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Biomedical subjects

A H Rook

Publications and source records attributed to A H Rook.

At least 19 recordsLinked to original sources
PubMed2005

Multi-gene epigenetic silencing of tumor suppressor genes in T-cell lymphoma cells; delayed expression of the p16 protein upon reversal of the silencing.

To understand better T-cell lymphomagenesis, we examined promoter CpG methylation and mRNA expression of closely related genes encoding p16, p15, and p14 tumor suppressor genes in cultured malignant T-cells that were derived from cutaneous, adult type, and anaplastic lymphoma kinase (ALK)-expressing T-cell lymphomas. p16 gene was epigenetically silenced in all but one of the 10 malignant T-cell lines examined, p15 gene silenced in roughly half of the lines, and p14 was the least frequently affected. Extensive methylation of the p16 promoter was seen in six out of 10 cutaneous T-cell lymphoma patient samples and corresponded with lack of p16 protein expression in the cases examined. Treatment of cultured T-cells with the DNA methyltransferase inhibitor, 5-aza-2-deoxy-cytidine, resulted in reversal of the p16 gene silencing. However, expression of p16 protein was delayed in relationship to p16 promoter demethylation and required up to 3 weeks to occur, seemingly reflecting late activation of the p16 gene. These findings indicate that epigenetic silencing affects in T-cell malignancies, often simultaneously, several tumor suppressor genes that impact on key cell functions. The observed differential silencing of p16 and p14, and to a lesser degree p15 gene, indicates that the silencing is governed by precise, promoter region-specific mechanisms. The study provides also further rationale for treatment of at least some types of T-cell lymphomas with DNA methyltransferase inhibitors to target the epigenetically silenced tumor suppressor genes.

Adult↗
PubMed2002

Identification of amplified clonal T cell populations in the blood of patients with chronic graft-versus-host disease: positive correlation with response to photopheresis.

Chronic graft-versus-host disease (cGVHD) is a multiorgan disorder with skin manifestations resembling scleroderma. Since photopheresis, a treatment that induces an anticlonotypic immune response, has proven to be effective in both cutaneous T cell lymphomas with circulating clonal T cells and in cGVHD, we have searched for circulating clonal T cell populations in patients with cGVHD, and determined whether T cell clonality in the blood is associated with therapeutic response. We screened blood samples from 27 patients after HLA-matched allogeneic bone marrow transplantation (allo-BMT), 10 without cGVHD and 17 with extensive cGVHD, for clonal T cell receptor gamma (TCR gamma) gene rearrangements using fluorescent-based polymerase chain reaction (PCR) and automated high-resolution capillary electrophoresis. Amplified populations of clonal T cells with unique TCR gamma gene rearrangements were found in six of 10 (60%) allo-BMT patients without cGVHD and 13 of 17 (76.5%) allo-BMT patients with cGVHD (P = 0.41), as compared to none of 10 (0%) healthy controls. Twelve patients with cGVHD were treated by photopheresis, and the presence of amplified populations of clonal T cells was found to be associated with a cutaneous response to photopheresis, as eight of eight (100%) clone-positive vs none of four (0%) clone-negative patients experienced a clinically significant cutaneous response to treatment (P = 0.001). Our findings suggest that patients with cGVHD that have detectable expanded clonal T cell populations in their peripheral blood, may be more likely to respond to treatment by photopheresis.

Adult↗
PubMed2001

Identification of clonal T cells in the blood of patients with systemic sclerosis: positive correlation with response to photopheresis.

OBJECTIVES: To search for circulating clonal T-cell populations in patients with systemic sclerosis (SSc), and to determine whether T-cell clonality in the blood predicts therapeutic response to photopheresis. DESIGN: Analysis of clonal T-cell receptor gamma gene rearrangements before photopheresis treatment and blinded clinical evaluation of cutaneous response to photopheresis in a case series. SETTING: University hospital setting. PATIENTS: Thirteen consecutive patients with SSc. INTERVENTIONS: Photopheresis in 11 patients. MAIN OUTCOME MEASURES: Clonality of T cells in the blood before photopheresis and clinical response to photopheresis. RESULTS: Screening of blood samples from 13 SSc patients for clonal T-cell receptor gamma gene rearrangements revealed a monoclonal T cell population in 6 (46%) of 13 SSc patients. Clinical response to photopheresis in 11 patients was evaluated in a blinded manner using skin severity scores. Clonality of T cells appeared to be associated with a higher chance of response to photopheresis therapy, as 4 (67%) of 6 patients in the clone-positive group vs 1 (20%) of 5 in the clone-negative group experienced a clinically significant response to treatment. CONCLUSIONS: A high proportion of patients with SSc have detectable expanded clonal T-cell populations in the peripheral blood, and such patients appear more likely to respond to photopheresis.

