Inmunoglobulinas en pacientes con actinomicetoma por Nocardia brasiliensis / Immunoglobulins in patients with Nocardia brasiliensis actinomycetoma

Considerando que algunos autores han reportado un aumento en la cantidad de algunas inmunoglobulinas en los pacientes con actinomicetoma, en este trabajo nos propusimos determinar diferencias en la producción de IgG1, IgG2, IgG3, IgG4 e IgM en 25 pacientes con actinomicetoma por Nocardia brasiliensis y 25 personas sanas provenientes de una zona endémica de micetoma. La determinación de inmunoglobulinas se realizó por medio de la técnica de ELISA. Para sensibilizar las placas se emplearon 6 antígenos de N. brasiliensis: un antígeno crudo denominado NB y cinco derivados del mismo (NB2, NB4, NB6, NB8 y NB10) separados por punto isoeléctrico. Los niveles de las cuatro subclases de IgG fueron mayores en los sueros de los pacientes que en el suero de los controles, con una diferencia máxima en IgG3 e IgG4; para esta última subclase, los seis antígenos fueron altamente reactivos. La concentración de IgM fue igual en ambos grupos. Es probable que como ocurre en otras infecciones, en la fisiopatogenia del actinomicetoma influya no sólo el aumento o deficiencia de una clase de inmunoglobulina, sino la relación que existe entre las diferentes subclases.

Considering that some authors have reported an increasing of some immunoglobulins in actinomycetoma patients, in this study we propose to determine differential production of IgG1, IgG2, IgG3, IgG4 and IgGM in 25 patients with actinomycetoma and 25 healthy individuals from a mycetoma endemic area. Immunoglobulins were determined by ELISA technique. To sensibilize the plates, six Nocardia brasiliensis antigens were used: a crude antigen denominated NB and five derivatives (NB2, NB4, NB6, NB8 and NB10) obtained by their isoelectric point. Results showed that all IgG subclasses were higher in the patients’ sera than in control sera, with a maximal difference to IgG3 and IgG4. To the latter subclass, six antigens were highly reactives. IgM levels were similar in both groups. As it occurs in other infections, in the actinomycetoma pathogenesis probably participate the increase or deficiency of a determined immunoglobulin class, as well as the relationship between different subclasses.

Immunoglobulin profile in mycetoma.

Serum samples obtained from 25 patients of mycetoma caused by Madurella mycetomi in 18, Streptomyces somaliensis in 5, Streptomyces madurae and streptomyces palletierii from 1 each and also from 25 healthy controls were evaluated for immunoglobulins IgG, IgM and IgA by radial immunodiffusion method using tripartigen plates. All the three classes of immunoglobulins showed increased concentration in cases of mycetoma by M. mycetomi and S. pelletierii. The raised levels of IgG and IgM in cases of mycetoma caused by S. madurae and S. somaliensis where bones were involved, were not statistically significant. IgA was consistently high in all cases of mycetoma irrespective of causative agent and tissue involved. These alterations may possibly reflect relatively poor IgG and IgM response in individuals with extension of mycetoma lesion to bones.

Investigation of the temporal humoral immune response in a murine model of actinomycetoma

The murine model of actinomycetoma offers the potential of studying many unknown aspects of this infection. In this work, the model was used to investigate the temporal humoral immune response to actinomycetoma agents. Groups of 7- to 9-week-old female BALB/c mice were inoculated in one of the hind footpads with one of four different Nocardia strains. To mimic the constant exposure of infected humans to the virulent soil inhabiting agents, a second injection consisting of live nocardiae in incomplete Freund's adjuvant was administered five months after the first one. Murine serum samples were collected throughout the study and their IgM and IgM titers were determined by ELISA and the Western blot assay. The results obtained indicate that the ELISA titers increased as the infection progressed and this correlated with a greater number of antigen bands being recognized in the blots. Overall, however, the ELISA titers were lower for the N. brasiliensis infected mice than those of the N. asteroides ones. This observation may be indicative of an immunosuppressive state and is worthy of further investigation

Status inmunológico del paciente con micetoma / Immunological status of the patient with mycetoma

Los resultados de las observaciones clínicas y las investigaciones inmunológicas de pacientes con micetomas sugieren que puede haber una alteración en algunas de las funciones de la inmunidad mediada por células. Los mecanismos de resistencia del hospedador a las infecciones por Nocardia han sido asociadas con: 1)la inhibición de las Nocardias por parte de los monocitos y leucocitos polinorfonucleares, 2)la activación de los macrófagos y 3)la citotoxicidad especifíca de una población contra las infecciones producidas por la Nocardia. Sin embargo, hay producción de anticuerpos los cuales podrían ser valiosos en el serodiagnóstico del micetoma