ABSTRACTS – ORAL PRESENTATIONS - AMCA, spol. s r.o.

50. THE PROGRESSION OF HIV INFECTION IN TERMS OF LABORATORY IMMUNOLOGY
Alexandra Lochmanová 1 , Lenka Olbrechtová 2 , Jitka Kolčáková 2 , Alena Zjevíková 2
1
Institute of Public Health, Department of Immunology and Allergy, Ostrava, Czech
Republic; alexandra.lochmanova@zuova.cz
2
Faculty Hospital Ostrava, Clinic of Infectious Medicine, Czech Republic
The pathogenesis of HIV infection includes depletion of the total body CD4+ T-cell pool,
leading to immunodeficiency. This effect is accompanied by activation of numerous
elements of immune system. Immune activation appears to be driven by both
homeostatic response to CD4+ T/cell depletion and an inflammatory response to HIV
infection.
The correlation between peripheral blood CD4+ counts and the spectrum of clinical
manifestations of HIV disease is well defined and has been recognized for many years.
Despite its value, the peripheral blood CD4+ count is recognized as an imperfect marker
of HIV disease progression. In some cases, the CD4+ percentage is a better marker of
immune competence than CD4+ count.
Measurements of T-cell function seems to be more effective and central to understanding
HIV disease. Three types of assays are typically used to measure T-cell function:
cytotoxicity, proliferation and cytokine secretion. Nonproliferation-base assessments
of immune activation include measuring expression of so-called “early” cell surface
markers such as HLA-DR, CD38, CD69 or CD25. A proliferative state as a definitive
indicator of activation accompanied by DNA synthesis can be assessed by 3 H-thymidine
uptake, measurements of intracellular proteins such as Ki67 or staining with tracking
dyes (CFSE).
Chronic HIV infection is accompanied by permanent activation of immune system a
persistent inflammation. The intensity of this process is associated with serious outcome
and poor prognosis. One of the most effective cytokine in thi sproces is IL-2, which is a
potent inducer of T-cell proliferation and participates in both induction and suppression
of inflammatory process.
Routine laboratory monitoring of HIV patients involves determining peripheral blood
CD3+, CD3+ CD4+ and CD3+CD8+ absolute count and T-cell proliferation measured by
3
H-thymidine incorporation after stimulation with PHA.
It was show that the degree of cell activation, resp. functional activity, clearly reflects
the depth of immunodeficiency. Reduction of functional activity indicates impairment
of immune competence, whose improvement can be achieved therapeutically. Longterm
unresponsiveness suggests a definite loss of immune competence and appears
in the terminal stage of the disease. Impaired ability of lymphocyte proliferation may
be caused by a lack of synthesis of ribonucleotides due to defect of relevant metabolic
pathways. However, IL-2 seems to be one of the most important components of this
process because IL2 is essential for lymphocyte proliferation. In accordance with these
findings correspond clinical studies which indicate that administration of recombinant
IL2 leads to a permanent increase in the number and function of CD4 + T cells in patients
in both early-and late-stage of HIV infection.
64 Analytical Cytometry VII