Depressed functions of T cells and the presence of suppressor macrophages in patients with sarcoidosis

Defective cell mediated immunity in sarcoidosis: effect of interleukin-2

Interleukin-2 has been reported to enhance the immune response in diseases characterised by defective cell mediated immunity. The effect of exogenous recombinant interleukin-2 was studied on the proliferative and cytotoxic responses of peripheral blood mononuclear cells from 39 patients with sarcoidosis and 14 healthy control subjects. The proliferative response to purified protein derivative was smaller in patients than in control subjects (p less than 0.001) whereas the response to 80 U interleukin-2 alone and to purified protein derivative and interleukin-2 did not differ significantly between the two groups. In addition, in eight patients but no control subjects tritiated thymidine incorporation induced by the combination of purified protein derivative and interleukin-2 was more than twice the sum of that induced by purified protein derivative and interleukin separately. Cytotoxic activity occurring spontaneously and induced by purified protein derivative and interleukin-2 in blood mononuclear cells was significantly less for patients with sarcoidosis than for control subjects (p less than 0.05 spontaneous, less than 0.001 purified protein derivative induced, less than 0.02 interleukin induced). Synergism between antigen and interleukin did not occur with respect to the cytotoxic response in either patients or controls. Defective interleukin-2 production may contribute to, but does not entirely explain, the functional abnormalities of peripheral blood lymphocytes from patients with sarcoidosis.

Abrogation of macrophage-mediated suppression of T-lymphocyte proliferation with hemoglobin and hemin is a function of iron content

Hemoglobin, hemin, and ferric ion (Fe) were shown to reverse peritoneal exudate cell (PEC)-mediated suppression of concanavalin A-elicited murine spleen cell activation. Titration of hemoglobin and hemin relative to Fe showed a direct relationship between Fe content and reversal of PEC suppression. Indomethacin enhanced the capacity of all three compounds to abrogate PEC suppression on the order of five- to eight-fold. The capacity of endogenous Fe-containing substances as hemoglobin and its catabolites, e.g., hemin, to modulate macrophage expression may be of special significance at sites of inflammation.

Sarcoidosis. An updated review

Sarcoidosis, a multisystem disease of unknown cause characterized by the formation of noncaseating granulomas, may involve any organ of the body, but the commonest sites of predilection are the lungs, lymph nodes, skin, and eyes. Sarcoidosis can be associated with polyclonal hyperglobulinemia, hypercalcemia, hypercalciuria, circulating immune complexes, cutaneous anergy, and in vitro depressed cell-mediated immunity. Recent studies of the cellular composition and cellular interactions of sarcoid-involved tissue have resulted in some insight into the pathophysiology of the disease. In early stages the predominance of activated T-helper cells in affected sites may account for many of the immunologic aberrations. The production of macrophage chemotactic substances by these cells may be the initial stimulus for the formation of the granuloma. The natural history of the disease is highly variable; the acute forms tend to resolve spontaneously, whereas the chronic forms rarely involute. Although multiple therapeutic modalities have been used and some have reportedly been effective, systemic corticosteroids remain the most effective available therapeutic agents.

Bronchoalveolar lavage in patients with the acquired immune deficiency syndrome (AIDS)

The lymphocytes retrieved by bronchoalveolar lavage (BAL) of three patients with the acquired immune deficiency syndrome were studied to determine the local immune status of these patients. These results were compared to those of patients with pulmonary sarcoidosis, who have similar systemic immune response (anergy, hypergammaglobulinemia). In these AIDS patients, the T4/T8 ratio in the BAL was 0.44 +/- 0.20. In eleven patients with pulmonary sarcoidosis, the bronchoalveolar lavage showed a T4/T8 ratio of 7.51 +/- 2.14. It is possible that patients with AIDS are unable to change the local immune response in the lung and thus are at risk for unusual infections.