Identification and glycobiological characterization of circulating immune complexes in patients with visceral leishmaniasis and post kala azar dermal leishmaniasis.

Here, we investigated the quantitative and qualitative differences in antibody classes and subclasses in serum immune complexes (ICs) of Visceral Leishmaniasis (VL), Post Kala-azar Dermal Leishmaniasis (PKDL) and different cross reactive diseases like Malaria, Leprosy, Vitiligo as compared to control subjects. IC levels were measured through a newly developed PEG ELISA, using L. donovani promastigote membrane antigen coated plate. Antibody classes and subclasses were identified using polyspecific sera and monoclonal antibodies, respectively. ICs were purified using polyethylene glycol (PEG) precipitation. Conditional logistic regression showed an association between IgG1-containing ICs and increased risk of PKDL (OR=75, P <0.05) and an association of IgG-containing ICs with VL (OR=621, P=0.001). PEG ELISA demonstrated almost 13-15 fold higher IgG containing ICs titers in VL as compared to control (P <0.001). The assay further established a significant (P <0.05) difference in the IgG containing ICs titers between VL and PKDL. The isolated ICs were further analyzed by subjecting them to one-dimensional PAGE and subsequently stained with combination of periodic acid schiff (PAS) with silver. A differential banding pattern between VL and PKDL was obtained. Four distinct bands with carbohydrate rich glycoconjugates were identified in PKDL ICs, which were absent in VL and control group. It suggests the scope for developing a novel differential diagnostic assay.

Histopathological characteristics of post kala-azar dermal leishmaniasis: A series of 88 patients.

Background: Post kala azar dermal leishmaniasis (PKDL) is a sequel to visceral leishmaniasis or kala azar seen predominantly in the Indian subcontinent and Africa. Histopathological descriptions of the condition are limited. Methods: Biopsies of 88 skin and 16 mucosal lesions were evaluated for histopathological findings on formalin-fixed, paraffin-embedded tissues. Results: There were 71 (80.7%) males and 17 (19.3%) females with a mean age of 24.8 and 28.5 years, respectively. A past history of kala azar was present in 64 (72.7%) patients and post kala azar dermal leishmaniasis developed a mean of 6.2 years after visceral leishmaniasis. Of the biopsies studied, the clinical lesions were macular in 14 (15.9%), papulo-nodular in 32 (36.3%) and showed both macules and papulo-nodules in 42 (47.8%). Follicular plugging was a common epidermal finding. A clear Grenz zone was frequently noted. The dermal infiltrates were arranged mainly in three patterns: superficial perivascular infiltrates in 16 (18.1%), perivascular and perifollicular infiltrates in 24 (27.3%) and diffuse infiltrates in 41 (46.6%) biopsies. Leishman-Donovan (LD) bodies were noted in 13 (44.9%) of 69 cases on slit-skin smear and in 25 (28.4%) of 88 biopsies. In 16 patients, where both skin and mucosal biopsies were available, LD bodies were identified in 10 (62.5%) mucosal biopsies as compared to 3 (18.7%) skin biopsies. Limitations: The retrospective nature of the study and the lack of controls were limitations. Conclusion: The various histomorphological patterns of post kala azar dermal leishmaniasis are a useful clue to the diagnosis even when LD bodies have not been detected. This study also suggests that LD bodies are more frequently seen in mucosal biopsies in comparison to cutaneous biopsies.