Original Article

Volume 30, Número 1, p. 54-63, 2014 http://dx.doi.org/10.4322/rbeb.2014.004

Study of advanced rheumatoid arthritis

Carolina da Silva Carvalho, Luiz Eduardo Coelho Andrade, Silene Peres Keusseyan, João Lucas Rangel,
Juliana Ferreira-Strixino, Airton Abrahão Martin, Leandro José Raniero*

Abstract Introduction: Rheumatic diseases are considered public health problems affecting millions of people
worldwide resulting in high and rising health-care costs. In this work, Fourier Transform Infrared spectroscopy
associated to Partial Least Square regression (PLS) analysis was used to diagnose rheumatoid arthritis (RA)
from human serum. Methods: The sera of 94 individuals were collected, which included 47 from rheumatic
patients and 47 from healthy individuals. The results from PLS analysis were compared to standard clinical
trials such as anti-citrullinated peptide antibodies, C- Reactive protein, and Rheumatoid factor. Results: For
clinical diagnosis, the anti-citrullinated peptide antibodies of second generation proved to be the most specific
to diagnosis rheumatoid arthritis even after long periods of drug therapy. Conclusions: The qualitative PLS
analysis has shown higher values of IgM of RA group, but the difference was very small. The RA patients
were under medication, which interfered with the IgM concentration.
Keywords FTIR spectroscopy, Human serum, Rheumatoid arthritis, Partial Least Square.

Introduction
Rheumatic diseases are considered public health Regarding the etiology of the disease, cigarette
problems affecting millions of people worldwide smoking is described as a possible risk factor for the
resulting in high and rising health-care costs onset or worsening of RA. Smoking is associated
(Cheng et al., 2010; Desai et al., 2010; Waljee and with a worse prognosis of the disease (Karlson and
Chung, 2011). For example, in 2003, the United Deane, 2012; Okamoto et al., 2011; Ruiz-Esquide
States of America spent a total of 128 billion US$ and Sanmartí, 2012). In contrast, little has been said
on rheumatoid arthritis (RA), which is just one type about better eating habits or the benefits of physical
activity in this population. The implementation of
of rheumatic disease (Birch and Bhattacharya, 2010;
programs of physical training and nutrition education
Centers…, 2011). Of this sum, 3.6 billion US$ were
could provide greater independence and quality of life
spent on drug therapies (Waljee and Chung, 2011) and
to RA patients (Külkamp et al., 2009; Plasqui, 2008).
about US$ 14,000 on cardiovascular disease associated Therefore, it is necessary to explore theses parameters
with an increased prevalence of coronary artery disease within a public health system.
present in RA (Desai et al., 2010). In the period from The clinical approach to diagnosis RA is based
2007 to 2009, US statistical data indicate an increase on the standard procedure established by the ACR
of approximately a million of new RA cases per year (American College of Rheumatology) in 1987.
(Cheng et al., 2010). However, this has been widely criticized due to
RA affects approximately 0.5-1% of the world the lack of sensitivity for early detection of the
population (Hambright et al., 2011; Martínez et al., disease. Therefore, the ACR and European League
2011), being more common in women than in men, and Against Rheumatism (EULAR) has developed a
in ages between 40 and 60 years (Ebringer et al., 2010). new set of criteria to classify RA based on new
RA is the most common systemic autoimmune disease laboratory parameters such as anti-citrullinated peptide
in the world (Haro et al., 2011), and it causes functional antibodies (anti-ACPA), C- Reactive protein (CRP),
disability and premature death. Approximately 70% of and Rheumatoid factor (RF). The new set of criteria
patients have irreversible joint destruction and 80% of aims to identify early RA patients in order to institute
active young adults in the labor market are affected by early drug therapy, thereby reducing the functional
stiffness and devastating pain (Filipovic et al., 2011). disability and articular lesions (Aletaha et al., 2010).
This situation generates a big loss of daily activities High concentrations of CRP, RF, and ACPA in serum
and vocational productivity resulting in significant are associated with unfavorable outcomes, including
reduction in quality of life (Waljee and Chung, 2011). persistent disease, joint destruction, and functional
*e-mail: lraniero@univap.br
Received: 07 August 2013 / Accepted: 12 November 2013
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Braz. J. Biom. Eng., 30(1), 54-63, Mar. 2014 Study of advanced rheumatoid arthritis 55

