CD4/CD8 lymphocytes in BALF during the efferent phase of lung delayed-type hypersensitivity reaction induced by single antigen inhalation.
BACKGROUND
The precise mechanisms involved in the pathogenesis of hypersensitivity pneumonitis (HP) have not been identified. HP is characterized by inflammatory lymphocytic alveolitis and a remarkable increase in T-lymphocytes detected in bronchoalveolar lavage fluid (BALF). It is suggested that both CD4+ and CD8+ T cells may contribute to the pathogenesis of HP. Experiments on animal models suggest that cell mediated immunity (CMI) is more important for the pathogenesis of HP than complex-mediated immunity, but the relationship between the subsets of BALF lymphocytes and humoral or cell-mediated allergic reactions is still not clear. The aim of our study was distinguish CD4+ and CD8+ T cells in BALF lymphocytes during a delayed-type hypersensitivity (DTH) reaction in the lung.


METHODS
The experiment was performed on guinea pigs sensitized with BCG vaccine and subjected to a single inhalation of tubercle bacilli antigens (tuberculin). 24 hours after tuberculin provocation (at the time of maximum lymphocyte infiltration), bronchoalveolar lavage was performed on both sensitized and non-sensitized (control) animals. The total cell count was estimated, and a differential microscopical examination of BAL-fluid cells was performed, along with the phenotyping of BALF lymphocytes (by flow cytometry).


RESULTS
In the BALF of the sensitized animals, as compared to the controls, there was a statistically significant increase in the percentage and absolute count of T-lymphocytes, CD4+ and CD8+. The CD4 / CD8 ratio in both groups did not differ significantly and was individually variable (2.94I0.72 SEM in the experimental group, vs 4.41I1.29 SEM in the control group).


CONCLUSIONS
Both CD4+ and CD8+ lymphocytes (with some predominance of helper cells) participate in the efferent phase of the delayed type hypersensitivity reaction in the lung induced by antigen inhalation.
Grubek-Jaworska
H
H
Department and Clinic of Internal Medicine, Pulmonology and Allergology, Medical University, Warsaw, Poland. hgj@amwaw.edu.pl
Hoser
G
G
Droszcz
P
P
Chazan
R
R
D000818:Animals; D001985:Bronchial Provocation Tests; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D005434:Flow Cytometry; D006168:Guinea Pigs; D006801:Humans; D006968:Hypersensitivity, Delayed / Q000276:immunology*; D008168:Lung / Q000276:immunology* / Q000502:physiology; D008297:Male; D014373:Tuberculin / Q000008:administration & dosage / Q000276:immunology
D014373:Tuberculin