The document discusses the possible causes of rheumatoid arthritis (RA) based on research evidence. The immune system, specifically the innate immune response involving macrophages and dendritic cells, plays an important role in the development of RA by causing inflammation and destroying joints. Genetics also contribute, as RA has been linked to chromosome 6. Some studies have found historical evidence suggesting an infectious agent may promote RA. Environmental factors like smoking, low vitamin D levels, diet, and cold weather have also been associated with increased risk or severity of RA. Understanding the causes of RA could help improve treatment and management of the disease.

1. María A. Rosa Vázquez
The Causes Behind Rheumatoid Arthritis
Abstract
This work discusses the possible causes of the disease. The immune system plays an
important role in the development of RA by causing inflammation and destroying the joints. In
genetics, RA is relating to the chromosome 6. Some researchers found historical evidence that
the disease could have an infectious agent. The disease have been promoted by environmental
factors such as smoking, lack of Vitamin D, diet and weather. Knowing the causes of the RA will
help to improve or developing treatments for the disease.
Table of Contents
1. Introduction .................................................................................................................1
2. Immunity .................................................................................................................2
3. Genetics .................................................................................................................2
4. Infectious .................................................................................................................3
5. Environmental factors .........................................................................................3
5.1 Smoking .....................................................................................................3
5.2 Vitamin D .....................................................................................................4
5.3 Diet and weather .........................................................................................4
6. Conclusion .................................................................................................................4
References .................................................................................................................5
1. Introduction
We are in an age where technology has advanced in many ways. Despite this, many
diseases have no cure, even if it is discovers at an early stage. An example of this is the
Rheumatoid Arthritis (RA), a disease that affects the articular tissues and extra articular organs.
This chronic, systemic and inflammatory disorder usually attacks women. Rheumatoid arthritis is
a progressive disease that destructs and deforms the joint. Thus, the patient will have a
dysfunctional status that can finish in premature death (Khurana and Berney, 2005). The
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2. problem with this disorder is that Scientists and researchers have not found the causes or
etiology of RA, the light or passage to finding a cure. However, there is many works that reports
and found possible causes for this disease that can be use by the people to prevent it.
2. Immunity
The first step to understanding RA is to introduce the major cause of it the immune
system, which attacks the cells of the patients with the disease. I will be focusing in the innate
immunity, which is the one that defend the body against infectious organisms. Falgaron et al.
(2005) found that the macrophages and dendritic cells, which are involved in the innate
immunity responses, activate the T and NK cells. The T cells regulate the inflammatory and
immune responses and the NK responses against viruses that produce TNF and IL-1, which
destroy the joints. They also found that the T cells reduce the elimination of macrophages that
express cytokines that enhance or inhibit inflammatory responses and that play part on the
cause of RA. On the other hand, the pineal neurohormone called melatonin (MLT), which
coordinates the organism’s adaptation and survival affecting the immunity. Maestroni et al.
(2005) present a research using rats where the old ones repair the inflammatory responses and
the young ones elevate the inflammatory effect when they consumed a high dose of MLT. In
humans, the concentration of melatonin is high in patients with RA than controls, which means
that the features that increase the production of MLT can be part of the etiology of RA.
3. Genetics
Developing a productive and healthy human body depends on many factors; but the
principal one is the genetics. In RA, the HLA (human leukocyte antigen) region of the
chromosome 6 has been related with the disease (Huizinga, 2003). Some researchers found
that the genetic variant is present in family members with RA than in family members without
the disease, using the multicase families’ analysis. Other studies have been done, but are
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3. unclear because is not known if the people, who have the mutation, will exhibit the disease.
Following that population might provide information in the future.
4. Infectious
As part of human life, the infections are organism in which the immune system deal and
protected body against them. Mackenzie and Dawson (2005) found a connection between the
RA and some infectious agents. That connection was dated from the ancient past; this means
that people living in America had RA before the Europeans arrived to the continent. That guides
them to propose that the Europeans gain the disease and spread it to Europe through an
infection. They also suggest that the viruses are the primary infectious agent in RA, because
they usually infect the monocyte/ macrophages, which are involved in some way with the
inflammatory response. Another study reports that the HTLV-1 (human T-lymphotropic virus 1)
has been located in people with a form of RA (Mackenzie and Dawson, 2005), which provoke a
chronic erosive lesions. Torrey and Yolken in 2001 presented the idea that the microorganism
T. gondii is associated with RA. This microorganism has been usually found in cats and a
researcher obtain that the people who had cats in the adolescence had the predisposition to
have the disease.
