The ying and yang of fever in rheumatic disease

[Fever in rheumatological diseases]

Fever is a frequent and important symptom in patients with rheumatological diseases and can be an expression of activity of the underlying rheumatological disease. There is great variability in the incidence of fever as a symptom of the disease between individual diseases. The growing understanding of the molecular signatures of the diseases can help to explain these discrepancies: A genetic overactivation of potently pyrogenic cytokines is the reason why fever is nearly always present in autoinflammatory syndromes. In contrast, fever is less common in polyarthritis and myositis and mostly limited to severe courses of disease. In the diagnostic work-up of fever, frequent differential diagnoses, such as infections, malignancies, side effects of drugs and hypersensitivity reactions should be considered. This article provides an overview of the physiology of the development of fever, describes the relevance of fever in individual rheumatological diseases and proposes a workflow for the clinical clarification of rheumatological patients who present with fever.

Rheumatoid arthritis autoantibodies benefit from inflammation temperatures

BACKGROUND

Symptoms of rheumatoid arthritis are associated with local inflammation and may include low-grade fever.

OBJECTIVE

To establish the role of fever/inflammation temperatures (38℃-39℃) on the activity of autoantibodies and therapeutic antibodies relevant for rheumatoid arthritis.

METHODS

Through the use of molecular dynamics and free energy calculations, we investigated the role of temperature on the formation of pertinent immune complexes.

RESULTS

Rheumatoid arthritis autoantibodies bind with higher affinity at febrile/inflammation temperatures.

CONCLUSIONS

Fever may modulate binding affinity of autoantibodies relevant for rheumatoid arthritis.

Febrile temperatures modulate the formation of immune complexes relevant for autoimmune diseases

BACKGROUND

Autoimmune disorders encompass a diverse subset of diseases whose common symptoms include, among others, fever. Fever of unknown origins, once an infectious or tumor agent have been ruled out as possible causes, may originate with an autoimmune disease.

OBJECTIVE

To determine the role of febrile temperatures on the stability of antigens pertinent to autoimmunity, and on the immune complexes they form with commercial therapeutic monoclonal antibodies.

METHODS

Using molecular dynamics simulations, the binding between four antigens belonging to a set of autoimmune diseases and their individual monoclonal antibodies was investigated under different febrile temperatures.

RESULTS

It was determined that at febrile temperatures, monoclonal antibodies used in the therapy of autoimmune diseases bind with higher binding free energy to pertinent antigens, once the autoimmune condition has been established and treatment is warranted.

CONCLUSION

Performing molecular dynamics simulations at fever temperatures may be important for delineating the role antibodies may play in other diseases, including in cancers and infections.

Differential Diagnosis of Inflammatory Arthropathy Accompanying Active Tuberculosis Infection

Objective

The study aimed to ascertain the clinical manifestations of inflammatory arthritis accompanying tuberculosis (TB) for the differential diagnosis.

Methods

We retrospectively reviewed patients with active TB who presented with inflammatory arthropathy at Seoul Medical Center. Among 2,872 patients with active TB infection, 47 had inflammatory arthropathy 14 had crystal-induced arthropathy; 12, TB arthritis; 12, Poncet's disease (PD); 8, Rheumatoid arthritis (RA); and 1, septic arthritis. The clinical characteristics and laboratory and radiographic findings of each group were analyzed.

Results

In TB arthritis, weight-bearing joints were more commonly affected than the elbow and wrist joints. When compared to TB arthritis, PD demonstrated a significantly higher proportion of polyarthritis and involved both large and small-to-medium-sized joints. The duration of arthritis symptoms after anti-TB treatment was significantly shorter in patients with PD (56 days vs. 90 days, p=0.028). When compared to PD, RA flares during active TB infection involved only small-to-medium-sized joints rather than a mixed distribution (62.5% vs. 16.7%, p=0.035). Patients with PD more commonly had fever at onset and showed a good response to nonsteroidal anti-inflammatory drugs alone or were in remission within 3 months after anti-TB treatment. The presence of rheumatoid factor or anti-cyclic citrullinated peptide and radiographic progression after 12 months was frequently observed in patients with RA flares.

