Dengue viremia kinetics in asymptomatic and symptomatic infection.

BACKGROUND: Dengue infection is a global health threat. While symptomatic cases contribute to morbidity and mortality, the majority of infected people are asymptomatic but serve as an important reservoir. However, the kinetics of viremia in asymptomatic infections remains unknown. METHODS: We enrolled 279 hospital-based symptomatic index cases and quantified dengue virus (DENV) RNA at enrollment and at the day of defervescence. To identify asymptomatic cases, 175 household members of index cases were monitored for clinical symptoms during follow-up, and blood was taken twice weekly to test for and quantify DENV RNA until cleared. RESULTS: We detected DENV in thirteen asymptomatic household members (7.43%). Their DENV serotypes were primarily the same as those of their family index cases. The median peak DENV viremia in asymptomatic subjects was lower than that of symptomatic individuals during the febrile phase, and the viral decay rate was slower in asymptomatic infections. CONCLUSIONS: DENV level and kinetics in asymptomatic individuals differed significantly from those of symptomatic cases. Despite the lower viremia, the slower decay rate in asymptomatic infections could lead to their prolonging the infectious reservoir. The improvement of transmission control to prevent such long-lived asymptomatic infections from transmitting the DENV is needed.

Coordinated In Vitro Release of Granulysin, Perforin and IFN-γ in TB and HIV/TB Co-Infection Associated with Clinical Outcomes before and after Anti-TB Treatment.

Granule-associated killing molecules released from cytotoxic T lymphocytes participate as a crucial step in immunity against tuberculosis (TB), but the role of coordinated production remains controversial. Coordinated release of effector molecules in vitro after stimulating peripheral blood mononuclear cells (PBMCs) of active TB or HIV/TB coinfection patients with PPD, purified protein derivative of tuberculin and avirulent Mtb, H37Ra, an attenuated strain were investigated in association with clinical outcomes. Perforin, granzyme-B, granulysin and IFN-γ were measured using ELISA. Before anti-TB treatment, PBMCs of TB stimulated with PPD or H37Ra released higher perforin, granzyme-B, and granulysin levels than in HIV/TB and released significantly higher IFN-γ (p = 0.045, p = 0.022). Granulysin positively correlated with perforin in TB (p = 0.042, r = 0.385), HIV/TB coinfection (p = 0.003, r = 0.941) after PPD stimulation, and after H37Ra stimulation in TB (p = 0.005, r = 0.549), but negatively correlated with granzyme B in TB (p = 0.042, r = -0.386), HIV/TB coinfection (p = 0.042, r = 0.754) were noted. After anti-TB treatment, increased levels of perforin, granulysin and IFN-γ in TB or HIV/TB upon PPD or H37Ra stimulation, and decreased granzyme-B levels after PPD (p = 0.003) or H37Ra (p = 0.028) stimulation in TB were observed. These results suggest that granulysin may act synergistic with perforin and IFN-γ in TB, indicating its crucial function in host immunity to tuberculosis. Future studies with larger numbers of patients ought to be conducted in the future.

Potential function of granulysin, other related effector molecules and lymphocyte subsets in patients with TB and HIV/TB coinfection.

