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Biomedical subjects

Mark Dybul

Publications and source records attributed to Mark Dybul.

10 recordsLinked to original sources
PubMed2003

Long-cycle structured intermittent versus continuous highly active antiretroviral therapy for the treatment of chronic infection with human immunodeficiency virus: effects on drug toxicity and on immunologic and virologic parameters.

We evaluated the effect of long-cycle structured intermittent therapy (SIT; 4 weeks without highly active antiretroviral therapy [HAART] followed by 8 weeks with HAART) versus continuous HAART. The study was prematurely terminated to new enrollment because of the emergence of genetic mutations associated with resistance to antiretroviral drugs in 5 patients. After 48 weeks, there was no significant difference between groups in lipid, hepatic transaminase, and C-reactive protein levels in 41 patients. Although there were no differences in CD4(+) or CD8(+) T cell counts or the percentage of cells that were CD4(+)CD25(+), CD8(+)CD25(+), or CD4(+)DR(+), patients who received SIT had a significantly higher percentage of CD8(+)CD38(+) and CD8(+)DR(+) cells. There was no clear autoimmunization effect by immunologic or virologic parameters. There was no benefit to long-cycle SIT versus continuous HAART with regard to certain toxicity, immunologic, or virologic parameters.

Alanine Transaminase↗
PubMed2003

Genetic characterization of rebounding human immunodeficiency virus type 1 in plasma during multiple interruptions of highly active antiretroviral therapy.

Various strategies of interrupting highly active antiretroviral therapy (HAART) are being investigated for the treatment of human immunodeficiency virus (HIV) infection. Interruptions of greater than 2 weeks frequently result in rebound of plasma HIV RNA. In order to discern changes in the viral population that might occur during cycles of treatment interruption, we evaluated the homology of HIV-1 envelope gene sequences over time in 12 patients who received four to seven cycles of 4 weeks off HAART followed by 8 weeks on HAART by using the heteroduplex tracking assay and novel statistical tools. HIV populations in 9 of 12 patients diverged from those found in the first cycle in at least one subsequent cycle. The substantial genetic changes noted in HIV env did not correlate with increased or decreased log changes in levels of plasma HIV RNA (P > 0.5). Thus, genetic changes in HIV env itself did not contribute in a systematic way to changes in levels of plasma viremia from cycle to cycle of treatment interruption. In addition, the data suggest that there may be multiple compartments contributing to the rebound of plasma viremia and to viral diversity from cycle to cycle of intermittent therapy.

Antiretroviral Therapy, Highly Active↗
PubMed2002

Guidelines for using antiretroviral agents among HIV-infected adults and adolescents.

