Multiple Biologics Replacement for the Treatment of SAPHO Syndrome

SAPHO syndrome is a syndrome characterized by synovitis, acne, pustulosis, hyperostosis and osteomyelitis, or SAPHO syndrome, first proposed by Chamot et al. in 1987. The disease mainly involves the skin, bone and joints, and is a chronic disease with recurrent episodes. In particular, bone involvement is characterized by recurrent episodes of multifocal osteitis, bone hypertrophy, and synovitis of the anterior chest wall, including the clavicle, low ribs, pelvis, and other medial and extremity bones. Because patients with SAPHO syndrome often present with skeletal changes, most people categorize SAPHO as one of the seronegative spondyloarthropathies (SpA).Skin lesions in SAPHO syndrome often present as pustular psoriasis, palmar and toe pustulosis, or severe acne, and diseases such as pustular sweatitis and follicular occlusive vasculitis have also been reported to occur in SAPHO syndrome. Several individual cases of successful treatment of SAPHO with TNF-a inhibitors have been reported. Although the role of TNF-a inhibitors in SAPHO is not completely certain, they are still a good option for patients with recalcitrant SAPHO. Successively, Wagner, Massara, and Moll C reported that infliximab combined with NSAIDs and non-biologic DMARDs drugs or etanercept in the treatment of recalcitrant SAPHO syndrome can effectively alleviate chest wall pain and pustulosis in patients with SAPHO, which led to a significant remission, respectively. Meanwhile, tissue biopsy revealed a large amount of TNF-a production in the patient’s bone tissue, further proving the effectiveness of TNF-a inhibitors. However, cases of TNF-a inhibitors (infliximab, adalimumab, etanercept) inducing psoriasiform rash and pustulosis of the palms and toes in the treatment of rheumatic diseases have been reported, and similarly, a tendency to exacerbate pustulosis of the palms and toes with the addition of biologics for the treatment of SAPHO syndrome has been found in the clinical study of Wagner, Massara, et al. However, the pustulosis of the species was locally relief with the use of steroid ointment. In addition, Arias-Santiago et al. have reported that switching to infliximab in a SAPHO patient who was ineffective on conventional therapeutic agents resulted in a significant reduction in bone pain but an aggravation of herpes pustule, followed by a switch to adalimumab, which resulted in sustained remission after 10 months, with a negative manifestation on a Tc-99m bone scan. In this individual patient, after 8 doses of infliximab, there was a significant reduction in bone pain but no significant relief of pustules on the palms and toes, a manifestation consistent with that reported by Massara et al. However, in this individual patient, the pustules on the palms and toes improved markedly but the relief of bone pain was not significant at the initial stage after switching to adalimumab therapy. Therefore, given the shortcomings of infliximab in the treatment of pustular disease of the palms and toes, the humanized TNF-a inhibitor, adalimumab, may be more advantageous for the treatment of SAPHO syndrome either alone or in alternation with infliximab. This case demonstrates that both TNF-a inhibitors can improve the clinical symptoms of SAPHO syndrome and promote remission to varying degrees; however, the use of TNF-a inhibitors must be based on the use of conventional DMARDs, i.e., biologics need to be used in conjunction with DMARDs in order to promote complete remission of the disease. Furthermore, the patient in this case had a transient thyroid function abnormality and parotid gland swelling after the use of multiple biologics, in order to clarify the specific mechanism of TNF-a inhibitors in the treatment of SAPHO and whether it will cause glandular and other organ damage and other adverse reactions need to be a large number of clinical and basic in-depth investigation.