Is precision medicine possible in rheumatic diseases? Lessons from selective use of targeted therapies in patients with psoriatic arthritis

Dawn of Precision Medicine in Psoriatic Arthritis

The establishment of precision medicine is considered particularly important in heterogeneous autoimmune diseases (e.g., psoriatic arthritis, systemic lupus erythematosus), which reveal clinical and molecular heterogeneity. The selection of optimal treatment strategies for individual patients may be more important and complex in autoimmune diseases than in other diseases. Two factors are important in precision medicine: patient stratification and use of targeted. When both factors work, patients are likely to have good outcomes. However, research into precision medicine and its practice in systemic autoimmune diseases is lacking. In contrast, the usefulness of peripheral immune cell phenotyping in the evaluation of immunological characteristics and stratification into subgroups of individual patients with systemic autoimmune diseases such as immunoglobulin 4-related disease, systemic lupus erythematosus, and anti-neutrophil cytoplasmic antibody-related vasculitis was reported. Furthermore, the potential of precision medicine using biological disease-modifying antirheumatic drugs based on peripheral immune cell phenotyping was recently demonstrated for psoriatic arthritis in the clinical setting. Precision medicine has not yet been sufficiently investigated in real world clinical settings. However, a dawn of precision medicine has emerged. We should shed further light on precision medicine in PsA and other autoimmune diseases. Here, we first review the usefulness of peripheral immune cell phenotyping in systemic autoimmune diseases and the potential of precision medicine in PsA based on this method.

The approach to precision medicine for the treatment of psoriatic arthritis

In rheumatic diseases, advances in biological molecular-targeted therapies have brought remarkable progress in treatment, but the molecular and clinical heterogeneity of the diseases can often pose a treatment challenge. In psoriatic arthritis, each patient exhibits various symptoms, and some may be resistant to treatment. It is difficult to improve all of these various symptoms simultaneously with the use of limited drugs. Therefore, precision medicine is an urgent concern that is required to overcome this problem. However, few studies focus on the precision medicine in rheumatic disease including psoriatic arthritis. We explored the potential of precision medicine in which patients with psoriatic arthritis are stratified by lymphocyte flow cytometry to select specific biologics. Selecting specific biologics according to different immunophenotypes of peripheral blood lymphocytes in psoriatic arthritis was shown to produce high therapeutic responses; in other words, the potential of precision medicine was suggested. The peripheral blood lymphocyte analysis can be applied to many other rheumatic diseases presenting various clinical features, such as spondyloarthritis and systemic lupus erythematous. We should shed light on the precision medicine not only in the psoriatic arthritis also in the other rheumatic disease.