Sigma-S, a measure of reactive sulfur groups of immunoglobulin G, is a sensitive tumor marker discriminating different stages of breast cancer

Article Abstract:

While proteins may be though of as a long chain of amino acid residues (the primary structure), a protein molecule is invariably twisted into a particular shape as the result of atomic forces. Among the determinants of a protein's three-dimensional shape is the disulfide bond, in which sulfur atoms from two amino acids are covalently bound. Binding two amino acids from different parts of the molecule forces the molecular structure to bend. Many protein molecules contain such disulfide bonds, including antibody molecules. Antibodies of the G class, immunoglobulin G, have a relatively constant number of disulfide bonds to free sulfhydryl groups (-SH, a sulfur and hydrogen atom) in their molecular structures. The total amount of disulfide bonds and sulfhydryl groups (sigma-S) in immunoglobulin G (IgG) has now been found to correlate with the progression of breast cancer. In this study, the sigma-S of 132 patients with benign breast disease was 1.48. In 198 patients with breast cancer, the average sigma-S was 1.22. When the different stages of breast cancer were considered separately, the sigma-S values were 1.27, 1.23, 1.19, and 1.10 for Stages I, II, III, and IV, respectively, indicating a clear correlation between disease stage and the sigma-S measurement. The decrease in the sigma-S measurement appears to be due to the decrease in the number of disulfide bonds in the antibody molecules. The number of free sulfhydryl groups changes little. The measurement of sigma-S appears to indicate changes in the relative amounts of IgG subclass 1. Since the sulfide bonds are different on different IgG subclasses, a decrease in amount of IgG1 in the patient's blood will appear as a decrease in sigma -S by the present test. While the average sigma-S values indicate a trend, individual variation limits the usefulness of the sigma-S measurement as a diagnostic indicator. According to data from the present study, the sigma-S value would identify about 78 percent of cases of malignant breast disease. The specificity of the test is 61 percent, indicating that about 61 percent of patients without breast cancer will score a negative result on the test. (Consumer Summary produced by Reliance Medical Information, Inc.)

Breast cancer, Immunoglobulins, Tumor markers

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Peripheral blood lymphocytes of nonleukemic lymphoma patients exhibit aberrant expression of T-cell activation markers after polyclonal stimulation in vitro

Article Abstract:

Lymphoproliferative disorders, such as lymphomas, are often associated with impaired immune system function. Although numerous defects have been described, the actual mechanisms responsible for the impaired function are not known. Nevertheless, in cases of lymphoma, indications of such impaired function may serve both as an aid to diagnosis and a prognostic factor. To evaluate the possible value of immunological parameters as an early diagnostic aid, various lymphocyte responses and antigen activation were measured in 22 lymphoma patients, including those with Hodgkin's and non-Hodgkin's disease. Lectins, which are a class of sugar-binding proteins found in many plants, stimulate the reproduction of many normal lymphocytes, presumably by binding to sugar-containing proteins on the lymphocyte cell surface. The lectins may be used as an assay for the ability of lymphocytes to respond to a very general stimulus; because the stimulation results in mitosis, the assay is called a mitogenic assay. In 13 of 22 patients, this mitogenic response to the lectins phytohemagglutinin and concanavalin A was abnormal. However, the response to the lectin pokeweed mitogen was normal in 18 of the 21 patients studied. The cells from the lectin assays were also examined for the presence of activation antigens on their cell surfaces using fluorescent antibodies and the automated cytofluorograph. Curiously, the number of cells showing activation antigens was abnormal in all cases, including those which seemed to be normal in the mitogenic assay. The researchers failed to find evidence to support the belief that the immune impairment in lymphoma may result from an imbalance in the numbers of suppressor T cells and helper T cells. The results also demonstrate that the cytofluorimetric analysis of activation antigens is superior to the lectin mitogenic assay as a means of detecting impaired cellular immune responses in these patients. (Consumer Summary produced by Reliance Medical Information, Inc.)

Abnormalities, Lymphoproliferative disorders, Immunoproliferative disorders, Immunity, Immunity (Physiology), Lymphomas, Mitogens

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Life expectancy of patients with chronic nonleukemic myeloproliferative disorders

Article Abstract:

The term myeloproliferative disorders refers to a collection of four disorders involving the proliferation of bone marrow cells. The most well-known of these is the malignant chronic granulocytic leukemia, or CGL. The remaining three myeloproliferative syndromes are not leukemic; they are known as polycythemia vera (PV), idiopathic myelofibrosis (IMF), and essential thrombocythemia (ET). To evaluate the life expectancy of patients with a nonleukemic myeloproliferative disorder, that is, a myeloproliferative disorder other than CGL, a review of case records of 1,067 patients was undertaken. Of these patients, 454 had PV, 247 had ET, and 366 had IMF. The survival of patients with polycythemia vera and essential thrombocythemia was slightly under the curve for the population as a whole, but the difference was not statistically significant. The same was not true of the patients with idiopathic myelofibrosis. Patients with IMF had a significantly lower rate of survival. Of the 366 patients with IMF, 178 have died. In a general population of the same age and sex distribution, 109 deaths would have been expected in the same period. The data analysis indicates that only 10 percent of the IMF patients may be expected to be alive after 16 years, representing a dramatic reduction in life span. The authors suggest that new therapeutic approaches to idiopathic myelofibrosis are needed. (Consumer Summary produced by Reliance Medical Information, Inc.)

Prognosis, Myeloproliferative disorders, Myelofibrosis, Thrombocytosis, Polycythemia vera

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