IMMUNOLOGY TEXTBOOK - Mercury Podillia 2013

MECHANISMS OF IMMUNE DEFENSE IN BACTERIAL, VIRAL, FUNGAL, AND PROTOZOAN INFECTIONS

Immune response to intracellular microorganism invasion

Intracellular parasites capable of long-term survival inside phagocytes and even multiplying within them (tuberculosis, tularemia, brucellosis, Listeriosis, chlamydia, mycoplasma, etc.).

The primary mechanisms enabling Bacteria to exhibit intracellular parasitism include:

- blockage of phagolysosomal fusion (Mycobacterium tuberculosis);

- bacterial resistance to lysosomal Enzymes (gonococci, staphylococci);

- the ability of bacteria to rapidly exit phagosomes after uptake and persist in the Cytoplasm (listeria).

The principal effector Cells involved in shaping the body's Immune Response against intracellular pathogens are macrophages, NK cells, and T lymphocytes. Their microbicidal and cytotoxic properties are sharply enhanced under METABOLISM/18.html">The Influence of IFN-α and IFN-γ, TNF-α, IL-1, IL-2, IL-12, and other cytokines produced following activation by pathogen Antigens in these same three Cell populations.

Cell-mediated Immunity is of particular importance in cases where phagocytic reactions fail to destroy the pathogens (incomplete phagocytosis), resulting in the persistence of pathogenic bacteria and The formation of clusters of lymphoid cells and macrophages (granulomas). Sometimes this leads to nonspecific macrophage stimulation, which causes increased resistance to other infections. For example, a high level of cell-mediated immunity against tuberculosis increases resistance to Fungi, Protozoa, brucellae, and listeria.

Consequently, diseases characterized by prolonged intracellular residence and Replication of the pathogen (persistence) feature the formation of granulomas in the affected tissue. Such bacteria become inaccessible to Antibodies and humoral antibacterial factors. The Mechanism of sanogenesis and immune formation in such disorders is primarily linked to the generation of cytotoxic T lymphocytes, which target cells containing the parasitic bacteria that are marked with MHC Class I receptors and present the antigens of these bacteria.

Thus, the main protective role in the immune response directed against intracellular parasites (Mycobacterium tuberculosis, fungi, protozoa, Viruses) belongs to cellular mechanisms. The ability of these microbes to survive and multiply inside cells shields them from the action of antibodies and The Complement System. Eliminating such microbes requires a specific cell-mediated response.

Patient L., 28 years old, presented with Complaints of pain in the left knee joint, stinging in the eyes, a burning sensation in the Urethra, and a feeling of heaviness in the right hypochondrium. These symptoms had periodically occurred over the past year, persisted for 2-3 weeks, and subsided following antibacterial and anti-inflammatory therapy. Upon examination, there is eyelid puffiness in both eyes, Swelling of the left knee joint; the Liver is not enlarged and is painless upon Palpation. Bacteriological examination OF the urethral mucosa revealed Chlamydia trachomatis. The patient was diagnosed with: chronic chlamydial urethritis, exacerbation. Acute left-sided gonitis, Conjunctivitis (Reiter's Syndrome). HCV carrier state. Granulocytic-type immune system dysfunction.

Immunogram. High ESR. Stab neutrophil shift. Relative lymphocytopenia. Appearance of atypical mononuclear cells in Circulation. Elevated levels of complement system Proteins (CH50) and C-reactive protein (CRP). High levels of circulating immune complexes (CICs) and IMMUNOGLOBULINS of all classes studied (Table 35).

Conclusion: signs of an acute-phase inflammatory process of predominantly viral Etiology. Persistent viral infection (HCV, HIV) should be ruled out.

The patient underwent HCV PCR testing, which yielded a positive result; liver function tests (total bilirubin, conjugated bilirubin, AST, ALT, alkaline phosphatase) were normal; liver ultrasound showed a lobular, unchanged liver Structure, with a normal-sized Spleen.

Based on the immunological profile, patient L., 28 years old, was prescribed the following regimen of immunotropic and etiotropic therapy to treat the clinical manifestations of Reiter's syndrome: 1) etiotropic antibacterial therapy - azithromycin 1 g orally once or doxycycline 100 mg twice daily orally for 7 days; 2) probiotic - Lactiv Ratiopharm 1 cap. twice daily for 3 weeks; 3) specific antibacterial therapy (immunotherapy with human anti-chlamydial immunoglobulin 1.5 ml [1 dose] once every 3 days i.m. up to 6 injections); 4) Viferon 150,000 IU, rectally every other day, 10 administrations.

Immunorehabilitation: 5) Polyoxidonium 6 mg suppositories once daily after bowel cleansing at bedtime for 3 days, then every other day, no. 10; 6) Cycloferon 12.5% 1 ml once daily According to the schedule on days 1, 2, 4, 6, 8, 11, 14, 17, 20, 23, 26, 29; 7) HCV follow-up testing after 6 months.

Table 35. Immunogram of patient L., 28 years old