http://www.aidsmap.com/en/news/EE26B606-4323-4030-BC28-C0AD669AC86E.asp

HIV alters immune response in lungs
Michael Carter, Friday, September 16, 2005

HIV infection alters the functioning of the immune system in the
lungs, researchers working in Malawi have found, but not to such an
extent that it could lead to a deficiency in innate pulmonary immune
function. The research is published in the October 15th edition of the
Journal of Infectious Diseases.

Bacterial pneumonia and invasive pneumococcal disease are common in
HIV-positive individuals and the specific immune defects rendering
HIV-infected patients more susceptible to such diseases are not fully
understood and innate immune responses in the lung fluid of
HIV-positive patients have not been described.

Investigators therefore compared concentrations of innate pulmonary
immune factors in patients with HIV with HIV-negative patients. The
concentrations measured were lactoferrin, lysozyme, immunoglobulins,
and secretory leukocyte protease inhibitor.

A total of 45 individuals were recruited to the study. Of these, 16
were HIV-positive with no history of pulmonary disease, eleven were
HIV-positive with a history of invasive pneumococcal disease and the
remaining 18 individuals were HIV-negative controls. All 45
individuals were well at the time of the study with no active
pulmonary disease.

Samples of bronchoalveolar lavage were obtained during a bronchoscopy
examination.

The percentage of bronchoalveolar lavage cells which were lymphocytes
was significantly higher in the HIV-positive patients (21%) than
HIV-negative individuals (11%, p = 0.02).

Concentrations of beta-chemokine were also significantly higher in the
HIV-infected patients than HIV-uninfected individuals (p < 0.001).
Concentrations were undetectable in the HIV-negatives, a mean of
57pg/ml in HIV-infected individuals with a CD4 cell count above 200
cells/mm3 and a mean of 130pg/ml in HIV-positive patients with a CD4
cell count below 200 cells/mm3.

The investigators found that beta-chemokine concentrations were
correlated with HIV viral load in bronchoalveolar lavage (p < 0.001),
but not with viral load in blood.

Lysozyme concentrations were higher in HIV-positive patients than the
HIV-negative controls (p = 0.03). There was no significant
relationship between lysozyme concentrations and viral load in either
bronchoalveolar lavage or blood.

Although concentrations of secretory leukocyte protease inhibitor in
pulmonary fluid did not differ significantly between the three groups
of patients, however in further statistical analysis they found that
that secretory leukocyte protease inhibitor concentrations were
significantly correlated to HIV viral load in the bronchoalveolar
lavage of HIV-positive patients (p = 0.01), but not plasma viral load.

Lactoferrin concentrations were lower in HIV-positive individuals than
the study members who were HIV-uninfected (p = 0.04). There was no
correlation between concentrations and viral load in pulmonary fluid
or plasma.

Immunoglobulin concentrations in pulmonary fluid were, as the
investigators expected, significantly higher in HIV-positive patients.
The investigators also found that concentrations were higher in HIV
patients with a history of lung disease than those who were well. Once
again, a correlation was established between immunoglobulin levels in
pulmonary fluid, but not for plasma.

"The present study has described altered concentrations of innate
immune factors in bronchoalveolar lavage fluid from HIV-infected
subjects" conclude the investigators, who add, "inappropriately low
lysozyme concentrations in the subjects with AIDS may have been
relevant to their susceptibility to pneumococcal disease, but no clear
defect in pulmonary innate immunity was demonstrated in this group."

Reference

Gordon SB et al. HIV-infection is associated with altered innate
pulmonary immunity. J Infect Dis 192 (online edition), 2005.