In this journal club review, clinical pharmacist Danielle Gatti Palumbo, breaks down a March 2025 study examining how guselkumab’s unique Fc-domain interactions with CD64-positive, IL-23–producing myeloid cells enhance its potency in neutralizing IL-23 signaling. The discussion explores the immunologic role of IL-23 in inflammatory diseases such as psoriasis, psoriatic arthritis, and inflammatory bowel disease, compares Fc-domain differences between IL-23 inhibitors, and highlights key in vitro findings using flow cytometry, live-cell imaging, and co-culture assays. This concise overview helps APPs and clinicians better understand emerging mechanisms that may influence therapeutic efficacy and treatment selection in IL-23–driven inflammatory conditions.

In this focused educational video, Heather Mambretti, PA-C, a rheumatology APP with over 12 years of experience and a faculty and board member for RhAPP, explains how hypophosphatasia (HPP) is diagnosed and highlights the key laboratory markers clinicians should not overlook. The discussion reviews the hallmark finding of persistently low serum alkaline phosphatase (ALP), additional supportive labs, characteristic clinical features in adult patients, and the role of imaging and genetic testing in confirming an HPP diagnosis. Designed for APPs and clinicians, this overview emphasizes practical strategies for identifying adult-onset hypophosphatasia, differentiating it from other musculoskeletal conditions, and improving diagnostic confidence in real-world rheumatology practice.

In this video, Lindsay Tom, PA-C, takes a focused look at the emerging connection between CD64 and IL-23 across inflamed joint, skin, and gut tissue. Drawing from real-world immunology and disease-state research, she explores why this pathway matters in immune-mediated inflammatory conditions such as psoriasis, psoriatic arthritis, and inflammatory bowel disease. The discussion highlights how CD64-expressing myeloid cells may influence inflammatory signaling, how this relationship shows up differently across tissues, and why these insights are shaping the way clinicians think about disease activity and treatment selection. This concise overview offers valuable perspective for APPs and clinicians looking to better understand the immunologic drivers behind these complex conditions and the therapies designed to target them. Visit the RhAPP Content Rheum or the RhAPP ACE 2.0 app for more rheumatology education.

In this educational rheumatology video, physician assistant Lindsay Tom, PA-C, from the Northern Virginia Center for Arthritis, provides a clear and clinically relevant overview of CD64, also known as FC gamma receptor I, and its role in immune system function. The discussion explores how CD64 is expressed on myeloid lineage cells such as monocytes, macrophages, and dendritic cells, and how it contributes to innate immunity by binding IgG antibodies and triggering phagocytosis and pro-inflammatory cytokine release, including TNF-α. The video also explains CD64’s role in adaptive immunity through antigen processing and presentation to T cells, leading to immune activation and immunologic memory. Importantly, this overview highlights how dysregulated or excessive CD64 activation may contribute to chronic inflammation, tissue damage, and antibody-mediated autoimmune diseases—making it a key concept for clinicians managing inflammatory and rheumatic conditions. This video is part of ongoing educational content designed for advanced practice providers seeking a deeper understanding of immunologic pathways relevant to rheumatology care.

In this short video, pediatric rheumatology advanced practice providers Brandon Ko, APRN, DNP, C-PNP, and Brandi Goble, PNP, share their personal journeys into pediatric rheumatology and discuss the critical role APPs play in expanding access to care—especially in rural and underserved communities. They highlight the challenges of entering a highly specialized field with limited formal training, the importance of mentorship, and how RhAPP and the Step Up to Rheumatology curriculum have helped build community, education, and confidence for pediatric rheumatology APPs nationwide. This conversation offers insight into workforce gaps, real-world training pathways, and the growing impact of APPs in pediatric rheumatology care.

In this video, Audrey Gibson, PA-C, a rheumatology physician assistant with nearly two decades of clinical experience, breaks down the unique dual mechanism of action of guselkumab and its role in targeting IL-23–driven inflammation. The discussion explores how this fully human monoclonal antibody selectively binds the IL-23 p19 subunit to inhibit downstream inflammatory signaling, while also engaging CD64 on inflammatory monocytes through its Fc region, addressing IL-23 at its source. Designed to clarify the science behind dual-acting IL-23 inhibition, this overview provides practical insight for clinicians managing immune-mediated rheumatic diseases and highlights emerging therapeutic strategies in modern rheumatology care.

In this FAQ, William Saalfeld, NP, breaks down why the modified van der Heijde–Sharp (mvdH-S) score remains the most widely used radiographic method in psoriatic arthritis (PsA) clinical trials. He highlights how the score delivers the strongest combination of reliability, sensitivity to change, and validation, making it ideal for detecting small but meaningful structural progression over typical trial timelines. Learn how its consistent use across randomized controlled trials—including recent NEJM studies—supports cross-trial comparability, regulatory acceptance, and its role as a trusted structural endpoint linked to long-term physical function and disability in PsA.

Discover how the APEX trial raised the bar in understanding structural damage risk in psoriatic arthritis. In this quick FAQ video module, William Saalfeld, NP, breaks down why APEX was designed differently from DISCOVER-2, what made its patient population unique, and how these changes help us better evaluate progression and treatment impact. If you want a clearer, faster way to understand the science behind PsA trial design, this is the perfect overview. Learn more on the RhAPP website or through the RhAPP ACE App.