Adult↗
PubMed2001

Successful reversal of severe refractory cardiac allograft rejection by photopheresis.

We treated 4 patients with refractory International Society of Heart and Lung Transplantation Grades IIIA to IV cardiac allograft rejection with extracorporeal photopheresis. Following treatment on 2 consecutive days, 3 patients demonstrated complete histologic reversal of rejection. The remaining patient improved more gradually, but manifested complete cessation of rejection following three 2-day treatments. We conclude that photopheresis is a safe and effective modality for the treatment of severe refractory cardiac allograft rejection and that these results support the use of photopheresis in this clinical setting.

Adult↗
PubMed2001

Dysregulation of lymphocyte interleukin-12 receptor expression in Sézary syndrome.

Initial phase I and II clinical trials with recombinant human interleukin-12 have demonstrated the therapeutic efficacy of this cytokine in early stage cutaneous T cell lymphoma as compared with more advanced stages such as the leukemic Sézary syndrome. In an effort to optimize the use of recombinant human interleukin-12, using flow cytometry we studied the regulation of the interleukin-12 receptor beta1 (high affinity chain) and beta2 (chain necessary for interleukin-12 signal transduction) on normal volunteer CD4+ and CD8+ T cells and CD4+ and CD8+ cells from eight patients with different degrees of leukemic involvement with Sézary syndrome. The beta1 chain was not readily detectable on resting normal and T cells from Sézary patients, but expression was induced following T cell activation with phytohemagglutinin. Similarly, the beta2 chain was not detectable on resting normal volunteer T cells, but could be induced following phytohemagglutinin stimulation. Moreover, the beta2 chain on normal volunteer T cells was markedly upregulated following short-term culture with interferon-gamma or recombinant human interleukin-12. CD8+ T cells routinely exhibited a greater expression of beta2 than did CD4+ T cells. In marked contrast, both CD4+ and CD8+ T cells from patients with Sézary syndrome and a high tumor cell burden (> 50% circulating atypical Sézary T cells) failed to express the beta2 chain under any culture conditions. Although, culture with anti-interleukin-10 also markedly increased beta2 expression on normal volunteer T cells, this failed to induce expression on either CD4+ or CD8+ T cells from Sézary patients and a high tumor burden. Investigation of patients with Sézary syndrome and a low tumor cell burden (< 15% circulating Sézary T cells) revealed a pattern of beta2 expression that was intermediate between advanced Sézary syndrome and normal volunteers. Both CD4+ and CD8+ peripheral blood T cells from these earlier stage patients were induced to express the beta2 chain, although at a lower frequency of positivity than T cells from normals, following culture with phytohemagglutinin, interferon-gamma, recombinant human interleukin-12, or anti-interleukin-10. These results indicate that short-term culture with interferon-gamma and recombinant human interleukin-12 potently upregulates beta2 chain expression on T cells from normal volunteers, whereas a similar, but less marked effect occurs on T cells from Sézary syndrome patients and a low circulating tumor cell burden. In contrast, the beta2 chain appears to be suppressed on both CD4+ and CD8+ T cells from Sézary patients with a heavy circulating tumor cell burden and it is not induced by interferon-gamma or recombinant human interleukin-12. Therefore, recombinant human interleukin-12 is likely to be most effective for early stage cutaneous T cell lymphoma due to a greater display of beta2 receptors on responding CD8+ anti-tumor cytotoxic T cells.

Antibodies↗
PubMed2001

Increased interleukin 5 production in eosinophilic Sézary syndrome: regulation by interferon alfa and interleukin 12.