BACKGROUND: Host effector mechanism against Mycobacterium tuberculosis (Mtb) infection is dependent on innate immune response by macrophages and neutrophils and the alterations in balanced adaptive immunity. Coordinated release of cytolytic effector molecules from NK cells and effector T cells and the subsequent granule-associated killing of infected cells have been documented; however, their role in clinical tuberculosis (TB) is still controversy. OBJECTIVE: To investigate whether circulating granulysin and other effector molecules are associated with the number of NK cells, iNKT cells, Vγ9(+)Vδ2(+) T cells, CD4(+) T cells and CD8(+) T cells, and such association influences the clinical outcome of the disease in patients with pulmonary TB and HIV/TB coinfection. METHODS: Circulating granulysin, perforin, granzyme-B and IFN-γ levels were determined by ELISA. The isoforms of granulysin were analyzed by Western blot analysis. The effector cells were analyzed by flow cytometry. RESULTS: Circulating granulysin and perforin levels in TB patients were lower than healthy controls, whereas the granulysin levels in HIV/TB coinfection were much higher than in any other groups, TB and HIV with or without receiving HAART, which corresponded to the number of CD8(+) T cells which kept high, but not with NK cells and other possible cellular sources of granulysin. In addition, the 17kDa, 15kDa and 9kDa isoforms of granulysin were recognized in plasma of HIV/TB coinfection. Increased granulysin and decreased IFN-γ levels in HIV/TB coinfection and TB after completion of anti-TB therapy were observed. CONCLUSION: The results suggested that the alteration of circulating granulysin has potential function in host immune response against TB and HIV/TB coinfection. This is the first demonstration so far of granulysin in HIV/TB coinfection.

Decreased plasma granulysin and increased interferon-gamma concentrations in patients with newly diagnosed and relapsed tuberculosis.

Granulysin and interferon-gamma (IFN-γ) have broad antimicrobial activity which controls Mycobacterium tuberculosis (M. tuberculosis) infection. Circulating granulysin and IFN-γ concentrations were measured and correlated with clinical disease in Thai patients with newly diagnosed, relapsed and chronic tuberculosis (TB). Compared to controls, patients with newly diagnosed, relapsed and chronic TB had lower circulating granulysin concentrations, these differences being significant only in newly diagnosed and relapsed TB (P < 0.001 and 0.004, respectively). Granulysin concentrations in patients with newly diagnosed and relapsed TB were significantly lower than in those with chronic TB (P= 0.003 and P= 0.022, respectively). In contrast, significantly higher circulating IFN-γ concentrations were found in patients with newly diagnosed and relapsed TB compared to controls (P < 0.001). The IFN-γ concentrations in newly diagnosed and relapsed patients were not significantly different from those of patients with chronic TB. However, in vitro stimulation of peripheral blood mononuclear cells (PBMCs) from patients with newly diagnosed, relapsed and chronic TB with purified protein derivative (PPD) or heat killed M. tuberculosis (H37Ra) enhanced production of granulysin by PBMCs. In vitro, stimulation of PBMCs of newly diagnosed TB patients with PPD produced greater amounts of IFN-γ than did controls, while those stimulated with H37Ra did not. The results demonstrate that patients with active pulmonary TB have low circulating granulysin but high IFN-γ concentrations, suggesting possible roles in host defense against M. tuberculosis for these agents.

IgG antibody profile to c-terminal region of Plasmodium vivax merozoite surface protein-1 in Thai individuals exposed to malaria.

Naturally acquired immune response to C-terminal region of Plasmodium vivax merozoite surface protein1 (PvMSP1) in 200 individuals with recent clinical episodes of malaria from malaria endemic areas along Thai-Myanmar border in the west and Thai-Cambodia border in the east of Thailand was evaluated by enzyme-linked immunosorbent assay (ELISA). The anti-PvMSP1-IgG antibody was observed in 110 individuals (55%). Among IgG responders, IgG1 coexpressed with IgG3 were the predominant subclasses. The levels of anti-PvMSP1 total IgG, IgG1 and IgG3 antibody response seem to be increased with age although no detectable significant correlation was found (r = 0.004, p = 0.484 for total IgG; r = 0.035, p = 0.386 for IgG1; r = -0.600, p = 0.142 for IgG2; r = 0.077, p = 0.227 for IgG3; r = 0.664, p = 0.051 for IgG4). However, the mean level of specific total IgG was highest in the age group of >40 years. These levels of either specific total IgG or each IgG isotype did not vary among individuals with different malaria episodes. A higher level of specific total IgG, IgG1 and IgG3 antibody response related with the lower of parasitemia density was observed although no significant correlation was found. Our data indicate that individuals exposed to vivax malaria in Thailand developed antibodies to the potential candidate vaccine antigen, PvMSP1 (C-terminal).