disability. The studies correlating clinical trials clinical practice due to the complexity of procedures
(symptoms and signs) with radiographic exams have and the need for qualified technicians (Liao et al.,
shown that patients with low titre and/or negative 2011; Santos et al., 1997).
RF/ACPA have a better prognosis (Malaviya et al., The several medications administrated to RA
2009). This RF in RA patients may have different
patients lead to changes in the serum composition.
classes of gammaglobulins such as IgM, IgG, or IgA.
Nevertheless, classes of IgM and IgG-RF are more The persistent and progressive inflammation of the
correlated with the disease and are abundantly produced synovial tissue causes joint destruction, affecting
by plasma cells in synovial tissue (Duquerroy et al., mainly the hands (Waljee and Chung, 2011). To try
2007; Firestein et al., 2009). to combat or reduce the loss caused by this disease,
The ACR and EULAR have been using these the medical community makes use of nonsteroidal
biomarkers as part of the classification criteria for anti-inflammatory drugs (NSAID) and low-dose
early diagnosis, thereby ensuring the opportunity glucocorticoids, associated with modifying anti-
of early treatment and prevention of irreversible rheumatic drugs (DMARDs) (Elefant et al., 2010;
deformities. However, there are some problems in Mouterde et al., 2011).
the tests due to the mismatch between specificity Nevertheless, the negative sides effects of steroids
and sensitivity. The ACR uses RF as a biomarker are a limiting factor, and the dose must be the lowest
that can be detected in 70-80% of patients with RA, possible to achieve therapeutic benefit. NSAIDs should
but it can also be found in other rheumatic diseases. not be used alone, as they do not change the course
Therefore, it is a test for a non-specific biomarker,
of the disease. Most RA treatment includes NSAIDs
which is also present in infections and about 5-10%
for pain control, glucocorticoids and the initiation of
of healthy individuals (Birch and Bhattacharya, 2010;
a DMARDs (Birch and Bhattacharya, 2010).
Ryu et al., 2011). The CRP test is based on the increase
in serum C-reactive protein, which is synthesized in Fourier Transform Infrared Spectroscopy (FTIR)
great amounts immediately after any tissue damage. analysis has the potential to provide rapid results and
Thus, CRP test is not specific and it is elevated in all may be adapted for a clinical test with high values
inflammatory and infectious processes as well as in of sensitivity and specificity (Carvalho et al., 2011;
the RA. Elevated plasma levels are detected within 4 Naumann, 2008; Raniero et al., 2011). In this article,
to 6 hours after injury and peak levels are found after FTIR (Petibois et al., 1999; Sankari et al., 2010) was
24 to 72 hours (Otterness, 1994). ACPA antibody is used as tool to investigate sera of RA and normal (N)
considered the most specific marker for RA, but the individuals, using Partial Least Square (PLS) regression
sensitivity is not greater than 70% (Cai et al., 2011). analysis (Muñoz de la Peña et al., 2007). The results
Another possibility for early diagnosis is the were compared to different laboratory techniques
antiperinuclear factor (APF) antibody, which was such as CRP, RF, anti-CCP, APF. In addition, we
originally described by Nienhius et al. (1964) by also analyzed possible interference of medication
indirect immunofluorescence technique. APF is an and food in the two evaluated groups.
autoantibody that reacts against antigens present in
keratohyalin granules of human oral mucosa. APF Methods
is distributed predominantly around the nucleus of
keratinocytes (Vander Cruyssen et al., 2005). High This work was approved by the Ethics Committee of
levels of APF are considered specific for RA and the Institute of Research and Development (IP&D),
the molecular characterization of these antigens University of Vale do Paraíba (UniVap) following the
resulted in the discovery of citrullinated peptides. Guidelines and Norms Regulating Research involving
From this characterization, enzyme immunoassays human, H119CEP/2010.
for antibodies to citrullinated peptide are produced Selection of the volunteers was done through a
commercially (ACPA) by ELISA method. These new questionnaire with information about diet, medications,
laboratory tests combined with imaging methods such lifestyle, and the most recent meal. The parameters
as ultrasound and magnetic resonance imaging of of exclusion and inclusion were pre-adjusted for
affected joints have largely contributed to the early both groups. The healthy group was comprised
diagnosis, which is very important to improve patient´s only of women from 30 to 60 years old, due to the
quality of life (Hsin-Hua et al., 2010; Narváez et al., predominance of the disease in women, and the
2008; Nienhius et al., 1964; Østergaard et al., 2008). disease group was formed by women with confirmed
However, most immunochemical assays for anti-CCP RA diagnosis, according to criteria established by
(ELISA) and APF have limited utility for routine the ACR 2010.
 Rev. Bras. Eng. Bioméd., v. 30, n.1, p. 54-63, mar. 2014
56 Carvalho CS, Andrade LEC, Keusseyan SP, Rangel JL, Ferreira-Strixino J, AA Martin, Raniero LJ Braz. J. Biom. Eng., 30(1), 54-63, Mar. 2014

