Circadian Rhythm’s Functions Against Autoimmune Disease: A Bibliometric Analysis

1. Abstract

The circadian rhythm (CR), regulated by the suprachiasmatic nucleus in the hypothalamus, governs the body’s 24-hour sleep-wake cycle and plays an essential role in maintaining immune homeostasis. This review examines how disruption of the CR influences susceptibility to autoimmune diseases (AD). A bibliometric search using Web of Science identified 112 relevant publications, from which the top 100 most-cited papers were analyzed to determine leading contributors and research trends in the field. The analysis showed a marked rise in influential publications after 2014 and identified Gionata Cavadini as the most highly cited senior author, particularly for work demonstrating how inflammatory cytokines such as TNF-α and IL-1 interact with clock-gene pathways. Across studies, core clock genes: BMAL1, CLOCK, and PER emerge as primary regulators of immune timing, affecting cytokine release, antigen presentation, and T-cell differentiation; their disruption weakens immune tolerance and increases chronic inflammation, thereby elevating the risk for autoimmune disorders. Melatonin, a hormone closely tied to circadian signaling, also demonstrates anti-inflammatory and immunoregulatory effects, with supplementation shown to reduce disease severity in models of autoimmune uveitis and Sjögren’s syndrome, suggesting that disturbed melatonin rhythms further heighten autoimmune susceptibility. Overall, the literature indicates that circadian disruption is a significant and modifiable risk factor for autoimmune disease. As research advances, circadian-based strategies—such as optimizing sleep, applying chronotherapy, and tailoring interventions to individual chronotypes—offer promising opportunities for shifting autoimmune care toward more preventative, personalized approaches.

Keywords: Autoimmune disease, Circadian rhythm, Immunology, Melatonin, Clock genes, Chrono-immunology

DEFINITIONS

Autoimmune Uveitis - An autoimmune disease where the immune system attacks the eye, causing inflammation and vision problems.

BMAL1, CLOCK, and PER - Genes that act like the gears of the body’s internal clock, working together to keep biological processes running on a 24-hour schedule by controlling the release of certain hormones and chemicals as the day continues.

Chronotherapy - A process where a person is assisted in creating an appropriate sleep-wake schedule for their chronotype

Chronotypes - A person’s natural tendency to feel awake or sleepy at certain times of day—basically whether someone is a morning person or a night owl.

Dysregulation - When a system in the body stops working properly and loses its normal balance or control, like a thermostat that can no longer regulate temperature correctly.

Foreign Pathogen - A harmful invader from outside the body, like a virus or bacteria, that the immune system is supposed to attack and destroy. 

Immunoregulatory - Anything that helps control or balance the immune system, keeping it from overreacting or underreacting.

Inflammatory Cytokines - Chemical signals released by the immune system that cause inflammation in order to signal your body to react against potential sickness.

Rheumatoid Arthritis - An autoimmune disease where the immune system attacks the joints, causing pain, swelling, and stiffness; most commonly occurring in the hands, wrists, and knees.

Sjogren’s Syndrome - When the immune system attacks moisture-producing glands, causing severe dry eyes and dry mouth.

Suprachiasmatic nucleus - A tiny region in the brain that acts as the body’s master clock. It detects light through the eyes and tells the rest of the body what time of day it is.

T-Cell Differentiation - The process where immune cells called T-cells grow and specialize into different types, each with a specific job in fighting off disease.

2. Introduction

The circadian rhythm (CR) regulates the sleep-wake cycle of animals via the suprachiasmatic nucleus (SCN) in the hypothalamus by responding to the light coming in through the eyes, creating a 24-hour cycle. This regulation is controlled by feedback loops including multiple ‘clock genes:’ brain and muscle ARNT-like protein-1-2 (BMAL1-2), Circadian Locomotor Output Cycles Kaput (CLOCK), period circadian regulator 1-3 (PER1-3), and cryptochrome circadian regulator 1-2 (CRY1-2) (Awuah, 2023). When the eyes are exposed to light, the SCN is given the signal to reduce production of melatonin, the sleeping hormone, but when they are exposed to a lack of light, melatonin production increases. This cycle is not isolated; rather, it affects multiple other systems, one of which is the immune system. 

The disruption of the CR has been linked with some autoimmune diseases. Autoimmune disease (AD) is a wide category of diseases where the immune system targets healthy tissue as if it were a foreign pathogen, affecting approximately 15 million people (~5%) in the US (Widt, 2025). Examples of AD include Rheumatoid Arthritis (RA), Systemic Lupus Erythematosus (SLE), and Inflammatory Myopathies (IM). There are many contributing factors to autoimmune disease, most of which are beyond the individual’s control like genetics, epigenetics, and environment (Awuah, 2023). One common hormone often attributed to sleep is melatonin, which also plays a role in immune regulation. Melatonin has demonstrated anti-inflammatory properties, which are especially relevant in some autoimmune models like uveitis and Sjögren’s syndrome, where melatonin supplements have shown to reduce severity and restore balance in the immune system (Liu et al., 2022). Thus, disruption of melatonin production can exacerbate immune dysregulation and increase the likelihood of autoimmune conditions.

An individual’s sleep-wake routine is modifiable, thus this paper serves to review the literature backing this topic using bibliometric research to contextualize the current research landscape, and to identify possible next steps in research between circadian rhythms and autoimmunity.

3. Methodology

A bibliometric search was conducted using the Web of Science database using the keywords ‘circadian rhythm,’ ‘autoimmune disease,’ ‘immunology,’ ‘sleep,’ and ‘hormone.’ All bibliometric data was then imported to an Excel spreadsheet. From 112 papers, the top 100 cited works were then analyzed for popular trends. Of those 100 works, there are 65 articles and 35 reviews on this topic. Using Excel, the data was sorted from greatest to least in the number of citations of senior authors and affiliated institutions, as shown in Figures 2 and 3. The purpose of this search is to find the most influential papers in this field, glean relevant insight from them, and look for trends in relevance over the years.

