Evaluation of the impact of highly active antiretroviral therapy on immune recovery in antiretroviral naive patients.

OBJECTIVES: To examine the extent of immune reconstitution in treatment-naive patients with CD4 T-cell counts <500 cells/microL following 48 weeks of highly active antiretroviral therapy (HAART). METHODS: Thirteen antiretroviral naive patients were evaluated longitudinally for 48 weeks on HAART utilizing immune functional and lymphocyte phenotyping assays, including lymphocyte proliferation assay, flow cytometric evaluation of cell surface markers, and delayed type hypersensitivity skin tests. Virologic responses were monitored using commercially available viral load assays and gag/pol mRNA quantification using simultaneous immunophenotyping/UltraSensitive fluorescence in situ hybridization (ViroTect In Cell HIV-1 Detection Kit; Invirion, Frankfort, MI). Thymic function was evaluated for a subset of four patients using real-time polymerase chain reaction (PCR) for T-cell receptor excision circle (TREC) quantification and thymic scans using computerized axial tomography (CT) of the thymus. RESULTS: HAART initiation resulted in a significant decline in plasma viremia and percentage of infected peripheral blood cells, and a rise in CD4 T cells from a baseline median of 207 cells/microL to a week-48 median of 617 cells/microL. The rise was predominately in CD4 memory cells. Naive T cells also increased in number, but at a slower rate. Activated (HLA-DR CD38) CD4 and CD8 T cells were elevated at baseline (24 and 62%, respectively) and declined by week 48 (17 and 36%, respectively) but did not reach normal levels. The number of Fas CD4 T cells increased from a baseline median of 169 to 381 cells/microL at week 48. Both soluble interleukin (IL)-2 and tumour necrosis factor (TNF) II receptors declined by week 48. HIV p24 lymphocyte proliferation assay responses were transiently detected in three patients. TREC values increased from a median 6400 copies/microg at baseline to a week-48 median value of 26 697 copies/microg. CONCLUSION: Immune functional reconstitution was not achieved in these HAART naive patients.

T cell receptor excision circle (TREC) content following maximum HIV suppression is equivalent in HIV-infected and HIV-uninfected individuals.

BACKGROUND: The adult human thymus contributes to de novo T cell synthesis; such synthesis can be assessed by analyzing T cell receptor excision circles (TREC). METHODS: TREC levels were measured in total peripheral blood mononuclear cells (PBMC) and CD4- and CD8-enriched cells of 29 HIV-positive patients with maximal viral suppression. The expression of CD45RA+CD45RO-, CD45RA+CD62L+, CD45RO-CD27+CD95low and HLA-DR+CD38+ was assessed using three-color flow cytometric analysis of whole blood. Thymic index score was based on computed tomographic scans of the thymus. The relationship of TREC with thymic index and the expression of the naive phenotypes was evaluated. RESULTS: TREC expression was not statistically different in these HIV-positive patients from that in age-matched HIV-negative controls. Among HIV-positive patients with CD4 cell count of > 500 x 10(6) cells/l after antiretroviral therapy (n = 15), PBMC TREC levels correlated with the expression of CD45RA+CD45RO- and CD45RA+CD62L+ naive phenotypes, and inversely correlated with the expression of HLA-DR+CD38+. The change between pre- and post-therapy CD4 cell counts for these 15 patients significantly correlated with both thymic index and expression of the CD45RA+CD45RO- phenotype. CONCLUSIONS: The finding that TREC expression was equivalent between HIV-positive patients after therapy and HIV-negative donors suggests that there is no reduction in thymic output among HIV-positive individuals after therapy. Given that TREC is inversely correlated with HLA-DR/CD38 expression, its analysis in studies of thymopoiesis should be evaluated in the context of maximum viral suppression to reduce HIV-mediated immune activation and/or by normalizing for cell turnover.

Response to immunization with recall and neoantigens after prolonged administration of an HIV-1 protease inhibitor-containing regimen. ACTG 375 team. AIDS Clinical Trials Group.

