HLA-B27 status and its association with clinical, laboratory and imaging features in reactive arthritis: A cross-sectional study

Arianit Bajraktari, Besim Demolli, Bastri Durmishi, Ismet H. Bajraktari, Valton Saiti, Naser Ramadani, Jehona Ismaili-Kadriaj, Rina Hoxha, Serbeze Kabashi-Muqaj, Simeon Grazio

Pozadina: Reaktivni artritis (ReA) je upalna reumatska bolest koja pripada skupini spondiloartritisa (SpA). Etiopatogeneza ReA, kao i većine drugih entiteta SpA, povezana je s prisutnošću HLA-B27. Međutim, ostaje znatna neizvjesnost u pogledu pozitivnosti HLA-B27 i njegove povezanosti s izvorom infekcije, kliničkim, laboratorijskim i slikovnim značajkama u ReA. Cilj: Procijeniti prevalenciju antigena HLA-B27 i njegovu povezanost sa spolom i dobi na početku, izvorom infekcije, značajkama perifernog artritisa, prisutnošću sakroileitisa i upalnim opterećenjem ReA. Metode: Pacijentima s dijagnozom ReA, koji su bili hospitalizirani radi pregleda i liječenja, procijenjen je HLA-B27 status. Demografski podatci (spol i dob na početku), SE i CRP, broj i distribucija klinički zahvaćenih zglobova te prisutnost slike sakroileitisa na MR dobiveni su i analizirani prema HLA-B27 pozitivnosti. Statistička značajnost postavljena je na P < 0,05. Rezultati: Uključena su ukupno 224 bolesnika prosječne dobi 32,2 ± 6,9 godina. Većina su bili muškarci (135 bolesnika, 60,3%) (P = 0,0021), a bolest je uglavnom počela u dobnoj skupini od 30 do 39 godina (P < 0,00001). Ukupna prevalencija HLA-B27 bila je 70,5%, bez značajne povezanosti s bilo kojim spolom (P = 0,153). Razina C-reaktivnog proteina (CRP) i sedimentacije eritrocita (SE) bila je značajno viša u HLA-B27-pozitivnih bolesnika (za oboje P = 0,001). Postojala je tendencija češćeg opažanja sakroileitisa u HLA-B27-pozitivnih pacijenata, iako rezultat nije dosegao značajnost (P = 0,0517). U usporedbi s drugim lokacijama, infekcija urogenitalnog trakta bila je povezana s najvećom prevalencijom HLA-B27 pozitivnosti (P < 0,00001). Zaključak: U našoj studiji pacijenata s ReA, rezultati pokazuju da profiliranje temeljeno na statusu HLA-B27 može biti povezano s urogenitalnim izvorom infekcije i dragocjeno je za predviđanje više razine sistemske upale, kao i tendencije otkrivanja sakroileitisa.

Background: Reactive arthritis (ReA) is an inflammatory rheumatic disease that belongs to the group of spondyloarthritis (SpA). Etiopathogenesis of ReA, as well as the majority of other SpA entities, is linked with the presence of HLA-B27. However, considerable uncertainty remains regarding the HLA-B27 positivity and its association with the source of infection, clinical, laboratory, and imaging features in ReA. Aim: To assess the prevalence of the HLA-B27 antigen and its relationship with gender and age at onset, source of infection, features of peripheral arthritis, presence of sacroiliitis, and inflammatory burden of ReA. Methods: Patients diagnosed with ReA, who were hospitalized for a work-up and treatment, were evaluated for HLA-B27 status. Demographic data (gender and age at onset), ESR and CRP, number and distribution of clinically affected joints, and presence of sacroiliitis imaging on MRI were obtained and analyzed towards HLA-B27 positivity. Statistical significance was set at P<0.05. Results: A total of 224 patients with a mean age of 32.2±6.9 years were included. The majority were males (135 patients, 60.3%) (P = 0.0021), and the disease mostly started in the age group of 30–39 years (P<0.00001). The overall prevalence of HLA-B27 was 70.5%, with no significant association with any gender
(P=0.153). C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) levels were significantly higher in HLA-B27 positive patients (for both P =0.001). There was a tendency to observe sacroiliitis more frequently in HLA-B27 positive patients, although the result did not reach significance (P = 0.0517). Compared to other locations urogenital tract infection was associated with the highest prevalence of HLA-B27 positivity (P<0.00001). Conclusion: In our study of ReA patients, results indicate that profiling based on HLA-B27 status can be associated with a urogenital source of infection and is valuable for predicting a higher level of systemic inflammation, as well as a tendency to detect sacroiliitis.