Blood samples or combined with low doses of glucocorticoids (up to

15 mg of prednisone) (Bértolo et al., 2007). In the N
The 94 blood samples were collected at UNIFESP
group, the only drugs allowed were anti-hypertensives
(Federal University of São Paulo) and the Department and oral hormone replacement therapy.
of Hemotherapy and Hematology of São José dos
The information about the most recent meal from
Campos, in agreement with requirements and
RA and N groups was evaluated through the TACO
recommendations of Brazilian Society of Clinical
table (Brazilian Table of Food Composition). The
Pathology (SBPC)/Laboratory of Medicine for venous
TACO Table contains the information about the
blood (Andriolo et al., 2009). Of the blood samples, 47 composition of Brazilian foods (Universidade…,
were from patients with RA (chronic phase and with 2011). This table was prepared by the Center for
long-term drug therapy) and 47 from healthy subjects. Studies and Research in Food (NEPA- UNICAMP)
The procedure adopted for collecting venous blood and approved by the National Agency for Sanitary
was as follows: 1) Collection of whole blood in the Vigilance.
antecubital region of the right arm using venipuncture;
2) Storage in sterile tube, gel-barrier vacuum (BD Fourier Transform Infrared Spectroscopy
Vacutainer SST Advance Tube, 5 mL, Gold) for 30
A thin serum film was made with a drop (1 µl) of the
min at room temperature; 3) Centrifugation at 4000 g
samples deposited on calcium fluoride (CaF2) window
for 6 min; and 4) Separation of serum, that was
and dried using an Eppendorf Concentrator 5301. The
stored in polypropilene tubes and placed in sealed
spectra of the samples were recorded in the range of
polypropylene styrene boxes for transportation and 4000-900 cm–1, with 64 scans and a spectral resolution
storage of the material at –23 °C. of 4 cm–1, using a FTIR spectrometer (Perkin-Elmer,
Clinical analysis Spotlight 400). The spectra were collected using the
single detector mode of the microscope. To analyze
The analysis of rheumatoid factor and C-reactive spectral data, the spectrum Image, Spotlight 400
protein were started immediately after the blood Software, version 3.6.2 was used.
collection. RF and CRP were evaluated by latex
agglutination test (Wama Diagnóstica®), based on Statistical analysis
indirect agglutination of latex particles coated with The values obtained through the questionnaire were
human IgG and monoclonal anti-CRP antibody, evaluated, consolidated, and tabulated using a binomial
respectively. distribution by the statistic software IBM SPSS® 19.0.
The sensitivity of the tests corresponded to 8 Ul/ PLS analysis was constructed from serum proteins
ml for RF and 6 mg/liter for CRP. The tests for APF known as bovine serum albumin (BSA) and human
(antiperinuclear factor) and ACPA 2nd generation immunoglobulin M class (IgM) antibodies, which
were performed at Rheumatology Division at Escola
were purchased from Sigma Aldrich. The human
Paulista de Medicina. The determination of ACPA2
and bovine albumins have very similar primary
was done using Quanta LiteTM CCP2 IgG Elisa, kit
structures, both being widely used in biochemical
(INOVA Diagnostics, Inc., San Diego, CA, USA),
and biophysical studies (Gelamo and Tabak, 2000).
according to the manufacturer’s instructions, which
From the spectroscopic view point, an important
set the cut off at 20 U/ml. ACPA titers between 20 and
difference between these proteins is that the albumin
39 U/ml were considered weakly positive, between 40
has only one tryptophan residue (Trp214) and bovine
and 59 U/ml as moderately positive, and ≥ 60U/ml as
strongly positive. APF was determined as described albumin possesses two tryptophan residues (Trp134
by Hoet et al. (1991) with slight modifications as and Trp212) (Cheng, 2012).
established in Brazil by Santos et al. (1997).
Results
Medications and diet
Figure 1 shows the sensitivity and specificity values
The drugs used in the RA group were non-
of CRP, RF, APF, and ACPA analysis for N and RA
biological and biological. The non-biological
groups. The RF and CRP analysis were performed
DMARDs were Methotrexate (MTX), leflunomide,
hydroxychloroquine, sulfazalasine, and cyclosporine. for both groups. However, the APF and ACPA were
The biological medications are divided in subgroup done only for RA group due to high specificity of
such as: 1) TNF blockers: Adalimumab, etanercept, and RA diagnosis (Lutteri et al., 2007; Santos et al.,
infliximab; 2) Depletors B lymphocytes: Rituximab; 1997; Swart et al., 2012). All tests have shown high
3) Modulators of co-stimulation: Abatacept. For pain values of specificity, but there are many differences
control and inflammation of the joints, nonsteroidal on sensitivity, which will be remarked upon later in
anti-inflammatory drugs (NSAIDs) were used alone this text.
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Braz. J. Biom. Eng., 30(1), 54-63, Mar. 2014 Study of advanced rheumatoid arthritis 57

