A genome wide association study identifies a IncRna as risk factor for pathological inflammatory responses in leprosy

Leprosy Type-1 Reactions (T1Rs) are pathological inflammatory responses that afflict a sub-group of leprosy patients and result in peripheral nerve damage. Here, we employed a family-based GWAS in 221 families with 229 T1R-affect offspring with stepwise replication to identify risk factors for T1R. We discovered, replicated and validated T1R-specific associations with SNPs located in chromosome region 10p21.2. Combined analysis across the three independent samples resulted in strong evidence of association of rs1875147 with T1R (p = 4.5x10-8; OR = 1.54, 95% CI = 1.32-1.80). The T1R-risk locus was restricted to a lncRNA-encoding genomic interval with rs1875147 being an eQTL for the lncRNA. Since a genetic overlap between leprosy and inflammatory bowel disease (IBD) has been detected, we evaluated if the shared genetic control could be traced to the T1R endophenotype. Employing the results of a recent IBD GWAS meta-analysis we found that 10.6% of IBD SNPs available in our dataset shared a common risk-allele with T1R (p = 2.4x10-4). This finding points to a substantial overlap in the genetic control of clinically diverse inflammatory disorders.

Molecular model for studying the uncultivated fungal pathogen Lacazia loboi.

Lacazia loboi is an uncultivated fungal pathogen of humans and dolphins that causes cutaneous and subcutaneous infections only in the tropical areas of the Americas. It was recently found by phylogenetic analysis that this unusual pathogen is closely related to Paracoccidioides brasiliensis and to the other fungal dimorphic members of the order Onygenales. That original phylogenetic study used universal primers to amplify well-known genes. However, this approach cannot be applied to the study of other proteins. We have developed a strategy for studying the gene encoding the gp43 homologous protein of P. brasiliensis in L. loboi. The gp43 protein was selected because it has been found that this P. brasiliensis antigen strongly reacts when it is used to test sera from patients with lacaziosis. The principle behind this idea was to obtain the gp43 amino acid sequence of P. brasiliensis and other homologous fungal sequences from GenBank and design primers from their aligned conserved regions. These sets of primers were used to amplify the selected regions with genomic DNA extracted from the yeast-like cells of L. loboi from experimentally infected mice. Using this approach, we amplified 483 bp of the L. loboi gp43-like gene. These sequences had 85% identity at the nucleotide level and 75% identity with the deduced amino acid sequences of the P. brasiliensis gp43 protein. The identity of the 483-bp DNA fragment was confirmed by phylogenetic analysis. This analysis revealed that the L. loboi gp43-like deduced amino acid sequence formed a strongly supported (100%) sister group with several P. brasiliensis gp43 sequences and that this taxon in turn was linked to the other fungal sequences used in this analysis. This study shows that the use of a molecular model for investigation of the genes encoding important proteins in L. loboi is feasible.

Immunohistochemical characterization of the cellular infiltrate in Jorge Lobo's disease.

Few studies have been conducted to evaluate the cellular composition of the granulomatous lesions induced by Lacazia loboi. Thus, the objective of the present study was to characterize the mononuclear cell population present in cutaneous lesions obtained from 15 patients with Jorge Lobo's disease. Histological sections were stained with hematoxylin-eosin and methenamine silver and the following mononuclear cells were identified by immunohistochemistry: T lymphocytes (CD3+), helper T lymphocytes (CD4+), cytotoxic T lymphocytes (CD8+), B lymphocytes (CD20+), plasma cells (CD79+), natural killer cells (CD57+) and histiocytes (CD68+). This study showed that the inflammatory infiltrate mainly consists of histiocytes and multinucleated giant cells, in addition to the presence of a large number of fungal cells. The identified inflammatory cells showed the following frequency: CD68+ histiocytes > CD3+ T lymphocytes > CD4+ T > CD8+ T lymphocytes > CD57+ natural killer cells > CD79+ plasma cells > CD20+ B lymphocytes. Based on the findings of a large number of fungal cells in the infected tissues and the disorganized cell arrangement in the granuloma, we hypothesize that patients with Jorge Lobo's disease present immunoregulatory disturbances, which are likely to be specific and perhaps responsible for the lack of containment of the pathogen.

Immunohistochemical characterization of the cellular infiltrate in Jorge Lobo's disease / Identificación imunohistoquímica del infiltrado inflamatorio de la enfermedad de Jorge Lobo

Few studies have been conducted to evaluate the cellular composition of the granulomatous lesions induced by Lacazia loboi. Thus, the objective of the present study was to characterize the mononuclear cell population present in cutaneous lesions obtained from 15 patients with Jorge Lobo's disease. Histological sections were stained with hematoxylin-eosin and methenamine silver and the following mononuclear cells were identified by immunohistochemistry: T lymphocytes (CD3+), helper T lymphocytes (CD4+), cytotoxic T lymphocytes (CD8+), B lymphocytes (CD20+), plasma cells (CD79+), natural killer cells (CD57+) and histiocytes (CD68+). This study showed that the inflammatory infiltrate mainly consists of histiocytes and multinucleated giant cells, in addition to the presence of a large number of fungal cells. The identified inflammatory cells showed the following frequency: CD68+ histiocytes > CD3+ T lymphocytes > CD4+ T > CD8+ T lymphocytes > CD57+ natural killer cells > CD79+ plasma cells > CD20+ B lymphocytes. Based on the findings of a large number of fungal cells in the infected tissues and the disorganized cell arrangement in the granuloma, we hypothesize that patients with Jorge Lobo's disease present immunoregulatory disturbances, which are likely to be specific and perhaps responsible for the lack of containment of the pathogen

Considerando la escasez de estudios sobre la composición celular del granuloma inducido por el Lacazia loboi y el pequeño número de pacientes evaluados, hemos estudiado la población de células mononucleares presentes en las lesiones cutáneas de 15 pacientes portadores de la enfermedad de Jorge Lobo. Se tiñeron los cortes histológicos con hematoxilina-eosina, plata metenamina y con el método imunohistoquímico se identificaron las siguientes células mononucleares: linfocitos T (CD3+), linfocitos T auxiliares (CD4+), linfocitos T citotóxicos (CD8+), linfocitos B (CD20+), plasmócitos (CD79+), células NK (CD57+) e histiocitos (CD68+). Los resultados obtenidos revelaron que el infiltrado inflamatorio estaba compuesto predominantemente por histiocitos y células gigantes multinucleadas, además de un gran número de hongos. La frecuencia de células encontradas fue la siguiente: histiocitos CD68+ > linfocitos T CD3+ > linfocitos T CD4+ > linfocitos T CD8+ > células NK CD57+ > plasmocitos CD79+ > linfocitos B CD20+. Así, considerando los resultados obtenidos, en los que observamos una gran cantidad de hongos en las lesions y una disposición desorganizada de las células en el granuloma, podemos sugerir que los pacientes con la enfermedad de Jorge Lobo presentan alteraciones imunorregulatorias, probablemente específicas, responsables de la no contención del patógeno