[Prevalence of tuberculosis infection in students in the city of Tijuana, Mexico]. / Prevalencia de infección tuberculosa en escolares de la ciudad de Tijuana, México.

OBJECTIVE: To determine the prevalence of tuberculosis infection in school children from Tijuana, Mexico. MATERIAL AND METHODS: A study sample was randomly chosen from the municipal school registry and 1,131 elementary and high school children were included. All received one doses of PPD 5TU (Mantoux). Subjects with induration > or = 10 mm were considered positive reactors. RESULTS: The overall prevalence of positive reactors was 57%. The proportion of positive reactors was significantly higher among BCG-immunized subjects than in non-immunized individuals (59.7 vs 45.6%; p < 0.001). Correlation was not significant between age of immunization with BCG and diameter of induration. CONCLUSIONS: The prevalence of tuberculosis infection in Tijuana is extremely high; this fact has important implications in the control of tuberculosis in this region.

Identification of human immunodeficiency virus hybridizing sequences in the peripheral blood of a patient with systemic lupus erythematosus.

Systemic lupus erythematosus, a multisystemic disorder, is considered a prototype of the autoimmune diseases. Although its cause remains unknown, a viral etiology has been proposed. We report that a rapid and sensitive messenger RNA in situ hybridization technique detected hybridizing sequences to the human immunodeficiency virus type in the peripheral blood cells of a woman with systemic lupus erythematosus in whom the presence of acquired immuno-deficiency syndrome was reasonably excluded.

Durable complete remissions after 2'-deoxycoformycin treatment in patients with hairy cell leukemia resistant to interferon alpha.

The efficacy of interferon alpha in treatment of hairy cell leukemia is well established. Our experience with low doses of 2'-deoxycoformycin, a competitive inhibitor of adenosine deaminase, showed that it was also effective against hairy cell leukemia in 10 of 11 patients studied whose disease was resistant to interferon alpha. Ten patients entered complete remission after five to 12 doses of 2'-deoxycoformycin (4 mg/m2 every other week), and one patient did not respond. No relapses were observed after median follow-up of 18.5 months; unmaintained complete remissions lasted from more than 10 to more than 30 months. The study demonstrated that 2'-deoxycoformycin induces a high rate of durable, unmaintained complete remissions in patients with hairy cell leukemia resistant to interferon alpha.

Tolerance to endotoxin in vitro: independent regulation of interleukin-1, tumor necrosis factor and interferon alpha production during in vitro differentiation of human monocytes.

Bacterial lipopolysaccharide (LPS)-induced production of three known endogenous pyrogens, interferon alpha (IFN-alpha), interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF-alpha) was studied during in vitro differentiation of human peripheral blood monocytes. In freshly seeded cells, secretion of IL-1 and TNF-alpha, but not IFN-alpha were readily induced by LPS. After 24 hr and for up to 14 days of culture, monocytes became irreversibly tolerant to LPS for the release of IL-1. IFN-alpha secretion was not induced by LPS in cells cultured for up to 8 days. Monocytes also became tolerant to LPS for TNF-alpha production 48 hr after an initial stimulation with LPS. This tolerant state, however, was transient, lasting from 6 to 8 days, after which competence for TNF secretion resumed. These observations demonstrate that regulation of production of IL-1, TNF-alpha and IFN-alpha by human mononuclear phagocytes is mutually independent, related to the stage of cell differentiation and modulated by cell stimulation. Since in vitro tolerance to LPS mimics the in vivo tolerance to LPS with respect to fever, we speculate that they are closely related.

Production of interferon-alpha induced by dsRNA in human peripheral blood mononuclear cell cultures: role of priming by dsRNA-induced interferons-gamma and -beta.

