value in patients under 45 years old presenting with early back pain.

LABORATORY BIOMARKERS FOR ANKYLOSING SPONDYLITIS

Ankylosing spondylitis (AS) is a chronic inflammatory disease from a group of spondyloarthritis (SpA), which is characterized by lesions of the sacroiliac joints and spine with the common involvement of entheses and peripheral joints in the pathological process. Advances in modern laboratory medicine have contributed to a substantial expansion of the range of pathogenetic, diagnostic, and prognostic biomarkers of AS. As of now, there are key pathogenetic biomarkers of AS (therapeutic targets), which include tumor necrosis factor-α (TNF-α), interleukin 17 (IL-17), and IL-23. Among the laboratory diagnostic and prognostic biomarkers, HLA-B27 and C-reactive protein are of the greatest value in clinical practice; the former for the early diagnosis of the disease and the latter for the assessment of disease activity, the risk of radiographic progression and the efficiency of therapy. Anti-CD74 antibodies are a new biomarker that has high sensitivity and specificity values in diagnosing axial SpA at an early stage. A number of laboratory biomarkers, including calprotectin, matrix metalloproteinase-3 (MMP-3), vascular endothelial growth factor, Dickkopf-1 (Dkk-1), and C-terminal telopeptide of type II collagen (CTX II) do not well reflect disease activity, but may predict progressive structural changes in the spine and sacroiliac joints in AS. Blood calprotectin level monitoring allows the effective prediction of a response to therapy with TNF inhibitors and anti-IL-17А monoclonal antibodies. The prospects for the laboratory diagnosis of AS are associated with the clinical validation of candidate biomarkers during large-scale prospective cohort studies and with a search for new proteomic, transcriptomic and genomic markers, by using innovative molecular and cellular technologies.

An update on biomarkers in axial spondyloarthritis.

Axial spondyloarthritis is a chronic inflammatory disease with the onset at a young age, and, if undiagnosed and untreated, it may result in permanent damage and lifelong disability. Rates of early diagnosis have improved, due in particular to the addition of magnetic resonance imaging into the diagnostic armamentaria; however, it is costly, not widely available, and requires experienced readers to interpret the findings. In addition to clinical measures and imaging techniques, biomarkers that will be described in this review may represent useful tools for diagnosis, monitoring disease activity and outcomes as well as therapeutic responses. Currently, HLA-B27 remains the best genetic biomarker for making a diagnosis, while CRP currently appears to be the best circulating measure for assessing disease activity, predicting structural progression and therapeutic response. Interestingly, key molecules in the pathogenesis of the disease and essential therapeutic targets, such as tumour necrosis factor (TNF)α, interleukin (IL)-17 and IL-23, show only limited association with disease characteristics or disease progression. Some genetic biomarkers and particularly anti-CD74 antibodies, may become a promising tool for the early diagnosis of axSpA. Further biomarkers, such as matrix metalloproteinases (MMP)-3, calprotectin (S100A8/9), vascular endothelial growth factor (VEGF), C-terminal telopeptide of type II collagen (CTX-II) or dickkopf-1 (DKK-1), are not sufficient to reflect disease activity, but may predict spinal structural progression. In addition, recent data have shown that monitoring calprotectin might represent a valuable biomarker of therapeutic response. However, all of these results need to be confirmed in large cohort studies prior to use in daily clinical practice.

Proinflammatory Signature of the Dysfunctional Endothelium in Pulmonary Hypertension. Role of the Macrophage Migration Inhibitory Factor/CD74 Complex.

Inflammation and endothelial dysfunction are considered two primary instigators of pulmonary arterial hypertension (PAH). CD74 is a receptor for the proinflammatory cytokine macrophage migration inhibitory factor (MIF). This ligand/receptor complex initiates survival pathways and cell proliferation, and it triggers the synthesis and secretion of major proinflammatory factors and cell adhesion molecules. We hypothesized that the MIF/CD74 signaling pathway is overexpressed in idiopathic PAH (iPAH) and contributes to a proinflammatory endothelial cell (EC) phenotype. Primary early passage cultures of human ECs isolated from lung tissues obtained from patients with iPAH and controls were examined for their ability to secrete proinflammatory mediators and bind inflammatory cells with or without modulation of the functional activities of the MIF/CD74 complex. In addition, we tested the efficacies of curative treatments with either the MIF antagonist ISO-1 or anti-CD74 neutralizing antibodies on the aberrant proinflammatory EC phenotype in vitro and in vivo and on the progression of monocrotaline-induced pulmonary hypertension. In human lung tissues, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selectin expressions are markedly up-regulated in the endothelium of distal iPAH pulmonary arteries. Circulating MIF levels are increased in the serum of patients with PAH compared with control subjects, and T-cell lymphocytes represent a source of this overabundance. In addition, CD74 is highly expressed in the endothelium of muscularized pulmonary arterioles and in cultured pulmonary ECs from iPAH, contributing to an exaggerated recruitment of peripheral blood mononuclear cells to pulmonary iPAH ECs. Finally, we found that curative treatments with the MIF antagonist ISO-1 or anti-CD74 neutralizing antibodies partially reversed development of pulmonary hypertension in rats and substantially reduced inflammatory cell infiltration. We report here that CD74 and MIF are markedly increased and activated in patients with iPAH, contributing to the abnormal proinflammatory phenotype of pulmonary ECs in iPAH.

FRI0279 High prevalence of anti-CD 74 antibodies with specificity for the class II-associated invariant chain peptide (clip) in patients with axial spondyloarthritis but not in controls

BackgroundThe pathogenesis of axial spondyloarthritis (axSpA) including ankylosing spondylitis (AS), although known to be strongly associated with genes such as the human leukocyte antigen (HLA) B27, is still largely unclear....

High prevalence of anti-CD74 antibodies specific for the HLA class II-associated invariant chain peptide (CLIP) in patients with axial spondyloarthritis

ObjectivesThe pathogenesis of axial spondyloarthritis (axSpA) is still unclear. There is a strong association with HLA-B27 and other genes. Recently, anti-CD74 antibodies with specificity to a class II-associated invariant chain...