Lymphocyte transformation in cutaneous leishmaniasis patients

Abstract

Cellular responses to L. mexicana amazonensis, L. infantum and phytohaemagglutinin (PHA) were measured in twenty-three cutaneous leishmaniasis patients, using the lymphocyte blast transformation test (LTT). Positive responses to leishmanial antigen, although variable, were observed in all patients, compared with the normal controls. Patient responses to PHA, however, were lower than those observed in the control group. No significant differences were shown between responses of active and convalescent patients to leishmanial antigen. Since it is unclear whether or not the presence of anti-Leishmania antibody may inhibit cellular immunity, LTT responses from ELISA-positive and ELISA-negative patients were compared using either leishmanial antigens or PHA. No significant LTT differences between their responses was found for leishmanial antigens or PHA. When cells from each patient and each normal control individual were cultured in either 10% AB+ serum or 10% autologous serum, no significant differences in responses to leishmanial antigen was found. Responses to PHA were just significantly lower in AB+ serum than in autologous serum. Since this was an overall trend and not peculiar to any one group, the most likely explanation is that the autologous serum constituted a slightly superior tissue culture medium. Specific antibody and non-specific serum factors do not appear to influence cell mediated responses to leishmanial antigens or PHA.