Transforming growth factor beta (TGF-beta), a potent inhibitor of erythropoiesis: neutralizing TGF-beta antibodies show erythropoietin as a potent stimulator of murine burst-forming unit erythroid colony formation in the absence of a burst-promoting activity

Transforming growth factor beta (TGF-beta) is a bifunctional regulator of the growth of myeloid progenitors and is here demonstrated to directly inhibit the growth of primitive erythroid progenitors by 95% to 100% regardless of the cytokines stimulating growth. Autocrine TGF- beta production of primitive hematopoietic progenitors has previously been reported. In the present study, a neutralizing TGF-beta antibody (anti-TGF-beta) added to serum-containing cultures, resulted in a 3-, 4- , and 25-fold increase in burst-forming unit erythroid (BFU-E) colony formation in response to interleukin-4 (IL-4) plus erythropoietin (Epo), SCF plus Epo, and IL-11 plus Epo, respectively. The growth of BFU-E progenitors has been suggested to require a burst-promoting activity in addition to Epo. Accordingly, we observed no BFU-E colony formation in serum-containing cultures in response to Epo alone. In contrast, 50 BFU-E colonies were formed when anti-TGF-beta was included in the culture. In serum-free cultures, Epo also stimulated BFU-E colony formation in the absence of other cytokines, whereas anti-TGF- beta had no effect on the number of colonies formed. Quantitation of TGF-beta 1 in serum by an enzyme-linked immunosorbent assay method showed predominantly the presence of precursor (latent) TGF-beta 1, but also showed active TGF-beta 1 at a concentration sufficient to potently inhibit erythroid colony formation. Thus, neutralization of active TGF- beta 1 in serum shows that Epo alone is sufficient to stimulate the growth of murine BFU-E progenitors.     

Fluorescent in vivo tracking of hematopoietic cells. Part I. Technical considerations

We report a new technology for in vivo tracking of hematopoietic cells, using fluorescent lipophilic probes. Because the probe is irreversibly bound in the lipids of the cell membrane; substantial numbers of dye molecules can be incorporated per cell and thus substantial signal to noise can be achieved. Although this technology can be used for all hematopoietic cells, these first findings are reported on red blood cells (RBCs) owing to the importance of the membrane to RBC function and integrity. We demonstrated that labeling 10% of the RBCs of a rabbit and reinjecting them into the animal makes possible the tracking of these cells at various times after injection. Furthermore, the labeling appears not to affect in vivo cell lifetime or cellular volume changes in response to hypotonic shock. The single cell fluorescence intensity of the labeled RBCs remains relatively constant for 60 days, and an immune response appears not to be generated against labeled cells. That labeled RBCs have lifetime kinetics in vivo, as shown in other studies, indicates that the membranes are functioning normally and are unaltered by the labeling technology. The technology we present is also applicable to white blood cells, bone marrow, and platelets.     

Management of extra-articular disease manifestations in rheumatoid arthritis

PURPOSE OF REVIEW: To discuss the rationale for various treatment strategies in rheumatoid arthritis with extra-articular manifestations, and to review advances in understanding the impact of extra-articular rheumatoid arthritis and its management. RECENT FINDINGS: Recent epidemiologic studies of extra-articular rheumatoid arthritis manifestations have emphasized their major role as predictors of premature mortality in patients with rheumatoid arthritis, and provide a rationale for aggressive ant-rheumatic treatment of extra-articular rheumatoid arthritis. Previous uncontrolled or nonrandomized studies favor the use of cyclophosphamide in patients with systemic rheumatoid vasculitis, and methotrexate in the case of other manifestations of extra-articular rheumatoid arthritis. Recent case reports indicate that patients with rheumatoid lung disease may respond to cyclosporine or tumor necrosis factor inhibitors, and that tumor necrosis factor blocking therapy also may be successful in cases of treatment-resistant vasculitis. By contrast, it has been suggested that tumor necrosis factor inhibitors may induce some manifestations of extra-articular rheumatoid arthritis. Data indicating a high risk of serious infections and cardiovascular disease in patients with extra-articular rheumatoid arthritis underline the importance of carefully monitoring such patients. SUMMARY: Extra-articular rheumatoid arthritis is a serious condition, and rheumatoid arthritis patients with extra-articular manifestations should be aggressively treated and monitored. Advances in the understanding of the pathogenesis of rheumatoid arthritis and developments of new, more specific drugs may be of particular benefit to patients with extra-articular disease.     

