Anti-cyclic citrullinated peptide antibodies and rheumatoid factor in rheumatoid arthritis patients and relatives from Brazil.
OBJECTIVE
To evaluate the prevalence of anti-cyclic citrullinated peptide (anti-CCP) antibodies and RF in RA patients and their relatives from Southern Brazil.


METHODS
Anti-CCP2 and IgM-RF were evaluated in 156 RA patients and 200 relatives. Sera from 100 healthy unrelated individuals were used as control. The anti-CCP2 was detected by ELISA and the IgM-RF using the latex agglutination test.


RESULTS
We identified 117 anti-CCP2 (75%)-positive and 106 RF (67.9%)-positive patients. Anti-CCP2 was increased in relatives (5.5%; 11/200) when compared with unrelated individuals (1%; P = 0.050). Titre of anti-CCP2 in RA patients did not differ from relatives [140.4 (75.7) vs 115.6 (84.2) U, respectively; P = 0.30]. Positive relatives were younger than patients for anti-CCP2 (P = 0.0081), RF (P < 0.001) and both concomitantly (P = 0.012), and although there was no difference for anti-CCP2 positivity according to gender, increased RF positivity and concomitant anti-CCP2/RF were observed in the female relatives (P = 0.067 and 0.082, respectively). No difference regarding the relative degree of tobacco use in relatives was detected. Among the 11 anti-CCP2-positive relatives, 2 females had RA diagnosis established and 6 individuals presented with joint symptoms suggestive of RA.


CONCLUSIONS
The results demonstrate a significant positivity of anti-CCP2 in relatives of RA patients from Brazil and reinforce the importance of serological tools to identify undiagnosed RA.
Goeldner
Isabela
I
Laboratory of Immunopathology, Clinical Hospital, Federal University of Paraná, Curitiba, Paraná, Brazil.
Skare
Thelma L
TL
de Messias Reason
Iara T
IT
Nisihara
Renato M
RM
Silva
Marília B
MB
Utiyama
Shirley R da Rosa
SR
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000974:Antibodies, Antinuclear / Q000235:genetics*; D001172:Arthritis, Rheumatoid / Q000235:genetics* / Q000503:physiopathology; D001938:Brazil; D016022:Case-Control Studies; D002648:Child; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D010456:Peptides, Cyclic / Q000037:antagonists & inhibitors* / Q000235:genetics; D011237:Predictive Value of Tests; D012217:Rheumatoid Factor / Q000235:genetics*; D013223:Statistics as Topic; D055815:Young Adult
D000974:Antibodies, Antinuclear; D010456:Peptides, Cyclic; C487763:cyclic citrullinated peptide; D012217:Rheumatoid Factor