Th1 CD41 T cells and their derived cytokines are crucial for protection against Mycobacterium tuberculosis. Using multiparametric flow cytometry, we have evaluated the distribution of seven distinct functional states (IFN-c/IL-2/TNF-a triple expressors, IFN-c/IL-2, IFN-c/TNF-a or TNF-a/IL-2 double expressors or IFN-c, IL-2 or TNF-a single expressors) of CD4 1 T cells in individuals with latent M. tuberculosis infection (LTBI) and active tuberculosis (TB). We found that triple expressors, while detectable in 85-90%TB patients, were only present in 10-15% of LTBI subjects. On the contrary, LTBI subjects had significantly higher (12-to 15-fold) proportions of IL-2/IFN-c double and IFN-c single expressors as compared with the other CD4 1 T-cell subsets. Proportions of the other double or single CD4 1 T-cell expressors did not differ between TB and LTBI subjects. These distinct IFN-c, IL-2 and TNF-a profiles of M. tuberculosis-specific CD4 1 T cells seem to be associated with live bacterial loads, as indicated by the decrease in frequency of multifunctional T cells in TB-infected patients after completion of anti-mycobacterial therapy. Our results suggest that phenotypic and functional signatures of CD4 1 T cells may serve as immunological correlates of protection and curative host responses, and be a useful tool to monitor the efficacy of anti-mycobacterial therapy. IntroductionInfections with Mycobacterium tuberculosis (M. tuberculosis) cause a global epidemic with almost 9 million new cases and over 1.6 million deaths per year [1,2]. Outcome of M. tuberculosis infection depends on early identification and proper treatment of individuals with active tuberculosis (TB), but the lack of accurate diagnostic techniques has contributed to the re-emergence of TB as a global health threat. More than 2 billion individuals are estimated to be latently infected with M. tuberculosis (LTBI). To date, however, Ã These authors have contributed equally to this work. There were a number of differences between TB patients and subjects with LTBI following stimulation with ESAT-6, Ag85B and the 16-kDa antigen (Fig. 2). Most notably, and in contrast with the previously reported results in chronic viral infections, we found a significantly higher proportion of 31 CD4 1 T cells simultaneously secreting IFN-g, IL-2 and TNF-a in patients with TB, as compared with LTBI subjects, upon stimulation with any of the three tested M. tuberculosis antigens (Fig. 2). Using a threshold of 0.01% to avoid systematic biases incurred by zeroing negative values (frequency values o0.01% were set to zero), we found that 31 CD4 1 T cells were detectable in very few LTBI subjects (3/18, 3/18 and 2/18 in response to Ag85B, ESAT-6 and 16 kDa, respectively), but were frequently detected in most TB patients (17/20, 18/20 and 17/20, in Eur. J. Immunol. 2010. 40: 2211-2220 Nadia Caccamo et al. 2212& 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.eji-journal.eu response to Ag85B, ESAT-6 and 16 kDa, respectively; see also Table 1 for comparison).In contrast, ...

PCR assay is a highly sensitive and specific tool for the diagnosis of visceral leishmaniasis in both immunocompetent and immunocompromised patients and can be reliably used for rapid parasite identification at the species level.

The aim of the present study was to describe the epidemiologic and clinical characteristics of acute viral gastroenteritis in hospitalised Italian children. A total of 215 stool specimens were collected from January to December 2003 from patients hospitalised in Palermo for acute diarrhoea. Samples were tested for group A rotavirus, astrovirus, adenovirus, norovirus, enteropathogenic bacteria, and parasites. Rotaviruses, mostly belonging to types G1-G4, were detected in 25.1% of samples, astrovirus in 7%, adenovirus in 6%, norovirus in 18.6%, and bacterial agents in 17.2%. No parasitic infections were diagnosed. Mixed infections represented 9.8% of all cases. The mean and median ages of children with rotavirus gastroenteritis were lower than those of children with other viruses (p = 0.029), with the highest median ages being found in astrovirus-infected patients. Vomiting and dehydration were more frequent among patients with viral infection (p < 0.01), and the severity score was significantly higher for children infected with astrovirus or group A rotavirus (p = 0.008). Rotavirus was the leading cause of prolonged hospitalisation (p = 0.005). In conclusion, viruses were confirmed in Italy as the most common cause of severe enteric illness in childhood, with rotavirus types G1-G4, which correspond to those included in the rotavirus vaccines being developed, playing the main role. Routine testing should be introduced for noroviruses, since they seem to represent an important cause of sporadic paediatric gastroenteritis.

CD8 T-cells contribute to control of Mycobacterium tuberculosis infection, but little is known about the quality of the CD8 T-cell response in subjects with latent infection and in patients with active tuberculosis disease. CD8 T-cells recognizing epitopes from 6 different proteins of Mycobacterium tuberculosis were detected by tetramer staining. Intracellular cytokines staining for specific production of IFN-γ and IL-2 was performed, complemented by phenotyping of memory markers on antigen-specific CD8 T-cells. The ex-vivo frequencies of tetramer-specific CD8 T-cells in tuberculous patients before therapy were lower than in subjects with latent infection, but increased at four months after therapy to comparable percentages detected in subjects with latent infection. The majority of CD8 T-cells from subjects with latent infection expressed a terminally-differentiated phenotype (CD45RA+CCR7−). In contrast, tuberculous patients had only 35% of antigen-specific CD8 T-cells expressing this phenotype, while containing higher proportions of cells with an effector memory- and a central memory-like phenotype, and which did not change significantly after therapy. CD8 T-cells from subjects with latent infection showed a codominance of IL-2+/IFN-γ+ and IL-2−/IFN-γ+ T-cell populations; interestingly, only the IL-2+/IFN-γ+ population was reduced or absent in tuberculous patients, highly suggestive of a restricted functional profile of Mycobacterium tuberculosis-specific CD8 T-cells during active disease. These results suggest distinct Mycobacterium tuberculosis specific CD8 T-cell phenotypic and functional signatures between subjects which control infection (subjects with latent infection) and those who do not (patients with active disease).

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