IgE antibody against surface antigens of Leishmania promastigotes in American cutaneous leishmaniasis

Hyper IgE in New Zealand black mice due to a dominant-negative CD23 mutation

Immunoglobulin E (IgE) plays a critical role in both resistance to parasitic infection and allergy to environmental antigens. The IgE response is in turn regulated by the B-cell co-receptor CD23, and CD23-deficient mice show exaggerated IgE responses and airway hyper-responsiveness. In this report, we show that New Zealand black (NZB) mice express a variant CD23 allele, with mutations in both the C-lectin-binding domain and stalk region, which fails to bind IgE at high affinity and has reduced expression on the cell surface. Expression of the variant CD23 chain interferes with trimerisation of the receptor and has a dominant-negative effect leading to reduced IgE binding in crosses between NZB and other strains. Genetic mapping shows that the variant CD23 leads to an exaggerated primary IgE response, which is independent of other strain-specific effects. These results suggest that NZB mice or mice carrying the variant allele will be useful models for studying both allergy and quantitative traits associated with atopy. The exaggerated IgE response provides an explanation for the natural resistance of NZB mice to parasitic infection by Leishmania.

Cutaneous leishmaniasis in mast cell-deficient W/Wv mice

Genetically mast cell-deficient W/Wv mice infected with Leishmania amazonensis showed progressive development of ulcerative skin lesions. However, no significant differences between the W/Wv mice and the normal littermates with respect to size of the lesions, anti-Leishmania immunoglobulin E antibody, and the number of eosinophils accumulated in the lesions were observed.

Immunoblot analysis of sera from Ethiopian cutaneous leishmaniasis by antibody class

We have determined the specificity of the classes of anti-leishmanial antibodies which are detectable in serum from patients with active cutaneous leishmaniasis. On immunoblots, differences exist in the patterns of antigen recognition by IgG, IgM, IgA and IgE antibodies present in localized cutaneous leishmaniasis (LCL) and diffuse cutaneous leishmaniasis (DCL) patient serum. Each class of antibody showed differing patterns of banding to the various molecular species of parasite antigens. There was significant variation in the specificities of the IgG antibody reactivities between individual patients. The patterns of IgM binding were generally homogeneous and restricted to antigens with M(r) greater than 40 kDa. The only class of anti-Leishmania antibodies which showed shared patterns of common antigen recognition by all of the patients studied were IgA antibodies. The reactivities of IgE antibodies encompassed two antigens of M(r) 36 and 46-48 kDa which were not recognized by any of the other isotypes. Such antibody class associated reactivity may be useful in the design of serodiagnostic assays for the detection of Leishmania infection or other infectious agents.

Current treatment recommendations for leishmaniasis

OBJECTIVE

To review the epidemiology, clinical presentation, risk factors for transmission, and pathogenesis of leishmaniasis, as well as current treatment options for this disease. DATA SOURCES/DATA SELECTION: We reviewed unclassified medical-threat briefing material, subject-matter reviews, and case reports from the world's infectious disease literature. We concentrated on literature pertaining to the pathogenesis and management of leishmaniasis indigenous to Southwest Asia.

DATA EXTRACTION

Data from subject reviews published in the English language were evaluated. Case reports and clinical trials provided supplemental data on evolving theories and management options.

DATA SYNTHESIS

The clinical presentation of leishmaniasis is highly variable. Management relies heavily upon the use of parenteral antimonial drugs. Although these agents are effective in most cases, toxicity and the emergence of resistance limit the usefulness of standard therapies. Alternative treatment modalities include heat, surgical curettage, ketoconazole, metronidazole, pentamidine, rifampin, amphotericin B, aminoglycosides, allopurinol, and immunotherapy.

CONCLUSIONS

Although the number of reported cases of leishmaniasis in the US has generally been low, there is a possibility that more cases may be reported in the future because of the large number of military personnel returning to this country from endemic areas. Medical personnel, particularly those working in governmental institutions, should be familiar with the pathogenesis of this unusual infection as well as potential treatment options.