Search

Disseminated histoplasmosis is an endemic systemic mycosis, caused by the dimorphic fungus Histoplasma capsulatum. The clinical manifestations depend on the inhaled fungal load, the immunological state of the patient and the virulence of the infecting fungal strain. The disseminated variant is most frequent in immunocompromised patients, with 90% of cases in patients with positive serology for HIV, In this series, 37 patients with diagnosis of HIV and disseminated histoplasmosis were evaluated. The 43.2% of the patients did not know their serology prior to the consultation due to histoplasmosis. The main clinical causes were impregnation syndrome (67.6%), fever (64.9%), respiratory symptoms (62.2%) and mucocutaneous manifestations (67.6%), among others. The 94.6% of the patients presented anemia, 75.7% had bicytopenia and 32.4% pancytopenia. The sensitivity of the blood cultures was 70.4%. The 86.5% of the patients did not have another opportunistic infection concomitant at the time of diagnosis. In 83.8% of patients, disseminated histoplasmosis was the first AIDS disease. A mortality of 14.7% was recorded.

The authors describe an enzymo-immunologic method of determination of the class of rheumatoid factors (RF). This technic includes 3 main stages : 1) extraction of RF by fixation on aggregated rabbit IgG previously adsorbed on the walls of a plastic tube; 2) recognition of RF linked to the solid phase by anti-IgG addition, and addition of human IgA and IgM linked to glucose oxidase; 3) revelation of the enzyme activity linked to the solid phase : this enzyme activity directly depends on the levels of RF to be estimated. The results are expressed as a percentage of the fixation of a reference serum obtained from a patient with rheumatoid arthritis (RA). This serum presents an antiglobulin activity in the 3 major classes of immunoglobulins. The coefficients of variation of intra- and intersystem reproductibility lay between 5,6 and 17.8%. The specificity of the estimation was controlled by the localisation of the antiglobulin activity of the sera after chromatography on Sephadex G200 and by estimation of RF after their absorption by an aggregated IgG immunoadsorbant. This technic was applied to the identification of RF in RA (90 cases); in diseases not related to RA and in control subjects : the sensitivity of this method appears greater than that of technics previously described (immuno-fluorescence, Rose-Waaler reaction) in fact, only 12,2% of sera of patients with RA remain negative with this new test. However, this greater sensitivity does not seem to have altered the clinical specificity of the test : in fact, only 8,4% of the sera of patients with diseases unrelated to RA are positive by this method, which, moreover, may be explained by the age of these subjects (average age 71.5 years).

In a 69-year-old man admitted to hospital for shock with symptoms suggesting acute cor pulmonale, laboratory tests showed low proteinaemia associated with haemoconcentration. Vascular filling led to recovery, but the condition relapsed 6 months later, heralded by weight increase, swelling of the face and profuse swelling; the patient again recovered. On this last occasion, a monoclonal peak of IgG kappa thought to have antibody activity was discovered. These attacks of hypovolaemic shock seem to be due to sudden increases in capillary permeability.

Anti-rabbit IgG sheep gamma-globulins were covalently coupled to periodate oxidized microcrystalline cellulose using the Schiff reaction. Optimal conditions (sodium m-periodate concentration and gamma-globulin amount) were studied measuring the ability of this solid-phase antibody to bind glucose oxidase-labeled rabbit IgG.

The authors present a kit marketed by Abbott for searching HBs antigen by an immunological method. This technic of sandwich type included 3 stages. During a first stage, the HBs antigen eventually present was extracted from the biological fluid by a specific antibody adsorbed on a polystyrène bead. After washing, a second specific antibody labelled with peroxidase was added. After incubation and washing, the peroxidase activity of the bead was revealed by adding a chromogenic substrate. The development of a colour indicated the presence of HBs antigen in the biological fluid under study. Very simple to use, this kit permits specific detection of HBs antigen with a sensitivity comparable to that of radio-immunoassay. A good correlation was obtained with the radio-immunological kit Austria II and with the enzymo-immunological kit Hepanostika.

The authors describe a method of enzymo-immunological estimation of rheumatoid factor. This estimation, of non-competitive type, includes 3 stages : the rheumatoid factor is first extracted from the serum by fixation on the aggregated IgG linked to cellulose powder; then its presence is revealed by fixation of an oxidase IgG glucose conjugate on the solid phase; finally, the enzyme activity linked to the solid phase is measured. This activity is directly related to the concentration of rheumatoid factor present. The estimation, carried out on 2 050 patients including 114 with rheumatoid arthritis, is well correlated with technic of the Rose-Waaler reaction. Furthermore, the greater sensitivity, the better reproducibility and the quantitative character of this method might improve the supervision of patients with rheumatoid arthritis.