Association of viral load in plasma samples of HIV-infected hemophilia patients with autoantibodies and gp120-containing immune complexes on CD4+ lymphocytes

Association of IL-12+ DC with High CD3+CD4-DR+ Lymphocyte Counts in Long-term HIV-infected Hemophilia Patients With Clinically Stable Disease

We investigated dendritic cell (DC) subsets as well as cellular and humoral immune parameters in long-term HIV-infected hemophilia patients with clinically stable disease. DC subsets were determined by their function to produce either IL-10 or IL-12. CD11c(+)CD83(+)CD40(+)IL-10(+) and CD11c(+)CD83(+)CD40(+)IL-12(+) DC were studied in freshly obtained blood samples of 28 HIV(+) and 15 HIV(-) patients and 39 healthy controls using four-color flow cytometry, and were analyzed in relation to blood lymphocyte subpopulation counts, proportions of IgG-coated CD4(+) blood lymphocytes, neopterin, and HIV-1 viral load in the plasma, and in vitro responses of patient lymphocytes to mitogens. Proportions and ratios of IL-10(+) DC and IL-12(+) DC were similar in HIV(+) and HIV(-) patients and healthy controls. Whereas IL-12(+) DC in HIV(+) patients were associated with high CD3(+)CD4(-)DR(+) lymphocyte counts, IL-10(+) DC were associated with the proportion of IgG-coated CD4(+) blood lymphocytes. These data suggest that long-term HIV-infected hemophilia patients with clinically stable disease have normal levels of functional IL-10(+) DC and IL-12(+) DC that might be involved in halting the progression of disease.

Dissociation of CD4+ cell counts from viral load and association with immune complexes in HIV+ hemophilia patients

OBJECTIVE

We have postulated that the host autoimmune response regulates and mediates CD4 depletion during HIV infection by opsonization of circulating CD4(+) lymphocytes carrying autoreactive immune complexes (IC) consisting of complement-fixing IgM and IgG, and during advanced stages of HIV disease of IgM/ IgG/gp120 complexes. In this retrospective study, we investigated whether HIV causes CD4 depletion by direct cytotoxicity or indirectly by induction of a host autoimmune response.

PATIENTS AND METHODS

In 1996, 12 HIV(+) hemophilia patients were converted to highly active antiretroviral therapy (HAART), while 10 other patients were maintained on conventional antiretroviral treatment and another 11 patients refused to be treated with antiretroviral drugs. The host immune response of these 33 HIV(+) patients was studied during the periods of minimum viral replication (Interval 1), subsequent rise in viral replication with strong replication dynamic (Interval 2), and maximum viral replication (Interval 3). The patients were categorized into three groups according to viral load (VL). Group A: patients with low level VL (n=10) showed a modest increase from <80 to <4 log 10 HIV-1 RNA copies per milliliter plasma during the observation period; Group B: patients with medium level VL (n=12) showed a stronger increase from <80 to >4 log 10 copies per milliliter plasma; and Group C: patients with high level VL (n=11) consistently had a median of >4 log 10 copies per milliliter plasma, during Intervals 1-3, with the exception of one patient who during Interval 2 had 4800 copies per milliliter. Blood lymphocyte subpopulations, proportions of CD4(+) blood lymphocytes coated with IgM, IgG, C3d and/or gp120, in vitro responses to mitogens and pooled allogeneic stimulator cells, as well as numbers of HIV-1 RNA copies per milliliter plasma were measured.

RESULTS

Sequential analysis of VL, IC load on CD4(+) blood lymphocytes and CD4 counts showed that an increasing VL was not associated with CD4 depletion, when the proportion of IC-coated circulating CD4(+) blood lymphocytes remained stable. When, CD4 counts and IC load were analyzed during corresponding intervals of retroviral replication in the three patient groups, a higher VL was associated with lower CD4 counts only when the IC load (IgG or gp120/IgG) on CD4(+) lymphocytes was higher as well.

CONCLUSION

These data suggest that HIV regulates and mediates CD4 depletion in part by the induction of autoreactive ICs against CD4(+) lymphocytes, especially complement-fixing autoreactive IgG and gp120/IgG complexes.

