Familial lecithin-cholesterol acyltransferase deficiency: If so rare, why so frequent in the state of Piauí, northeastern Brazil?

Lecithin-cholesterol acyltransferase (LCAT), an enzyme that participates in lipoprotein metabolism, plays an important role in cholesterol homeostasis. Mutations in the LCAT gene can cause two rare genetic disorders: familial LCAT deficiency (FLD), which is characterized by corneal opacities, normocytic anemia, dyslipidemia, and proteinuria progressing to chronic renal failure, and fish-eye disease (FED), which causes dyslipidemia and progressive corneal opacities. Herein, we report six suspected cases of FLD in the backlands of Piauí, located in northeast Brazil. A genetic diagnosis was performed in index cases. Among these, a further investigation was performed to identify new cases in the families. In addition, molecular analyses were performed to verify the levels of consanguinity within families and the existence of a genetic relationship between them. All six index cases were confirmed as FLD with an identical mutation (c.803G > A, p.R268H). The genetic investigation confirmed another 7 new cases of FLD, 52 heterozygous and 6 individuals without mutations. The rate of consanguinity revealed that marriages within the family did not contribute to the high number of FLD cases within the restricted region. The elders of each family (patriarchs and matriarchs) were subjected to a kinship analysis and were more genetically related to each other than the control group. Bayesian analysis was implemented to confirm the hypothesis of connectivity among patriarchs and matriarchs and indicated that they were genetically more related to each other than would be randomly expected, thus suggesting the occurrence of a possible founder effect in these families.

pHLA3D: Updating the database of predicted three-dimensional structures of HLA with HLA-DR, HLA-DQ and HLA-DP molecules.

To improve the availability of three-dimensional (3D) structures of HLA molecules, we created the pHLA3D database. In its first version, we modeled and published 106 3D structures of HLA class I molecules from the HLA-A, HLA-B, and HLA-C loci. This paper presents an update of this database, providing more 127 3D structures of HLA class II molecules (41 DR, 42 DQ, and 44 DP), predicted via homology modeling with MODELLER and SWISS-MODEL. These new 3D structures of HLA class II molecules are now freely available at pHLA3D (www.phla3d.com.br) for immunologists and other researchers working with HLA molecules.

Novel recombinant multiepitope proteins for the detection of anti-Cryptococcus antibodies.

AIM: To produce and test recombinant multiepitope proteins as an alternative assay for the serological diagnosis of cryptococcosis. MATERIALS & METHODS: Previously, synthetic peptides were used to detect anti-Cryptococcus antibodies, and in silico analyses showed that the union of peptides would improve the results. Here, the coding sequences of these peptides were assembled into synthetic genes. Four genes have been cloned and expressed in Escherichia coli, producing recombinant multiepitope proteins: proteins A, B, C and D. RESULTS: All constructs yielded good results; however, protein D showed the best results, with a sensitivity of 88.57% and specificity of 100%. CONCLUSION: The multiepitope proteins were shown to be potential antigens for the diagnosis of cryptococcosis in an attempt to detect anti-Cryptococcus antibodies.

Immunoreactivity of synthetic peptides derived from proteins of Cryptococcus gattii.

AIM: To determine the immunoreactivity of synthetic Cryptococcus-derived peptides. MATERIALS & METHODS: A total of 63 B-cell epitopes from previously identified Cryptococcus gattii immunoreactive proteins were synthesized and evaluated as antigens in ELISAs. The peptides were first evaluated for their ability to react against sera from immunocompetent subjects carrying cryptococcal meningitis. Peptides that yielded high sensitivity and specificity in the first test were then retested with sera from individuals with other fungal pathologies for cross-reactivity determination. RESULTS: Six of 63 synthetic peptides were recognized by antibodies in immunoassays, with a specificity of 100%, sensitivity of 78% and low cross-reactivity. CONCLUSION: We successfully determined the immunoreactivity of selected synthetic peptides of C. gattii derived proteins.