Infectious etiology of chronic diarrhea in patients with primary immunodeficiency diseases.

Summary: Background.Primary immunodeficiency diseases (PIDs) are life-threatening disorders, which manifest commonly with gastrointestinal (GI) signs, mainly as chronic diarrhea. Objective. To investigate and compare infectious etiology of chronic diarrhea in different PIDs. Patients and methods. Assessing clinical features, obtaining immunological profiles, as well as characterizing infectious etiology of diarrhea were performed in 38 PID patients with chronic diarrhea. Stool samples and/or biopsy specimens were checked using culture, microscopic examination, RT-PCR, and PCR, as appropriate. The patients were diagnosed to have common variable immunodeficiency (CVID), severe combined immunodeficiency (SCID), X-linked agammaglobulinemia (XLA), and hyper-IgM (HIgM) syndrome. Results. In 32 patients we identified 41 infectious agents including 16 parasitic (39.0%, the most common Giardia lamblia), 11 bacterial (26.8%, the most common salmonella spp), 8 viral (19.5%, the most frequent group A rotavirus), and 6 fungal organisms (14.7%, the most common Candida albicans). From 6 of the patients, no infectious agent was isolated. In CVID bacteria and parasites, in SCID bacteria and viruses, in XLA parasites, and in individuals with HIgM syndrome parasites were the leading causes of chronic diarrhea. Infection with giardia and cryptosporidium were more frequent in XLA and HIgM, respectively. Conclusion. The current study suggests considering both usual and unusual pathogens in laboratory investigation and in the empiric treatment of chronic diarrhea. Opportunistic pathogens should be taken into account when no other pathogen is identified, especially in patients on long-term treatment or prophylaxis with antifungals/antibiotics and in those from geographical locations that favor pathogenicity of these organisms.

Differential expression of innate immune response genes in clinical phases of chronic hepatitis B infection.

We investigated innate immune gene expression in clinical phases of chronic hepatitis B infection, including immune tolerant (IT), immune active (IA), inactive carrier (IC) and hepatitis B e antigen (HBeAg)-negative phases, as well as healthy controls. Expression levels of interferon types I, II and III, their receptor subunits, IRFs, TLRs and other IFN-induced genes in peripheral blood mononuclear cells were compared. Forty HBsAg-positive treatment-naïve subjects without co-infection with HIV, HCV or HDV were enrolled. To complement the viral load, the expression levels of 37 innate immune genes were measured by qPCR. The highest response of the innate immune system was observed in the IT and HBeAg-negative phases, and the IC phase had the lowest response; 31 of the 37 studied genes reached their maximum mRNA expression levels in the IT and HBeAg-negative phases, and the minimum expression levels of 23 genes were found in the IC phase. The highest mRNA expression levels of IFNs, IFN receptor subunits, IRFs and TLRs genes in all clinical phases were IFN-λ2 and 3, IFN-γR2, IRF7 and TLR7, and the lowest levels of mRNA expression were observed for IFN-α, IFN-λR1, IRF8 and TLR2. We conclude that innate immune response genes are expressed differentially among chronic HBV phases, and this difference may help to develop new precise and noninvasive methods to determine the progression of disease in chronic HBV patients.

Molecular identification of animal isolates of Echinococcus granulosus from Iran using four mitochondrial genes.

Mitochondrial genes have more power than nuclear genes in reconstructing phylogenetic relationships among closely related species because of their faster sequence evolution. The aim of this study was to use the complete or near-complete sequences from three mitochondrial genes (cox1, nad1 and atp6) and partial sequences of the 12S rRNA gene to infer relationships among isolates of Echinococcus granulosus from Iran. Two hundred and twenty-nine isolates of E. granulosus were collected from cattle, camels, sheep, buffalo and goats from different geographical areas. Most individuals were found to possess the G1 genotype but some of the camel samples belonged to the G6 genotype. Newly designed primers for cox1, nad1 and atp6 genes amplified bands of 1830, 708 and 1157 bp for the G1 genotype and 1856, 705, 1054 bp for the G6 genotype, respectively. The result of this survey showed that atp6 and nad1 genes are good molecular markers for identifying E. granulosus isolates from a range of hosts in Iran.

Molecular epidemiology of hepatitis B virus in Iran.

Hepatitis B virus (HBV) infection is a major cause of liver disease worldwide. Eight genotypes and 24 subgenotypes of HBV have been identified. The aim of this study was to determine the distribution of HBV genotypes, subgenotypes and subtypes, and to understand HBV genetic variability in the HBV genome circulating in Iranian provinces. Two hundred and forty-nine sera from HBV-infected patients living in 25 provinces of Iran were collected (2004-2007). A part of the HBV S/pol and whole BCP/C genes were amplified, sequenced and then subjected to phylogenetic, recombination and genetic variability analysis. Results revealed genotype D of HBV in all samples and subgenotypes D1 (98.52%), D2 (0.74%) and D3 (0.74%) among Iranian patients living in different provinces of Iran. Subtypes ayw2 (94.4%), ayw1 (2.8%), ayw3 (2%) and ayw4 (0.4%) were deduced, on the basis of HBV small surface antigen (HBsAg) amino acid sequences. The mean percentage intra-genotypic distance of S plus core regions was 2.8%; the mean percentage inter-genotypic distance of this region between Iranian strains and genotype D isolates was 3.1%; and this rate for other genotypes was 5.2-11.4%. Various rates of point mutations have been found within different HBV genes, e.g. HBsAg (17.2%), precore-G1896A (59.5%) and Basal core promoter (BCP) double mutations (49.2%), whereas no recombination was found. In conclusion, these results indicate that the only genotype circulating in the provinces of Iran is genotype D. There exist high genetic variabilities in the S/pol and BCP/C regions among the Iranian HBV isolates.