RESEARCH - Discovery on nature of RA lung disease may offer patients therapy

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Discovery on nature of rheumatoid arthritis lung disease may offer patients

therapy, Mayo Clinic

Main Category: Arthritis News

Article Date: 08 Jan 2005 - 0:00am (PDT)

A discovery by a Mayo Clinic research team may pave the way for the creation

of new drugs to treat rheumatoid arthritis (RA) lung disease, which affects

an estimated 500,000 patients in the United States. Currently, there are no

effective treatments for RA lung disease.

In a paper that appears in today's online version of the Jan. 13 edition of

Arthritis & Rheumatism, http://www3.interscience.wiley.com/cgi-bin/jtoc/

76509746/, the researchers report that RA lung disease may operate much

differently from other forms of lung disease. If further studies support

this finding, it could change the way RA lung disease is treated as well as

the design focus of drugs developed to treat it.

The Mayo Clinic research paper describes a staining method the team refined

for identifying markers in RA patients' lung tissues. The results establish

two key points never before fully documented in the laboratory:

-- Certain specific T cells of the immune system, whose normal job in

healthy people is to attack disease organisms that invade the body, are more

abundant in tissue samples from patients with RA lung disease than in tissue

samples from patients who have other forms of lung disease. This finding

supports the concept that RA lung disease may be fundamentally different

from other forms of lung disease -- and should be treated differently.

-- RA lung disease detection can be improved through the technological

advance of computer-assisted image analysis. This improvement allows the

disease to be diagnosed early and treated aggressively as a disease of the

immune system.

" Many doctors who have seen our results say, 'This is what I've always

believed.' But no one had proved it to them, " says Carl Turesson, M.D.,

Ph.D., former Mayo Clinic research fellow now working at Malmo University

Hospital in Sweden. Says Dr. Turesson, " Our work provides the evidence that

was lacking, so from that standpoint, it is a very helpful demonstration

that hopefully will lead to the development of new treatment strategies for

RA lung disease. "

The Investigation

In the Mayo Clinic laboratories, Dr.Turesson and colleagues examined 31 lung

tissue biopsy specimens. Of those, 15 were from patients previously

diagnosed with RA lung disease, and 16 were from patients who, although not

suffering from RA lung disease, also had a disease affecting the lung

tissue, interstitial lung disease. No one on the research team knew the

diagnosis of a given specimen. All specimens were stained to enhance certain

T cell subtypes and then examined by digital images magnified 100 times. The

staining patterns were quantified using computer-assisted image analysis.

Results from the 11,412 images analyzed indicated that tissue samples from

RA lung disease patients consistently showed elevated numbers of a subset of

T cells known as CD4 and CD3 cells.

Practical Implications of the Research

At least two immediate implications of this research could change the way

researchers are attempting to design RA lung disease drugs and how

aggressively RA lung disease patients are treated. First, the abundance of

CD4 and CD3 cells in RA lung disease tissue suggests therapies specifically

directed against T cells and T cell function may succeed where earlier

therapeutic approaches did not. Explains Dr. Turesson: " This is a rationale

for trying newer approaches to treating RA lung disease that involve drugs

that block T cell action. That might help us make progress against this

disease. " Studies are ongoing to examine other important subtypes of cells

involved in RA lung disease and to discover how these are related to its

cause and the damage to the joints, lungs and other tissues of the body

which result.

Second, data from the researchers shows that the form of RA disease that

spreads beyond joints to involve the lungs is more likely to be fatal.

However, if physicians can use the Mayo Clinic method for detecting early

telltale signs of RA lung disease, they can decide to treat the disease

aggressively in its early stages and thus potentially prolong lives,

according to Dr. Turesson.

About Rheumatoid Arthritis

Rheumatoid arthritis belongs to a class of diseases in which the immune

system erroneously attacks the body. These are called " autoimmune " diseases.

Because it is a systemwide disorder that can affect different parts of the

body, RA can cause a variety of symptoms. It can work silently for years

without symptoms, as in the early stages of both joint damage and RA lung

disease. Symptoms can include joint pain, stiffness, inflammation,

persistent cough, shortness of breath and fever. RA affects an estimated 1

percent of the U.S. population, about 2.1 million Americans, according to

the Arthritis Foundation, http://www.arthritis.org. Of these, nearly

one-half may have some abnormal lung function. Up to one-fourth -- about

500,000 Americans -- develop RA lung disease. In RA lung disease, the air

sacs of the lung (alveoli) and the structures that support them become so

damaged by inflammation that they become scarred, impairing effective lung

functioning.

http://www.medicalnewstoday.com/medicalnews.php?newsid=18702

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