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Interleukins (ILs) are a large family of cytokines that function as key mediators of immune cell communication, regulating cell proliferation, differentiation, motility, and survival across both innate and adaptive immunity.[1] The term interleukin was first introduced in the late 1970s to describe leukocyte-derived cytokines, with IL-1 identified as a leukocytic pyrogen and IL-2 as a T-cell growth factor. Since then, more than 60 cytokines have been designated as interleukins, and to date, at least 38 have been formally recognized (IL-1 through IL-38).[2] Interleukins are structurally diverse but are commonly grouped into families based on receptor usage, sequence homology, and biological function. Major families include the following: IL-1 family: IL-1α, IL-1β, IL-18, IL-33, IL-36, IL-37, and IL-38 Common γ-chain family: IL-2, IL-4, IL-7, IL-9, IL-15, and IL-21 IL-6/IL-12 family: IL-6, IL-11, IL-12, IL-23, and IL-27 IL-17 family: IL-17A through IL-17F and IL-25 Each family orchestrates specific pathways in host defense, inflammation, hematopoiesis, and tissue repair.[1][2][3][4] From a historical perspective, IL-1 and its receptor antagonist (IL-1Ra) have become the prototypes for understanding the balance between pro- and anti-inflammatory cytokines.[5] IL-2, initially described as a T-cell mitogen, was later shown to play a central role in immune regulation and tolerance.[6] IL-10 emerged as a master anti-inflammatory cytokine, functioning as a key regulator in infection and autoimmunity.[7][8][9] The discovery of T-helper (Th)17 cytokines, particularly IL-17 and IL-23, provided new insights into chronic inflammation and autoimmunity.[10][3] Collectively, these discoveries established the conceptual framework that interleukins act not only as immune stimulators but also as immunoregulators. Clinically, interleukins have become both biomarkers and therapeutic targets. Dysregulated signaling is implicated in autoimmune diseases, such as rheumatoid arthritis, inflammatory bowel disease, and psoriasis, as well as in malignancies, infections, and hyperinflammatory states, including cytokine storms. Therapeutic blockade of interleukin pathways, including anakinra (IL-1Ra), tocilizumab (IL-6 receptor blocker), and secukinumab (IL-17A inhibitor), has transformed management across rheumatology, dermatology, oncology, and infectious diseases.[2][11]

Optimal use of interleukin-based therapies requires a coordinated, multidisciplinary approach. Clinicians and advanced practitioners are responsible for patient selection, stratifying risk, and tailoring biologic therapy to the clinical context.[2] Pharmacists ensure safe prescribing, screen for drug interactions, and provide counseling on biologic handling and administration.[11] Nurses reinforce adherence, teach self-injection techniques, and monitor for early signs of adverse effects.[13] Infectious disease specialists may be consulted to perform tuberculosis or viral reactivation screening before initiating IL-targeted therapies. In contrast, laboratory professionals provide timely biomarker data such as C-reactive protein, IL-6, or soluble IL-2 receptor to guide clinical decision-making.[17] A gastroenterologist should be consulted for the use of biologics in the treatment of ulcerative colitis or eosinophilic esophagitis.[50] Immunologists and rheumatologists should collaborate in the management of complex disorders, such as Castleman disease.[77][78][79] Ethical responsibilities include obtaining informed consent, discussing risks such as opportunistic infections, ensuring vaccination status, and maintaining transparency regarding therapeutic costs and accessibility. Interprofessional communication and care coordination are critical: effective information sharing among clinicians, pharmacists, nurses, and laboratory teams helps reduce errors, improve patient safety, and fosters trust.[1] By prioritizing patient-centered care, reinforcing adherence, and integrating timely monitoring, healthcare teams can optimize clinical outcomes and enhance overall team performance in the management of interleukin-directed therapies.[2] An interprofessional approach and open communication among primary care physicians, advanced practice providers, immunologists, rheumatologists, gastroenterologists, nurses, and pharmacists are essential to optimize patient outcomes related to interleukin-based therapies.