Study of Plasma Anti-CD26 Autoantibody Levels in a Cohort of Treatment-Naïve Early Arthritis Patients

• Published in: Archivum Immunologiae et Therapiae Experimentalis 2022-12, Vol.70 (1), p.12-12, Article 12
• Main Authors: Cordero, Oscar J., Viéitez, Irene, Altabás, Irene, Nuño-Nuño, Laura, Villalba, Alejandro, Novella-Navarro, Marta, Peiteado, Diana, Miranda-Carús, María-Eugenia, Balsa, Alejandro, Varela-Calviño, Rubén, Gomez-Tourino, Iria, Pego-Reigosa, José M.
• Format: Article
• Language: English
• Subjects: Arthritis; Arthritis, Rheumatoid; Autoantibodies; Biomarkers; Biomedical and Life Sciences; Biomedicine; Dipeptidyl Peptidase 4; Dipeptidyl-peptidase IV; Disease; Humans; Immunoglobulin A; Immunoglobulin G; Immunoglobulin M; Immunology; Isotypes; Original; Original Article; Patients; Pharmacology/Toxicology; Prospective Studies; Rheumatoid arthritis; Rheumatoid Factor; Rheumatology
• ISSN: 0004-069X; 1661-4917
• DOI: 10.1007/s00005-022-00649-6

In rheumatoid arthritis (RA), the identification of biomarkers to adjust treatment intensity and to correctly diagnose the disease in early stages still constitutes a challenge and, as such, novel biomarkers are needed. We proposed that autoantibodies (aAbs) against CD26 (DPP4) might have both etiological importance and clinical value. Here, we perform a prospective study of the potential diagnostic power of Anti-CD26 aAbs through their quantification in plasmas from 106 treatment-naïve early and undifferentiated AR. Clinical antibodies, Anti-CD26 aAbs, and other disease-related biomarkers were measured in plasmas obtained in the first visit from patients, which were later classified as RA and non-RA according to the American College of Rheumatology criteria. Two different isotype signatures were found among ten groups of patients, one for Anti-CD26 IgA and other for Anti-CD26 IgG and IgM isotypes, both converging in patients with arthritis (RA and Unresolved Undifferentiated Arthritis: UUA), who present elevated levels of all three isotypes. The four UUA patients, unresolved after two years, were ACPA and rheumatic factor (RF) negatives. In the whole cohort, 51.3% of ACPA/RF seronegatives were Anti-CD26 positives, and a similar frequency was observed in the seropositive RA patients. Only weak associations of the three isotypes with ESR, CRP and disease activity parameters were observed. Anti-CD26 aAbs are present in treatment-naïve early arthritis patients, including ACPA and RF seronegative individuals, suggestive of a potential pathogenic and/or biomarker role of Anti-CD26 aAbs in the development of rheumatic diseases.