This study describes the effect of ferritin on lymphocyte function in vitro. Peripheral blood lymphocytes isolated from normal donors were incubated with purified human splenic ferritin, and the mitogenic effect of phytohaemagglutinin (PHA), concanavalin A (Con A), pokeweed mitogen (PWM) and mixed lymphocyte reaction (MLR) were assessed by the uptake of 3H-thymidine (3H-TdR). Ferritin (0.25--5.0 micrograms/ml culture) caused a marked suppression of PHA nad Con A blastogenesis but had no suppressive effect on PWM-induced transformation. Maximal suppression was obtained at a ferritin concentration of 1 microgram/ml and this was not enhanced by increasing ferritin concentrations. Ferritin also reduced the Con A capping phenomenon in normal lymphocytes from 22% to 6%, suppressed the MLR reaction but had no effect on the ability of normal lymphocytes to form E, EA and EAC rosettes or on in vitro lymphocyte cytoxicity against the K-562 cell line. Visual proof of the suppressive effect of ferritin on mitogen induced blastogenesis was provided by scanning electron microscopy, and direct evidence for the ability of lymphocytes to bind ferritin was obtained from studies with radioiodine labelled ferritin. The above findings indicate that ferritin suppresses certain parameters of T-lymphocyte function in vitro. The relation of the present findings to recognized abnormalities of T-cell function encountered in certain neoplastic disorders associated with high serum ferritin levels is at present unknown.

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Human B lymphocytes are immortalized by Epstein-Barr virus (EBV, ref. 1). The virus can be used to establish lymphoblastoid cell lines that produce and actively secrete specific antibodies. The original method, which we have used for various antigens is based on selection of the specific surface antigen receptor-positive lymphocytes from the peripheral blood lymphocytes of a donor who was previously sensitized to the corresponding antigen. Furthermore, by cloning the polyclonal anti-NNP cell line we have produced human monoclonal antibodies for the first time in vitro. About 5-20 microgram ml-1 stably produced specific antibody is obtained in the supernatant of the cell lines. This approach can be used for the in vitro production of monoclonal human autoimmune antibodies by EBV-immortalized lymphocytes from patients with autoimmune diseases. We demonstrate the continuous production in vitro of a monoclonal IgM and anti-IgG antibody (rheumatoid factor, r.f.) by a lymphoblastoid cell line established from a patient with rheumatoid arthritis.

The prevalence and causes of anemia have been studied in 104 patients over 60 years of age admitted to a general medical ward in Jerusalem. In males and females, mean hemoglobin levels were about 1 g less than in the corresponding groups of healthy younger controls. A primary nutritional anemia could not be implicated in any of the 15 patients with hemoglobins below 11 g/dl. The most important causes of anemia were chronic renal failure, metastatic carcinoma, gastrointestinal bleeding, and infection. Conversely, in diseases with no adverse effect on erythropoiesis such as chronic ischemic heart disease, hypertension and diabetes, hemoglobin levels were equal to those of the younger controls. These findings indicate that although diminished serum iron and RBC folate levels may occasionally be found in elderly subjects, nutritional deficiency is seldom responsible for anemia in this age group in Israel, and anemia when present is often the manifestation of a chronic underlying disease.

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