Continuous oral cytarabine ocfosfate with interferon-alpha-2b for patients with newly diagnosed chronic myeloid leukaemia: a pilot study

Recombinant(R) interferon alpha (r-IFN-alpha) has been shown to be an effective drug for chronic myeloid leukaemia (CML). However, higher response rates can be achieved using cytarabine along with r-IFN-alpha. YNK01 is a derivative of cytosine arabinoside for oral administration. So far, the only published experience with continuous YNK01 was in advanced CML (10 cases). We have performed a pilot study to evaluate the efficacy and toxicity of the combined therapy r-IFN-alpha and daily oral YNK01 in patients with newly diagnosed Ph+ CML. Ten previously untreated patients were included in the study. Among those patients evaluable for cytogenetic response, 87% (seven out of eight) reached a major cytogenetic response with four reaching complete cytogenetic response (50%). The most significant side-effects were gastrointestinal. Macrocytic anaemia was observed in three patients. In conclusion, continuous oral administration of YNK01 in combination with IFN-alpha is safe and can result in high-cytogenetic response rates.

Use of the 27-kilodalton recombinant protein from Paracoccidioides brasiliensis in serodiagnosis of paracoccidioidomycosis

Paracoccidioidomycosis (PCM) is one of the most important endemic mycoses in Latin America; it is usually diagnosed by observation and/or isolation of the etiologic agent, Paracoccidioides brasiliensis, as well as by a variety of immunological methods. Although the latter are effective, two circumstances, cross-reactions with other mycotic agents and antigen preparation that is marked by extreme variability among lots, hinder proper standardization of the procedures. To circumvent this lack of reproducibility, molecular biology tools were used to produce a recombinant 27-kDa-molecular-mass antigen from this fungus; a sizable quantity of this antigen was obtained through fermentation of Escherichia coli DH5alpha, which is capable of expressing the fungal protein. The latter was purified by the Prep-Cell System (Bio-Rad); the recovery rate of the pure protein was approximately 6%. A battery of 160 human serum samples, consisting of 64 specimens taken at the time of diagnosis from patients with PCM representing the various clinical forms plus 15 serum specimens each from patients with histoplasmosis and aspergillosis, 10 each from patients with cryptococcosis and tuberculosis, 6 from patients with coccidioidomycosis, and 40 from healthy subjects, were all tested by an indirect enzyme-linked immunosorbent assay with the purified 27-kDa recombinant protein. The latter was used at a concentration of 1.0 microgram/well; there were three serum dilutions (1:1,000, 1:2,000, and 1:4,000). The experiment was repeated at least twice. The average sensitivity for both experiments was 73.4%; in comparison with the healthy subjects, the specificity for PCM patients was 87.5% while for patients with other mycoses, it was 58.7%. Important cross-reactions with sera from patients with aspergillosis and histoplasmosis were detected. The positive predictive value of the test was 90.4%. These results indicate that it is possible to employ recombinant antigenic proteins for the immunologic diagnosis of PCM and, by so doing, achieve high coverage rates. Furthermore, antigen reproducibility can now be ensured, thus facilitating inter- and intralaboratory standardization.

Modulation of immunity to Borrelia burgdorferi by ultraviolet irradiation: differential effect on Th1 and Th2 immune responses

Ultraviolet B (UVB) radiation suppresses the delayed-type hypersensitivity (DTH) response to alloantigen by a mechanism involving interleukin (IL)-10. It has been hypothesized, based on this result, that UV irradiation shifts the immune response from a Th1 to a Th2 response. We tested this hypothesis using Borrelia burgdorferi (Bb) as an antigen under conditions where both DTH and antibody responses could be assessed. Mice were irradiated with a single dose of UV and then immunized with Bb in complete Freund's adjuvant (CFA). DTH was assessed by footpad challenge. At various time points thereafter, mice were bled, and the serum antibodies to Bb were quantitated. Only IgG1, IgG2a, and IgG2b were produced in response to Bb. The IgG2a and IgG2b antibody responses, as well as the DTH response to Bb, showed UV dose-dependent reductions after UV irradiation. The primary IgG1 response to Bb was very low and was unaffected by UV irradiation; however, the IgG1 secondary response was elevated in UV-irradiated mice. Injection of anti-IL-10 antibody into UV-irradiated mice within 24 h after UV exposure restored the DTH response, as well as the IgG2a and IgG2b antibody responses. In addition, injecting recombinant murine IL-10 mimicked some of the effects of UV radiation. Our results support the hypothesis that in vivo, UV irradiation down-regulates Th1 immune responses, while leaving Th2 responses intact, and suggest that IL-10 is an important mediator of this effect.