OBJECTIVES: To ascertain if immunization results in the restoration of responses to recall antigens, in the development of responses to presumed neoantigens, and to identify the virologic and immunologic correlates of these responses in persons with HIV-1 infection. DESIGN AND SETTING: Open-label study carried out at three university-affiliated AIDS Clinical Trials Units in the United States. SUBJECTS AND METHODS: Thirty-one subjects participating in AIDS Clinical Trials Group Protocol 375 who had received zidovudine, lamivudine, and ritonavir for at least 48 weeks. Subjects were immunized with tetanus toxoid (TT) at entry and with inactivated hepatitis A vaccine (hep A) and keyhole limpet hemocyanin (KLH) at entry and 6 weeks. The development of antibody, lymphocyte proliferative assay (LPA), and delayed-type hypersensitivity (DTH) responses after immunization were monitored. RESULTS: The LPA and DTH responses to TT improved in 57 and 68% of participants, respectively; 73 and 65% developed enhanced LPA and DTH responses to KLH. Forty-eight percent of patients developed a four-fold increase in antibody concentration to tetanus. Seventy-three percent of patients without detectable hepatitis A antibodies at baseline developed antibodies after immunization. Eighty-three percent of patients experienced at least a four-fold rise in KLH antibody concentration. Immune activation and viral load predicted poor recall responses and the number of memory CD4+ T-cells predicted good responses to recall antigens. Naïve CD4+ T-cell numbers, decrease in viral load, increases in CD4+ and CD28+ cells, and decreases in immune activation were associated with responses to presumed neoantigens. CONCLUSIONS: Most HIV-infected patients treated with potent combination antiretrovirals develop responses to recall and presumed neoantigens after immunization. Functional immune restoration in response to immunization is related to control of viral replication, decreased immune activation as well as to both quantitative and qualitative restoration of circulating T- lymphocyte subpopulations.

Thymic size and lymphocyte restoration in patients with human immunodeficiency virus infection after 48 weeks of zidovudine, lamivudine, and ritonavir therapy.

Human immunodeficiency virus (HIV) infection is associated with progressive loss of circulating CD4+ lymphocytes. Treatment with highly active antiretroviral therapy (HAART) has led to increases in CD4+ T lymphocytes of naive (CD45RA+62L+) and memory (CD45R0+RA-) phenotypes. Thymic computerized tomography scans were obtained on 30 individuals with HIV disease to investigate the role of the thymus in cellular restoration after 48 weeks of HAART. Individuals with abundant thymic tissue had higher naive CD4+ T lymphocyte counts at weeks 2-24 after therapy than individuals with minimal thymic tissue. Individuals with abundant thymic tissue had significantly larger increases in naive CD4+ cells during the first 4 weeks of therapy. These individuals were also more likely to experience viral rebound despite comparable initial declines in plasma HIV-1 RNA. These findings suggest that there is a complex relationship among the thymus, viral replication, and lymphocyte restoration after application of HAART in HIV disease.

Ceftazidime-resistant Klebsiella pneumoniae and Escherichia coli bloodstream infection: a case-control and molecular epidemiologic investigation.

In a molecular, microbiologic, and case-control study to describe the epidemiology of ceftazidime-resistant Klebsiella pneumoniae and Escherichia coli bloodstream infection, 32 unique isolates were recovered over 31 months from the blood of patients hospitalized in a 900-bed hospital in Chicago. Multivariate analysis revealed cases occurred more frequently in debilitated nursing home patients with central venous catheters than in younger, healthier patients. Mortality rates were similar for cases and controls. Case-patients were less likely to die if they received appropriate antibiotic treatment within 3 days of bacteremia onset (P = .02). Pulsed-field gel electrophoresis analysis indicated a polyclonal outbreak, with strain-specific temporal and geographic clustering. Isoelectric focusing results suggested that a predominant enzyme, TEM-10, was responsible for the ceftazidime resistance. The resistance gene was usually carried on a large conjugative plasmid. The polyclonality of the resistant strains suggests that ceftazidime resistance due to TEM-10 is now endemic in Chicago.

The leukemias. Definition, treatment, and nursing care.

While leukemia continues to represent a dreaded, often terminal disease, many new drugs and treatments have been developed in the past two decades. The life span of those afflicted by leukemia has been lengthened, and in some instances the patients have been cured. The treatment is often aggressive with life-threatening side effects. The nurse is faced with many demands when caring for the patient with leukemia who is undergoing therapy. An understanding of the disease process and the treatment is necessary to give optimal nursing care. In addition, the psychologic impact of this disease on patient and family requires time and special interventions from the nursing staff. Care of these challenging patients need not be viewed with pessimism and gloom. When quality care is delivered, both patient and nurse share the gratifying experience of working to achieve the hope and goal of continued life.