Increased soluble Fas in HIV-infected hemophilia patients with CD4+ and CD8+ cell count increases and viral load and immune complex decreases

Previous studies interpreted increases of soluble Fas (sFas) in the plasma during disease progression in HIV-infected patients as evidence of increased apoptosis of CD4(+) lymphocytes. We studied whether sFas and sFas ligand (sFasL) plasma levels are associated with CD4(+) and CD8(+) lymphocyte counts, plasma viral load, and IgM, IgG, C3d, and gp120 complexes on circulating CD4(+) blood lymphocytes in long-term surviving HIV-infected hemophilia patients, most of whom were receiving HAART. Twenty-six hemophilia patients who were infected with HIV in the early 1980s were investigated in 1997, 1998, and 1999. HAART was initiated in 1996 and 1997 in most patients. Lymphocyte subpopulations and immune complex-coated CD4(+) lymphocytes in the blood were investigated by flow cytometry, plasma viral load (HIV-1 mRNA copies/ml plasma) was tested with HIV-1 QT Nuclisens kits, sFas (ng/ml) and sFasL (ng/ml) plasma levels were measured with MBL ELISA kits, and the in vitro response of patient lymphocytes was tested in cell cultures. During the period from 1997 to 1999 we observed an increase in sFas plasma levels (p = 0.003) as well as in CD4(+) (p = 0.004) and CD8(+) (p = 0.023) cell counts; a decrease in IgG (p = 0.047), C3d (p = 0.024), and gp120 (p = 0.001)-coated CD4(+) lymphocytes in the blood; and a decrease in the number of impaired mitogen stimulation assays (p = 0.013). sFas was negatively associated with viral burden (r = -0.662, p = 0.0002) as well as with CD4(+)IgM(+) (r = -0.554, p = 0.004), CD4(+)IgG(+) (r = -0.431, p = 0.031), CD4(+)C3d(+) (r = -0.551, p = 0.041), and CD4(+)gp120(+) (r = -0.430, p = 0.041) blood lymphocytes, CD8(+)DR(+) cell counts (r = -0.700, p = 0.016), and impaired in vitro responses of patient lymphocytes to PHA (r = -0.475, p = 0.016). sFasL was negatively associated with total lymphocyte counts (r = -0.433, p = 0.027), as well as with absolute numbers of CD3(+) (r = -0.492, p = 0.011) and CD8(+) (r = -0.432, p = 0.027) cells. We conclude that, contrary to expectations, sFas plasma levels increased in long-term surviving HIV-infected hemophilia patients receiving HAART, concomitant with increases in CD4(+) and CD8(+) cell counts. Increased sFas may reflect the growing pool of T lymphocytes that recovers because of a decreasing viral burden and a decreasing immune complex load of CD4(+) lymphocytes.

Association of immune complexes and plasma viral load with CD4+ cell depletion, CD8+ DR+ and CD16+ cell counts in HIV+ hemophilia patients. Implications for the immunopathogenesis of HIV-induced CD4+ lymphocyte depletion

OBJECTIVE

There is evidence that HIV induces CD4+ depletion in part by the formation of immune complexes (IC) that attach to CD4+ blood lymphocytes. In the present study we examined the relationship of IC-coated CD4+ blood cells with retroviral replication in HAART-treated patients.

PATIENTS AND METHODS

52 hemophilia patients were studied from 1997 to 1999. Lymphocyte subsets, IgM, IgG and gp120 on CD4+ blood cells, in vitro responses of lymphocytes to mitogens, plasma neopterin and plasma viral load were measured.

RESULTS

Patients with detectable viral replication and without ICs on CD4+ blood lymphocytes had a lower viral load (4100 versus 21000 HIV-1 mRNA copies/ml; P = 0.079) and higher CD4+ cell counts (310/microl versus 161/microl; P = 0.035) than patients with ICs on circulating CD4+ lymphocytes. Among patients with < 80 HIV-1 mRNA copies/ml, IC- individuals had slightly higher CD4+ lymphocyte counts than IC+ patients (384/microl versus 316/microl; n.s.). Further evidence for the clinical relevance of the ICs was obtained when 18 patients who had an undetectable viral load at previous investigations were analyzed. Among patients with a stable undetectable viral load, CD4+ counts increased in 6 of 8 IC- but in none of 2 IC+ individuals. In patients whose viral load increased during the observation period, 5 of 6 IC- but none of 2 IC+ individuals showed higher CD4+ cell counts. Impaired virus killing is suggested by lower CD16+ (35/microl versus 107/microl; P = 0.016), higher CD3+ DR+ (178/microl versus 66/microl; P = 0.006), and higher CD8+ DR+ (142/microl versus 34/microl; P = 0.017) cell counts in IC(-) patients compared to IC- patients without detectable viral load. Strong retroviral replication induced strong T cell dysfunctions. Fewer CD3+ 25+ blood lymphocytes (19/microl versus 47/microl; P = 0.006) and a lower in vitro response of T lymphocytes to the mitogens Con A (RR: 0.3 versus 1.2; P=0.023) and CD3 mab (RR: 0.5 versus 2.4; P = 0.012) was observed in IC+ patients with detectable versus undetectable viral load.

