Biomedical subjects

R H Van Oers

Publications and source records attributed to R H Van Oers.

3 recordsLinked to original sources

PubMed2001

Management of AIDS-related non-Hodgkin's lymphomas.

The incidence of non-Hodgkin's lymphoma in individuals infected with HIV is approximately 60- to 100-fold increased over the general population. The majority of patients with AIDS-related lymphoma (ARL) present with stage III-IV disease and with B-symptoms. They often have multiple extranodal localisations, with a high incidence of central nervous system involvement. Histologically, most tumours are either diffuse large cell lymphomas or Burkitt lymphomas. Several factors, such as disrupted immune surveillance, Epstein-Barr virus infection, chronic antigenic stimulation, cytokine dysregulation and the acquisition of genetic lesions, are thought to contribute to the pathogenesis. Patients with ARL have a poor prognosis: overall survival ranges from 1.5 to 18 months. The most important adverse prognostic factors are poor performance status, a low CD4+ cell count and a history of opportunistic infections. Results of treatment with polychemotherapy compare unfavourably to results in patients without HIV infection. Since the advent of highly active antiretroviral therapy (HAART), there appears to be a decrease in the incidence of ARL. In addition, the use of HAART in combination with chemotherapy and the use of new treatment modalities may improve the outcome of this disease.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1996

Antigen receptor function in chronic lymphocytic leukemia B cells.

Functional studies revealed that two groups of B chronic lymphocytic leukemia (B-CLL) can be distinguished based on their capacity to mount a proliferative response following B-cell antigen receptor (BCR) cross-linking. The molecular basis for the functional distinction between these B-CLL groups most probably resides within or proximal to the BCR since non-responsive B-CLL, in marked contrast to responsive B-CLL, do not respond to BCR ligation with tyrosine phosphorylation of cellular substrates and increases in the free intracellular [Ca++]. Detailed biochemical analysis showed overall structural identity between responsive and non-responsive B-CLL with respect to both transmembrane and intracellular associates of the BCR complex. However expression levels of the protein tyrosine kinase syk, which is a key enzyme for the early signalling through the BCR, were found to be markedly lower in non-proliferating B-CLL. Here we will review current functional and biochemical data on responding and non-responding B-CLL and discuss the relevance of these findings for disease progression and our insight into the immunobiology of B-CLL.

Cell Division↗

PubMed1989

The influence of cyclosporin A on the alternative pathways of human T cell activation in vitro.

To gain further insight into the mechanism of action of the immunosuppressant cyclosporin A (CyA), we investigated the influence of CyA on proliferative responses of human T lymphocytes, induced via different membrane molecules. As was previously shown, activation of T cells via the T cell receptor (Ti)/CD3 complex with an anti-CD3 monoclonal antibody was inhibited by CyA. Likewise, triggering of T lymphocytes via the alternative, CD2(T11)-mediated pathway of activation was strongly inhibited. In contrast, responses induced by phorbol myristate 13-acetate (PMA; 100 ng/ml) or the combination of an anti-CD28 monoclonal antibody and a suboptimal concentration of PMA (1 ng/ml) were found to be insensitive to CyA. CyA-induced inhibition of both anti-CD3- and anti-CD2-mediated proliferation could not be reversed by addition of either PMA (1 ng/ml) or anti-CD28. An increase in the intracellular free Ca2+ concentration [( Ca2+]i) is an early event observed after stimulation of T cells via CD3 or CD2, whereas stimulation with PMA and anti-CD28 does not lead to a rise in [Ca2+]i. This suggests that the inhibitory action of CyA is related to Ca2+-dependent signaling pathways. Since we observed that CyA does not interfere with anti-CD3- or anti-CD2-induced increases of [Ca2+]i, our data suggest that CyA-mediated inhibition is related to a later event in these intracellular signaling pathways.

Antibodies, Monoclonal↗