Host-Response Modulating Therapies for Reducing Physiological Disturbance During Recurrent Fever

Abstract

Recurrent fever syndromes present significant clinical challenges due to repeated physiological disturbances that can impact patient quality of life and long-term health outcomes. Recent progress in understanding the host immune response has highlighted novel pathways for therapeutic intervention. This review provides an evidence-based overview of host-response modulating therapies aimed at mitigating the physiological derangements associated with recurrent fever, emphasizing clinical applicability, mechanism-driven strategies, and the latest advances from recent literature.

Introduction

Recurrent fever syndromes, encompassing both hereditary and acquired etiologies, are characterized by repeated episodes of elevated body temperature often accompanied by systemic symptoms. These syndromes include, but are not limited to, familial Mediterranean fever (FMF), TNF receptor-associated periodic syndrome (TRAPS), and periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA). Management has traditionally focused on symptomatic relief; however, mounting evidence suggests modulating the host immune response can attenuate physiological disturbances and improve outcomes. This review synthesizes current knowledge regarding host-response modulating therapies in this context, targeting a clinical audience.

Epidemiology / Disease Burden

Recurrent fever syndromes are relatively rare, but their cumulative burden is substantial. Prevalence varies globally, with FMF being most common in populations of Mediterranean descent, affecting up to 1 in 200 individuals. Pediatric populations are particularly susceptible to autoinflammatory recurrent fevers, often resulting in frequent medical consultations, school absences, and significant psychosocial impact. The chronicity and unpredictability of episodes lead to diminished quality of life and, in some cases, long-term complications such as amyloidosis, underscoring the need for effective host-response modulation.

Pathophysiology

Recurrent fever syndromes are driven by dysregulated innate immune responses, often due to genetic mutations affecting inflammasome components (e.g., MEFV gene in FMF, TNFRSF1A in TRAPS). Fever results from the release of endogenous pyrogens, including interleukin-1β (IL-1β), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6), which disrupt hypothalamic thermoregulation and trigger systemic inflammatory cascades. The resultant physiological disturbances include increased metabolic demand, hemodynamic instability, and potential end-organ dysfunction. Understanding these mechanisms is pivotal for targeted therapeutic strategies.

Risk Factors

Genetic predisposition is the primary risk factor for hereditary recurrent fever syndromes. Family history, consanguinity, and specific ethnic backgrounds (e.g., Armenian, Turkish, Arab, and Sephardic Jewish) increase susceptibility. Acquired factors, such as chronic infections, autoimmune diseases, and malignancies, can also manifest as recurrent fever. Environmental triggers, including stress and temperature extremes, may precipitate febrile episodes in predisposed individuals. Comprehensive risk assessment is essential for accurate diagnosis and individualized management.

Clinical Features

Clinically, recurrent fever episodes are characterized by abrupt onset of high-grade fever, often accompanied by systemic symptoms such as myalgia, arthralgia, abdominal pain, rash, and lymphadenopathy. The frequency, duration, and associated features vary among syndromes. Between episodes, patients are typically asymptomatic, although subclinical inflammation may persist. Chronic inflammation can lead to complications such as amyloidosis, particularly in inadequately managed cases. Recognizing these features facilitates timely diagnosis and intervention.

Diagnosis

Diagnosis of recurrent fever syndromes requires a comprehensive clinical evaluation, including detailed history, physical examination, and exclusion of infectious, neoplastic, and autoimmune etiologies. Laboratory investigations may reveal elevated acute-phase reactants (e.g., CRP, ESR, SAA) during febrile episodes. Genetic testing (e.g., MEFV, TNFRSF1A, MVK mutations) is definitive for hereditary syndromes. Diagnostic criteria vary by syndrome, with tools such as the Tel Hashomer criteria for FMF and Eurofever classification criteria aiding in standardization. Early and accurate diagnosis is critical for guiding host-directed therapy.

Treatment & Management

Conventional management has relied on nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, and disease-specific agents such as colchicine for FMF. However, these approaches may not adequately control inflammation or prevent physiological disturbances in all patients. The emergence of host-response modulating therapies, particularly biologics targeting IL-1, IL-6, and TNF-α, has transformed the therapeutic landscape. Anakinra and canakinumab (IL-1 inhibitors), tocilizumab (IL-6 inhibitor), and etanercept (TNF-α inhibitor) have demonstrated efficacy in reducing fever frequency, inflammation, and risk of complications. Individualized therapy based on phenotype, genotype, and response is recommended.

Recent Advances / Emerging Therapies

Recent advances include the development of next-generation biologics and small molecule inhibitors targeting novel pathways involved in innate immunity. Janus kinase (JAK) inhibitors, such as baricitinib and ruxolitinib, have shown promise in early-phase trials by modulating cytokine signaling and reducing inflammatory flares. NLRP3 inflammasome inhibitors are under investigation for their potential to directly attenuate the pathogenic process in monogenic autoinflammatory syndromes. Furthermore, precision medicine approaches leveraging genomic profiling and biomarker-driven stratification are optimizing therapeutic selection and monitoring.

Guideline Recommendations

Contemporary clinical guidelines, such as those from the European League Against Rheumatism (EULAR) and the American College of Rheumatology (ACR), advocate for early use of biologic agents in patients with inadequate response to standard therapy or those at risk for complications. Regular monitoring for efficacy, adverse effects, and long-term sequelae is emphasized. Multidisciplinary care involving rheumatology, genetics, and allied specialties is recommended to ensure comprehensive management. Patient education regarding trigger avoidance and adherence is integral to optimizing outcomes.

Conclusion

Host-response modulating therapies represent a paradigm shift in the management of recurrent fever syndromes, offering targeted control of physiological disturbances and improved long-term outcomes. Ongoing research continues to refine our understanding of disease mechanisms and therapeutic targets, heralding a future of increasingly precise and effective interventions. Clinicians must remain abreast of emerging evidence and guideline updates to deliver optimal, individualized care for patients affected by these complex conditions.