Rheumatoid Arthritis: Lozano F

Ramos-Casals M, Brito-Zerón P, Soria N, Nardi N, Vargas A, Muñoz S, Bové A, Suárez B, Lozano F. · Department of Autoimmune Diseases, Laboratory of Autoimmune Diseases Josep Font, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain. · Rheumatology (Oxford). · Pubmed #19056797 No free full text.

Abstract: OBJECTIVE: To investigate the association of mannose-binding lectin (MBL)-low genotypes with the clinical and immunological expression of primary SS. METHODS: Eighty-one patients with primary SS who fulfilled the 2002 classification criteria were included in the study. MBL2 polymorphisms were investigated by sequence-based DNA typing of the promoter and exon 1. Genotypes 0/0, 0/XA or XA/XA were considered as MBL-low and XA/A, A/0 and A/A as MBL-sufficient. Control groups included 46 patients who exclusively fulfilled the 1993 SS criteria, 114 SLE patients and 104 healthy individuals. RESULTS: Twelve (15%) SS patients had MBL-low genotypes, of whom six (7%) had genotype 0/XA, five (6%) had genotype 0/0 and one (1%) had genotype XA/XA. A higher prevalence of the XA/A genotype (32 vs 17%, P = 0.01) was found in primary SS patients in comparison with SLE patients. No patient with primary SS carrying MBL-low genotypes had purpura, glomerulonephritis or neurological involvement (0 vs 29%, P = 0.025). Immunologically, patients carrying MBL-low genotypes had a lower frequency of anti-Ro/SS-A antibodies (17 vs 55%, P = 0.014), anti-La/SS-B antibodies (8 vs 48%, P = 0.009) and low C4/C3 levels (0 vs 32%, P = 0.016). No patient with primary SS carrying the homozygous MBL-deficient genotype 0/0 had anti-Ro/SS-A or anti-La/SS-B antibodies, low C3/C4 levels or circulating cryoglobulins. CONCLUSION: SS patients with MBL-low genotypes have a less pronounced systemic and immunological disease expression in comparison with those carrying MBL-sufficient genotypes. In primary SS, MBL deficiency may represent a protective factor against the development of more aggressive autoimmune damage.

Ramos-Casals M, Font J, García-Carrasco M, Calvo J, Places L, Padilla O, Cervera R, Bowen MA, Lozano F, Ingelmo M. · Systemic Autoimmune Diseases Unit and. Department of Immunology, Hospital Clínic, Department of Medicine, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), School of Medicine, University of Barcelona, Barcelona, Spain. · Rheumatology (Oxford). · Pubmed #11561119 links to  free full text

Abstract: OBJECTIVE: To determine the existence of circulating levels of soluble scavenger receptors (sCD5 and sCD6) in patients with primary Sjögren's syndrome (SS), and to analyse the correlation with clinical and immunological features of SS. METHODS: Ninety consecutive patients with primary SS were studied. All patients fulfilled four or more of the European diagnostic criteria for SS. sCD5 and sCD6 levels were determined using a specific enzyme-linked immunosorbent assay (ELISA) developed in our laboratory. RESULTS: Detectable levels of sCD5 were found in 39 (43%) SS patients. The mean+/-standard error values of sCD5 were 3.5+/-0.5 ng/ml for patients with SS and 1.9+/-0.1 ng/ml for healthy blood donors (P<0.001). We found higher levels of sCD5 in patients with hypocomplementaemia (6.5 vs 3.5 ng/ml, P=0.03) and cryoglobulinaemia (6.9 vs 2.6 ng/ml, P=0.001). On the other hand, detectable levels of sCD6 were found in 60 (67%) SS patients. The mean+/-standard error values of sCD6 were 25.5+/-7.8 ng/ml in SS patients and 5.27+/-1.40 ng/ml in healthy blood donors (P=0.01). When the sCD6 levels were compared according to the presence or absence of immunological features, patients with cryoglobulinaemia showed higher levels of circulating sCD6 (77.3 vs 17 ng/ml, P=0.01) than those without cryoglobulinaemia. CONCLUSION: Patients with primary SS showed higher levels of circulating sCD5 and sCD6 when compared with controls. Moreover, the existence of some immunological features (hypocomplementaemia and cryoglobulinaemia) was associated with high levels of both soluble scavenger receptors. These facts may reflect an enhanced lymphocytic activation in patients with primary SS.

Calvo J, Places L, Espinosa G, Padilla O, Vilà JM, Villamor N, Ingelmo M, Gallart T, Vives J, Font J, Lozano F. · Servel d'Immunologia, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Barcelona, Spain. · Tissue Antigens. · Pubmed #10488739 No free full text.

Abstract: CD5 is a 67 kDa type I glycoprotein which belongs to the Scavenger Receptor Cysteine-Rich (SRCR) family of receptors. This family includes either cell-surface (e.g. CD6) or secreted (e.g. Spalpha) proteins implicated in the development of the immune system and the regulation of immune responses. In this study, we purified and characterised a circulating natural soluble CD5 form (nsCD5) which is indistinguishable (in apparent molecular mass, glycosylation pattern, and antibody reactivity) from a recombinant soluble CD5 form (rsCD5) composed of the three extracellular SCRC domains. The nsCD5 is a N-glycosylated 52 kDa molecule present in normal human serum and in supernatants of in vitro phorbol ester- and CD3-stimulated peripheral blood mononuclear cells. The nsCD5 concentration in sera from healthy donors is relatively low (median 1.75 ng/ml, rn=166) and is similar to that found in sera from patients suffering of various autoimmune (systemic lupus erythematosus, primary Sjogren syndrome, rheumatoid arthritis) and non-autoimmune (chronic renal failure, B-cell chronic lymphocytic leukemia) disorders. In vitro experiments indicate that nsCD5 is released by proteolytic cleavage of the membrane form. These results represent the first evidence of proteolytic release of a transmembrane SRCR family member following cell activation.