Estudio del polimorfismos de receptores Fcylla en pacientes chilenos con lupus erimatoso sistémico / Polymorphisms of Fcylla receptors in chilean patients with systemic lupus erythematosus

Background: Polymorphisms of Fc receptors for IgG (FcgR) have been proposed as a genetic factor that influences susceptibility for systemic lupus erythematosus (SLE). Human FcgRIIa has 2 codominantly expressed alleles, H131 and R131, which differ at amino acid position 131 in the second extracelular domain (histidine or arginine respectively) and differ substantially in their ability to bind human IgG2. The H131 allele binds IgG2 efficiently, whereas R131 binds it poorly. Because IgG2 is a poor activator of the classical complement pathway, the H131 is essential for the disposal of IgG2 immune complexes. Aim: To determine the distribution of FcgRIIA genes in a cohort of Chilean SLE patients, with or without a history of lupus nephritis. Patients and methods: We studied 52 Chilean SLE patients fulfilling the 1982 American College of Rheumatology (ACR) criteria, 20 of whom had a history of nephritis, and 44 ethnically matched disease-free controls. FcgRIIa allotypes were genotyped by PCR. Results: No significant association was observed between the low affinity FcgRII receptor (FcgRIIa-R131) and the presence of SLE or lupus nephritis. However, genotype frequencies in SLE patients but not in controls, departed from the proportions predicted by the Hardy-Weinberg equilibrium, suggesting this locus might be related to the disease. Conclusions: Our results suggest that in Chilean patients with SLE, as well as in many other populations, the R131 allotype is not a major factor predisposing to the development of SLE or lupus nephritis

Capacidad de predecir una recaída de lupus eritematoso generalizado, mediante anticuerpos anti-DNA de hebra doble, por la técnica de Farr / Predictive capacity of double stranded anti DNA antibodies for relapses in patients with inactive systemic lupus erythematosus using Farr technique

Background: Patients with inactive systemic lupus erythematosus (SLE) and elevated high affinity double-stranded anti-DNA antibodies (anti-dsDNA), measured using Farr technique, would have a risk of relapse that fluctuates between 40 to 80 percent according to different series. Aim: To study the association between anti-dsDNA levels measured using Farr technique and disease activity and their predictive capacity for relapses. Material and methods: Anti-dsDNA antibodies were measured according to Farr method in 60 healthy subjects, 69 patients with other connective tissue diseases and in 120 patients with SLE. Farr positive were considered those individuals with anti-dsDNA levels over 10.4 IU/ml. Disease activity, assessed using MEX-SLEDAI score was related with anti-dsDNA levels in 101 patients. Forty seven patients with inactive disease were followed for 17ñ14 months. Results: Anti-dsDNA levels were 3ñ2.5 IU/ml (range 1-26) in subjects without LED, and 127ñ500 IU/ml (range 1-5280) in patients with LED. Sixty subjects had an active SLE and 43 (72 percent) were Farr positive; in 41 the disease was inactive and 13 (32 percent) were Farr positive (p <0.001), OR 5.45. Twelve of the 47 followed patients had a relapse and 10 (83 percent) were Farr positive. Of those that did not have a relapse, 13 (37 percent) were Farr positive (p< 0.02, RR 5.22). Six of 15 patients that were followed for more than on year (40 percent), were Farr positive. Conclusions: Elevated anti-dsDNA antibodies measured using Farr technique in patients with inactive generalised lupus erythematosus, predicted the risk of relapse. However less than half of patients with inactive disease and elevated Farr relapsed in a period of one year. The need to treat patients with inactive SLE and positive Farr should therefore be considered debatable

Artritis seronegativas: reexamen del diagnóstico inicial y pronóstico al cabo de 10 años / Seronegative arthritis: diagnosis and prognostic reassessment after 10 years

Seronegative arthritides are a heterogeneous group of diseases that includes rheumatoid arthritis with negative rheumatoid factor. Between 1980 and 1984 we studied 38 patients with seronegative arthritis. Thirty of these patients were reassessed in 1994 after 9 or 20 years of evolution. Seventeen patients had a diagnosis of seronegative rheumatoid arthritis; this diagnosis was maintained in 12, changed to seropositive rheumatoid arthritis in 3, to psoriatic arthritis in 1 and connective tissue disease in 1. Thirteen patients had a diagnosis of undifferentiated arthritis; in 1994 the diagnosis was maintained in 3, 7 patients were diagnosed as having a sppondyloarthropathy, 2 as having a reactive arthritis and 1 as having a connective tissue disease. In 1994, nine patients fulfilled the 1991 criteria for spondyloarthritis and 6 of these did so on admission. Six of 12 patients with seronegative rheumatoid arthritis had an active disease or used antiinflammatory drugs and 64 percent had erosions on hand X ray examination. These figures are in contrast with the enigm evolution classically attributed to this disease and agree with recent reports. The usefulness of classification criteria for rheumatoid arthritis and spondyloarthritis in the initial assessment of patients with seronegative arthritis is emphasized

Arteritis de la temporal y polimialgia reumática: estudio clínico / Temporal arteritis and polymyalgia rheumatica: a clinical study

La arteritis de la arteria temporal es una vasculitis granulomatosa cuya frecuencia aumenta en las personal de edad. Clínicamente puede manifestarse por compromiso del estado general, síndrome depresivo y síntomas derivados de la obstrucción vascular como claudicación de mandíbula, dolor en el trayecto arterial y ceguera. En el 50% puede presentarse como polimialgia reumática, la que se caracteriza por mialgias y artrialgias proximales, síndrome febril, eritrosedimentación elevada y compromiso del estado general. Se analizan 18 pacientes, diez con polimialgia reumática y ocho con arteritis de la temporal; los hallazgos clínicos más frecuentes son: mialgias proximales y decaimiento 83%, artralgias y cefalea 66%, rigidez 50% y dolor en la arteria temporal 38%. La alteración de laboratorio más frecuente fue eritrosedimentación elevada. Esta serie clínica confirma la presencia de arteritis de temporal y polimialgia reumática en nuestro medio, sugiriendo que son más frecuentes de lo que se ha reportado a la fecha