Treatment intensification does not reduce residual HIV-1 viremia in patients on highly active antiretroviral therapy.

In HIV-1-infected individuals on currently recommended antiretroviral therapy (ART), viremia is reduced to <50 copies of HIV-1 RNA per milliliter, but low-level residual viremia appears to persist over the lifetimes of most infected individuals. There is controversy over whether the residual viremia results from ongoing cycles of viral replication. To address this question, we conducted 2 prospective studies to assess the effect of ART intensification with an additional potent drug on residual viremia in 9 HIV-1-infected individuals on successful ART. By using an HIV-1 RNA assay with single-copy sensitivity, we found that levels of viremia were not reduced by ART intensification with any of 3 different antiretroviral drugs (efavirenz, lopinavir/ritonavir, or atazanavir/ritonavir). The lack of response was not associated with the presence of drug-resistant virus or suboptimal drug concentrations. Our results suggest that residual viremia is not the product of ongoing, complete cycles of viral replication, but rather of virus output from stable reservoirs of infection.

Suppression of HIV replication in the resting CD4+ T cell reservoir by autologous CD8+ T cells: implications for the development of therapeutic strategies.

CD8+ T cell-mediated antiviral activity against HIV has been described consistently in infected individuals; however, the role of this activity in controlling replication of HIV in the latently infected, resting CD4+ T cell reservoir is unclear. By using an ex vivo system, we show that replication of HIV in this viral reservoir is effectively suppressed in coculture by autologous CD8+ T cells in long-term nonprogressors (LTNPs) and in patients whose viremia was controlled by highly active antiretroviral therapy (HAART), but not in therapy-naive patients who had substantial levels of plasma viremia. This antiviral activity was largely independent of cytotoxic CD8+ T lymphocytes (CTL). When the role of soluble CD8+ T cell-derived factors was examined, we found that CC-chemokines played a major role in inhibition of viral replication in the latent viral reservoir in some LTNPs and patients receiving HAART, but not in chronically infected patients who were not receiving antiretroviral therapy. Potent antiviral activity, independent of CC-chemokines, was found mainly in patients in whom HAART was initiated shortly after the acute phase of HIV infection. These results indicate that CD8(+) T cells provide potent suppressive activity against HIV replication in the latent viral reservoir via direct cellular contact in patients who are naturally LTNPs or in those who are treated with HAART. Furthermore, the profound antiviral activity exerted by non-CC-chemokine soluble factors in infected patients who began HAART early in HIV infection suggests that preservation of this HIV-suppressive mechanism by early initiation of therapy may play an important role in the containment of viral replication in infected patients following interruption of therapy.

Longitudinal changes in CD4+ T cell antigen receptor diversity and naive/memory cell phenotype during 9 to 26 months of antiretroviral therapy of HIV-infected patients.

Although skewing of the CD4+ TCR repertoire in advanced HIV infection is well documented, increases in polyclonality during antiretroviral therapy have been less consistently observed. Ten patients, each with documented abnormalities within the CD4+ TCR repertoire, were studied by CDR3 spectratyping, semiquantitative PCR, and SSCP during 9-26 months of therapy. Naive and memory cell phenotypes were analyzed by flow cytometry. Six of 10 patients showed increased polyclonality of their TCR repertoires, 1 showed no change, and 3 showed increased TCR skewing, despite suppressed viral replication. Overall, there was no significant change in the percentage of abnormal BV subfamilies (from a mean of 25.5 to 17.1%) or the percentage of naive CD4+ T cells (from a mean of 18 to 25%). Further, progression of TCR repertoire disruptions was observed in some patients even with suppression of plasma viral RNA below 500 copies/ml. Although a spectrum of changes may be seen within the CD4+ TCR repertoire in the setting of antiretroviral therapy, increases in polyclonality are observed in some patients.

CD40 ligand trimer and IL-12 enhance peripheral blood mononuclear cells and CD4+ T cell proliferation and production of IFN-gamma in response to p24 antigen in HIV-infected individuals: potential contribution of anergy to HIV-specific unresponsiveness.

It has been suggested that CD4+ T cell proliferative responses to HIV p24 Ag may be important in the control of HIV infection. However, these responses are minimal or absent in many HIV-infected individuals. Furthermore, while in vitro and in vivo responses to non-HIV recall Ags improve upon administration of highly active antiretroviral therapy, there does not appear to be a commensurate enhancement of HIV-specific immune responses. It is possible that CD4+ p24-specific T cells are deleted early in the course of infection. However, it is also possible that a discrete unresponsiveness, or anergy, contributes to the lack of proliferation to p24. To evaluate the possible contribution of unresponsiveness to the lack of CD4+ T cell proliferation to p24 in HIV-infected individuals, we attempted to overcome unresponsiveness. CD40 ligand trimer (CD40LT) and IL-12 significantly increased PBMC and CD4+ T cell proliferative responses to p24 Ag in HIV-infected, but not uninfected, individuals. No increase in proliferative response to CMV Ag was observed. CD40LT exerted its effect through B7-CD28-dependent and IL-12- and IL-15-independent mechanisms. Finally, the increase in proliferation with CD40LT and IL-12 was associated with an augmented production of IFN-gamma in most, but not all, individuals. These data suggest the possible contribution of HIV-specific unresponsiveness to the lack of CD4+ T cell proliferation to p24 Ag in HIV-infected individuals and that clonal deletion alone does not explain this phenomenon. They also indicate the potential for CD40LT and IL-12 as immune-based therapies for HIV infection.