5. Environmental factors
The human body is always adjusting with its environment. There is now evidence that smoking,
nutrition and even weather could play an important role in the development of some diseases,
as RA.
5.1 Smoking
The act of smoking affects the immune system and some adrenal hormones that have
been identified in the etiology of RA. Krishnan (2003) in his work with data from the BRFSS
(behavioral risk factor surveillance system) found that ever-smoked men has a higher risk of
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4. develop RA than controls; but that don’t happen in young woman for the reason that
menstruating ones obstruct the smoking factor that develop RA. That doesn’t occurs in
postmenopausal woman, in where a study with the Iowa Women’s Health Study (Criswell et al.,
2002), shows that women who smoke develop RA and were younger at menopause.
5.2 Vitamin D
Recent studies researchers discover a Vitamin D receptor in the immune system, which
lets them to propose that it can have immunoregulatory properties and can stop the antibody
secretion and autoantibody production (Cutolo et al., 2007). Kiran and Debashish (2008)
presented an investigation with mice infected with B. burgdorferi, an agent identified as a cause
of arthritis. The arthritis in the experimental mice was reduced or stops using a dietary
supplement of 1,25-dihydroxy Vitamin D, which is the active form of Vitamin D. Interestingly,
they found that the people who live in high latitudes and were less exposed to the sunlight have
a higher incidence of RA than the ones who live in the tropics. Sunlight activates Vitamin D in
the body.
5.3 Diet and weather
Some researches attribute the high occurrence of RA to other factors like the diet. It
seems that having a wealthy diet in oily fish and vegetables will decrease the effects of the RA
(Symmons, 2003). They also, suggest that low temperature weather (cold ones) and high
atmospheric pressure increase the pain levels of RA patients. However, there is not scientific
evidence that support those effects in the disease.
6. Conclusion
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5. If we start to inform ourselves about the possible causes of the disease, we can prevent
it by avoid those things that are risk for them. We should avert the people about them using
conferences and making writings. In general, is important to have a good source of Vitamin D
and take right exposure to the sun; have a diet in fish and vegetable; avoid the cold weather, do
exercise and take care of the body to prevent or decrease the effects of RA. The researches
about the disease will continue to know more about the effects of mutated chromosome 6 and
the components of the innate immunity as the macrophages and dendritic cells, which produce
the disease. Their perseverance some day will decode the unknowns of RA and develop better
treatments until its cure.
References
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2002. Cigarette smoking and the risk of rheumatoid arthritis among postmenopausal
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Cutolo M, Otsa K, Uprus M, Paolino S, Seriolo B. 2007. Vitamin D in rheumatoid arthritis.
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Falgarone G, Jaen O, Boissier MC. 2005. Role for Innate Immunity in Rheumatoid Arthritis.
Joint Bone Spin. 72:17-25.
Huizinga TWJ. 2003. Genetics in rheumatoid arthritis. Best Practice & Research Clinical
Rheumatology 17:703-716.
Khurana R, Berney SM. 2005. Clinical aspects of rheumatoid arthritis.
Pathophysiology.12:153-165.
Kiran G, Debashish D. Vitamin D and rheumatoid arthritis: is there a link? 2008. International
Journal of Rheumatic Diseases. 11:206-211.
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6. Krishnan E. 2003. Smoking, gender and rheumatoid arthritis–epidemiological clues to etiology
Results from the behavioral risk factor surveillance system. Joint Bone Spine. 70:496-502.
Mackenzie AR, Dawson J. 2005. Could rheumatoid arthritis have an infectious aetiology? Drug
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Maestroni GJM, Cardinali DP, Esquifino AI, Pandi-Perumal SR. 2005. Does melatonin play a
disease-promoting role in rheumatoid arthritis? Journal of Neuroimmunology.
158:106-111.
Symmons DPM. 2003. Environmental factors and the outcome of rheumatoid arthritis. Best
Practice & Research Clinical Rheumatology. 17:717-727.
Torrey EF, Yolken RH. 2001. The Schizophrenia–Rheumatoid Arthritis Connection: Infectious,
Immune, or Both? Brain, Behavior, and Immunity. 15:401-410.
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