Bronchoalveolar lavage fluid evaluation in rheumatoid arthritis

Rheumatoid arthritis (RA), a systemic disorder of unknown cause, is associated with a variety of well-recognized pulmonary abnormalities including interstitial lung disease. To investigate possible pathogenic events in this disorder, we performed bronchoalveolar lavage (BAL) in 24 patients with classic or definite RA. Using radiographic and physiologic parameters as well as BAL cell differentials, 3 distinct groups emerged. Group I consisted of 9 patients with evidence of clinical interstitial lung involvement. Group II consisted of 5 patients without evidence of clinical interstitial lung disease (normal chest roentgenogram and functional testing) but who had abnormal BAL cellular differentials. The 10 remaining patients (Group III) had no evidence of clinical interstitial lung disease and had normal BAL cell differentials. Bronchoalveolar lavage in Group I had a significantly increased percentage of neutrophils (12.4 ± 4.2; p < 0.05) compared with group II (2.4 ± 0.8) and Group III (2.9 ± 0.6). All patients in Group II had elevated BAL lymphocytes (24.4 ± 6.4) compared with Group I (10.1 ± 3.8; p > 0.05) and Group III (5.4 ± 0.7; p < 0.01). Both Groups I and II had detectable IgM in BAL (0.02 ± 0.01 and 0.04 ± 0.02 mg/mg of albumin, respectively), whereas Group III patients and normal control subjects did not (p < 0.01). There was a marked reduction in BAL T-lymphocyte Leu 3/Leu 2A (helper/suppressor) cell ratios in Group I (0.92 ± 0.02; p < 0.05) compared with Group II (2.6 ± 0.6) and Group III (1.6 ± 0.1). This decreased BAL T-lymphocyte Leu 3/Leu 2A ratio in group I was not reflected in the peripheral blood of this group where the Leu 3/Leu 2A ratio in Group I was not reflected in the peripheral blood of this group where the Leu 3/Leu 2A ratio was 1.95 ± 0.2 (p < 0.05 compared with BAL). Peripheral blood Leu 3/Leu 2A ratios were not significantly different from BAL ratios in Group II (3.8 ± 0.5) and Group III (2.1 ± 0.2) (p > 0.05, both comparisons), but the value for group II was significantly greater than those for Groups I and III (p < 0.05). These findings of lower respiratory tract abnormalities in a group of patients with RA with and without established interstitial lung disease suggest that BAL may be a useful tool for studying potential pathogenic mechanisms in rheumatoid lung disease.