Conclusion

The differential diagnosis of inflammatory arthritis accompanying active tuberculosis infection is challenging. Comprehensive history taking and physical examination, synovial fluid analysis, and a high level of clinical suspicion are essential to avoid delayed diagnosis and to reduce the significant morbidity involved.

Autoinflammatory Mechanisms in Crystal-Induced Arthritis

Crystal-induced arthritides have been classified as “type-1 autoinflammatory diseases” for their main features which resemble those of the monogenic autoinflammatory syndromes. They are in fact characterized by spontaneous onset, recurrence of the episodes, self-limitation and resolution, inflammasome activation with huge production of IL-1β and a prevalent involvement of the innate immune system. The term “auto” refers also to the induction of IL-1β gene expression, processing and secretion by IL-1β itself. The concept of autoinflammation in crystal-induced arthritis has been finally reinforced by the efficacy of IL-1 blockade in treating acute and chronic state of this disease. The aim of this article is to review the autoinflammatory mechanisms in crystal-induced arthritis, considering both clinical and molecular aspects.

Differentiating Disease Flare From Infection: A Common Problem in Rheumatology. Do 18F-FDG PET/CT Scans and Novel Biomarkers Hold The Answer?

PURPOSE OF REVIEW

Fever is common within rheumatology but it is often challenging to identify its source. To do so correctly is paramount in patients with an underlying inflammatory condition receiving immunosuppressive therapy. This review article looks at the available evidence and merits of both 18F-fluoro-deoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) scans and new proposed biomarkers in determining the cause of fever within rheumatology.

RECENT FINDINGS

18F-FDG PET/CT scans are already an established tool in the detection and diagnosis of malignancy and are emerging for use in fever of unknown origin. More recently, they have been used to identify rheumatological causes of fever such as large vessel vasculitis and adult-onset Still's disease. Within these conditions, biomarkers such as procalcitonin and presepsin may help to differentiate endogenous from exogenous pyrogens. 18F-FDG PET/CT scanning shows promise in locating the source of pyrogens and may be superior to other conventional forms of imaging. As evidence and test availability increases, its use is likely to become commonplace in the diagnostic work-up of fever. Once a source is located, selected biomarkers may be used to confirm a cause.

Opportunistic infections in patients with idiopathic inflammatory myopathies

AIM

To describe the prevalence, clinical characteristics and risk factors of opportunistic infection (OI) in a cohort of patients with inflammatory myopathies, and compare mortality rates between those with and without OIs.

METHODS

In total, 204 patients from our myositis cohort were reviewed to identify patients who had experienced an OI during the period 1986-2014. The patients' clinical characteristics, treatments received, and outcomes were systematically recorded. Disease activity at the OI diagnosis and the cumulative doses of immunosuppressive drugs were analyzed, as well as the specific pathogens involved and affected organs.

RESULTS

The prevalence of OI in the total cohort was 6.4%: viruses, 44.4% (varicella-zoster virus, cytomegalovirus); bacteria, 22.2% (Salmonella sp., Mycobacterium tuberculosis, M. chelonae); fungi, 16.7% (Candida albicans, Pneumocystis jirovecii); and parasites, 16.7% (Toxoplasmosis gondii, Leishmania spp.). Lung and skin/soft tissues were the organs most commonly affected (27.8%). Overall, 55.6% of OIs developed during the first year after the myositis diagnosis and OI was significantly associated with administration of high-dose glucocorticoids (P = 0.0148). Fever at onset of myositis (P = 0.0317), biological therapy (P < 0.001) and sequential administration of four or more immunosuppressive agents during myositis evolution (P = 0.0032) were significantly associated with OI. All-cause mortality in the OI group was 3.69 deaths per 100 patients/year versus 3.40 in the remainder of the cohort (P = 0.996).

CONCLUSIONS

The prevalence of OI was 6.4% in our myositis cohort, higher than the rest of the inpatients of our hospital (1.7%; P < 0.01). High-dose glucocorticoids at disease onset and severe immunosuppression are the main factors implicated.