The availability of an increasing number of antiretroviral agents and the rapid evolution of new information have introduced substantial complexity into treatment regimens for persons infected with human immunodeficiency virus (HIV). In 1996, the Department of Health and Human Services and the Henry J. Kaiser Family Foundation convened the Panel on Clinical Practices for the Treatment of HIV to develop guidelines for clinical management of HIV-infected adults and adolescents (CDC. Report of the NIH Panel To Define Principles of Therapy of HIV Infection and Guidelines for the use of antiretroviral agents in HIV-infected adults and adolescents. MMWR. 1998;47[RR-5]:1-41). This report, which updates the 1998 guidelines, addresses 1) using testing for plasma HIV ribonucleic acid levels (i.e., viral load) and CD4+ T cell count; 2) using testing for antiretroviral drug resistance; 3) considerations for when to initiate therapy; 4) adherence to antiretroviral therapy; 5) considerations for therapy among patients with advanced disease; 6) therapy-related adverse events; 7) interruption of therapy; 8) considerations for changing therapy and available therapeutic options; 9) treatment for acute HIV infection; 10) considerations for antiretroviral therapy among adolescents; 11) considerations for antiretroviral therapy among pregnant women; and 12) concerns related to transmission of HIV to others. Antiretroviral regimens are complex, have serious side effects, pose difficulty with adherence, and carry serious potential consequences from the development of viral resistance because of nonadherence to the drug regimen or suboptimal levels of antiretroviral agents. Patient education and involvement in therapeutic decisions are critical. Treatment should usually be offered to all patients with symptoms ascribed to HIV infection. Recommendations for offering antiretroviral therapy among asymptomatic patients require analysis of real and potential risks and benefits. In general, treatment should be offered to persons who have <350 CD4+ T cells/mm3 or plasma HIV ribonucleic acid (RNA) levels of >55,000 copies/mL (by b-deoxyribonucleic acid [bDNA] or reverse transcriptase-polymerase chain reaction [RT-PCR] assays). The recommendation to treat asymptomatic patients should be based on the willingness and readiness of the person to begin therapy; the degree of existing immunodeficiency as determined by the CD4+ T cell count; the risk for disease progression as determined by the CD4+ T cell count and level of plasma HIV RNA; the potential benefits and risks of initiating therapy in an asymptomatic person; and the likelihood, after counseling and education, of adherence to the prescribed treatment regimen. Treatment goals should be maximal and durable suppression of viral load, restoration and preservation of immunologic function, improvement of quality of life, and reduction of HIV-related morbidity and mortality. Results of therapy are evaluated through plasma HIV RNA levels, which are expected to indicate a 1.0 log10 decrease at 2-8 weeks and no detectable virus (<50 copies/mL) at 4-6 months after treatment initiation. Failure of therapy at 4-6 months might be ascribed to nonadherence, inadequate potency of drugs or suboptimal levels of antiretroviral agents, viral resistance, and other factors that are poorly understood. Patients whose therapy fails in spite of a high level of adherence to the regimen should have their regimen changed; this change should be guided by a thorough drug treatment history and the results of drug-resistance testing. Because of limitations in the available alternative antiretroviral regimens that have documented efficacy, optimal changes in therapy might be difficult to achieve for patients in whom the preferred regimen has failed. These decisions are further confounded by problems with adherence, toxicity, and resistance. For certain patients, participating in a clinical trial with or without access to new drugs or using a regimen that might not achieve complete suppression of viral replicatioing a regimen that might not achieve complete suppression of viral replication might be preferable. Because concepts regarding HIV management are evolving rapidly, readers should check regularly for additional information and updates at the HIV/AIDS Treatment Information Service website ( http://www.hivatis.org ).

Adolescent↗
PubMed2002

Evaluation of initial CD4+ T cell counts in individuals with newly diagnosed human immunodeficiency virus infection, by sex and race, in urban settings.

The CD4+ T cell count is an important determinant of disease stage and prognosis in human immunodeficiency virus (HIV)-infected individuals. This study evaluated the CD4+ T cell counts in individuals at the time of diagnosis of HIV infection at 4 community clinics in large urban settings with relatively high frequencies of HIV infection. Of 2223 individuals, 57% and 36% had CD4+ T cell counts < 350 and < 200 cells/mm(3), respectively, at the time of diagnosis. There were no clear differences by sex or race. Enhanced educational efforts regarding the importance of HIV testing for at-risk individuals across sex and race strata in community settings may be important for early identification of individuals with HIV infection. This in turn could impact efforts to reduce transmission, and it could impact the prognosis for patients who receive antiretroviral therapy.

Black or African American↗
PubMed2002

Guidelines for using antiretroviral agents among HIV-infected adults and adolescents. Recommendations of the Panel on Clinical Practices for Treatment of HIV.