Figure 1. Sensitivity and specificity values of laboratory tests.

Risk factors, diet, and medications Partial Least Square analysis

Table 1 shows the prevalence of smoking, physical Figure 2 shows the frequency in serum concentration
activity and nutrition of N and RA groups. The values of IgM and BSA of the rheumatic and normal groups.
p ≤ 0.05 indicate significant differences between the The normal individuals have values ranging from 2.4 to
variables, a fact apparent in both N and RA groups. By 4.0, while rheumatic individuals vary from 2.6 to 4.2.
identifying such similarities, it is possible to correlate
the variations found in both groups. Initially it was Discussion
found that the role of smoking in the inflammatory
process is still the subject of study. Our study suggests that even after long-term drug
The positive reactions of RF and ACPA antibodies therapy (9 ± 7.9 years), the biomarker ACPA is
in RA patients were compared in smokers, ex-smokers, still present in the circulatory system of rheumatic
individuals. This autoantibody showed high specificity
and non-smokers, with 24 non-smokers and 23 smokers
and less sensitivity (see Figure 1). Similarly, Swart et al.
or ex-smokers. The frequency of positive ACPA assay
(2012) evaluated rheumatic patients (disease duration
was similar in both RA subgroups (66.7% and 78.3%
8.5 years) using the same ACPA 2nd generation kit,
with a difference of 11.6% respectively). A positive
and obtained the following values of sensitivity/
RF assay was 4.2% for non-smokers and 13% for
specificity (77.3/98.1%). Van Venrooij et al. (2006)
smokers or ex-smokers, with a difference of 8.8%.
report that the sensitivity of the test ranges between
With respect to physical activity, both groups
60% (early RA) and 77% (established RA). The ACPA
had a sedentary lifestyle with p < 0.05, showing that positive patients usually remain positive despite
most of the population studied did not practice regular treatment, and slight declines or even an increase
physical activity. the titers of ACPA may occur (Niewold, 2007).
The statistic results of food taken in the most recent These differences make it impossible to confirm
meal found a higher cholesterol level for rheumatic the effectiveness of anti-rheumatic medications on
patients compared to normal individuals. However, stability/reduction of this autoantibody. The use of
with respect to other variables both groups showed this biomarker in the monitoring of rheumatic patients
similar variations, with p < 0.05, demonstrating a during treatment or their relation to disease activity
percentage intra-group fairly heterogeneous. is still controversial and unexplored. Currently, it is
Table 2 shows the most used medications for necessary to standardize evaluative concepts, such as:
rheumatic and healthy individuals in this study. 1) monitoring of biomarkers before and during the
Methotrexate, leflunomide, and prednisone are among course of the disease; 2) detailing of the medications;
the most widely prescribed rheumatics drugs due to and 3) evaluation of clinical and functional signs.
their clinical efficacy and low toxicity. In both groups, Although the ACPA is more specific for RA, it does
the use of antihypertensive drugs is present. not exclude the diagnosis of other autoimmune diseases
 Rev. Bras. Eng. Bioméd., v. 30, n.1, p. 54-63, mar. 2014
58 Carvalho CS, Andrade LEC, Keusseyan SP, Rangel JL, Ferreira-Strixino J, AA Martin, Raniero LJ Braz. J. Biom. Eng., 30(1), 54-63, Mar. 2014