BACKGROUND: Peripheral eosinophilia occurs in a small subpopulation of patients with cutaneous T-cell lymphoma (CTCL) and denotes a poor prognosis. Clinical studies have suggested that the Sézary cell is a T(H)2 type helper T cell that produces cytokines that enhance the differentiation and activation of eosinophils. Interferon alfa (IFN-alpha) and interleukin 12 are effective therapeutic agents for CTCL and other hematologic disorders. OBJECTIVE: Our purpose was to determine the inhibitory activity of IFN-alpha and IL-12 on IL-5 production in vitro by peripheral blood mononuclear cells (PBMCs) obtained from patients with CTCL and eosinophilia. METHODS: Suppression of IL-5 production by IFN-alpha and IL-12 was assessed by comparing IL-5 production by PBMCs from patients with Sézary syndrome and eosinophilia when cultured alone or in the presence of either IFN-alpha or IL-12. RESULTS: A marked increase in IL-5 production by PBMCs from patients with Sézary syndrome and eosinophilia was observed. IL-5 production was markedly reduced when PBMCs were exposed to IFN-alpha or IL-12. CONCLUSION: These results suggest that IFN-alpha and perhaps IL-12 may produce a therapeutic response in patients with CTCL and eosinophilia through direct suppression of IL-5 production by malignant Sézary cells.

Cells, Cultured↗
PubMed2001

Complete molecular remission during biologic response modifier therapy for Sézary syndrome is associated with enhanced helper T type 1 cytokine production and natural killer cell activity.

BACKGROUND: Cutaneous T-cell lymphoma (CTCL) is a clonally derived, skin-invasive malignancy of CD4(+) T lymphocytes with the phenotype of mature helper T cells. Advancing stages of CTCL are associated with depressed cell-mediated immunity, increased production of T helper type 2 cytokines and decreased levels of T helper type 1 cytokines. OBJECTIVE: Our purpose was to evaluate the cytokine secretion pattern and cell-mediated cytotoxicity in peripheral blood mononuclear cells of patients with Sézary syndrome in relation to the presence of the malignant clone. METHODS: Serial polymerase chain reaction for the T-cell receptor-beta or T-cell receptor-gamma gene rearrangement was used to determine the presence of the malignant clone. Enzyme-linked immunosorbent assays were used to determine the levels of interleukin 4 and interferon gamma produced by the peripheral blood mononuclear cells from the patients with Sézary syndrome. RESULTS: We demonstrate 3 cases of Sézary syndrome with typically suppressed cell-mediated cytotoxicity, elevated production of interleukin 4, and depressed production of interferon gamma by their peripheral blood mononuclear cells before institution of therapy with biologic response modifier therapy. In all 3 cases after clinical and molecular remission, we observed striking immunologic changes, including an increase in levels of natural killer cell activity and interferon gamma production and decreased production of interleukin 4. CONCLUSIONS: The observation that the cytokine secretion pattern by peripheral blood mononuclear cells from 3 patients with Sézary syndrome normalized with the disappearance of the malignant clone from the peripheral blood suggests that the malignant T cells account for the aberrant cytokine production. Moreover, the aberrant cytokine production may be the cause for suppression of cell-mediated immunity seen in advancing stages of CTCL.

Aged↗
PubMed2001

Regression of multifocal, skin-restricted, CD30-positive large T-cell lymphoma with interferon alfa and bexarotene therapy.

We report the case of a 43-year-old male patient with persistent multifocal, skin-restricted, CD30-positive, large T-cell lymphoma. Combination therapy of systemic interferon alfa and oral bexarotene was initiated on an experimental basis in the hope of circumventing therapies such as methotrexate, radiotherapy, or multiple-agent chemotherapy that may be required in such cases. This treatment was associated with rapid and marked regression of the patient's cutaneous lesions.

Administration, Oral↗
PubMed2001

The role for interleukin-12 therapy of cutaneous T cell lymphoma.

Recent phase I and phase II trials using recombinant human interleukin-12 (rhIL-12) for cutaneous T cell lymphoma (CTCL) have been completed. Observations on 32 evaluable patients revealed an overall response rate approaching 50 percent. Biopsy of regressing lesions revealed an increase in numbers of CD8+ and/or TIA-1+ T cells. These results suggest that rhIL-12 may induce lesion regression by augmenting antitumor cytotoxic T cell responses. Future trials will be focused on strategies for further immune enhancement by the concomitant use of additional immune augmenting cytokines with rhIL-12.