The role of IL-4, IL-10, and TNF-alpha in the immune suppression induced by ultraviolet radiation

Cytokines produced by keratinocytes play an essential role in the induction of immune suppression following ultraviolet (UV) exposure. Using antibodies specific for either interleukin-10 (IL-10) or tumor necrosis factor alpha (TNF-alpha), we present evidence indicating that IL-10 suppresses delayed-type hypersensitivity (DTH) but not contact hypersensitivity (CHS), whereas TNF-alpha suppresses CHS but not DTH following UV exposure. UV exposure also activates antigen-specific suppressor T cells. To determine whether the antigen-specific CD4+ T cells that transfer suppression in this system mediate their suppressive effect by releasing IL-4 or IL-10, we transferred UV Ts into normal mice that were then injected with either anti-IL-4 or anti-IL-10 antibody. Both anti-IL-4 and anti-IL-10 blocked the ability of UV Ts cells to suppress DTH in the recipient animals. When UV Ts that suppress CHS were transferred into normal recipients, however, neither antibody was able to block the UV Ts activity. These findings suggest that UV Ts suppress DTH by secreting IL-4 and IL-10 and appear to act like Th2 cells. Because anti-IL-4 and anti-IL-10 did not block the activity of the UV Ts that regulate contact hypersensitivity, their effects appear to be mediated by a different mechanism.

Systemic suppression of delayed-type hypersensitivity by supernatants from UV-irradiated keratinocytes. An essential role for keratinocyte-derived IL-10

Exposing murine keratinocyte cultures to UV radiation causes the release of a suppressive cytokine that mimics the immunosuppressive effects of total-body UV exposure. Injecting supernatants from UV-irradiated keratinocyte cultures into mice inhibits their ability to generate a delayed-type hypersensitivity reaction against allogeneic histocompatibility Ag, and spleen cells from mice injected with supernatant do not respond to alloantigen in the in vitro MLR. A unique feature of the immunosuppression induced by either total-body UV-exposure or injecting the suppressive cytokine from UV-irradiated keratinocytes is the selectivity of suppression. Although cellular immune reactions such as delayed-type hypersensitivity are suppressed antibody production is unaffected. Because the selective nature to the UV-induced immunosuppression is similar to the biologic activity of IL-10, we examined the hypothesis that UV exposure of keratinocytes causes the release of IL-10. Keratinocyte monolayers were exposed to UV radiation and at specific times after exposure mRNA was isolated or the culture supernatant from the cells was collected. IL-10 mRNA expression was enhanced in UV-irradiated keratinocytes. The secretion of IL-10 by the irradiated keratinocytes was determined by Western blot analysis. A band reactive with anti-IL-10 mAb was found in supernatants from the UV-irradiated but not the mock-irradiated cells. IL-10 biologic activity was determined by the ability of the supernatants from the UV-irradiated keratinocytes to suppress IFN-gamma production by Ag-activated Th 1 cell clones. Anti-IL-10 mAb neutralized the ability of supernatants from UV-irradiated keratinocytes to suppress the induction of delayed-type hypersensitivity in vivo. Furthermore, injecting UV-irradiated mice with antibodies against IL-10 partially inhibited in vivo immunosuppression. These data indicate that activated keratinocytes are capable of secreting IL-10 and suggest that the release of IL-10 by UV-irradiated keratinocytes plays an essential role in the induction of systemic immunosuppression after total-body UV exposure.

Systemic suppression of delayed-type hypersensitivity by supernatants from UV-irradiated keratinocytes. An essential role for keratinocyte-derived IL-10

