ACCESSORY FUNCTION OF ALVEOLAR MACROPHAGES FROM PATIENTS WITH SARCOIDOSIS AND OTHER GRANULOMATOUS AND NONGRANULOMATOUS LUNG-DISEASES

Background: Accessory function (AF) is one way antigen presenting cell s generate sufficient secondary signals for optimal T-cell proliferati on and IL-2 production. In general, alveolar macrophages (AM) are infe rior accessory cells in comparison to monocytes whereas in sarcoidosis AF of AM is increased. Methods: We compared the accessory index (AI) of AM and peripheral blood monocytes (PBM) of 41 patients with inactiv e sarcoidosis (SAR I, n = 12); active sarcoidosis with new or progress ing symptoms (SAR II, n = 19), active sarcoidosis with spontaneous rem ission (SAR III, n = 10), tuberculosis (TB, n = 12), hypersensitivity pneumonitis (HP, n = 12), Wegener's disease (WD, n = 2), undefined alv eolitis (UA, n = 8) and chronic obstructive pulmonary disease (COPD, n = 6) by employing the histoincompatibility-insensitive Jurkat cells a s indicator cells. Results: Compared with the controls (1.08 +/- 0.3) AMs of all groups but SAR I (AI: 0.96 +/- 0.42) exhibited significantl y increased AIs (SAR II: 3.6 +/- 3.9; SAR III: 3.2 +/- 2.4; TB: 2.8 +/ - 2.2; HP: 3 +/- 2; UA: 2.7 +/- 23; COPD: 3.1 +/- 2.2; p < 0.05 for al l comparisons), Only in HP, AI of PBM was significantly increased comp ared with controls (3 +/- 1.5, 13 +/- 0.5, respectively; p < 0.001), A lveolar macrophages from patients with arcoidosis, TB, and HP express the costimulatory molecule CD80 on their surface and anti-CD80 antibod ies inhibited the IL-2 release of Jurkat cells in this system to 59 +/ - 27%. Conclusions: Our data demonstrate that AM from patients with va rious diseases have the capability to act as competent accessory cells and that the reported accessory function of these cells is at least i n part mediated by the expression of CD80.