Poly(I):poly(C) (rIn.rCn), mismatched poly(I):poly(C) [rIn.r(C12U)n], and poly(I):poly(C) poly-lysine carboxymethylcellulose [poly(ICLC)] were studied for their capacity to induce interferon-alpha (IFN-alpha) in human peripheral blood mononuclear cell (MNC) cultures and in their subpopulations. In MNC, poly(I):poly(C) and mismatched poly(I):poly(C) induced IFN-alpha in a dose-dependent manner, whereas poly(ICLC) was unable to do so in concentrations that ranged from 1 to 160 micrograms/ml. In contrast, all three molecules were incapable of inducing IFN-alpha when added into either purified monocyte or lymphocyte cultures. The capacity of poly(I):poly(C) to induce IFN-alpha was reestablished only in monocyte cultures when, prior to the stimulation, the cells were exposed for at least 2 h to supernatants from poly(I):poly(C)-stimulated lymphocyte cultures. IFN-beta and IFN-gamma were found in those supernatants and the ability of each dsRNA to induce IFN-alpha correlated with its ability to induce IFN-gamma. Further studies using recombinant human IFN-gamma and IFN-beta and their specific antibodies corroborated an important role of these molecules for the induction of IFN-alpha with dsRNA. Because each IFN type is produced by different cells, our studies show that complex cell-to-cell interactions via other IFNs have to take place in peripheral blood mononuclear cells (MNC) cultures before IFN-alpha can be induced by dsRNA.

Stimulation of myelopoiesis in patients with aplastic anemia by recombinant human granulocyte-macrophage colony-stimulating factor.

Aplastic anemia is a syndrome in which pancytopenia occurs in the presence of hypocellularity of the bone marrow. To assess the biologic activities of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) in aplastic anemia, we gave GM-CSF (60 to 500 micrograms per square meter of body-surface area) to 10 patients with moderate or severe disease, by continuous intravenous infusion daily for two weeks, and repeated the treatment after a two-week rest period. The treatment increased the white-cell count (1.6- to 10-fold) in all patients, primarily because of an increase in the numbers of neutrophils (1.5 to 20-fold), eosinophils (12- to greater than 70-fold), and monocytes (2- to 32-fold). Rates of hydrogen peroxide production in purified granulocyte fractions increased during GM-CSF treatment. Increases in bone marrow cellularity, myeloid precursor cells, and myeloid:erythroid cell ratios accompanied the white-cell response. Despite the in vivo response of the white-cells, the concentration of colony-forming cells remained the same. Measurable concentrations of interleukin-2 (2 to 15 units per milliliter) were found in the serum of 8 patients, and high levels of erythropoietin (81 to 1200 IU per liter) were found in 10 patients. The predominant side effects were constitutional symptoms. These results indicate that recombinant human GM-CSF is effective in stimulating myelopoiesis in patients with severe aplastic anemia and may benefit some patients in whom the disorder is refractory to standard forms of therapy.

Idiopathic production of interleukin-1 in acquired immune deficiency syndrome.

We determined the capacity of peripheral blood monocytes from 19 patients with acquired immune deficiency syndrome (AIDS) or related conditions (1 with lymphadenopathy, 8 with AIDS-related complex, and 10 with AIDS) to produce intracellular and extracellular interleukin-1 (IL-1) spontaneously and upon stimulation with bacterial endotoxin. All patients were anti-human T-cell lymphotropic virus type III antibody positive. Results were compared with those obtained with 10 normal controls of similar age. A subset of patients who spontaneously produced high amounts of intracellular and extracellular IL-1 was identified. Total production of IL-1 in this subset was an average of 2.9 times that of controls. It is suggested that spontaneous production of IL-1 in this group represents an in vivo phenomenon since it was associated with more than 3 g of globulins per deciliter of serum, more than 2,300 mg of immunoglobulins per deciliter of serum, higher IgA values, higher titers of anti-Epstein-Barr virus antibodies, and lower neutrophil counts in peripheral blood. The role of Epstein-Barr virus, human immunodeficiency virus itself, or other infectious agents in spontaneous IL-1 production by these patients remains to be determined. Stimulation with endotoxin induced intracellular and extracellular IL-1 production to similar levels in patients and controls. These results show that AIDS patients are able to produce and release IL-1. High idiopathic production of IL-1 identified in some patients can help to explain the hypergammaglobulinemia seen in AIDS patients and might also be related to progression and severity of the disease.

Mid-term observations on the efficacy of alpha-interferon in hairy cell leukemia and status of the interferon system of patients in remission.