Exposing murine keratinocyte cultures to UV radiation causes the release of a suppressive cytokine that mimics the immunosuppressive effects of total-body UV exposure. Injecting supernatants from UV-irradiated keratinocyte cultures into mice inhibits their ability to generate a delayed-type hypersensitivity reaction against allogeneic histocompatibility Ag, and spleen cells from mice injected with supernatant do not respond to alloantigen in the in vitro MLR. A unique feature of the immunosuppression induced by either total-body UV-exposure or injecting the suppressive cytokine from UV-irradiated keratinocytes is the selectivity of suppression. Although cellular immune reactions such as delayed-type hypersensitivity are suppressed antibody production is unaffected. Because the selective nature to the UV-induced immunosuppression is similar to the biologic activity of IL-10, we examined the hypothesis that UV exposure of keratinocytes causes the release of IL-10. Keratinocyte monolayers were exposed to UV radiation and at specific times after exposure mRNA was isolated or the culture supernatant from the cells was collected. IL-10 mRNA expression was enhanced in UV-irradiated keratinocytes. The secretion of IL-10 by the irradiated keratinocytes was determined by Western blot analysis. A band reactive with anti-IL-10 mAb was found in supernatants from the UV-irradiated but not the mock-irradiated cells. IL-10 biologic activity was determined by the ability of the supernatants from the UV-irradiated keratinocytes to suppress IFN-gamma production by Ag-activated Th 1 cell clones. Anti-IL-10 mAb neutralized the ability of supernatants from UV-irradiated keratinocytes to suppress the induction of delayed-type hypersensitivity in vivo. Furthermore, injecting UV-irradiated mice with antibodies against IL-10 partially inhibited in vivo immunosuppression. These data indicate that activated keratinocytes are capable of secreting IL-10 and suggest that the release of IL-10 by UV-irradiated keratinocytes plays an essential role in the induction of systemic immunosuppression after total-body UV exposure.

Suppression of the immune response to alloantigen by factors released from ultraviolet-irradiated keratinocytes

The immune response to allogeneic histocompatibility Ag can be suppressed by injecting allogeneic spleen cells into mice that have been previously exposed to UV radiation. The suppression is associated with Ag-specific suppressor T cells found in the spleens of the UV-irradiated mice. An intriguing and as yet unanswered question is how the irradiation of the animal's dorsal skin leads to the induction of splenic Ag-specific suppressor cells. Our data suggest that soluble factors released by UV-irradiated keratinocytes are involved in the induction of Ag-specific suppressor cells. Injecting culture supernatants from UV-irradiated keratinocytes into normal mice produced the same effect as whole-body UV irradiation and suppressed the induction of delayed hypersensitivity to alloantigen. Spleen cells from these mice were unable to respond to the alloantigen in the MLR. Radiation-resistant, suppressor T cells (CD3+, CD4+, CD8-) were found in the spleens of the mice injected with suppressive supernatants. Treating the keratinocytes with cycloheximide or treating the supernatants from the UV-irradiated keratinocytes with trypsin removed all suppressive activity, suggesting the active material is a protein. The suppressive activity bound to agarose beads coupled with Con A, and was eluted with alpha-methyl-D-mannoside, further suggesting the suppressive material is a glycoprotein. Because the suppression of the immune response to alloantigen induced by this suppressive cytokine mimicked the suppression found after exposure to UV radiation, these findings support the concept that the induction of systemic suppression by UV-irradiation results from the release of suppressive substances by UV-irradiated keratinocytes. In addition, these data suggest that the induction of Ag-specific suppressor cells by this factor may provide a novel method of suppressing allograft rejection.

Suppression of the immune response to alloantigen by factors released from ultraviolet-irradiated keratinocytes

The immune response to allogeneic histocompatibility Ag can be suppressed by injecting allogeneic spleen cells into mice that have been previously exposed to UV radiation. The suppression is associated with Ag-specific suppressor T cells found in the spleens of the UV-irradiated mice. An intriguing and as yet unanswered question is how the irradiation of the animal's dorsal skin leads to the induction of splenic Ag-specific suppressor cells. Our data suggest that soluble factors released by UV-irradiated keratinocytes are involved in the induction of Ag-specific suppressor cells. Injecting culture supernatants from UV-irradiated keratinocytes into normal mice produced the same effect as whole-body UV irradiation and suppressed the induction of delayed hypersensitivity to alloantigen. Spleen cells from these mice were unable to respond to the alloantigen in the MLR. Radiation-resistant, suppressor T cells (CD3+, CD4+, CD8-) were found in the spleens of the mice injected with suppressive supernatants. Treating the keratinocytes with cycloheximide or treating the supernatants from the UV-irradiated keratinocytes with trypsin removed all suppressive activity, suggesting the active material is a protein. The suppressive activity bound to agarose beads coupled with Con A, and was eluted with alpha-methyl-D-mannoside, further suggesting the suppressive material is a glycoprotein. Because the suppression of the immune response to alloantigen induced by this suppressive cytokine mimicked the suppression found after exposure to UV radiation, these findings support the concept that the induction of systemic suppression by UV-irradiation results from the release of suppressive substances by UV-irradiated keratinocytes. In addition, these data suggest that the induction of Ag-specific suppressor cells by this factor may provide a novel method of suppressing allograft rejection.