(Print ISSN 1478-6354; Online ISSN 1478-6362). This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original URL. AbstractClonal expansion of CD4 + CD28 -T cells is a characteristic finding in patients with rheumatoid arthritis (RA). Expanded CD4 + clonotypes are present in the peripheral blood, infiltrate into the joints, and persist for years. CD4 + CD28 -T cells are oligoclonal lymphocytes that are rare in healthy individuals but are found in high percentages in patients with chronic inflammatory diseases. The size of the peripheral blood CD4 + CD28 -T-cell compartment was determined in 42 patients with RA and 24 healthy subjects by two-color FACS analysis. The frequency of CD4 + CD28 -T cells was significantly higher in RA patients than in healthy subjects. Additionally, the number of these cells was significantly higher in patients with extra-articular manifestations and advanced joint destruction than in patients with limited joint manifestations. The results suggest that the frequency of CD4 + CD28 -T cells may be a marker correlating with extra-articular manifestations and joint involvement.Keywords: arthritis, CD4 + CD28 -, lymphocytes Open AccessAvailable online http://arthritis-research.com/content/5/4/R210 R211In the present study we evaluated the correlation between the CD4 + CD28 -T-cell subset and extra-articular manifestations, magnitude of joint involvement, and presence of rheumatoid factor. Material and methods PatientsForty-two patients (26 women, 16 men, age 24-74 years, mean 51.7 years) with rheumatoid arthritis diagnosed according to the criteria of the American College of Rheumatology were included in the study. The disease duration was 4-19 years (mean 12.8 years). Patients were recruited from the outpatient and inpatient population of the Department of Rheumatology, University Hospital, Szczecin, Poland. All subjects were white and were from the Pomeranian region of Poland.

Our study-the first such performed for the Polish population-provides a consistent observation with previous reports on the genetic association of HERV-K113 integrations in autoimmune disorders. Here, we found that the prevalence of insertionally polymorphic HERV-K113 was significantly increased in Polish patients with SLE and RA.

Chronic inflammatory syndromes such as rheumatoid arthritis (RA) are associated with high frequencies of CD4+CD28- T cells. The number of these cells is genetically determined and may also be a consequence of chronic exposure to tumor necrosis factor-alpha (TNFalpha). The aim of this study was to examine whether the reported efficacy of anti-TNFalpha therapy in RA involves a resurgence of T cell populations that re-express CD28. After 36-week therapy with infliximab, a significant decrease in CD4+CD28- T cells in RA patients was observed in comparison with baseline. The results suggest that TNFalpha-neutralizing therapy may restore T cell homeostasis and reduce expansion of the CD28- T cells, which are cytotoxic and may contribute to organ manifestations in RA.

NAT2 slow acetylation genotype may be a risk factor of individual susceptibility to RA.