Antigens, Differentiation, T-Lymphocyte↗
PubMed2001

Therapeutic advances in biological response modifiers in the treatment of cutaneous T-cell lymphoma.

Cutaneous T-cell lymphoma (CTCL) is most often a skin-infiltrating malignancy of clonal CD4+ T-cells. Therapy is based on staging and the likelihood of progression. Biological response modifiers and chemotherapeutic agents are used to preserve the integrity of the host antitumour response while selectively targeting the malignant cells. The biological response-modifying treatment options currently used to treat CTCL are bexarotene, denileukin diftitox, interferon-alpha, interferon-gamma and interleukin-12, as well as extracorporeal photopheresis and phototherapy. A combination therapy approach maximises response in patients with advanced CTCL. Biological response modifiers in combination with photopheresis are used for patients with the leukaemic phase of the disease. Among the majority of patients with advanced stage disease so treated, immune response augmentation appears to prolong survival. Future areas of research should assess not only survival and optimal treatment combinations, but also quality of life during the treatment period.

Bexarotene↗
PubMed2000

Chlamydia pneumoniae inhibits apoptosis in human peripheral blood mononuclear cells through induction of IL-10.

Chlamydia pneumoniae is a common cause of pulmonary infection, with serum positivity in at least 50% of the general population. In this study, we report that human PBMCs exposed to C. pneumoniae are resistant to apoptosis induced by the potent photoactivated chemotherapeutic agents 8-methoxypsoralen and hypericin. In contrast, PBMCs treated with a heat-inactivated inoculum exhibit normal susceptibility to apoptosis. We also observed that human PBMCs are responsive to C. pneumoniae infection by secretion of key immune regulatory cytokines, including IL-12 and IL-10. While IL-12 may play an important role in limiting C. pneumoniae proliferation within cells, IL-10 serves an anti-inflammatory function by down-regulating proinflammatory cytokines such as IL-12 and TNF-alpha. Depletion of endogenous IL-10, but not of IL-12, abolished the apoptosis resistance of C. pneumoniae-infected PBMCs. Furthermore, addition of exogenous IL-10, but not IL-12, significantly increased the resistance of control inoculum-treated PBMCs to photoactivated 8-methoxypsoralen- and hypericin-induced apoptosis. Therefore, we conclude that C. pneumoniae possesses an antiapoptotic mechanism. The resistance to apoptosis observed in PBMCs exposed to C. pneumoniae is due, at least partially, to the IL-10 induced during C. pneumoniae infection.

Anthracenes↗
PubMed2000

Successful reversal of recalcitrant hepatic allograft rejection by photopheresis.

Extracorporeal photopheresis (ECP) is an immunologic modality that has shown efficacy in the treatment of clonal T-cell diseases, including Sézary syndrome and allograft rejection. In this case report, we expand on this observation to include recalcitrant hepatic allograft rejection. A 14-year-old boy with hepatic allograft rejection refractory to high-dose corticosteroid and lymphocytolytic therapy was treated with 4 sessions of ECP over a 6-week period. After 2 sessions, a liver biopsy showed complete reversal of acute cell-mediated rejection. No opportunistic infections or other adverse events were noted. Photopheresis appears to be a safe and effective modality for the treatment of refractory hepatic allograft rejection.

Adolescent↗
PubMed1999

Depressed IL-12-mediated signal transduction in T cells from patients with Sézary syndrome is associated with the absence of IL-12 receptor beta 2 mRNA and highly reduced levels of STAT4.

