Impaired production of cytokines in a case of human leishmaniasis

Three Leishmania/L. species--L. infantum, L. major, L. tropica--as causative agents of mucosal leishmaniasis in Iran

Cases of human oro-mucosal leishmaniasis are mainly reported in areas where Leishmania (Viannia) braziliensis perpetuates and the damages are mainly located at the cartilaginous nasal septum and frontal portions of the nasal fossa. In Iran, an area free of any L.(V) braziliensis, three Leishmania species are known to perpetuate through distinct (i) blood-feeding sand flies and (ii) rodents or (iii) canidae. Thus while establishing the diagnosis of any human oro-mucosal lesions, three Leishmania species - L. infantum, L. major, and L. tropica - must be considered as potential etiological agents of these damages. With these objectives in mind, features such as localization, extent, severity of oro-mucosal lesions, and duration of symptoms at the time of diagnosis were recorded from 11 patients with respect to the presence or absence of cutaneous lesions in other body parts. The biopsy samples were collected from the oro-mucosal and cutaneous lesions and were processed for further identification of the Leishmania species. The lesions ranged from mucosal nodules without ulceration, nodules with erosion, and shallow to deep ulcerations. Leishmania major was isolated from six (55%) cases showing lesions or scars. The scars were restricted to upper and lower extremities. For the other five patients who did not display any signs of former or active cutaneous leishmaniasis, L. major, L. tropica, and L. infantum were isolated from their lesions. In conclusion L. major, L. infantum, and L. tropica, regardless of common tropism, can be seen in mucosal tissues. However, L. major was the predominant species detected from the lesions in the nasal, gingival, and hard and soft palates, and L. tropica was isolated from the gingival and lower lip lesions. Leishmania infantum was isolated from two severe cases of deep mucosal damage displayed by the epiglottis, cricoarytenoid muscle, and laryngeal mucosa. One important finding was the association of L. major with active or scarred skin lesions.

A patient presenting with diffuse cutaneous leishmaniasis (DCL) as a first indicator of HIV infection in India

Opportunistic parasitic infections such as leishmaniasis are common in human immunodeficiency virus (HIV)-infected patients and are usually acquired several days after initial diagnosis of HIV infection. Here, we report on a patient who presented with diffuse cutaneous leishmaniasis (DCL) caused by Leishmania tropica as the first and only clinical manifestation of HIV infection. To the best of our knowledge, this is the first case that illustrates that DCL could be the first clinical indicator of HIV infection. Cutaneous leishmaniasis (CL) and DCL are becoming frequent opportunistic infections in HIV-infected individuals throughout the world. To date, all documented cases of CL and HIV coinfections have been reported in patients who were known cases of HIV and who subsequently developed CL. In this report, we present a case that illustrates that DCL could be the first clinical indicator of HIV infection.

THE HUMAN CYTOKINE RESPONSE TO LEISHMANIA MAJOR EARLY AFTER EXPOSURE TO THE PARASITE IN VITRO

Leishmaniasis is caused by the protozoan parasite Leishmania spp. In murine leishmaniasis, a T helper cell type-I (Th1) response, characterized by the secretion of interferon (IFN)-gamma is necessary for clearing the infection. whereas a Th2 response, accompanied by the production of interleukin (IL)-5, can exacerbate the disease. Moreover, the early cytokine milieu is thought to play an important role in determining the outcome of infection. In human leishmaniasis little is known about this early cytokine response. Because of this, we cocultured human peripheral blood mononuclear cells (PBMC) with Leishmania major in vitro and measured the production of IFN-gamma, IL-5, and IL-10. We also treated PBMC cultures with various cytokines and neutralizing anticytokines. We found that the principal cytokine produced was IFN-gamma and that its production was regulated by IL-10 and IL-12. In contrast, only low levels of Th2 cytokines such as IL-5 were produced. Therefore, the Th1-Th2 dichotomy that exists in inbred strains of mice does not appear to apply to the response of humans to L. major. Rather, Th2 cytokines may play a role in regulating IFN-gamma production.

Transcriptional and translational regulation of heat shock proteins in leukocytes of endurance runners

Heat shock proteins (HSP) represent cell-protective and antioxidant systems that may be induced by reactive oxygen species, cytokines, and hyperthermia. In the present study, we evaluated the influence of heavy endurance exercise and training on HSP27 and HSP70 in peripheral leukocytes of 12 athletes (before and at 0, 3, and 24 h after a half-marathon) and 12 untrained controls on protein and mRNA levels by flow cytometry and RT/PCR, respectively. HSP transcripts increased significantly immediately after acute exertion accompanied by elevated levels of corresponding proteins. HSP protein expression remained high until 24 h postexercise. Significant increases of plasma interleukin-8, myeloperoxidase, and creatine kinase occurred after exercise. Basal HSP expression was usually lower in trained compared with untrained subjects. Applying in vitro heat shock to resting blood samples of all subjects significantly stimulated HSP mRNA, showing higher increases in trained individuals. The exercise-induced alterations indicate that immunocompetent cells became activated. In addition to heat stress, other exercise-associated stress agents (oxidants, cytokines) may have also participated in stimulation of HSP expression in leukocytes. The expression pattern of HSP due to training status may be attributed to adaptive mechanisms.