The immune microenvironment in cutaneous leishmaniasis.

BACKGROUND: Cutaneous leishmaniasis is an infection that has spread to non-endemic regions, stimulating recent interest for the enhanced understanding of this disease. Downregulation of the CD1a receptor on Langerhans cells has been described in various cutaneous infections. OBJECTIVE: In this study, the immune response across different Ridley patterns and parasitic indices is outlined in a case series of cutaneous leishmaniasis. METHODS: Skin punch biopsies from the interface of normal and lesional cutaneous leishmaniasis were collected from 33 patients with molecularly confirmed Leishmania tropica or L. major infection. Ridley patterns (2-5) were assessed for various clinicopathological features including age, gender, disease duration, parasitic index and constituents of the inflammatory infiltrate. CD1a, CD68, CD3, CD4, CD8, CD20 and CD138 stains were performed on normal skin tissue, cutaneous leishmaniasis biopsies and cytospin/cell block cytology preparations of cultured leishmania promastigotes. CD1a was quantified per mm2 in the epidermis and dermis. The remaining stains were graded according to a 4-tiered grading system [0 (0-4%); 1 (5-24%); 2 (25-49%); 3 (50-74%) and 4 (75-100%). RESULTS: Total CD1a expression significantly decreased (14-fold) from parasitic indices (0-2) to (5-6); (ρ < 0.001). CD1a expression in the epidermis was at least 5-fold lower than normal skin (58 vs. 400 cells/mm2), inversely correlating with the parasitic index. There was an increase in dermal CD1a Langerhans cells (33 vs. 0 cells/mm² in the dermis). CD1a and CD68 staining of amastigotes was strong and diffuse, whereas promastigotes were negative. The major inflammatory infiltrate, in all Ridley patterns, consisted of macrophages and double-negative CD3(+) CD4(-) CD8(-) T lymphocytes. The double-negative CD3 T cells formed a ring around the parasitic laden macrophages. Apart from CD1a, there was no significant difference in inflammatory markers between the various Ridley patterns and parasitic indices. Disease duration did not correlate with Ridley pattern. CONCLUSION: The significant decrease in CD1a expression is postulated by two mechanisms; either via direct CD1a receptor uptake by leishmania amastigotes and/or negative feedback inhibition of CD1a Langerhans cells by double-negative CD3 T-regulatory cells. Modulation of the immune microenvironment in cutaneous leishmaniasis represents a potential therapeutic and prophylactic target.

Study of KIR genes in Lebanese patients with tuberculosis.

A total of 103 Lebanese tuberculosis (TB) cases and 38 controls without TB were studied for the killer cell immunoglobulin-like receptors (KIR) genotypic profile using polymerase chain reaction sequence-specific primers. Patients and controls were assigned to the AA, AB or BB genotypes based on their A or B haplotype genetic make-up, and KIR gene frequencies were compared. We found an increase in the KIR A haplotype in TB patients compared to controls, and only KIR 2DL3 was found to be significantly more prevalent among TB patients. This confirms the findings of another unique international study performed in the Mexican population showing a greater repertoire of inhibitory KIR genes among TB patients than controls.

Resistance to aspirin and clopidogrel therapy.

INTRODUCTION: Despite increasing evidence on the roles of aspirin and clopidogrel in decreasing morbidity and mortality from cardiovascular disease, resistance to therapy remains an emerging clinical entity. The aim of this review was to revisit current knowledge of the mechanisms, laboratory evaluation, clinical impact and management of resistance to aspirin and clopidogrel therapy. METHODS: Potentially relevant studies were identified from an electronic search of MEDLINE and PubMed databases. There were no language or publication year restrictions. References in published articles were also reviewed. RESULTS: Several definitions for resistance have been set, and various laboratory testing modalities are available. The pathophysiological mechanisms remain poorly understood; yet, several extrinsic, intrinsic and genetic factors are described. The clinical implications of this phenomenon are alarming and warrant concern. Management is currently limited to dosing alteration and introduction of other antiplatelet agents. CONCLUSION: Data from ongoing and future studies are awaited to better understand this entity and to highlight the most appropriate treatment strategies.

Survival and complications of beta-thalassemia in Lebanon: a decade's experience of centralized care.

beta-Thalassemia major is a debilitating disease with a considerable incidence in Lebanon (around 2-3% carriership). The present article describes our experience to this day with 214 patients, emphasizing the survival of beta-thalassemia major and development of complications among patients with different parameters. Fifteen deaths were reported. The most common cause of death was heart failure (60%). Patients with a ferritin level of 3,000 ng/ml showed better survival than those with a level >3,000 ng/ml (p < 0.006). In addition, patients with a ferritin level of 1,500 ng/ml showed less complication-free survival than those with a level >1,500 ng/ml (p < 0.024). High level of ferritin (1,500 ng/ml) is associated with increased risk of heart failure. Overall and complication-free survival were statistically different among patients classified according to birth cohort or ferritin level. The Chronic Care Center, a multidisciplinary center located in the suburbs of Beirut, led to an increase in complication-free as well as overall survival. Although patients are being diagnosed earlier and chelation therapy is being initiated at an earlier age, complications due to iron overload still persist. The introduction of new oral iron chelators and better iron overload quantitation methods will most likely modify this picture, and a follow-up study will examine their impact.