Gut inflammation in psoriatic arthritis: a prospective ileocolonoscopic study

Some forms of psoriatic arthritis (PsA) are classified as spondylarthropathy, and subclinical gut inflammation is found in spondylarthropathies. Our study was designed to determine if inflammatory gut lesions were also present in PsA, and if the prevalence of subclinical gut involvement was different in the subgroups of this disease. The relationship with HLA subtypes was also determined.

Ileocolonoscopy was performed on 64 patients with PsA (37 men, 27 women).

Inflammatory gut lesions were found in 10 of the 64 patients (16%): in 3 of the 15 patients (20%) with oligoarthritis and in 7 of the 23 patients (30%) with axial involvement. None of the 26 patients with polyarthritis showed these lesions. The prevalence of HLA-B27, Bw62, and B17 was significantly raised in our total group of patients with PsA. HLA-B27 and Bw62 were significantly more prevalent in patients with gut inflammation, 60 and 50%, respectively.

Gut inflammation is only present in PsA subgroups that belong to the spondylarthropathy concept. This suggests that the gut plays a role in the pathogenesis of locomotor inflammation in these subgroups. The prevalence of gut inflammation in psoriatic spondylarthropathy is significantly lower than in nonpsoriatic spondylarthropathies. Consequently, not only the gut but also the skin may be a portal of entry for causative antigens in PsA.