The availability of an increasing number of antiretroviral agents and the rapid evolution of new information has introduced substantial complexity into treatment regimens for persons infected with human immunodeficiency virus (HIV). In 1996, the Department of Health and Human Services and the Henry J. Kaiser Family Foundation convened the Panel on Clinical Practices for the Treatment of HIV to develop guidelines for clinical management of HIV-infected adults and adolescents (CDC. Report of the NIH Panel To Define Principles of Therapy of HIV Infection and Guidelines for the use of antiretroviral agents in HIV-infected adults and adolescents. MMWR 1998;47[RR-5]:1-41). This report, which updates the 1998 guidelines, addresses 1) using testing for plasma HIV ribonucleic acid levels (i.e., viral load) and CD4+ T cell count; 2) using testing for antiretroviral drug resistance; 3) considerations for when to initiate therapy; 4) adherence to antiretroviral therapy; 5) considerations for therapy among patients with advanced disease; 6) therapy-related adverse events; 7) interruption of therapy; 8) considerations for changing therapy and available therapeutic options; 9) treatment for acute HIV infection; 10) considerations for antiretroviral therapy among adolescents; 11) considerations for antiretroviral therapy among pregnant women; and 12) concerns related to transmission of HIV to others. Antiretroviral regimens are complex, have serious side effects, pose difficulty with adherence, and carry serious potential consequences from the development of viral resistance because of nonadherence to the drug regimen or suboptimal levels of antiretroviral agents. Patient education and involvement in therapeutic decisions is critical. Treatment should usually be offered to all patients with symptoms ascribed to HIV infection. Recommendations for offering antiretroviral therapy among asymptomatic patients require analysis of real and potential risks and benefits. Treatment should be offered to persons who have <350 CD4+ T cells/mm3 or plasma HIV ribonucleic acid (RNA) levels of >55,000 copies/mL (by b-deoxyribonucleic acid [bDNA] or reverse transcriptase-polymerase chain reaction [RT-PCR] assays). The recommendation to treat asymptomatic patients should be based on the willingness and readiness of the person to begin therapy; the degree of existing immunodeficiency as determined by the CD4+ T cell count; the risk for disease progression as determined by the CD4+ T cell count and level of plasma HIV RNA; the potential benefits and risks of initiating therapy in an asymptomatic person; and the likelihood, after counseling and education, of adherence to the prescribed treatment regimen. Treatment goals should be maximal and durable suppression of viral load, restoration and preservation of immunologic function, improvement of quality of life, and reduction of HIV-related morbidity and mortality. Results of therapy are evaluated through plasma HIV RNA levels, which are expected to indicate a 1.0 log10 decrease at 2-8 weeks and no detectable virus (<50 copies/mL) at 4-6 months after treatment initiation. Failure of therapy at 4-6 months might be ascribed to nonadherence, inadequate potency of drugs or suboptimal levels of antiretroviral agents, viral resistance, and other factors that are poorly understood. Patients whose therapy fails in spite of a high level of adherence to the regimen should have their regimen changed; this change should be guided by a thorough drug treatment history and the results of drug-resistance testing. Because of limitations in the available alternative antiretroviral regimens that have documented efficacy, optimal changes in therapy might be difficult to achieve for patients in whom the preferred regimen has failed. These decisions are further confounded by problems with adherence, toxicity, and resistance. For certain patients, participating in a clinical trial with or without access to new drugs or using a regimen that might not achieve complete suppression of viral replication might be preferable. Because concepts regarding HIV management are evolving rapidly, readers should check regularly for additional information and updates at the HIV/AIDS Treatment Information Service website (http://www.hivatis.org).

Adolescent↗
PubMed2002

HIV preferentially infects HIV-specific CD4+ T cells.

HIV infection is associated with the progressive loss of CD4(+) T cells through their destruction or decreased production. A central, yet unresolved issue of HIV disease is the mechanism for this loss, and in particular whether HIV-specific CD4(+) T cells are preferentially affected. Here we show that HIV-specific memory CD4(+) T cells in infected individuals contain more HIV viral DNA than other memory CD4(+) T cells, at all stages of HIV disease. Additionally, following viral rebound during interruption of antiretroviral therapy, the frequency of HIV viral DNA in the HIV-specific pool of memory CD4(+) T cells increases to a greater extent than in memory CD4(+) T cells of other specificities. These findings show that HIV-specific CD4(+) T cells are preferentially infected by HIV in vivo. This provides a potential mechanism to explain the loss of HIV-specific CD4(+) T-cell responses, and consequently the loss of immunological control of HIV replication. Furthermore, the phenomenon of HIV specifically infecting the very cells that respond to it adds a cautionary note to the practice of structured therapy interruption.

