RESUMEN
OBJECTIVE: To determine the effect(s) of reactive sulfonamide metabolites on antibody production by human lymphocytes. METHODS: Human peripheral blood cells (PBMCs) were isolated from control volunteers and incubated with the hydroxylamine of sulfamethoxazole (SMX H/A), a reactive metabolite of the most commonly used sulfonamide, in increasing concentrations. PBMCs were then stimulated to produce antibody with pokeweed mitogen. After incubation for 8 days, concentrations of IgG and IgM were determined in supernatant using an ELISA assay. RESULTS: Production of both IgG and IgM was significantly suppressed by sub-lethal concentrations of SMX H/A in a concentration-dependent fashion (p < 0.05). Suppression was more marked for IgM production (maximal decline to 80% of baseline antibody production) than for IgG production (maximal decline to 57% of baseline antibody production). No suppression was seen when cells were incubated with sulfamethoxazole in concentrations up to 400 microM. This suppression was not related to changes in cell viability; at a concentration of 25 microM of SMX H/A, IgM and IgG concentration were reduced by 47 +/- 8.7% and 73 +/- 7.2%, while cell viability (percentage of live cells) was 93 +/- 5%. Suppression was time-dependent, increasing over the incubation periods to reach a plateau after 2 h of incubation. CONCLUSION: Sulfonamide reactive metabolites, in concentrations which are achieved during therapy, suppress antibody production by PWM-stimulated human cells. This may explain, in part, the alterations in immunity associated with hypersensitivity reactions to the sulfonamides. This may also have implications for patients receiving sulfonamide therapy and concurrent immunosuppressive therapy.
Asunto(s)
Antiinfecciosos/farmacología , Linfocitos B/efectos de los fármacos , Linfocitos B/inmunología , Inmunoglobulina G/biosíntesis , Inmunoglobulina M/biosíntesis , Mitógenos de Phytolacca americana/inmunología , Sulfametoxazol/análogos & derivados , Formación de Anticuerpos , Humanos , Tolerancia Inmunológica , Leucocitos Mononucleares/inmunología , Leucocitos Mononucleares/metabolismo , Sulfametoxazol/farmacologíaRESUMEN
We previously demonstrated the capacity of the hydroxylamine metabolite of sulfamethoxazole (SMX-HA) to inhibit mitogen-induced T-cell proliferation. We studied the interaction of SMX-HA with the immuno-suppressants cyclosporin A (CsA), FK506 and rapamycin. Human peripheral blood mononuclear leukocytes were treated with SMX-HA and combined in culture with CsA or FK506 or rapamycin. The cells were stimulated with phytohaemaglutinin, and phorbol myristate acetate and proliferation was determined by cellular uptake of 3H-thymidine. Using median-effect analysis and concentration reduction index calculations to assess immunosuppressive drug interactions, we produced synergistic immunosuppression by SMX-HA/CsA and SMX-HA/FK506. Concentration reductions at the 50% inhibitory level of over 46-fold and 64-fold with CsA and FK506, respectively, were observed with 25 microM SMX-HA, and this effect was not associated with reduced cell viability. SMX-HA failed to augment the suppressive capacity of rapamycin in inhibiting mitogen-induced cellular proliferation. SMX-HA at immunosuppressive concentrations also failed to interfere with interleukin-2 mRNA transcription and interleukin-2 protein production, which suggests that signaling events proximal to cytokine production are not affected by the metabolite. Synergy between SMX-HA/FK506 and SMX-HA/CsA suggests that the mechanism(s) of action of reactive sulfonamide metabolites may occur in later stages of lymphocyte activation.