Table 1. Percentage values (%) of smokers, individuals who practice physical activity (at least 3 times per week), and food intake before the
venous blood test in N and RA groups. Source: Universidade Estadual de Campinas (2011) (Anvisa/Ministry of Health).
N (%) RA (%)
Variables
Yes No p Yes No p
Smokers 19 81 *0.000 15 85 *0.000
Physical activity 32 68 *0.019 28 72 *0.03
Fasting 0 100 *0.000 13 87 *0.000
Lipids 70 30 *0.008 68 32 *0.019
Cholesterol 15 85 *0.000 64 36 0.079
Saturated 74 26 *0.001 68 32 *0.019
Monounsaturated 74 26 *0.001 68 32 *0.019
Polyunsaturated 74 26 *0.001 68 32 *0.019
Carbohydrate 83 17 *0.000 87 13 *0.000
Proteins 79 21 *0.000 70 30 *0.008
*p < 0.05 in relation to the intra-group differences.

Figure 2. Differences of IgM/Albumin ratio for RA and N groups by PLS.

Table 2. Medications commonly used by the rheumatism and (psoriatic arthritis, systemic lupus, and Sjögren´s
normal groups.
syndrome) (Vander Cruyssen, 2005).
Medications Yes Not p
In the present study, the high specificity and
Methotrexate 64 36 0.079 reduced sensitivity found in the RF analysis may be
Prednisone 55 45 0.560 due to the low sensitivity of our method by indirect
Leflunomide 26 74 *0.001 agglutination. Swart et al. (2012) and Liao et al. (2011)
Chloroquine 13 87 *0.000 observed a higher sensitivity and lower specificity of
Adalimumab 11 89 *0.000 RF (65.2/89.6% and 67.4/84.3%) by turbidimetry and
Sulfasalazine 09 91 *0.000 nephelometry analysis, respectively. This variation
can be attributed to the choice of technique used.
Hydroxychloroquine 06 94 *0.000
RA group Nevertheless, the specificity and sensitivity of RF
Etanercept 06 94 *0.000
have been improved by the development of enzyme-
Infliximab 04 96 *0.000 linked immunosorbent assays (ELISA), which permit
Rituximab 02 98 *0.000 the detection and quantitative measurement of RF of
Abatacept 02 98 *0.000 various IgG-, IgA-, and IgM-RF class immunoglobulins
Cyclosporine 02 98 *0.000 (Vallbracht and Helmke, 2005). The more specific
Antihypertensives 47 53 0.771 techniques for testing these classes by ELISA are
NSAIDs 19 81 *0.000 nephelometry and turbidimetry with 90% sensitivity
Hormones (T4) 08 92 *0.000
(Firestein et al., 2009). However, discrepancies in
the values of RF measurements are widely found
N group Contraceptive 21 79 *0.000
(Van der Linden et al., 2011). Recent data suggest
Antihypertensive 06 94 *0.000
that IgM-RF as well as other RFs play an important
*p< 0.05 in relation to the intra-group differences. role in the pathogenesis of rheumatoid arthritis, thus
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Braz. J. Biom. Eng., 30(1), 54-63, Mar. 2014 Study of advanced rheumatoid arthritis 59