Historical perspective of vasculitis: Polyarteritis nodosa and microscopic polyangiitis

The original and early case reports of vasculitis provide a historical context and foundation for understanding current concepts of these diseases. These early case reports are valuable as reference points for the current efforts in diagnosing, treating, and classifying vasculitis. In addition, they emphasize the importance of careful clinical observation in these efforts and the essential nature of medical science. Polyarteritis nodosa was the first noninfectious vasculitis to be described and studied in detail. Research on this group of vasculitides has been the cornerstone for understanding the pathophysiology of other forms of idiopathic vasculitis. Historically, most forms of vasculitis described subsequently have been characterized and classified on the basis of features similar to or distinct from polyarteritis.     

Increased CD4+ T cell infiltrates in rheumatoid arthritis-associated interstitial pneumonitis compared with idiopathic interstitial pneumonitis

OBJECTIVE: To study lymphocyte markers in rheumatoid arthritis (RA)-associated interstitial pneumonitis (IP) compared with idiopathic IP. METHODS: Paraffin-embedded lung biopsy specimens from patients with RA (n = 15) and from those without RA (n = 16), all of whom had a diagnosis of either nonspecific IP or usual IP, were studied. Tissue sections from each patient were reviewed by a pathologist, who was blinded to the clinical data. Age and pulmonary function test results were similar in RA and non-RA patients. After high-temperature antigen unmasking, sections were incubated with mouse monoclonal antibodies directed against CD3, CD4, CD8, CD16, and CD20. All slides were coded, and digital images (100x magnification) of the entire tissue area were obtained. Staining was quantified using computer-assisted image analysis. RESULTS: Staining for CD4 was more prominent in patients with RA than in the non-RA comparison group (median 9.3 cells/mm(2), interquartile range [IQR] 5.5-27.3 versus 0.6 cells/mm(2), IQR 0.2-1.9; P = 0.002). CD4+ cell counts were increased in RA patients with nonspecific IP as well as in RA patients with usual IP, with no major difference between these groups. Results were similar for quantification of CD3 (P = 0.012). There was a less striking trend toward more CD8+ cells in RA patients (P = 0.27 versus those with non-RA lung disease). CONCLUSION: IP lesions in patients with RA are characterized by an increased number of CD4+ cells, as compared with that in patients with idiopathic IP. This finding suggests that CD4+ T cells are critical for the development of pulmonary manifestations in RA, and may have implications for the treatment of RA-associated lung disease.     

The Mr 95,000 gelatin-binding protein in differentiated human macrophages and granulocytes

Cultured adherent human macrophages and a promonocytic cell line, U 937, were previously shown to produce a Mr 95,000 gelatin-binding protein. The protein has no immunologic cross-reactivity with the well- characterized gelatin-binding protein fibronectin and the Mr 70,000 gelatin-binding protein produced by a variety of mesenchymal or epithelial cell types (T. Vartio et al, J Biol Chem 257:8862, 1982). In the present study the Mr 95,000 protein was found in Triton X-100 extracts of granulocytes purified from human blood buffy coat. The protein, as isolated by gelatin-agarose, was immunologically cross- reactive with the corresponding macrophage protein in immunoblotting assay. When peripheral blood and bone marrow cells were examined for the presence of the Mr 95,000 protein by indirect immunofluorescence, positive staining was detected only in differentiated granulocytes but not to any significant extent in metamyelocytes, myelocytes, promyelocytes, or in normal or leukemic blasts. In granulocytes the protein had a granular cytoplasmic distribution. In freshly prepared monocyte cultures, the Mr 95,000 protein was detected in low amounts in the cytoplasm, while along with differentiation of the cells into macrophages, the immunofluorescence increased in a reticular and vesicular cytoplasmic pattern and in a juxtanuclear cap, probably representing the Golgi complex. In conclusion, the Mr 95,000 gelatin- binding protein was specifically detected in macrophages and granulocytes and may thus serve as a differentiation marker for these phagocytic cells.