Figure 1: Bibliometric Search

Figure 1 is a flowchart of the methodology used, beginning with a Web of Science Search using the aforementioned keywords: ‘circadian rhythm,’ ‘autoimmune disease,’ ‘immunology,’ ‘sleep,’ and ‘hormone.’ Only the top 100 papers out of 112 results were analyzed which were split between 65 articles and 35 reviews.

4. Results

Figure 2: Top 20 authors with the most citations

Figure 2 highlights the most cited senior authors from the top 100 most cited papers. Gionata Cavadini from the division of Clinical Immunology at University Hospital Zurich was the leading contributor, with 377 citations. Specifically, in Cavadini et al. 2007, TNF-alpha suppresses the expression of clock genes by interfering with E-box-mediated transcription, investigates how the genes TNF-α and IL-1, that are associated with autoimmune disease, and their role in the circadian rhythm observed in mice, during non-rapid eye movement sleep (NREM sleep).

Figure 3: Number of publications over the years from the top 100 cited papers

Figure 3 illustrates the number of publications each year since 1991 featured in the top 100 most cited papers. This field demonstrated limited research output until 2014, when there was a substantial increase in annual publications compared to prior years. This boost in research production may reflect a growing interest in chrono-immunology. It is important, however, to mention that this only involves the top 100 most cited papers, so additional publications may exist under circadian rhythm and autoimmune disease beyond the scope of this paper. 

5. Discussion

Disruption of the circadian rhythm is a significant factor in developing autoimmune disease, with the specific agents being core clock genes: BMAL, CLOCK, and PER1. These genes help regulate the rhythmic expression of parts of the immune system, including cytokine production, antigen presentation, and T-cell differentiation (Xiang et al., 2021). Studies on rheumatoid arthritis have demonstrated that a loss or mutation of these genes can lead to an impairment of how the immune system functions, leaving patients with painful joints as the immune system is left attacking regions that are actually local to the body. This is a type of dysregulation where tolerance of one’s own body is compromised which leads to a loss of self-recognition, thus illustrates the increasing susceptibility to a vast array of autoimmune disorders and disease beyond rheumatoid arthritis.

The bibliometric data adds context to the findings about how the circadian rhythm regulates autoimmunity. Figure 2 reveals that the research here is concentrated among a small number of senior authors with a relatively disproportionate spread with the top 2 authors Cavadini and Martel having significantly more citations than the following authors. This signals a gap in diversity. Over-reliance on a small group of authors limits perspectives, methodologies, and population representation, which narrows the applicability of research into real-world solutions and practice. This bibliometric pattern suggests a need for greater collaboration and investment in emerging researchers working in chronobiology and immunology because there is high potential to find further benefits or interactions between them because of how limited the scope of the most popular papers are alone, and these future findings can potentially be applied to peoples’ lives in order to improve health overall.

Figure 3 suggests another trend: the rise in publications after 2014 indicate that the topic of chrono-immunology is a relatively young field that is accelerating in size. Limited output preceding 2014 suggests that the connection between sleep-wake cycles and autoimmunity was largely unexplored, and the surge afterwards likely reflects growing awareness of circadian biology. This growth is likely due to the campaigning of the National Healthy Sleep awareness project that had gained lots of popularity that year. However, recency of growth also indicates that the research is still new, and utilizes more premature models, meaning that there could be more relevant biological pathways and long-term solutions to be discovered.

6. Conclusion

Disruption of the circadian rhythm has a significant impact on immune regulation which can result in autoimmune diseases. The circadian rhythm modulates key immune functions including secretion of melatonin and activity of T cells. When disturbed, either through irregular sleep patterns or genetic variations, immune tolerance can become dysregulated, leading to increased inflammation and self-reactivity. Melatonin plays a protective role in suppressing pro-inflammatory pathways and stabilizing immune response.

As research behind the relationship between immune regulation and circadian rhythm continues, the next step should be to utilize such information into shareable practices for autoimmune disease prevention and create more personalized treatment. Future studies should explore how individual chronotypes, which are natural variations in each person’s body’s preference for sleep-wake cycles, can affect autoimmune risk, and whether behavioral changes such as sleep optimization can restore balance. Ultimately, recognizing the circadian rhythm as a modifiable factor reframes autoimmune care from being reactive to proactive, lifestyle-based preventions.

This study acknowledges that there are several limitations when interpreting findings. First, the analysis was relatively narrow, taking only the top 100 most-cited papers from one database, Web of Science, which may exclude relevant research elsewhere. Second, citation counts are only a proxy for influence as it does not always directly reflect the exact qualities it is cited for, and older papers naturally have more citations regardless of their current relevance due to their stakes in often providing context for newer papers. Third, this paper does not conduct a systematic study or meta-analysis of all the studies used; it analyzes bibliometric patterns rather than evaluating methodologies and academic rigor of each paper. These constraints taken together should be used to conclude that this paper is to best be used to understand the current research landscape, rather than a definitive answer or summary.

Despite these limitations, the gaps identified are still relevant for future direction, promoting research diversification and future investment for long term studies. Findings analyzed from the sources used conclude that sleep health is a legitimate and controllable factor in combating autoimmune disease. Integrating circadian awareness into patient education, preventive care guidelines, and treatment plans can create a low-entry yet high-impact to reduce potential burden. Overall, this paper functions as a general overview and a tool to guide what comes next in the junction of chronobiology and autoimmunity.

7. References

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