No abstract

Aging has been associated with diminished lung function and increased susceptibility to lung infection. To determine whether changes suggestive of immune dysregulation and inflammation appear in the lungs of clinically normal individuals as a function of advancing age, we performed bronchoalveolar lavage (BAL) on discontinuous age groups (20-36, 45-55, and 65-78 yr old) of clinically normal volunteer subjects. We measured immunoglobulin (IgG, IgA, IgM), albumin, interleukin-6 (IL-6), and interleukin-10 concentrations in BAL fluid. Bronchoalveolar cell profiles, cell surface antigen expression, and superoxide anion production were also measured. A significant increase in total cell concentration, neutrophils, and BAL immunoglobulin content was observed in the oldest age group compared with the youngest age group. Mean lymphocyte subset (CD4+/CD8+) ratios were significantly increased in blood (2.6 +/- 0.4 versus 1.6 +/- 0.1; p<0.03) and to a greater degree in BAL (4.8 +/- 1.0 versus 1.9 +/- 0.2; p<0.01) for the oldest versus youngest age groups. Similarly, BAL-derived cells displayed significantly increased phorbol myristate acetate-stimulated release of superoxide anion (8.8 +/- 1.3 versus 4.5 +/- 0.7 nmol/5 x 10 5 cells/h; p<0.01) for the oldest versus youngest subject group, and mean BAL IL-6 concentrations were significantly elevated in the oldest age group (0.86 +/- 0.13 ng/ml) compared with the youngest age group (0.53 +/- 0.03 ng/ml; p<0.01). Our observations suggest that altered inflammatory cell profiles and low-grade inflammation exist in the lower respiratory tracts of many asymptomatic, clinically normal volunteers of advanced age.

Annexin I is a 36 kilodalton (kD) calcium-dependent phospholipid-binding protein which may have anti-inflammatory properties. Previous investigations which sampled lower respiratory tract epithelial lining fluid (ELF) via bronchoalveolar lavage (BAL) have demonstrated that annexin I can be degraded in inflammatory lung disease. We analyzed BAL fluid from patients with cystic fibrosis (CF) to determine the effects of lung inflammation on the structure and activity of annexin I. Intact annexin I was absent in 17 out of 20 BAL fluid samples from patients with CF, due largely to degradation to a 33 kD protein. The three CF BAL fluids in which annexin I was detectable had very little or no unopposed neutrophil elastase activity in contrast to the 17 in which no annexin I was detectable. Annexin I was present in all BAL fluid samples from 10 normal volunteer (NV) subjects and 12 patients with interstitial lung disease (ILD). The 33 kD annexin I breakdown product was not detectable in samples from NV, but was detectable only in ILD patients with relatively high percentages of neutrophils on BAL differential cell counts. Annexin I appeared to be cleaved by neutrophil elastase at the N-terminal portion between Val-36 and Ser-37 to yield the 33 kD protein. Cleavage of the N-terminal portion of annexin I was accompanied by a marked change in the annexin I isoelectric point (pI) value (from 6.0 to 8.5-9.0) and greatly diminished annexin I functional activity. Our findings demonstrate that annexin I degradation in epithelial lining fluid is closely related to lung inflammation.

Chest radiography in patients with cystic fibrosis (CF) frequently shows more severe changes in the upper lobes. We performed bronchoalveolar lavage (BAL) on 12 clinically stable, young adult patients with CF to determine whether inflammation varies significantly among geographically distinct areas of the lung. We found that absolute numbers of neutrophils were generally greater in BAL fluid from the upper lobe (25.7 +/- 7.9 x 10(5) neutrophils/ml [mean +/- SEM]) of the right lung than that obtained from the right lower lobe (6.8 +/- 2.8 x 10(5) neutrophils/ml; p < 0.01). The mean value of unopposed neutrophil elastase activity in upper-lobe BAL fluid (227 +/- 91 nmol peptide hydrolyzed/ml/min) was also significantly greater than that in lower-lobe BAL fluid (84 +/- 43 nmol/peptide hydrolyzed/ml/ min; p < 0.01), and similar differences were found for myeloperoxidase activity and DNA content. Neutrophil influx and unopposed neutrophil elastase for a given region correlated inversely with lung function or percentage of ideal body weight, and upper-versus lower-lobe differences were more pronounced in subjects with better preservation of lung function. Our findings suggest that regional variation in inflammation must be considered when utilizing BAL to study lower respiratory tract inflammation in CF or to monitor responses to therapeutic interventions that can potentially diminish lung inflammation. Our findings may also have implications for the study of the natural history of lung inflammation and infection in neonates, infants, and young children with CF.

Summary:Prolonged isolated thrombocytopenia, defined as recovery of other cell counts with continuous dependence on platelet transfusions for greater than 90 days after hematopoietic stem cell transplantation (HSCT), develops in approximately 5% of patients who undergo HSCT. Although the clinical conditions associated with prolonged isolated thrombocytopenia have been studied, a systematic review of bone marrow biopsies has not been performed and the pathophysiologic basis has not been defined. We reviewed all HSCT at one center from 1990 to 1995 (n = 454) and found 12 cases that met criteria for prolonged isolated thrombocytopenia (incidence = 12/454 or 3%). Bone marrow core biopsies from 12 patients with prolonged isolated thrombocytopenia were reviewed to determine cellularity, numbers of megakaryocytes, the presence of atypical forms, and clusters of megakaryocytes. These marrow megakaryocyte counts were compared to age and disease matched controls, and 11 normal donors. Patients (aged 1-56 years, mean 32 years) who underwent HSCT (four sibling HLA-identical, five autologous bone marrow, three autologous peripheral stem cell) with prolonged isolated thrombocytopenia had a statistically significant lower absolute megakaryocyte count in bone marrow biopsies performed before transplantation and more than 30 days after transplantation compared to control patients (aged 4 months to 50 years, mean 31 years) who underwent HSCT (four sibling HLA-identical, four autologous bone marrow, four autologous peripheral stem cell) for similar conditions. No apparent differences were seen in size of megakaryocytes, nuclear-cytoplasmic ratios, or clustering of megakaryocytes. Overall marrow cellularities were similar in the three groups. These findings suggest that decreased differentiation of megakaryocytes from stem cells, rather than ineffective platelet production or peripheral destruction of platelets, causes prolonged isolated thrombocytopenia in HSCT patients. Low megakaryocyte counts prior to HSCT may be a useful prognostic indicator, as this feature was associated with the development of prolonged isolated thrombocytopenia.