Impairment of beta chemokine and cytokine production in patients with HIV related Pneumocystis jerovici pneumonia

BACKGROUND

Pneumocystis jerovici pneumonia (PJP) remains a frequent opportunistic infection in HIV infected patients which markedly upregulates HIV replication by mechanisms so far poorly elucidated. PJP triggers the production of proinflammatory mediators with activating effects on HIV. However, anti-inflammatory factors with inhibiting effects on HIV are normally produced in parallel. We postulated that an imbalance of mediators normally controlling HIV replication could underlie its marked increase during PJP.

METHODS

The production of tumour necrosis factor alpha (TNFalpha), interleukins IL-6 and IL-10, and beta-chemokine by bronchoalveolar lavage (BAL) cells recovered from HIV infected patients with and without PJP was compared. The pulmonary viral load was determined and correlations with cytokine and chemokine production were examined.

RESULTS

TNFalpha and IL-6 release was similar in patients with and without PJP but IL-10 and beta-chemokine release was markedly lower in the PJP group (IL-10: p<10(-2), RANTES, MIP-1alpha and MIP-1beta: p<0.001). The pulmonary viral load was markedly higher in patients with PJP (p<0.001) and correlated negatively with levels of MIP-1alpha, RANTES and IL-10 in BAL fluid cells (p<0.05).

CONCLUSION

Pulmonary IL-10 and beta-chemokine production is markedly defective in HIV infected patients with PJP, while pulmonary TNFalpha and IL-6 levels are normal. The resulting excess of these latter factors, which are known to upregulate HIV replication, might contribute to the increase in pulmonary viral load and to the more rapid HIV disease progression observed in patients with PJP.

Human alveolar macrophage subpopulations isolated on discontinuous albumin gradients. Cytological data in normals and sarcoid patients

Cells recovered by bronchoalveolar lavage (BAL) from ten subjects (five normals and five sarcoid patients) were centrifuged on discontinuous albumin gradients to study alveolar macrophage (AM) heterogeneity. The gradient was made with nine bovine albumin concentrations (from 8 to 30%). After centrifugation (4000 X g) cells were recovered from the interfaces. The majority of AM was recovered in upper and medium layers with AM purity reaching 90-100% in upper layers, while lymphocytes and granulocytes were found in lower layers. Alveolar macrophage morphology was different along the gradient. Large cytoplasmic vacuoles were found in AM from upper layers. Alveolar macrophage cytoplasmic diameters decreased from the top to the bottom of the gradient, but AM from sarcoid patients appeared larger than AM from normals. Alveolar macrophage nucleo-cytoplasmic ratios increased from top to bottom, but were lower in sarcoid patients than in normals. Alveolar macrophage peroxidase activity was rare (0.5-2% of AM) but reached a higher proportion in upper and lower layers.