Sézary syndrome (SS) is the leukemic phase of cutaneous T cell lymphoma characterized by the proliferation of clonally derived CD4+ T cells that release cytokines of the Th2 T cell phenotype (IL-4, IL-5, IL-10), whereas Th1 T cell cytokines (IL-2, IFN-gamma) are markedly depressed as is expression of IL-12, a pivotal cytokine for Th1 cell differentiation. Normal Th1 cells express both the beta 1 and beta 2 chains of the IL-12 receptor (IL-12R) and tyrosine phosphorylate STAT4 in response to IL-12. Th2 T cells express only the IL-12R beta 1 and thus do not tyrosine phosphorylate STAT4 in response to IL-12. To determine whether SS cells are Th2-like at the level of IL-12 signal transduction, we analyzed RNA from seven patients for the presence of message for the IL-12R beta 1 and beta 2 genes using RNase protection assays and assessed whether IL-12 induced tyrosine-phosphorylation of STAT4 by immunoblotting. In PBL from six of seven SS patients tested, beta 2 message was expressed at low to undetectable levels and its expression could not be stimulated by either IFN-alpha or IFN- gamma, which stimulated beta 2 expression in control PBL. The absence of beta 2 expression is further supportive evidence for the Th2 lineage of SS cells. However, unlike normal Th2 cells, SS cells also showed severely reduced levels of STAT4, suggesting that they have a depressed response to any inducer of the STAT4 signal transduction pathway, including IFN-alpha. This is the first observation linking STAT4 gene expression with a human disease and suggests that dysregulation of STAT4 expression may be significant to the development and/or progression of SS.

CD8-Positive T-Lymphocytes↗
PubMed1999

Interleukin-12 therapy of cutaneous T-cell lymphoma induces lesion regression and cytotoxic T-cell responses.

Progression of cutaneous T-cell lymphoma (CTCL) is associated with profound defects in cell-mediated immunity and depressed production of cytokines, which support cell-mediated immunity. Because we have observed marked defects in interleukin-12 (IL-12) production in CTCL and because IL-12 is critical for antitumor cytotoxic T-cell responses, we initiated a phase I dose escalation trial with recombinant human IL-12 (rhIL-12) where patients received either 50, 100, or 300 ng/kg rhIL-12 twice weekly subcutaneously or intralesionally for up to 24 weeks. Ten patients were entered: 5 with extensive plaque, 3 with Sezary syndrome, and 2 with extensive tumors with large cell transformation. One patient with Sezary syndrome dropped out after 1 week for personal reasons. Subcutaneous dosing resulted in complete responses (CR) in 2 of 5 plaque and partial responses (PR) in 2 of 5 plaque, and 1 of 2 Sezary syndrome (overall response rate CR+PR 5 of 9, 56%). A minor response also occurred in 1 of 5 plaque patients. Intralesional dosing resulted in individual tumor regression in 2 of 2 patients. Biopsy of regressing lesions showed a significant decrease in the density of the infiltrate in all cases and complete resolution of the infiltrate among those with clinical lesion resolution. An increase in numbers of CD8-positive and/or TIA-1-positive T cells were observed on immunohistochemical analysis of skin biopsy specimens obtained from regressing skin lesions. Adverse effects of rhIL-12 on this regimen were minor and limited and included low-grade fever and headache. One patient discontinued rhIL-12 at week 6 because of depression. These results suggest that rhIL-12 may augment antitumor cytotoxic T-cell responses and may represent a potent and well-tolerated therapeutic agent for CTCL.

Adult↗
PubMed1999

Extracorporeal photochemotherapy does not suppress T- or B-cell responses to novel or recall antigens.

BACKGROUND: Extracorporeal photopheresis (ExP) is an effective therapy for several conditions including cutaneous T-cell lymphoma, scleroderma, and allograft rejection. Experimental animal models suggest that ExP may induce antigen-specific immunosuppression. OBJECTIVE: Our purpose was to determine the effect of photopheresis on humoral and cell-mediated immunity in human subjects. METHODS: Recall and primary immune responses of patients with scleroderma receiving monthly ExP treatments were assessed by delayed type hypersensitivity skin tests, T-cell proliferative responses after immunizations with tetanus toxoid and keyhole limpet hemocyanin, and serum antibody titers against common viral pathogens. RESULTS: After 6 months of ExP, viral antibody titers and delayed type hypersensitivity responses were not significantly different from baseline values in all 7 patients tested. T-cell responses to tetanus toxoid remained normal in 3 of 3 patients tested for a minimum of 6 months after booster immunization. Immunization with the protein antigen keyhole limpet hemocyanin after initiation of ExP therapy resulted in sustained T-cell proliferative responses up to 6 months in 3 of 3 patients. CONCLUSION: These results, along with the observation of no increased incidence of opportunistic infections or neoplasms, suggest that ExP is not broadly immunosuppressive and does not prevent primary responses to vaccination or other antigenic challenges.

Antibody Formation↗