Anti-HIV Agents↗
PubMed2002

Structured Treatment Interruption: Approaches and Risks.

Although highly active antiretroviral therapy suppresses HIV replication resulting in extraordinary clinical benefits, toxicity, adherence difficulties, and the monetary cost of medications limit the long-term effectiveness and availability of therapy for many HIV-infected individuals. Strategies to interrupt therapy have been proposed as a means to enhance the sustainability of antiretroviral treatment. Widely different approaches with varied patient populations, theoretical concepts, and clinical designs are frequently lumped together as "structured treatment interruptions." This review summarizes the approaches and risks of treatment interruptions in HIV infection. Currently, none of these strategies can be recommended in standard clinical practice.

Journal Article↗
PubMed2002

Human immunodeficiency virus type 1 bound to B cells: relationship to virus replicating in CD4+ T cells and circulating in plasma.

Human immunodeficiency virus type 1 (HIV-1) virions bind to B cells in the peripheral blood and lymph nodes through interactions between CD21 on B cells and complement-complexed virions. B-cell-bound virions have been shown to be highly infectious, suggesting a unique mode of HIV-1 dissemination by B cells circulating between peripheral blood and lymphoid tissues. In order to investigate the relationship between B-cell-bound HIV-1 and viruses found in CD4+ T cells and in plasma, we examined the genetic relationships of HIV-1 found in the blood and lymph nodes of chronically infected patients with heteroduplex mobility and tracking assays and DNA sequence analysis. In samples from 13 of 15 patients examined, HIV-1 variants in peripheral blood-derived B cells were closely related to virus in CD4+ T cells and more divergent from virus in plasma. In samples from five chronically viremic patients for whom analyses were extended to include lymph node-derived HIV-1 isolates, B-cell-associated HIV-1 and CD4+-T-cell-associated HIV-1 in the lymph nodes were equivalent in their divergence from virus in peripheral blood-derived B cells and generally more distantly related to virus in peripheral blood-derived CD4+ T cells. These results indicates virologic cross talk between B cells and CD4+ T cells within the microenvironment of lymphoid tissues and, to a lesser extent, between cells in lymph nodes and the peripheral blood. These findings also indicate that most of the virus in plasma originates from cells other than CD4(+) T cells in the peripheral blood and lymph nodes.

B-Lymphocytes↗
PubMed2001

Pilot study of the effects of intermittent interleukin-2 on human immunodeficiency virus (HIV)-specific immune responses in patients treated during recently acquired HIV infection.

Highly active antiretroviral therapy (HAART) initiated during acute human immunodeficiency virus (HIV) infection may preserve HIV-specific CD4+ T cell responses that are thought to enhance HIV-specific CD8+ T cell function. The present pilot study was designed to determine whether preserved HIV-specific immune responses are augmented by the administration of the immunomodulatory agent interleukin (IL)-2. Nine persons recently (<6 months) infected with HIV were randomized to receive HAART alone or HAART plus 3 cycles of intermittent IL-2 during a 12-month period. Although HAART plus IL-2 significantly increased counts of total and naive CD4+ T cells, compared with HAART alone, there was no increase in CD4+ or CD8+ HIV-specific immune responses. In addition, adjuvant IL-2 therapy did not reduce the pool of HIV-infected resting CD4+ T cells. Thus, although intermittent IL-2 plus HAART quantitatively increased CD4+ T cells, this increase was not selective for HIV-specific CD4+ or CD8+ T cell responses in recently infected persons.

Alkynes↗