being one of the more frequently used RFs in research conditions, disease progression, or joint damage.
(Ahmed et al., 2010; Zavala-Cerna et al., 2008). Benhamou et al. (2007) warns that prolonged bed
ACPA has a specificity of (91-98%), which is more rest in patients with RA may lead to deconditioning
specific than RF (Romic et al., 2009; Ryu et al., 2011). and functional decline. In contrast, more detailed
The ACPA and RF biomarkers are distinct, but are investigations about the role of physical activity on
complementary tools to investigate RA. the progression of RA should be conducted.
The CRP and RF values are similar to those In relation to eating, an important challenge for
described in the literature by indirect agglutination the present methodology is sample standardization,
(Carvalho et al., 2011). Our findings show a decrease in because serum carries several relevant components,
sensitivity values of CRP, which suggests a stabilization such as protein, lipids, vitamins, carbohydrates, etc.
of disease activity and joint destruction. In general, The concentrations of each of these are not constant,
improvement in CRP levels indicates that a drug but depend on the diet content, interval between
has produced a beneficial effect and may be useful meals and sample collection, medications, hormone
for monitoring effects of therapy (Otterness, 1994). cycles, genetic factors, metabolic activity, etc. Among
The APF analysis had a lower sensitivity compared this enormous variation, the main objective is to
to with CRP tests. Cordonnier et al. (1996) investigated identify biomarkers that could reliable correlate to
the APF marker in individuals with RA for a period relevant clinical parameters despite the influence of
of 24 months, obtaining a sensitivity/specificity extraneous factors. Many experts describe the high
of 28.6/95%. Approximately 50% of patients with potential of the infrared technique to diagnose different
RA early-onset and FR-negative (< 2 years) have diseases from serum, but the influences of the above
APF positive and sensitivity/specificity of 59/95% mentioned extraneous factors in spectral interpretation
(Santos et al., 1997). The results shown are consistent is still largely unknown (Déléris and Petibois, 2003;
with the current literature. Other studies correlating Petibois et al., 2001; Staib et al., 2001).
this biomarker with advanced RA could not be found. The current study presents the most used
Table 1 illustrates some risk factors such as medications for treating rheumatism, especially
smoking and physical inactivity. Our study shows methotrexate (64%) and prednisone (55%).
an involvement of smoking in the aggravation of Alarcón et al. (1990) reports that MTX causes a
the positivity of RF and ACPA rheumatic markers. suppression of rheumatoid factors class A and M
However, the role of smoking in the inflammatory immunoglobulin in human serum, which leads to a
process is still unknown. Goeldner et al. (2011) decrease of these autoantibodies in all patients who
verified that smoking influences the frequency of used the drug. Bathon et al. (2000) describes that
ACPA2 positivity, increasing by 2.7 times the risk MTX reduced disease activity, and this correlated
for high titer ACPA. In addition, they observed that with the absence of progressive radiographic evidence.
the females exposed to tobacco had this rate 7.7 Lipsky et al. (2000) also reports that MTX associated
times increased compared to men. Alsalahy et al. with infliximab significantly improved clinical benefit
(2010) also claims that the levels of ACPA and RF and radiographic progression stops. Klaasen et al.
are higher in smokers. Arnson et al. (2010) described (2011) demonstrates that therapy with infliximab
that cigarette smoking affects the immune system in reduces the levels of RF and ACPA antibodies after
diverse ways, both increasing inflammatory allergic 16 weeks of treatment, which was also confirmed in
and autoimmune reactions, and decreasing systemic our results for patients with lowest treatment time,
activity against infections. Smokers with RA have a 13 months. Other drugs such as adalimumab and
disease characterized by a greater proportion of auto- etanercept, also known as biologic DMARDs or
antibody positivity. This emphasizes the importance TNF blockers, and non-biological DMARDs also
of prevention/eradication of its use in order to avoid showed similar effects, with reduced levels of RF
respiratory complications and autoimmune conditions. and ACPA throughout drug treatment (Atzeni et al.,
The N and RA groups presented similar 2006; Fries et al., 1996). Thus, the lowest values of
characteristics in relation to physical activity, being autoantibodies were evidenced by efficient treatment
composed of large number of sedentary individuals. through stabilization of immune activities. However,
Plasqui (2008) describes that exercise contributes to the a long period of autoantibodies suppression can lead
improvement of aerobic conditioning and stretching. to a hazardous situation of infections (Ateş et al.,
Consequently, the quality of life and activities of 2007). Glucocorticoids are frequently associated with
daily living are improved. Furthermore, exercise the described medications above, because prednisone
does not cause deleterious effects on the health of exerts potent inhibitory effects on transcription and
the rheumatoid patient, i.e., it does not increase pain action of cytokines (IL-1β, IL-2, IL-3, IL-6, TNF-α,
 Rev. Bras. Eng. Bioméd., v. 30, n.1, p. 54-63, mar. 2014
60 Carvalho CS, Andrade LEC, Keusseyan SP, Rangel JL, Ferreira-Strixino J, AA Martin, Raniero LJ Braz. J. Biom. Eng., 30(1), 54-63, Mar. 2014

