Background and aim of the work: We have previously shown that HLA DR17 is associated with a favourable prognosis in Scandinavian sarcoidosis patients. By studying inflammatory parameters in these patients we wished to increase the knowledge of the involved mechanisms that may underlie good prognosis.
Methods: BAL was performed in 118 sarcoidosis patients, 67 HLA DR17 positive and 51 DR17 negative. BAL cell profile was analysed. The CD4 and CD8 lymphocyte phenotype was determined by flow cytometry. BALF-albumin, BALF-fibronectin (FN) and BALF-procollagen III aminoterminal peptide (PIIINP) were analysed by nephelometric, ELISA and RIA methods respectively. Neopterin and soluble interleukin-2 receptor (sIL2R) in serum were also determined by ELISA. Angiotensin-converting enzyme (ACE) in serum was analysed by spectrophotometry.
Results: In DR17+ patients, BAL lymphocytes and eosinophils were significantly decreased (median 30.2 and 0.19 x10(6)/L) compared to DR17- (median 50.2 and 0.64 x 10(6)/L respectively). However the BAL CD4/CD8 ratio was increased in the DR17+ group compared to DR17- (6.2 vs. 4.3). BALF-albumin, FN and PIIINP did not differ between the groups. Serum parameters were 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 BAL lymphocytosis, was seen in a subgroup of sarcoidosis patients earlier associated with a favourable prognosis. Our results support that an increased BAL CD4/CD8 ratio is a favourable parameter in sarcoidosis. The lower ACE activity in the DR 17+ group indicates a reduced granuloma burden in this patient subgroup.