Asunto(s)
Ciclosporina/farmacología , Inmunosupresores/farmacología , Activación de Linfocitos/efectos de los fármacos , Sulfametoxazol/análogos & derivados , Linfocitos T/efectos de los fármacos , Tacrolimus/farmacología , Actinas/genética , División Celular/efectos de los fármacos , Sinergismo Farmacológico , Humanos , Interleucina-2/biosíntesis , Interleucina-2/genética , Polienos/farmacología , ARN Mensajero/análisis , Sirolimus , Sulfametoxazol/farmacología , Linfocitos T/inmunologíaRESUMEN
It has been suggested that the high rates of adverse reactions to sulfonamides among patients with AIDS may be related to an increased sensitivity to reactive drug metabolites among HIV-infected cells. To study this hypothesis, we investigated the toxicity of the hydroxylamine of sulfamethoxazole in HIV-infected and noninfected MOLT-3 cultured human T-lymphoblasts. Toxicity was assessed by trypan blue dye exclusion. The hydroxylamine of sulfamethoxazole produced concentration-dependent toxicity in HIV-infected cells, with marked toxicity seen when HIV-infected cells were incubated with 400 microM of the hydroxylamine (82 +/- 8%); this was significantly greater than the toxicity seen among noninfected cells (p < 0.01). There was no concentration-dependent toxicity seen among noninfected cells or in cells infected with HTLV-I, suggesting that the concentration-dependent toxicity seen was specifically related to HIV infection. HIV-infected cells had significantly lower glutathione concentration than did noninfected cells (p < 0.05). Incubation with the hydroxylamine of sulfamethoxazole produced a concentration-dependent decline in glutathione content that was similar in infected and non-infected cells. Co-incubation with glutathione or N-acetylcysteine significantly reduced the toxicity of hydroxylamine of sulfamethoxazole in HIV-infected cells (p < 0.05). Our data supports the role of reactive sulfonamide metabolites in the pathogenesis of adverse reactions to sulfonamides among patients with AIDS.
Asunto(s)
Infecciones por Deltaretrovirus/tratamiento farmacológico , Infecciones por VIH/tratamiento farmacológico , Sulfametoxazol/análogos & derivados , Linfocitos T/efectos de los fármacos , Adulto , Células Cultivadas , Relación Dosis-Respuesta a Droga , Hipersensibilidad a las Drogas/etiología , Humanos , Modelos Biológicos , Sulfametoxazol/toxicidad , Linfocitos T/virología , Pruebas de ToxicidadRESUMEN
It has been suggested, on the basis of work in cell-free systems, that sulfonamide hydroxy-lamines are metabolized to nitroso metabolites which may be the proximate toxins mediating sulfonamide hypersensitivity reactions. We performed time-course experiments investigating the toxicity of the hydroxylamine and nitroso derivatives of sulfamethoxazole to investigate this hypothesis. The nitroso derivative of sulfamethoxazole was significantly more toxic than the hydroxylamine derivative (P < 0.05). When the LC50 was compared over time, there was a significant decrease in the LC50 of the hydroxylamine of sulfamethoxazole over time, while there was no change in the LC50 of the nitroso derivative. There was an equivalent reduction in toxicity demonstrated when the hydroxylamine or nitroso derivatives were co-incubated with glutathione. This supports the role of the nitroso as a proximate toxin mediating sulfonamide hypersensitivity reactions and suggests an explanation for the high rate of adverse reactions to sulfonamides among patients with AIDS.
Asunto(s)
Hidroxilaminas/toxicidad , Linfocitos/efectos de los fármacos , Sulfametoxazol/análogos & derivados , Sulfonamidas/metabolismo , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Dimetilsulfóxido/farmacología , Fluorescencia , Glutatión/farmacología , Humanos , Dosificación Letal Mediana , Modelos Lineales , Sulfametoxazol/metabolismo , Sulfametoxazol/toxicidad , Sulfonamidas/toxicidad , Factores de TiempoRESUMEN
Hypersensitivity adverse drug reactions, characterized by fever and multi-organ involvement, are the most severe adverse reactions to sulphonamides. Although there is evidence that these reactions are initiated by metabolic events, these reactions appear to be propagated on an immune basis. We investigated the effect of a sulphonamide reactive metabolite, the hydroxylamine of sulphamethoxazole (SMX H/A), on the ability of T-lymphocytes to respond to stimulation with mitogens. Peripheral blood mononuclear cells (PBMCs) were collected and incubated with SMX H/A in increasing concentrations. PBMCs were then incubated with phytohaemagglutinin (PHA) and phorbol myristate acetate (PMA) or with PHA and ionomycin. T-lymphocyte proliferation was then determined by tritiated thymidine uptake. The hydroxylamine of sulphamethoxazole produced a concentration-dependent decrease in T-lymphocyte proliferation; this decrease was significant even at concentrations of hydroxylamine that were not associated with a decrease in cell viability. PBMCs incubated with SMX H/A that were washed and then added to fresh PBMCs failed to inhibit the proliferation of fresh PBMCs. The hydroxylamine of sulfamethoxazole produces profound suppression of T-lymphocyte proliferation. This suppression appears to be a direct event and does not involve the activation of suppressor cells. These findings may explain the infectious complications contributing to mortality associated with sulphonamide hypersensitivity reactions.
