Study For Immunological And Virological Characteristics In Patients With Severe Acute Respiratory Syndrome And Acquired Immunodeficiency Syndrome, Respectively

Objective In this study, we, on the one hand, retrospectively studied the characteristics and dynamic changes of immunological and virological parameters in patients with severe acute respiratory syndrome (SARS) and analyzed the association between steroid treatment with the immunological parameters as well as the disease progression. We, on the other hand, investigated the clinical characteristics of immunological and virological parameters in HIV-1-infected children and dynamic changes of viral loads and immunocytes during the in vitro culture of peripheral blood mononuclear cells (PBMC) from HIV adults' carriers or patients, as well as their association with the disease progression. Methods Various clinical specimens from 74 patients with clinical diagnosis of SARS or 14 HIV-1-infected children were investigated. Flow cytometry was applied to study the alteration of numbers and frequencies in circulating DC, T-cell subsets and CTLs. The IgM/IgG antibodies were detected using an indirect enzyme-linked immunosorbent assay (ELISA). The viral RNA was screened using nested reverse transcription-polymerase chain reaction (RT-PCR). Intracellular HIV-1 mRNA was detected using flow cytometry and fluorescence-in-situ hybridization to semi-quantify it in CD4+CD45RO+ cells. In addition, PBMC from 14 HIV-infected adults and 6 healthy controls were incubated in serum-free AIM-V medium containing cocktail cytokines. The phenotype of CD3, CD4, CD3CD56 and CD25 was identified by flow cytometric analysis every two days. The cytokine productions in the supernatants, including IL-1α, IL-12, TNF-αand IL-10 were measured by ELISA. The HIV-1 RNA load in culture supernatant was determined by real-time PCR. Results (1) All patients with SARS exhibited a rapid, dramatic decrease in number of circulating myeloid and plasmacytoid dendritic cells (mDCs and pDCs) during the first two weeks of illness, with slow restoration to normal level during convalescence. Similar trends was exhibited on numbers of circulating CD4 and CD8 T cells .A significant inverse correlation was observed between the numbers of DC or T-cell subsets and high-dose steroid treatment. In addition, both IgM and IgG antibodies began to be detectable in the 2nd week of the disease course, and the positive rates for both antibodies were progressively increased in parallel for the next three weeks. Afterwards, IgM progressively declined and IgG progressively increased for next few weeks. Interestingly, we observed that the patients with faster restoration of mDCs and pDCs in peripheral blood had a better antibody response to SARS-CoV than patients with slower restoration of the cell subsets. (2) The virus was most likely detected in sputum in acute phase, and simultaneous detection of different specimens could raise positive rate. Dynamically, the positive rate was highest at week 2 of illness in combination of different specimens, but different in various specimens. (3) Fourteen of HIV-1-infected children exhibited a dramatic decrease in frequencies and number of circulating mDCs and pDCs compared with healthy controls. In particular, there was a significant inverse association between pDC frequency and plasma viral load, and a significant positive association between pDC frequency and CD4 T-cell absolute number in these children. Moreover, HIV-specific CTL was detectable by tetramer assay in 84.7% HIV-infected children. (4) After incubation of PBMCs, 7 of 14 HIV-infected adults succeeded in expanding in the culture.The expanded cells were phenotypically heterogeneous with various ratio of CD3+CD4+ T cells, CD3+CD8+ T cells and CD3+CD56+ NKT cells on average at day 16 of incubation for HIV-infected adults. HIV-1-positive PBMCs were found to produce an elevated ratios of IL-12:IL-10 compared to healthy controls. Furthermore, serial analyses of HIV-1 RNA levels showed an inverted V type dynamic change during 16-day incubation period. Conclusion: (1) Peripheral DC and T-cell numbers significantly decrease in the acute phase, but reversible in the convalescent phase of SARS. It is suggested that SARS-CoV infection contribute to the initial reduction of peripheral DC and T-cell numbers, and high-dose steroid administration may subsequently exacerbate and prolong low expression of the cell subsets.