Epidemiology of Leishmania Carriers in Tan Chang County, Gansu Province, China.

Background: Leishmaniasis is a regional infectious disease caused by the bite of Leishmania-carrying sandflies. The clinical symptoms include prolonged fever, spleen enlargement, anemia, emaciation, leukopenia, and increased serum globulin levels. If not appropriately treated, patients may die of complications caused by leishmaniasis within 1-2 years after the onset of the illness. Therefore, further investigation of the mechanisms of infection by this pathogen is required. Here, an epidemiological study of Leishmania carriers was conducted. The potential mechanism of infection through domestic animals as carriers of the parasite was investigated to identify potential reservoir hosts for Leishmania. Methods: The rK-39 strip test was performed on blood samples from previously infected patients. Blood samples were collected from the patients and their families. The blood, liver, spleen, and diaphragm muscle samples were collected from livestock. To perform nested polymerase chain reaction (PCR), DNA was extracted and the internal transcribed spacer sequence was used. The amplified products were then subjected to restriction fragment length polymorphism and phylogenetic analyses. Results: Among previously infected patients, 40% (12/30) showed positive results in the rK-39 strip test. The nested PCR positive rates for previously infected patients/relatives and livestock samples were 86% (77/90) and 80% (8/10), respectively. Moreover, the phylogenetic analysis showed that the pathogen was Leishmania infantum. Dogs, patients, and domesticated animals carrying Leishmania were found to be a potential source of infection for leishmaniasis. Conclusions: The results of this study provide a basis for developing disease prevention and control strategies for leishmaniasis.

Hypomethylation of perforin regulatory elements in CD4+ T cells from rat spleens contributes to the development of autoimmune emphysema.

BACKGROUND AND OBJECTIVE: It is widely accepted that perforin regulatory elements are hypomethylated in CD4+ T cells from patients with active lupus, but whether this is the case in autoimmune emphysema is not known. METHODS: Twenty rats were randomly divided into a normal control group and an emphysema group. Rat models of emphysema were established by intraperitoneal injection with xenogeneic endothelial cells. The levels of tumour necrosis factor-α, interleukin-8 and matrix metalloproteinase (MMP)-9 in bronchoalveolar lavage fluid (BALF) were measured, lung mean linear intercept and destructive index measured. Mean methylation of perforin gene promoter in CD4+ T cells and the expression of perforin were investigated. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling methods were used to examine the percentage of apoptotic cells in the alveolar septa. RESULTS: The levels of MMP-9 in BALF were higher in emphysema group than in control group (P < 0.05). The mean linear intercept and destructive index were higher in emphysema group than in control group (P < 0.05). The mean perforin gene promotor methylation of emphysema group was significantly decreased as compared with control group, while the expression levels of perforin gene were relatively higher (P < 0.05). There were more terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling-positive cells in the alveolar septa in control group than in emphysema group. CONCLUSIONS: Hypomethylation of perforin regulatory elements in CD4+ T cells may result in the lung septal cell apoptosis associated with the development of experimental autoimmune emphysema. MMP-9 may play an important role in the pathogenesis of this kind of disease.