Asunto(s)
Activación de Linfocitos/efectos de los fármacos , Sulfametoxazol/análogos & derivados , Linfocitos T/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Humanos , Tolerancia Inmunológica/efectos de los fármacos , Técnicas In Vitro , Mitógenos/farmacología , Sulfametoxazol/efectos adversos , Linfocitos T/inmunologíaRESUMEN
Hypersensitivity reactions are the most common adverse events associated with therapy with the sulphonamide antibiotics. These reactions have been shown to occur among individuals with pharmacogenetically determined differences in the capacity of their cells to detoxify reactive products of oxidative metabolism of the sulphonamides. These reactions appear to be propagated by an inflammatory response by the immune system. To investigate the role of the cytokine tumour necrosis factor (TNF-alpha) in these reactions, we studied the production of TNF-alpha by peripheral blood mononuclear cells (PBMCs) that had been incubated with sulfamethoxazole and murine microsomes in the presence and absence of a microsomal-activating system and TNF-alpha production by PBMCs in the presence and absence of the hydroxylamine derivative of sulfamethoxazole. The PBMCs showed a time-related increase in the production of TNF-alpha. There was no increase in TNF-alpha production seen during incubation with sulphonamide reactive metabolites; rather, there was a decrease in TNF-alpha elaboration that was most marked when PBMCs were incubated with the hydroxylamine of sulfamethoxazole. There is no evidence from these in vitro studies that TNF-alpha is involved as a mediator of the inflammatory response in sulphonamide hypersensitivity adverse drug reactions.
Asunto(s)
Sulfonamidas/toxicidad , Factor de Necrosis Tumoral alfa/biosíntesis , Animales , Pruebas Inmunológicas de Citotoxicidad , Hipersensibilidad a las Drogas/inmunología , Humanos , Técnicas para Inmunoenzimas , Técnicas In Vitro , Ratones , Monocitos/inmunología , Sulfonamidas/metabolismoRESUMEN
To examine the possible relationship between the cells mediating resistance to tumour cells and those mediating rejection of foreign bone marrow transplants (BMT), the effect of tumour-bearing on BMT rejection has been measured by means of the spleen colony assay. Moderate doses (less than 5.0 X 10(6] of bone marrow cells from DBA/2 strain mice, which normally produce few haemopoietic spleen colonies in gamma-irradiated (950R) CBA/J strain mice, gave numerous (confluent) colonies when given soon after injection of Ehrlich ascites tumour (EAT) cells. Transfusion of [3H]UdR-labelled DBA/2 bone marrow cells demonstrated that the increased spleen colony formation in tumour-bearing mice was not due simply to changes in the total number of injected cells homing to the spleen. Injection of EAT ascites fluid alone, given to CBA/J mice before 950R + BMT, transiently reduced spleen colony development, the effect being more marked when fluid from older tumors was used. Supernatant fluid from EAT cells grown in vitro also depressed growth of BMT in vivo. The results reveal two processes in progress in mice bearing an ascites tumour: (1) an early reduction in the natural resistance to BMT allowing successful grafting and spleen colony formation, and (2) a progressive production by the tumour cells of short-acting soluble factors tending to suppress the proliferation of colony forming bone marrow cells in the transplant. The effect of the tumour-bearing state in weakening the natural resistance to foreign BMT strongly suggests that both tumour and foreign marrow graft resistance are mediated by the same or closely related effector cells.