Evaluation of lymph node virus burden in human immunodeficiency virus-infected patients receiving efavirenz-based protease inhibitor--sparing highly active antiretroviral therapy.

Although efavirenz-containing regimens effectively suppress plasma levels of human immunodeficiency virus (HIV) RNA, it is now clear that undetectable plasma viremia may not reflect a lack of viral replication. Because lymphoid tissue is an active site of HIV replication, the lymph node virus burden was analyzed in persons who received highly active antiretroviral therapy (HAART) containing either efavirenz or a protease inhibitor (PI). Testing with in situ hybridization revealed no detectable follicular dendritic cell-associated HIV RNA in either group, and only 2 of 8 persons in the efavirenz group and 1 of 4 in the PI group had detectable RNA in lymph node mononuclear cells (LNMC) when tested by use of nucleic acid sequencebased amplification. Low levels of replication-competent HIV were identified in both groups by use of quantitative coculture assays. There was no evidence of development of resistance to either regimen in virus isolated from LNMC. These data support the use of efavirenz as an alternative to a PI in initial HAART regimens.

Lymph node architecture preceding and following 6 months of potent antiviral therapy: follicular hyperplasia persists in parallel with p24 antigen restoration after involution and CD4 cell depletion in an AIDS patient.

OBJECTIVES: To evaluate changes in architecture, viral RNA, and viral protein over 6 months in lymph nodes from retroviral-naïve HIV-infected persons before and after commencing highly active antiretroviral therapy (HAART). METHODS: Nine antiretroviral-naïve HIV-infected persons had lymph nodes excised at baseline and at 2 and 6-8 months after beginning a four-drug combination regimen containing zidovudine, lamivudine, nevirapine, and indinavir. Two patients had AIDS. Lymph nodes were examined by immunohistochemical staining for Gag p24 HIV, CD3, CD21, CD20, HAM 56, and Ki67 antigens and by in-situ hybridization (ISH) for HIV RNA and H3-histone RNA. RESULTS: Eight of nine baseline lymph nodes showed follicular hyperplasia and germinal center and paracortical mononuclear cell activation. At 2 months, the lymph nodes from seven patients, including the AIDS patients, showed more follicular hyperplasia and activation than their baseline specimens but with decreased mononuclear cell activation. By 6 months, seven lymph nodes were less hyperplastic and activated than their corresponding 2 month specimens. Combined ISH/immunohistochemical staining of baseline lymph nodes revealed productively infected T (CD3) and B (CD20) cells and macrophages (HAM56+). HIV RNA-positive mononuclear cells were infrequent at 2 months, and rare at 6 months. HIV RNA was still associated with follicular dendritic cells (FDC) at 2 months, but not at 6 months. HIV p24-positive antigen in germinal centers persisted through all 6, and the one 8 month specimens. The baseline lymph nodes from one of the AIDS patients was involuted and T cell depleted, whereas the follow-up lymph nodes were hyperplastic with normal T cell levels. CONCLUSION: Follicular hyperplasia and cell activation, possibly caused by persistent viral protein in germinal centers, may help explain why HIV viremia rebounds so rapidly after the interruption of HAART. Restoration of architecture may follow the treatment of patients with AIDS who initially had involuted and CD4 cell-depleted lymph nodes.

Effect of interleukin-2 on the pool of latently infected, resting CD4+ T cells in HIV-1-infected patients receiving highly active anti-retroviral therapy.

The size of the pool of resting CD4+ T cells containing replication-competent HIV in the blood of patients receiving intermittent interleukin (IL)-2 plus highly active anti-retroviral therapy (HAART) was significantly lower than that of patients receiving HAART alone. Virus could not be isolated from the peripheral blood CD4+ T cells in three patients receiving IL-2 plus HAART, despite the fact that large numbers of resting CD4+ T cells were cultured. Lymph node biopsies were done in two of these three patients and virus could not be isolated. These results indicate that the intermittent administration of IL-2 with continuous HAART may lead to a substantial reduction in the pool of resting CD4+ T cells that contain replication-competent HIV.

Progression of human immunodeficiency virus disease is associated with increasing disruptions within the CD4+ T cell receptor repertoire.

