Considerations on the changes of certain immunologic cells in silicosis.

Cell-mediated immunity was estimated in a group of 68 patients divided into three subgroups according to the evolutive stage of disease. It was demonstrated that in silicosis there is a disturbance of immunity. The detection of E rosettes and of activated rosettes was carried out according to the classical method. The mean percentage of total T lymphocytes was found lower in silicosis (62 +/- 2% statistically significant for p < 0.05), compared to the control group (66 +/- 4.6%). The study revealed a decrease of T helper lymphocytes, an increase of T suppressor/cytotoxic lymphocytes and a decrease of the T helper/T suppressor ratio (1.96 +/- 0.13) in silicosis as compared to the control group (2.83 +/- 0.31). The presence of these changes in silicotic patients suggested the participation of cell-mediated immunity in the pathogenesis of disease, the cell mediated immunity being directly responsible for the evolution of silicosis.

Antineutrophil cytoplasm antibodies in patients with silicosis.

The presence of antineutrophil cytoplasm antibodies (ANCA) was followed up in silicosis with or without renal involvement. From the 68 patients with silicosis, 5 presented renal involvement. Of these 3 showed the presence of pANCA. The other 63 patients without renal involvement presented cANCA only in 2 cases. The control group showed no presence of ANCA. The incidence of ANCA in silicosis with renal involvement was discussed in view of an eventual elucidation of the pathogenesis of this disease, which was frequently associated with autoimmunity diseases.

Study of lung antibodies in patients with silicosis.

The presence of lung antibodies was determined in a group of 68 patients with silicosis in various stages of evolution and in a control group of 35 healthy subjects, by the standard indirect immunofluorescent technique with fluorescent conjugate anti human gammaglobulin and monospecific fluorescent conjugates anti human IgG, IgA and IgM. In the group of patients investigated, lung antibodies were detected by means of fluorescent conjugate anti human gammaglobulin, in 47 cases of the 68 examined. As regards the investigations using monospecific fluorescent conjugates it was observed that all the 47 patients presented lung antibodies of the IgG class, 32 presented lung antibodies of the IgA class and 15 presented lung antibodies of the IgM class. The presence of lung antibodies in silicotic patients suggests the participation of acquired humoral immunity in the pathogeny of disease without, however, being directly responsible for the evolution of disease. The association of silicosis with various other autoimmune diseases pleads for the existence of an immune component in the evolution of this pneumoconiosis.

The role of certain immunologic parameters in silicosis.

The paper presents some possibilities of estimating the immunologic aggression in silicosis in a group of 68 patients divided into three subgroups according to the evolutive stage of disease. The results were compared with the data obtained in a control group of 35 clinically healthy subjects not subjected to respiratory noxae. Parameters such as the immunogram (IgG, IgA IgM, IgD), the C3 complement, the circulating immune complexes (CIC) and the C reactive protein (CRP) were investigated using classical immunochemical methods. It was observed that the immunoglobulin titer presented a polyclonal increase. The mean values of C3 complement decreased in stages I and II of disease. The CIC level presented high mean values unrelated to the stage of the disease. The incidence of CRP was found high in stage III. It was demonstrated that there is no significant correlation between the humoral immunologic abnormalities and the radiologic changes or the depression of the pulmonary functional test. These changes suggest that the humoral immunologic abnormalities are not directly responsible for the lung changes in silicosis and cannot be used as a predictive indicator of the severity of the disease or of its progress. The data obtained showed a hyperreactivity of the humoral mediated immunity over the whole course of the disease thus supporting the assumption of an immunopathogenic mechanism in this disease.

Demonstration of the neutrophil granulocyte functional capacity in silicosis, using the NBT test.

The functional capacity of neutrophils was studied using the NBT test in 68 patients with silicosis in various evolutive stages, comparatively with a group of 35 controls. The NBT test showed an initial increase of nonspecific cellular reactivity which decreased as the disease evolved. The results in the control group showed 9 +/- 5% NBT positive neutrophils. The highest proportion of NBT positive neutrophils (17.6 +/- 2.3, p < or = 0.05) was found in stage I of the disease and then decreased gradually with the evolution of the disease. The proportion of NBT positive neutrophils may be considered as a biochemical marker of neutrophil functionality.

Comparative study of the variations of the phagocytic capacity of polymorphonuclear leukocytes and of total plasma antioxidants in patients with pneumoconioses and lung cancer.

A comparative, preliminary study of the phagocytic capacity of polymorphonuclear leukocytes, and of the total plasma antioxidants was carried out in a group of workers professionally exposed to mineral dusts and in a group of patients with lung cancer. Both groups exhibited advanced respiratory failure stages II and III. The phagocytic capacity of polymorphonuclear leukocytes was found significantly increased in workers with pneumoconioses and moderately increased in patients with lung cancer. On the other hand, the peroxides and total plasma antioxidants exhibited great individual variations. Thus in lung cancer it was observed that peroxides had a tendency to decrease and antioxidants to increase. The individual study of the variations of these three parameters might be able to differentiate the reversible from the irreversible stages of the respiratory changes.

Relationship between the lead concentration in hair and occupational exposure.

The lead content of hair in workers occupationally exposed was correlated with the blood lead concentration. Determinations of lead in blood and hair were performed by electrothermal atomic absorption spectrophotometry in two exposed groups and a control group. A significant correlation was observed between the blood lead and hair lead concentrations, and a regression analysis showed an exponential accumulation of the lead content in hair, simultaneously with the increase of the values in blood. The colour of the hair and the age of the subject did not influence the lead accumulation in hair in the occupationally exposed subjects. The assessment of lead in hair is considered a useful screening test in estimating occupational exposure.