CONCLUSION

Our data suggest that ICs on circulating CD4+ blood lymphocytes are primarily associated with CD4+ lymphocyte depletion whereas the plasma viral load is primarily associated with decreased T lymphocyte activation, lower CD16+ counts, and higher CD8+ DR+ lymphocytes which might be the effector cells for virus elimination.

Switch from cyclosporine A to tacrolimus in renal transplant recipients: impact on Th1, Th2, and monokine responses

We showed previously that pretransplant CD4 helper defects and low in-vitro IL-10 responses predict a low risk of acute kidney graft rejection. To compare the effect of tacrolimus (Tacr) and cyclosporine A (CsA) on the humoral immune response we assessed T helper function, B cell/monocyte responses and in-vitro cytokine responses (TNF-alpha, GM-CSF, IL-1 beta, IL-2, IL-4, IL-6, IL-10) in 20 renal transplant recipients before and 3 months after they were switched from CsA to Tacr because of hyperlipoproteinemia, hirsutism, or gum hyperplasia. T helper function was assessed using a PWM-driven allogeneic coculture system of patient T cells together with control B cells. B cell/monocyte responses were determined using a PWM-stimulated allogeneic coculture system, SAC I-stimulated B-cell cultures and LPS-stimulated monocyte cultures. Immunoglobulin-secreting cell (ISC) responses were assessed in a reverse hemolytic plaque assay, and ELISA were used to determine cytokine secretion. Treatment with Tacr resulted in a decreased expression of costimulatory ligands and adhesion molecules (T cells: CD40L, p < 0.05; CD28 and CD54, p < or = 0.01; B cells: CD25, p = 0.05; CD40, p < 0.001; monocytes: CD40, p < 0.05), which coincided with decreased PHA-stimulated T cell IL-2 responses (398 +/- 153 versus 43 +/- 15 pg/ml, p < 0.05), impaired CD4 helper activity (117% +/- 22% versus 73% +/- 19%, p < 0.05) and increased CD4 suppressor activity (-120% +/- 28% versus -18% +/- 27%, p = 0.02). We observed enhanced CD4 IL-10 responses (p < 0.01) and LPS-stimulated monocyte responses (TNF-alpha, IL-1 beta, and IL-6, p < 0.005; IL-10, p < 0.05), indicating an increased humoral immune responsiveness under treatment with tacrolimus. Our data show that switching of immunosuppressive therapy from CsA to tacrolimus results in suppression of costimulatory ligands, adhesion molecules, Th1 responses and CD4 helper activity. However, enhanced humoral immune responses, Th2 and monokine responses, might have a negative impact on long-term graft function.

CD4 depletion in HIV-infected haemophilia patients is associated with rapid clearance of immune complex-coated CD4+ lymphocytes

The predominant immunological finding in HIV+ haemophilia patients is a decrease of CD4+ lymphocytes during progression of the disease. Depletion of CD4+ lymphocytes is paralleled by an increase in the proportion of immune complex-coated CD4+ cells. We examined the hypothesis that the formation of immune complexes on CD4+ lymphocytes is followed by rapid clearance of immune complex-coated CD4+ lymphocytes from the circulation. In this study, the relationship of relative to absolute numbers of immune complex-loaded CD4+ blood lymphocytes and their association with viral load were studied. Two measurements of relative and absolute numbers of gp120-, IgG- and/or IgM-loaded CD4+ lymphocytes were analysed in HIV+ and HIV- haemophilia patients, with a median interval of approx. 3 years. Immune complexes on CD4+ lymphocytes were determined using double-fluorescence flow cytometry and whole blood samples. Viral load was assessed using NASBA and Nuclisens kits. Whereas the proportion of immune complex-coated CD4+ lymphocytes increased with progression of the disease, absolute numbers of immune complex-coated CD4+ lymphocytes in the blood were consistently low. Relative increases of immune complex-coated CD4+ blood lymphocytes were significantly associated with decreases of absolute numbers of circulating CD4+ lymphocytes. The gp120 load on CD4+ blood lymphocytes increased in parallel with the viral load in the blood. These results indicate that immune complex-coated CD4+ lymphocytes are rapidly cleared from the circulation, suggesting that CD4+ reactive autoantibodies and immune complexes are relevant factors in the pathogenesis of AIDS. Relative increases of immune complex-positive cells seem to be a consequence of both an increasing retroviral activity as well as a stronger loading with immune complexes of the reduced number of CD4+ cells remaining during the process of CD4 depletion. The two mechanisms seem to enhance each other and contribute to the progressive CD4 decrease during the course of the disease.