Electron microscopic study of contactual interaction of sensitized lymphocytes with homologous target cells

When the lymph node cells sensitized by Ehrlich ascites tumor were mixed and cultured with JTC-ll cells derived from Ehrlich ascites tumor, the interaction of the two cell groups exhibited a contactual phenomenon accompanied by the destruction of JTC-ll cells. These two cell groups in contact were fixed with OsO4, solution and the ultra-thin sections were observed in the electron microscope. As a result the following findings were obtained. In the interaction where lymph node cells become attached to JTC-ll cells, resulting in the destruction of JTC-ll cells, lymphnode cells were also destroyed. Effector cells seem to be a kind of cells in the lymph nodes, and from their morphological characteristics they are considered to be lymphocytes. Electron microscopic observations of the surface of contact revealed the following: some cells are adhered to one another at the surfaces of the cell membranes that run in parallel; some are in contact by means of filamentous projection of lymhocytes; the cell membranes of the two cells form interdigitation; and both surfaces of two cell membranes are disrupted at the point of contact and the cytoplasm of the two cells appears to be directly connected with one another.</p

Expression of thyroglobulin on follicular dendritic cells of thyroid mucosa-associated lymphoid tissue (MALT) lymphoma

Reportedly, thyroid mucosa-associated lymphoid tissue (MALT) lymphoma is closely associated with Hashimoto's thyroiditis. However, it remains unknown which antigen is closely associated with thyroid MALT lymphoma. We examined whether B cell response to thyroglobulin (Tg), which is a common thyroid-specific autoantigen, is related etiologically to the pathogenesis of thyroid MALT lymphoma. Expression of human Tg antigens and Cluster of differentiation (CD) 35 was examined immunohistochemically in 15 cases of thyroid MALT lymphoma using paraffin-embedded, formalin-fixed tissue specimens. In all cases of thyroid MALT lymphoma, human Tg was detected immunohistochemically in the follicular epithelial cells and follicular dendritic cells (FDCs). These FDCs were positive by double immunostaining for anti-human Tg rabbit polyclonal antibody (Ab) and for CD35. Results showed that the Tg, a thyroid autoantigen, had immunostained the germinal center of the thyroid MALT lymphoma. The Tg was present in the FDCs, as revealed by the staining pattern of the germinal center;this fact was confirmed by double immunostaining of anti-human Tg mouse monoclonal Ab and anti-CD35 mouse monoclonal Ab. The results of our study suggest that Tg is an autoantigen that is recognized by thyroid MALT lymphoma cells.</p

Cancer immunotherapy with surgery

With the recent advances in the immunological surveillance system, an understanding of the role of host immunity has become essential to the management of carcinogenesis, tumor proliferation, recurrence and metastasis. Although it is important to continue chemical and surgical treatment of cancer, support of the anti-tumor immune system of the host should also be considered. Long term remission has been reported in leukemia by treating with BCG after chemotherapy whereas surgical treatment is usually more effective in preventing cancer recurrence in digestive organ cancer. The first step is extirpating the tumor as thoroughly as possible and the second step is chemo-immunotherapy. Cancer immunity, however weak, constitutes the basis for other treatments in selectively attacking cancer cells remaining after surgery, chemotherapy or irradiation. Immunotherapy should thus not replace chemotherapy or radiotherapy, but these methods should be employed in combination to attain more favorable results.</p

Calculating confidence intervals for impact numbers

BACKGROUND: Standard effect measures such as risk difference and attributable risk are frequently used in epidemiological studies and public health research to describe the effect of exposures. Recently, so-called impact numbers have been proposed, which express the population impact of exposures in form of specific person or case numbers. To describe estimation uncertainty, it is necessary to calculate confidence intervals for these new effect measures. In this paper, we present methods to calculate confidence intervals for the new impact numbers in the situation of cohort studies. METHODS: Beside the exposure impact number (EIN), which is equivalent to the well-known number needed to treat (NNT), two other impact numbers are considered: the case impact number (CIN) and the exposed cases impact number (ECIN), which describe the number of cases (CIN) and the number of exposed cases (ECIN) with an outcome among whom one case is attributable to the exposure. The CIN and ECIN represent reciprocals of the population attributable risk (PAR) and the attributable fraction among the exposed (AF(e)), respectively. Thus, confidence intervals for these impact numbers can be calculated by inverting and exchanging the confidence limits of the PAR and AF(e). EXAMPLES: We considered a British and a Japanese cohort study that investigated the association between smoking and death from coronary heart disease (CHD) and between smoking and stroke, respectively. We used the reported death and disease rates and calculated impact numbers with corresponding 95% confidence intervals. In the British study, the CIN was 6.46, i.e. on average, of any 6 to 7 persons who died of CHD, one case was attributable to smoking with corresponding 95% confidence interval of [3.84, 20.36]. For the exposed cases, the results of ECIN = 2.64 with 95% confidence interval [1.76, 5.29] were obtained. In the Japanese study, the CIN was 6.67, i.e. on average, of the 6 to 7 persons who had a stroke, one case was attributable to smoking with corresponding 95% confidence interval of [3.80, 27.27]. For the exposed cases, the results of ECIN = 4.89 with 95% confidence interval of [2.86, 16.67] were obtained. CONCLUSION: The consideration of impact numbers in epidemiological analyses provides additional information and helps the interpretation of study results, e.g. in public health research. In practical applications, it is necessary to describe estimation uncertainty. We have shown that the calculation of confidence intervals for the new impact numbers is possible by means of known methods for attributable risk measures. Therefore, estimated impact numbers should always be complemented by appropriate confidence intervals