Informe sobre el ejercicio de estandarización de inmunofluorescencia indirecta (IFI) para la detección de anticuerpos antinucleares (ANA). Taller de autoinmunidad, Santander 2004 / Report on the indirect immunofluorescence (IFI) standardisation assay for the detection of antinuclear antibodies (ANA). Workshop on autoimmunity, Santander, May 2004

Para reducir las diferencias que se observan a la hora de titular por diferentes laboratorios un mismo suero ANA+, sugerimos el uso de unidades estándar. Con esta finalidad, en el presente Taller de Autoinmunidad, se distribuyeron cinco alícuotas de un mismo suero control, diluido seriadamente con PBS. A los laboratorios participantes se les pidió que diluyeran cada alícuota hasta su título final. Con estos datos se construyó una recta patrón para cada laboratorio. Además, se enviaron cuatro muestras problema. Estas muestras consistían en duplicados y diluciones de un mismo suero, con la finalidad de determinar si los laboratorios participantes eran capaces de replicar los duplicados y ordenar correctamente las diluciones. Los títulos remitidos para cada suero en diluciones se transformaron en unidades usando la curva patrón previamente obtenida por cada laboratorio. Los resultados obtenidos muestran que: 1) algunos laboratorios participantes no fueron capaces de replicar los duplicados o de ordenar adecuadamente las diluciones; 2) el uso de unidades en vez de diluciones disminuye la dispersión de los resultados obtenidos por los laboratorios participantes, para un suero dado. Por tanto, proponemos el uso de unidades estándar en lugar de diluciones cuando se informen títulos de ANA (AU)

El sistema inmunitario de las mucosas: una breve revisión / Mucosal immune system: a brief review

La mayoría de los antígenos que entran en contacto con el sistema inmune durante la vida de un ser vivo lo hacen a través de la superficie de la mucosa de los tractos respiratorio, gastrointestinal y urogenital. Ocupan una superficie de 400 m2 y forman el área de mayor tamaño en contacto directo con el ambiente externo. Las mucosas separan el ambiente externo del ambiente interno, estéril, y representan una primera línea de defensa. Esta barrera está en contacto tanto con patógenos que han desarrollado mecanismos eficaces para la colonización de epitelios e invasión de mucosas, como con antígenos inocuos, tales como comida, o la flora bacteriana comensal. En el primer caso se necesita una respuesta inmune eficaz y robusta, mientras que en el segundo se requiere una respuesta caracterizada por ignorancia o supresión activa. En estas condiciones, las mucosas han desarrollado un complejo sistema inmune, con características anatómicas y funcionales particulares, capaz de generar rigurosas respuestas frente a antígenos patogénicos, mientras mantiene una situación de ignorancia o supresión activa frente a antígenos no patogénicos (AU)

Higher proliferative capacity of T lymphocytes from patients with Crohn disease than from ulcerative colitis is disclosed by use of Herpesvirus saimiri-transformed T-cell lines.

BACKGROUND: T lymphocytes play a crucial role in the pathogenesis of inflammatory bowel disease. Achieving stable T-cell lines, rather than continuous bleeding of patients, is desirable in order to dissect their implication in the disease. METHODS: Long-lasting T-cell lines from patients with Crohn disease and ulcerative colitis and from healthy volunteers have been obtained by transformation of T lymphocytes using the lymphotropic Herpesvirus saimiri. Lines were subjected to phenotypic and functional analyses, and the results compared with freshly isolated peripheral blood mononuclear cells. RESULTS: Fresh cells revealed only minor differences between patients and controls, with regard to phenotype and proliferative capacity. In contrast, the use of T-cell lines showed that cells from Crohn disease patients, but not ulcerative colitis patients, over-responded to several membrane or cytoplasmic stimuli when compared to control T-cell lines. Thus, higher responses were found when stimulated with alphaCD3 and IL2, alphaCD3 and alphaCD28, IL2 alone, phorbol esters (PMA) and alphaCD3 and, finally, PMA and alphaCD2 (P < 0.05 in all instances). Further, lines from patients with Crohn disease responded more vigorously to alphaCD3 and alphaCD28 or alphaCD3 and PMA when compared to ulcerative colitis (P < 0.05 in both instances). CONCLUSIONS: The data obtained with these lines suggest that T cells from patients with Crohn disease differ in vivo in their proliferative capacity, as compared with those from ulcerative colitis patients, a finding that may reflect the clear Th-1 phenotype found in the former and absent in the latter.

Origin of Mayans according to HLA genes and the uniqueness of Amerindians.

The HLA allele frequency distribution of the Mayans from Guatemala was studied and compared with those of other First American Natives and worldwide populations (a total of 12,364 chromosomes and 6182 individuals from 60 different populations). The main conclusions were (1): the closest Amerindian group to Mayans is the Arhuacs, who were the first recorded Caribbean Islands' inhabitants (2). Mayans are not so close to Mesoamerican Zapotec, Mixe and Mixtec Amerindians, who genetically cluster together. Mixe had been related to Mayans only on linguistic bases (3). DRB1*0407 and DRB1*0802 alleles are found in 50% of Mayans; these alleles are also found in other Amerindians, but the Mayans' high frequencies may be showing a founder effect for this Mesoamerican-Caribbean population (4). Extended Mayan specific HLA haplotypes are described for the first time (5). Language and genes do not completely correlate in microgeographical studies (6). Significant genetic input from outside is not noticed in Meso and South American Amerindians according to the genetic analyses; while all world populations (including Africans, Europeans, Asians, Australians, Polynesians, North American Na-Dene Indians and Eskimos) are genetically related. Meso and South American Amerindians tend to remain isolated in the neighbour joining analyses.

Intrinsic defects explain altered proliferative responses of T lymphocytes and HVS-derived T-cell lines in gastric adenocarcinoma.

We have taken advantage of a recently described technique of transformation and immortalization of T lymphocytes using the lymphotropic Herpesvirus saimiri, to achieve long-lasting T-cell lines from gastric cancer patients and healthy volunteers. Blood samples were drawn and T lymphocytes were transformed. Once sustained growth was observed, lines were subjected to phenotypic and functional analyses, and the results compared with freshly isolated peripheral blood mononuclear cells. Cytofluorometric analysis revealed that CD3 and CD45 were found at lower proportion in primary cells from patients than from control individuals (54% vs 75%, p<0.001, 90% vs 96%, p<0.05, respectively), and in HVS-derived T-cell lines (90% vs 98%, p<0.05, 97% vs 100%, p<0.05, respectively). Proliferative analyses showed that primary isolated cells were unable to respond adequately to CD3-, CD2-, and PHA-mediated stimulation, as compared to controls. Similarly, T-cell lines from patients proliferated to a lesser extent when CD3- and CD2-mediated stimuli were considered, especially when simultaneous stimulation via CD3 and CD2 molecules was carried out (47,824 counts per minute [cpm] vs 121,478 cpm, p<0.05). Altogether these results show that the defects reported in T cells from patients with cancer are not exclusively due to tumour-derived factors, since the alterations persist in long-lasting, HVS-transformed, T-cell lines, suggesting that this model seems a suitable one to disclose them.