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therapy, the ACPA is the most specific and sensitive to cyclic citrullinated peptide in patients with early arthritis.
to monitor the progress of RA. Finally, the influence Clinical Rheumatology. 2007; 26(4):499-504. http://dx.doi.
of medication and eating on both spectral analyzes org/10.1007/s10067-006-0309-z
was discussed. In addition to the possible influence Atzeni F, Sarzi-Puttini P, Dell’Acqua D, De Portu S, Cecchini
of risk factors such as smoking, the increased levels G, Cruini C, Carrabba M, Meroni PL. Adalimumab clinical
of ACPA in rheumatic individuals stand out. efficacy is associated with rheumatoid factor and anti-cyclic
citrullinated peptide antibody titer reduction:one-year
Acknowledgements prospective study. Arthritis Research & Therapy. 2006;
8(1):1-8. http://dx.doi.org/10.1186/ar1851
The authors would like to thank all voluntaries Bathon JM, Martin RW, Fleischmann RM, Tesser JR,
and the financial support given by CNPQ (Project Schiff MH, Keystone EC, Genovese MC, Wasko MC,
301022/2012-7) and CAPES for the master fellowship. Moreland LW, Weaver AL, Markenson J, Finck BK. A
The authors also thank Alene Alder-Rangel for comparison of etanercepte and methotrexate in patients
reviewing the English. with early rheumatoid arthritis. New England Journal of
Medicine. 2000; 343(22):1586-93. http://dx.doi.org/10.1056/
NEJM200011303432201
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Authors
Carolina da Silva Carvalho, João Lucas Rangel, Juliana Ferreira-Strixino, Airton Abrahão Martin, Leandro Raniero*
Instituto de Pesquisa e Desenvolvimento – IP&D, Universidade do Vale do Paraíba – UniVap, Av. Shishima Hifumi, 2911,
Urbanova, CEP 12244-000, São José dos Campos, SP, Brazil

Luiz Eduardo Coelho Andrade, Silene Peres Keusseyan

Divisão de Reumatologia, Departamento de Medicina, Universidade Federal de São Paulo – UniFesp, São Paulo, SP, Brazil