We summarize our experience using alpha-interferon (IFN-alpha) in the treatment of 93 patients with hairy cell leukemia. Both partially purified interferon and recombinant IFN-alpha produced over 85% response rate. Equal efficacy at 12 months of treatment was found for both types of IFN-alpha. However, continuation of treatment up to 24 months with partially purified IFN-alpha resulted in an increased number of complete remissions. An increase in the number of bone marrow's hairy cells occurred in 70-80% of the patients in whom a treatment was discontinued. Only 20% of the patients required reinitiation of treatment, and in all, reinduction of remission was readily obtained. Toxicity to IFN-alpha in patients with hairy cell leukemia was minimal. IFN-alpha production by patients in remission was studied. Only those patients in complete remission showed adequate IFN-alpha production. The role of endogenous IFN-alpha in the induction and sustenance of remission in hairy cell leukemia is discussed.

Alpha interferon production in patients with hairy cell leukemia: correlations with disease activity and remission status.

Nineteen patients with hairy cell leukemia (HCL) were studied for in vitro production of alpha interferon (IFN alpha). The patients were divided into three groups. The first group consisted of 8 patients with active disease, all of whom showed a severe deficiency in IFN alpha production (no detectable titers in 6 and less than 40 units/ml in the other 2) compared to normal controls (range: 320-10,500 units/ml; median: 2,560 units/ml). The second group consisted of 6 patients who achieved a partial remission (PR) after IFN alpha treatment. These 6 patients had normal numbers of mononuclear cells in the peripheral blood, but still had deficient IFN alpha production (titers of IFN alpha were below 10 units/ml in 5 of the 6 patients). The third group consisted of 5 patients in complete remission (3 after IFN alpha treatment and 1 each after splenectomy and infection). This group had IFN alpha production that was not significantly different from that of controls 35 years or older (median: 640 units/ml; range 60-2,560 units/ml for patients vs. 1,513 units/ml; range 320-5,120 units/ml for controls; p greater than 0.05). These data show a direct relationship between the activity of HCL and the capacity to produce IFN alpha in vitro. The data also suggest that deficiency of endogenous production of IFN alpha may be relevant to the induction and sustenance of remissions in this disease and that relapses may be partly associated with failure to fully restore endogenous IFN alpha production.

Differences between intra- and extracellular interleukin-1.

The intracellular (IC) and extracellular (EC) pools of interleukin 1 (IL-1) of human monocyte cultures were found to differ in their molecular size and charge characteristics. EC activity was found by Sephadex G-75 chromatography to consist mainly of a single peak in the 15,000-17,000 mol. wt range. In contrast, IC activity was distributed in four peaks (mol. wts of approx. 15,000, 26,000, 45,000 and greater than 70,000). Treatment of a pool of the IC 26,000, 45,000 and greater than 70,000 mol. wt species with CHAPS, a zwitterionic detergent, yielded a large amount of the 15,000 mol. wt species, thus suggesting that a portion of the larger species consists of aggregates of the 15,000 mol. wt molecule. Both IL-1 pools were found by isoelectrofocusing to be composed of three molecular species with pIs of 5.5, 6.7. However, the proportions of these species differed markedly between the EC and IC pools. The large majority of IC activity (approximately 90%) was found at pI 5.5, while 55-60% of EC activity had a pI of 6.7 and 35-40% had a pI of 5.5. The differences in their biophysical properties support the notion that the IC and EC pools of IL-1 also differ in their functions.

Dual effect of phorbol myristate acetate (PMA) on murine thymocyte cultures.

4 beta-phorbol 12-myristate 13-acetate (PMA), a potent tumor promoter, was found to have a dual effect on interleukin 1-(IL 1) stimulated murine thymocyte cultures. In the absence of 2-mercaptoethanol (2-ME) or other sulfhydryl containing compounds, PMA inhibited 3H-thymidine incorporation, while at the same concentrations but in the presence of sulfhydryl agents, PMA exerted a potent stimulatory effect. The other sulfhydryl compounds giving effects resembling 2-ME were dithiothreitol and cysteine, while glutathione and various oxygen radical scavengers (catalase, superoxide dismutase, histidine, alpha-tocopherol or mannitol) had no such effect. 2-ME enhanced the response of thymocytes incubated with PMA even when added 24 h after initiation of the cultures, but not at the 48 h interval. Harvesting the thymocyte cultures at various intervals showed that the inhibitory effect of PMA was already fully pronounced 48 h after initiation of the cultures. On the other hand, the stimulatory effect of PMA on cultures activated with IL 1 in the presence of 2-ME took place mainly during the last 24 h of the 72-h culture period. The modulation of the effect of PMA on thymocyte activation by 2-ME or similar agents may account for the apparent discrepancies in the literature concerning the action of PMA in lymphocyte cultures.

