Diagnostic parameters of serological ELISA for invasive amoebiasis, using antigens preserved without enzymatic inhibitors.

Amoebiasis is the third cause of death due to parasites in the world. Although, numerous serodiagnostic and salivary tests have been developed, the majority of these assays lack sensitivity in endemic zones to detect acute amoebic liver abscess. The two main limiting factors to develop reliable assays are the high levels of anti-amoeba antibodies in populations living in endemic zones, and the proteolysis of amoebic extracts even treated with inhibitors. Our group reported a method to preserve amoebic antigens without using enzymatic inhibitors (IC:MC fraction) that shows stability for years. Here we describe the development of a serologic ELISA to diagnose amoebiasis made with IC: MC antigens, and its validation for clinical use in endemic areas. In our study, we included sera from 66 patients diagnosed with acute amoebic liver abscess and 33 volunteers living in an endemic area for amoebiasis. Our assay was compared with an indirect haemagglutination assay (IHA) an ELISA elaborated with antigens derived from untreated trophozoites. The ELISA made with IC: MC antigens presented more reproducibility compared to other assays. Sera from 95% ALA patients showed a positive value. The ELISA (IC: MC) detected 97% of patients with ALA compared to an 81% using IHA. The parameters of ELISA (vs. IHA) were Sensitivity 98% (81%), Specificity 96% (97%), Positive predictive value 98% (96%), Negative predictive value 96% (73%) and Accuracy 98% (87%). A negative serologic test does not rule out the diagnosis of invasive amoebiasis. The ELISA made with antigens preserved without using enzymatic inhibitors has valuable serodiagnostic value to diagnose acute amoebic liver abscess, even in populations living in endemic zones of amoebiasis carrying antibodies against amoebas. In conclusion, ELISA-IC:MC presented better diagnostic parameters than IHA although a negative serologic test does not rule out acute invasive amoebiasis.

Determinación de la frecuencia alélica del SNP 19 del gen Calpaína 10 (CAP10) y factores de riesgo de diabetes 2 en población peruana / Determination of SNP allele frequency of Calpain 19 of the gene 10 (CAP10) and risk factors for type 2 diabetes in Peruvian population

La diabetes tipo 2 es una enfermedad compleja que tiene un componente genético. Se ha comprobado que calpaína 10 (CAPN10) localizado en 2q37.3, constituye un gen de susceptibilidad para esta enfermedad. La asociación alélica y haplotípica con diabetes, observada en poblaciones amerindias (México-americana, pima, surui y maya), y algunas europeas (finlandesas y alemanas), confirmarían estos resultados. El origen ancestral amerindio nos hace suponer que CAPN10 constituiría un gen de susceptibilidad en población peruana nativa y mestiza. Para utilizar los alelos del CAPN10 como factores de riesgo genético necesitamos establecer la frecuencia en la población normal. En el presente trabajo se observa la frecuencia de los alelos SNP19 en 116 controles normales de Lima, mayormente de origen mestizo. La frecuencia alélica analizada es similar a la descrita en las poblaciones mexico-americanas.

Type 2 diabetes is a complex disorder where genetic factors play an important role. Several studies suggest that some genetic variants of calpain 10 (CAPN10) increase susceptibility to type 2 diabetes. Some allelic and haplotype combinations are associated with increased risk in Amerindian populations (Mexican American, Pima and Surui) and Finnish and German groups. The ancestral Amerindian origin suggests that CAPN10 is a susceptibility gene in native and admixed Peruvian populations. To use CAPN10 alleles as genetic risk factors, we need to establish their baseline frequencies in normal populations. Allele frequencies of SNP19 in 116 individuals of Lima (admixed population) are similar to those reported for Mexican American groups.