The immunodeficiency caused by human immunodeficiency virus (HIV) infection may be related to loss of diversity in the T cell receptor (TCR) repertoire. A cross-sectional study of the CD4 TCR repertoire was done for patients at various stages of HIV infection. Semiquantitative polymerase chain reaction was used to study the relative usage of the variable chain beta (BV) subfamilies and the size distributions of transcripts (CDR3 size analysis) within these subfamilies. The relative usage of the TCRBV subfamilies of patients and controls was not significantly different. The proportion of subfamilies with abnormal CDR3 size patterns was higher in the HIV-infected patients (25%, 95% confidence interval [CI], 17%-33%) than in the controls (7.2%, 95% CI, 2.3%-12.1%; P < .001), with a significant negative correlation between the number of CD4 cells and the percentage of abnormal TCRBV subfamilies. These results indicate that progressive loss of CD4 T cells is accompanied by increasing disruptions within the T cell receptor repertoire.

Systemic mastocytosis: CT and US features of abdominal manifestations.

PURPOSE: To study the imaging findings in patients with systemic mastocytosis and to correlate the findings with the severity of disease on the basis of an established classification system. Pathologic findings, when available, were correlated with imaging findings. MATERIALS AND METHODS: Computed tomographic (CT) and ultrasound (US) scans and corresponding pathologic findings, when available, were retrospectively reviewed in 27 patients with systemic mastocytosis. RESULTS: Only five (19%) of the patients in our series had normal abdominal CT and/or US examination results. Common abdominal imaging findings associated with systemic mastocytosis were hepatosplenomegaly, retroperitoneal adenopathy, periportal adenopathy, mesenteric adenopathy, thickening of the omentum and the mesentery, and ascites. Less common findings included hepatofugal portal venous flow, Budd-Chiari syndrome, cavernous transformation of the portal vein, ovarian mass, and complications such as chloroma. The findings were more common in patients with category II and those with category III disease. CONCLUSION: Abdominal findings at CT and US are common in patients with systemic mastocytosis. Although the findings in patients with systemic mastocytosis are not specific to the disease, they are useful in directing further studies for diagnostic confirmation and in estimating the extent of systemic involvement.

Hepatic involvement in mastocytosis: clinicopathologic correlations in 41 cases.

Mastocytosis is a disease of mast cell hyperplasia that may involve several organ systems, including liver. Between 1988 and 1991, we conducted a retrospective-prospective study of 41 patients with mastocytosis and found 61% had evidence of liver disease. Hepatomegaly was detected in 24%, splenomegaly in 41%, and elevated serum alkaline phosphatase, serum aminotransaminases, 5'nucleotidase, or gamma-glutamyltranspeptidase (GGTP) in 54% of the patients. Alkaline phosphatase levels directly correlated with GGTP levels, hepatomegaly, splenomegaly, and liver mast cell infiltration and fibrosis. Elevated alkaline phosphatase levels and splenomegaly were observed more frequently in patients with categories II and III mastocytosis. Five patients in combined disease categories II or III developed ascites or portal hypertension and died of complications of mastocytosis; three had hypoprothrombinemia at the time of death. Thirty-five liver biopsy specimens from 25 patients were examined. Mast cell infiltration was commonly observed in the biopsy specimens, more severe in those patients with either category II or III disease, and correlated with hepatomegaly, splenomegaly, alkaline phosphatase levels, and GGTP levels. Mast cells were often only detected by using special stains (toluidine blue and chloracetate esterase). Increased portal fibrosis was seen in 68% of the biopsy specimens and correlated with mast cell infiltration and portal inflammation. Cirrhosis was not observed. Nodular regenerative hyperplasia, portal venopathy, and venoocclusive disease was observed in eight biopsy specimens and may have been the cause of the portal hypertension or ascites in four patients. These findings demonstrate that liver disease with mast cell infiltration is a common finding in patients with mastocytosis.(ABSTRACT TRUNCATED AT 250 WORDS)

A retrospective analysis of bone scan abnormalities in mastocytosis: correlation with disease category and prognosis.

UNLABELLED: To investigate the usefulness of bone scintigraphy in systemic mastocytosis (SM), the scans of 73 patients were retrospectively reviewed and correlated with disease category. METHODS: A modification of a previously described method for bone scan classification in this disease was used. In addition to the group as a whole, two subsets of patients with multiple bone scans were identified for closer analysis: those with (n = 13) and without (n = 12) scintigraphic evidence of progression of disease. RESULTS: Overall, patients with more aggressive SM tended to have increasingly abnormal initial bone scans (p2 = 0.0003), although there was a considerable degree of overlap. Of patients undergoing serial studies, those with scintigraphic progression also tended to have more aggressive disease (p2 = 0.006) and a poorer prognosis than those with stable bone scans. CONCLUSIONS: Both the degree of abnormality on initial bone scan and progression of scintigraphic abnormalities with serial scanning appear to correlate with the presence of more aggressive systemic mastocytosis. Based on the patterns seen, in many cases this may be a reflection of bone marrow expansion, which in turn probably reflects increased marrow disease.

