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

Enfermedad de Lyme en Chile: estudio de prevalencia en grupos seleccionados / Lyme's disease in Chile: prevalence study in selected groups

The prevalence of Lyme disease in Chile is unknown. To study the existence and epidemiology of Lyme Disease in Chile. One hundred eighteen patients with signs or symptoms suggestive of Lyme disease were studied. Antibodies against Borrelia burgdorferi were measured using ELISA and indirect immunofluorescence screening tests. Positive cases were confirmed with ELISA using a purified antigen and Western Blot analysis. Human biological samples and ticks were cultured in BSK-H medium. Five patients, 3 with dermatological manifestations and two with facial palsy and other neurological symptoms, had antibodies against Borrelia, measured by ELISA and indirect immunofluorescence. However, the presence of IgM antibodies by ELISA using purified antigen, was confirmed in only one case. All sera and cerebrospinal fluids were negative on Western Blot analysis. No plasma, skin, CFS or thick culture yielded Borrelia. We could not confirm the existence of Lyme disease in Chile. Positive screening with negative confirmatory test suggests false positive non-specific reactivity or that local Borrelia are antigenically different compared to North American strains

Pérdida recurrente del embarazo en pacientes con anticuerpos anticardiolipinas; AACL / Recurrent pregnancy lost in patients with anticardiolipin antibodies

Se presenta la experiencia en 7 pacientes con antecedentes de pérdida recurrente del embarazo (x=3,7 rango 2-6) con AACL(+) en las cuales se descartó otra etiología; éstas pacientes totalizaban 26 gestaciones no tratadas concluidas en 24 pérdidas fetales (constando en 9 la muerte fetal in útero) y 2 RN vivos. La duración promedio de esas gestaciones fue 17,4 semanas (rango 8-37). Fueron tratadas con prednisona 20 mg/día y ASA 100 mg/día obteniéndose 7 RN vivos y 1 mortinato. En todas las pacientes se obtuvo descenso de los AACL. La duración promedio de las gestaciones tratadas fue de 31,7 semanas (rango 26-28). Se concluye que la presencia de AACL se correlaciona con alta mortalidad y bajo peso fetal y que con el tratamiento se obtiene gestaciones significativamente más largas que en las no tratadas y mayor relación de niños vivos respecto al número de embarazos