Inflammatory BAL-fluid and serum parameters in HLA DR17 positive vs. DR17 negative patients with pulmonary sarcoidosis

Background and aim of the work: We have previously shown that HLA DR17 is a ssociated with a favourable prognosis in Scandinavian sarcoidosis patients. By studying inflammatory parameters in these patients we wished to increas e the knowledge of the involved mechanisms that may underlie good prognosis . Methods: BAL was performed in 118 sarcoidosis patients, 67 HLA DR17 posit ive and 51 DR17 negative. BAL cell profile was analysed. The CD4 and CD8 ly mphocyte phenotype was determined by flow cytometry. BALF-albumin, BALF-fib ronectin (FN) and BALF-procollagen III aminoterminal peptide (PIIINP) were analysed by nephelometric, ELISA and RIA methods respectively. Neopterin an d soluble interleukin-2 receptor (sIL2R) in serum were also determined by E LISA. Angiotensin-converting enzyme (ACE) in serum was analysed by spectrop hotometry. Results: In DR17+ patients, BAL lymphocytes and eosinophils were significantly decreased (median 30.2 and 0.19 x 10(6)/L) compared to DR17- (median 50.2 and 0.64 x 10(6)/L respectively). However the BAL CD4/CD8 rat io was increased in the DR17+ group compared to DR17- (6.2 vs. 4.3). BALF-a lbumin, FN and PIIINP did not differ between the groups. Serum parameters w ere decreased in DR17+ patients compared to DR17- (ACE median 28.7 vs. 35.1 U/L, neopterin 9.1 vs. 12.7 nmol/L and sIL2R 296 vs. 605 U/L). Conclusions : The study revealed that an increased BAL CD4/CD8 ratio, in contrast to BA L lymphocytosis, was seen in a subgroup of sarcoidosis patients earlier ass ociated with a favourable prognosis. Our results support that an increased BAL CD4/CD8 ratio is a favourable parameter in sarcoidosis. The lower ACE a ctivity in the DR17+ group indicates a reduced granuloma burden in this pat ient subgroup.