Diagnostic immunology最新文献

Fifty-seven sera from 53 patients were assayed simultaneously on KB and HEp-2 cells and compared with regard to pattern and titer. Additionally, KB cell fluorescent antinuclear antibody (FANA) titer and pattern in 310 sera from 194 patients were compared with regard to the presence of antinative DNA antibodies (anti-nDNA ab) as determined by the Crithidia luciliae assay. Sixty-five percent (37/57) of the sera had the same titer on both KB and HEp-2 cells; the remainder had higher titers using KB cells. Regression analysis yielded a highly significant, unbiased correlation between the substrates. Forty-four percent (25/57) of these sera gave identical patterns on both substrates, another 25 of the 57 sera (44%) gave different patterns on the two substrates and 12% (7/57) could not be compared because they were negative on HEp-2 cells. KB cells detected positive FANA in 30 of 30 (100%) diagnosed cases of systemic lupus erythematosus; HEp-2 cells detected 29/30 (97%). From the standpoint of sensitivity, these data indicate a slight advantage to the use of KB over HEp-2 cells. Seventeen percent (53/310) of the sera were positive for anti-nDNA ab. The highest percentage of these positive sera occurs at reciprocal FANA titers between 320 and 1280. No association was found between KB FANA patterns and a positive Crithidia luciliae assay.

Antibodies against the major capsular polysaccharide of Cryptococcus neoformans, glucuronoxylomannan (GXM), and a minor secreted polysaccharide, galactoxylomannan (GalXM), were surveyed by indirect enzyme immunoassay (EIA) in patients with cryptococcosis, with other mycoses, and in normal controls. Measurement of IgG levels against GalXM revealed cross reactions in candidiasis patients that were reduced by adsorption with Candida albicans cell walls. Measurement of IgM levels were subject to fewer cross reactions. The combination of adsorption with C albicans cell walls and measurement of IgM detected antibodies in 12 of 55 cryptococcosis patients. An end point equal to or greater than a titer of 1/16 excluded reactions in normals and limited cross reactivity in candidiasis patients to below 7%. This test has potential diagnostic significance in cryptococcosis patients who show no evidence of cryptococcal antigen circulating in the cerebrospinal fluid or serum. Reactions in this IgM assay were not spuriously due to rheumatoid factor. The major capsular GXM was much less serologically active and was subject to cross reactions with agents of bacterial sepsis. The specificity of the GalXM is directed mainly by the mannose and to a lesser extent by galactosyl residues.

The exact nature of the immune defect in the acquired immune deficiency syndrome (AIDS) is not known. Most studies have focused on abnormal T-cell functions which occur in AIDS. Although polyclonal elevation of serum immunoglobulins is also consistently reported in AIDS, there have been no statistical studies measuring the isotypes (classes) comprising this hypergammaglobulinemia. Quantitative serum immunoglobulin levels of IgG, IgA, IgM, and IgD in patients with AIDS (n = 33) were compared to healthy homosexual (n = 71) and healthy heterosexual (n = 32) controls. Serum IgD levels are increased tenfold in AIDS compared to healthy heterosexuals, and threefold compared to healthy homosexuals. Serum IgA levels are increased more than twofold that of either control group. In contrast, the elevations of IgG and IgM are relatively small and show much greater overlap compared to controls. We conclude from a statistical analysis of the data that these elevations of IgD and IgA are characteristics of AIDS.

Immunodiagnostic tests for human protozoan and helminthic infections are reviewed. The need for immunodiagnostic tests varies with each infection but is of paramount importance in those infections that cannot be parasitologically diagnosed readily such as toxoplasmosis, pneumocystosis, Chagas' disease, trichinosis, hydatidosis, cysticercosis, and visceral larva migrans. Immunoassays are also needed for those worldwide highly prevalent infections with severe morbidity to be used in seroepidemiology and in the follow-up evaluation of control programs. The most important are malaria, schistosomiasis, onchocerciasis, lymphatic filariasis, and trypanosomiasis. Major advances have been made in the use of enzyme-linked immunosorbent assay (ELISA) as a practical and rapid test for use in endemic countries and in the identification and isolation of diagnostic parasite antigens aided in particular by the use of monoclonal antibodies. Development of immunodiagnostic tests for specific parasite antigens in body fluids for many infections is being actively pursued.

HLA Class II antigens (human la) are coded by Major Histocompatibility Complex and play important biological roles in health and disease. In this report we describe the generation and characterization of nine murine monoclonal antibodies (MoAbs) specific for determinants localized on the human la molecules. The reactivity of these MoAbs inferred from serological analysis along with the data obtained from biochemical characterization of the target structures allowed a classification of these reagents as monomorphic and polymorphic. Two monomorphic MoAbs, identifying different subsets of human la molecules, were studied in detail.

The effect of overnight storage, either at room temperature or at 4 degrees C, on total T cells, helper cells, suppressor cells, and HLA-DR-positive cells was determined by flow cytometry and fluoresceinated monoclonal antibodies on peripheral whole blood samples. No differences were noted in any of the subsets regardless of storage conditions when samples were analyzed within 24 hr.

Peripheral blood monocytes from 10 systemic lupus erythematosus (SLE) and 10 rheumatoid arthritis (RA) patients as well as from 24 controls were studied for such functions as phagocytosis, bactericidal capacity, iodination, and PGE2 production. Phagocytosis of opsonized erythrocytes, exploring only the Fc receptor, was increased in SLE and RA. Killing of Staphylococcus aureus was decreased in both SLE and RA in the presence of AB serum, but not in the presence of autologous serum. Iodination was, on the average, normal in SLE and elevated in RA. Prostaglandin E2 production was decreased in SLE (except with the highest concentration of Con A) and increased in RA. In SLE, functional alterations were more pronounced in clinically active than in inactive disease. These results show that in SLE and RA peripheral blood monocytes have alterations of their functions that are independent of serum factors. It is suggested that these abnormalities may be relevant to the pathogenetic mechanisms and evolution of these diseases.

A rapid, sensitive indirect immunofluorescence assay utilizing flow cytometry to detect immune-mediated thrombocytopenia is described. Fluorescein-conjugated F(ab')2 antihuman IgG or IgGAM is reacted with donor platelets after their incubation with test sera and the resulting immune complex is measured using flow cytometric analysis. With this technique excess of Ig on the platelet, expressed as a ratio of fluorescence of test sera/autologous control sera, was noted in 24 of 30 patients (80%) with immune thrombocytopenias caused by auto- or allo-antiplatelet antibodies. Twenty-four sera from nonimmune thrombocytopenic patients were consistently negative. This technique has the advantage of being highly reproducible and avoids the subjective interpretation inherent with manual immunofluorescence assays.