Philippe Chalem

Polyautoimmunity and familial autoimmunity in systemic sclerosis.

Characterization of the extent to which particular combinations of autoimmune diseases occur in excess of that expected by chance may offer new insights into possible common pathophysiological mechanisms. The goal of this study was to investigate the spectrum of polyautoimmunity (i.e. autoimmune diseases co-occurring within patients) and familial autoimmunity (i.e. diverse autoimmune diseases co-occurring within families) in patients with systemic sclerosis (SSc). A cross-sectional study of two convenience samples of patients with SSc, one in Canada and the other in Colombia, was performed. History of other autoimmune diseases in the SSc patients as well as a family history of autoimmunity was obtained. Of 719 patients, 273 (38%) had at least one other autoimmune disease. A total of 366 autoimmune diseases were reported, of which the most frequent were autoimmune thyroid disease (AITD, 38%), rheumatoid arthritis (RA, 21%), Sjögrens syndrome (18%), and primary biliary cirrhosis (4%). There were 260 (36%) patients with first-degree relatives with at least one autoimmune disease, of which the most frequent were RA (18%) and AITD (9%). Having at least one first-degree relative with autoimmune disease was a significant predictor of polyautoimmunity in SSc patients. No significant differences in polyautoimmunity or familial autoimmunity were noted between diffuse and limited subsets of disease. Our results indicate that polyautoimmunity is frequent in patients with SSc and autoimmune diseases cluster within families of these patients. Clinically different autoimmune phenotypes might share common susceptibility variants, which acting in epistatic pleiotropy may represent risk factors for autoimmunity.

Single anti-P ribosomal antibodies are not associated with lupus nephritis in patients suffering from active systemic lupus erythematosus.

BACKGROUND In clinical practice, it is sometimes difficult to diagnose a relapse in patients suffering from systemic lupus erythematosus (SLE) and lupus nephritis (LN) having potential complications, including renal failure and death. Some immunological markers can help to determine their association with LN and, therefore, diagnose the early onset of complications. OBJECTIVES Evaluating the association between systemic and/or kidney activity and anti-P ribosomal and anti-dsDNA antibodies in patients suffering from active SLE. METHODS 389 patients were evaluated, 140 of whom were subsequently included in the study. The patients were divided into two groups by means of case-control studies, including Colombian patients having American College of Rheumatology (ACR) classification criteria for SLE (1997). The SLE disease activity index (SLEDAI) was applied and all patients presenting an increase of 5 or more compared to their last evaluation, as well as presenting renal manifestations, were considered to be cases; all patients had an activity score. An ELISA kit and the indirect immunofluorescence method with Crithidia luciliae were used for determining the presence of anti-P ribosomal and anti-dsDNA antibodies, respectively. RESULTS No association was found between anti-P ribosomal antibodies and LN (p=0.2971) but anti-P ribosomal antibodies showed association with a >5 SLEDAI score (OR=4.87; 1.32-17.98 95% CI; p=0.008). The coexistence of anti-P ribosomal and anti-dsDNA antibodies was associated with LN (OR=3.52; 1.07-13.42 95% CI; p=0.019) and anti-dsDNA was associated with LN (p=0.001). CONCLUSION There was no association between anti-P ribosomal antibodies and LN but anti-P ribosomal antibodies coexisting with anti-dsDNA antibodies was associated with LN, thereby suggesting that the coexistence of two antibodies is nephritogenic to a greater extent. Additional studies are needed to evaluate the coexistence of kidney-specific antibodies in SLE to determine the biological nature of LN.

Design and validation of LupusCol, an instrument for the evaluation of health-related quality of life in Colombian adult patients with systemic lupus erythematosus

OBJECTIVE The aim of this study was to design and validate LupusCol, an instrument for the evaluation of health-related quality of life (HRQoL) in Colombian adult patients with SLE. METHODS Items and domains of the initial instrument were defined. Preliminary tests were made with the participation of patients. Validity and reliability tests of the administration method were conducted. Usability tests were applied to the version obtained in the previous phases to complete the validation process. RESULTS Following preliminary tests, six items and one domain were excluded and two new items were added to the instrument, producing a form with 44 questions and 7 domains, which was submitted for validity and reliability tests. Factor analysis excluded three items, obtaining a Pearsons correlation (PC) for the criteria validity of -0, 48; a Cronbachs α coefficient for internal consistency of 0, 96; an intraclass correlation coefficient (ICC) for personal test-retest-telephone of 0.96 and an ICC personal test-retest-personal of 0.96. For interrater concordance a PC of 0.8, an ICC of 0.77 and a Lins coefficient of 0.86 were found. Sensitivity to change was demonstrated through analysis of variance, obtaining significant indicators about the scale, demonstrating the instruments ability to detect changes in HRQoL. CONCLUSION The design and validation process was completed successfully. The scale has significant values for validity, reliability and sensitivity to change in the studied population.