Radiotherapy of refractory bone pain due to systemic mast cell disease.

Systemic mastocytosis is a rare disease characterized by mast cell infiltration of organs. Bony pain is present in up to 28% of cases and is frequently chronic and difficult to palliate. Historical attempts at pain control have exclusively involved medical therapy. We report three cases of refractory bone pain in two patients with advanced systemic mast cell disease and associated bony involvement, which were treated with radiotherapy. This report represents some of the first uses of radiotherapy in this disease. Two patients with a primary diagnosis of systemic mastocytosis and bony pain unresponsive to medical therapy were referred for palliative radiotherapy. In the first case, referral was made because of a painful thoracolumbar spine and left shoulder, and in the second, for bilateral lower extremity pain. Patients were irradiated on megavoltage equipment to 30 Gy in 200 and 300 cGy daily fractions. For the first patient, treatment reduced pain scores from 8/10 (severe) to 3-4/10 (moderate) by 1 month posttreatment, with subsequent varying pain until his death 4 months after his second treatment. The second patient achieved pain relief from 10/10 pretreatment to 1-2/10 while on treatment. This proved durable for 9 months until her death due to disease progression. The first patient had a slight exacerbation of his thrombocytopenia during his initial treatment, but otherwise neither patient experienced any acute complications from the radiation treatments. When patients with advanced systemic mastocytosis require large narcotic doses for incomplete bone pain control associated with demonstrable bony involvement, the relatively slight risks of palliative radiation to bone may be favorably weighed against the likelihood of pain relief.

Effect of IL-3 and stem cell factor on the appearance of human basophils and mast cells from CD34+ pluripotent progenitor cells.

Hemopoietic stem cell factor (SCF), which is the ligand for the proto-oncogene c-kit receptor (allelic with W locus) and the product of Sl locus of the mouse, has recently been cloned. The human homologue has also been cloned, and recombinant protein (human rSCF) expressed and purified to homogeneity. To determine the effect of human rSCF in the presence or absence of human rIL-3 on human bone marrow-derived mast cells and basophils, human CD34+ pluripotent progenitor cells, highly enriched (greater than 99%) from bone marrow mononuclear cells, were cultured over agarose surfaces (interphase cultures) in the presence of human rIL-3, human rIL-3 and increasing concentrations of human rSCF, or human rSCF alone. Over 3 to 4 wk, human rSCF acted synergistically with human rIL-3 at all concentrations, producing a three- to fivefold increase in total, mast cell, and basophil numbers over human rIL-3 alone when used at 100 ng/ml. The percentage of cell types in the human rIL-3 and human rIL-3 plus human rSCF cultures, however, remained the same, with basophils constituting 18 to 35% of the final cultured cells, and mast cells 3% or less of the final cell number. In the presence of human rSCF alone, the combined total percentage of mast cells and basophils was 0 to 1.0%, the majority of cells being macrophages. Mast cells cultured in human rIL-3 plus human rSCF, but not human rIL-3 alone, were berberine sulfate positive, suggesting the presence of heparin proteoglycans within granules. Electron microscopic examination of cultures supplemented with human rIL-3 and rSCF, but not human rIL-3 alone, revealed that after 3 wk in culture, mast cell granules contained tryptase and exhibited scroll, reticular, and homogeneous patterns as seen previously in CD34+/3T3 fibroblast cocultures. Thus, CD34+ cells cultured in the presence of both human rIL-3 and rSCF give rise to cultures containing increased numbers of basophils and mast cells, with the mast cells by ultrastructural studies showing evidence of maturation although the percentages of basophils and mast cells arising in these cultures remained unchanged.

Arthritis and mast cell activation.

The significance of the mast cell in the pathogenesis of rheumatic diseases continues to receive attention. Increased numbers of mast cells are found in the synovial tissue and fluid of patients with inflammatory arthritides, and these mast cells can be activated by many of the substances found in inflammatory synovial fluid. This activation results in the release of mediators that are capable of amplifying the inflammatory process within the joint space. Recent research has shown that mast cells also produce a variety of cytokines and hematopoietic growth factors that may have paracrine and autocrine functions that are important to the development of the inflammatory cell infiltrate. Increased numbers of mast cells are also found in many fibrotic conditions, including scleroderma. These mast cells, directly or through mediator generation, affect the function of endothelial cells, fibroblasts, and growth factors important to the proliferation and function of these cells. A clearer understanding of mast cell involvement in the inflammatory arthritides and fibrotic processes should lead to new therapeutic strategies.