Analysis of the cytotoxic effects of light-exposed HEPES-containing culture medium.

The addition of N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES) to RPMI 1640 medium markedly increases the production of cytotoxic products during exposure of the medium to visible light. The cytotoxicity has been analyzed by measuring uptake of [3H]thymidine by murine thymocytes cultured in preirradiated medium containing 25 mM HEPES. Complete inhibition of thymidine uptake was produced by exposing 50% of the culture medium to light for 3 h before addition of cells. The HEPES-mediated effect requires only that HEPES and riboflavin be exposed to light; other medium constituents are not necessary. Hydrogen peroxide is a principal cytotoxic agent produced in this system. It is demonstrated that most, but not all, of the inhibition of thymidine uptake can be attributed to hydrogen peroxide.

Production of intra- and extracellular interleukin-1 (IL-1) by human monocytes.

Human monocytes, separated by adherence and cultured in plastic wells, produced "spontaneously" high levels of intracellular interleukin-1 (IL-1) during the first 20 hr in culture while releasing in most cases less than 10% of it into the medium. The addition of bacterial lipopolysaccharides (LPS), quartz silica particles, zymosan, or phorbol myristate acetate (PMA) enhanced 3 to 50 times the overall production and 25 to 2000 times the release of IL-1. From 24 to 44 hr of culture, the "spontaneous" production and release of IL-1 decreased to negligible amounts. During the same period of time, the addition of silica particles or PMA had clearly less effect while the addition of LPS or zymosan produced high levels of intracellular IL-1 but only a modest release of it. When any of the stimuli was added after the first 48 hr and up to 6 days of culture, no release of IL-1 was detected and only a small amount of the intracellular fraction was seen when using LPS or zymosan. These results were not due to cell death prior to the addition of the stimuli but rather to a decrease in the responsiveness of the mononuclear phagocytes that coincides with their transformation into macrophages. The different patterns of production and release observed with time suggest that synthesis and secretion of IL-1 by human monocytes are two distinct biological events.

Silica-stimulated monocytes release fibroblast proliferation factors identical to interleukin 1. A potential role for interleukin 1 in the pathogenesis of silicosis.

Previous study strongly suggests that silicotic fibrosis is mediated by macrophages and their soluble mediators. The biochemical properties of the mediators involved in silicotic fibrosis, however, are as yet ill defined. The current study, therefore, determined whether human monocyte-macrophages treated with fibrogenic silica dust released factors capable of activating fibroblasts as measured by an increase in fibroblast proliferation. Silica, but not nonfibrogenic diamond dust, stimulated the release of fibroblast proliferation factors. Moreover, the level of fibroblast proliferation activity was comparable with the level of thymocyte proliferation (interleukin-1) activity in the same culture supernatants. The factors responsible for these seemingly diverse activities were found to behave identically when analyzed by gel filtration chromatography, size exclusion chromatography, isoelectrofocusing, ion exchange chromatography, and hydrophobic chromatography. Moreover, the response of these factors to four different proteases and heat (56 degrees C) was also identical, which shows that their comigration on various separation media could not be explained by noncovalent interaction between otherwise unrelated species. The data demonstrate that a monocyte-derived thymocyte proliferation factor having the molecular properties of interleukin 1 is capable of regulating fibroblast proliferation. In silicosis and other fibrotic diseases, the local release of interleukin 1 may contribute to abnormal connective tissue deposition by stimulating fibroblast proliferation, and thereby, amplifying other signals stimulating the synthesis of connective tissue components.

Laser nephelometry quantitation of fibrinogen-related antigens.

A laser nephelometric procedure to quantitate fibrinogen related antigens (FRA), that joined the best characteristics of the immunological available techniques, is proposed. It is sensitive, rapid, simple, reproducible, antiserum saving and accurate since it correlates very well with the tanned red cell hemagglutination inhibition immunoassay (TRCHII) at the most commonly found clinical levels (r = 0.98, p less than 0.0005), but with the advantage of a more objective quantitation and thus, reliable for any concentration of FRA. Prepared samples of different known levels of fibrinogen, assayed with the laser method and the TRCHII, showed a higher correlation with the laser procedure (r = 0.97, p less than 0.0005) than the obtained with the TRCHII (r = 0.85, p less than 0.001). The technic is useful in emergency situations, routine work and research.