A patient with visceral leishmaniasis and acute renal failure in necrotizing glomerulonephritis

Renal involvement is an unusual complication of human visceral leishmaniasis (VL). The kidney lesions are characterized more by interstitial damage than glomerular or vascular damage. This case represents a 20 years-old man admitted with pancytopenia, purpura, acute renal failure, and nephrotic syndrome associated with heavy proteinuria. The diagnosis of VL was made on bone marrow smear cytology where Leishmania amastigotes were found. The renal biopsy revealed a segmental necrotising glomerulonephritis with 70% crescents. Treatment with liposomal amphotericine B alone has been ineffective on the course of renal failure, however, partial recovery was obtained after the administration of high dose corticosteroids. We present the various clinical, biological, and histological aspects of this case, from the south of France. It gave us the opportunity to discuss these unusual manifestations of immunomediated necrotising skin and renal lesions.     

Enrichment of invariant natural killer T cells in the bone marrow of visceral leishmaniasis patients

Lipid antigens of Leishmania donovani like lipophosphoglycans are shown as a potent ligand for the activation of invariant natural killer T (iNKT) cells. It is reported that activation of iNKT cells augments the disease pathology in experimental visceral leishmaniasis (VL). In this study, we demonstrate the enrichment of iNKT cells in the bone marrow, one of the disease sites among patients with VL.     

Subpopulations of T lymphocytes in Kenyan patients with visceral leishmaniasis

Populations of peripheral blood T lymphocytes from patients with Kenyan visceral leishmaniasis were studied using specifically defined antisera (monoclonal antibodies, Ortho-mune OKT3, OKT4, OKT6, and OKT8). The levels of total T lymphocytes and circulating thymocytes were within the same range as those of clinically normal individuals. However, the proportions of the helper/inducer T cells were lower in untreated patients than in the controls (18.9% vs. 39.7%) while the levels of suppressor/cytotoxic T cells were higher than in the controls (40.5% vs. 27.8%). After successful antileishmania treatment these levels showed a gradual return towards normal over a period of one year. It was concluded that immunosuppression observed is due to the levels of peripheral blood helper/inducer and suppressor/cytotoxic T lymphocytes.     

Tick modulation of the in-vitro expression of adhesion molecules by skin-derived endothelial cells

As a tick feeds, its saliva induces innate and acquired immune responses in the host, including leucocyte infiltration into the bite site. Tick salivary glands produce molecules, however, that counteract many host defences against blood feeding. The effects of salivary-gland extracts (SGE) of Dermacentor andersoni and Ixodes scapularis on the expression of various adhesion molecules [E-selectin, P-selectin, intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1)] by the sEND.1 cell line (which is based on cells from the subcutaneous tissue of mice) have now been investigated in vitro. The effects were found to differ with the tick species. The SGE of D. andersoni significantly down-regulated the expression of ICAM-1, whereas a similar extract prepared from I. scapularis significantly reduced the expression of P-selectin and VCAM-1. Tick salivary proteins therefore appear to have direct effects on adhesion-molecule expression, in addition to their previously established roles in down-regulating the pro-inflammatory cytokines that activate endothelial cells. It remains unclear exactly how the reduction of adhesion-molecule expression in the host's endothelial cells benefits the feeding tick but it may alter leucocyte migration to the bite site and/or reduce antigen presentation by the endothelial cells. It may also modulate the interactions between the host's leucocytes and any tick-borne pathogens, during initial infection of the endothelium.     

Hyponatremia in visceral leishmaniasis

There are few reports linking hyponatremia and visceral leishmaniasis (kala-azar). This is a study of 55 consecutive kala-azar patients and 20 normal individuals as a control group. Hyponatremia and serum hypo-osmolality were detected in 100% of kala-azar patients. High first morning urine osmolality (750.0 ± 52.0 vs. 894.5 ± 30.0mOsm/kg H?O, p < 0.05), and high 24-hour urine osmolality (426.0 ± 167.0 vs. 514.6 ± 132.0 mOsm/kg H?O, p < 0.05) demonstrated persistent antidiuretic hormone secretion. Urinary sodium was high (82.3 ± 44.2 vs.110.3 ± 34.7 mEq/L, p < 0.05). Low seric uric acid occurred in 61.8% of patients and increased fractional urinary uric acid excretion was detected in 74.5% of them. Increased glomerular filtration rate was present in 25.4% of patients. There was no evidence of extracellular volume depletion. Normal plasma ADH levels were observed in kala-azar patients. No endocrine or renal dysfunction was detected. It is possible that most hyponatremic kala-azar patients present the syndrome of inappropriate antidiuretic hormone secretion.     

American visceral leishmaniasis in Chiapas, Mexico

We report the results of a study conducted during 1990-2006 with 89 cases of American visceral leishmaniasis in Chiapas State in southeastern Mexico and a seroprevalence study performed with 726 persons and 224 dogs that lived near cases of American visceral leishmaniasis. Clinical aspects, epidemiologic profiles, and risk factors are described. Most cases were in children ≤ 5 years of age, the prevalence of seropositive persons was 77%. The main risk factors associated with this disease were having 1-3 rooms in a house compared with ≥ 4 rooms, having a roof that was not made of cement, and having domestic animals. In contrast, only 19% of dogs were seropositive, suggesting that this species is not important in the transmission cycle of Leishmania. These data indicate that active transmission is taking place in the central valley of Chiapas State, Mexico, in communities located < 1,000 meters above sea level near the Grijalva River.     

Androgen modulation of adhesion and antiadhesion molecules in PC-3 prostate cancer cells expressing androgen receptor

The metastatic spread of cancer cells involves a complex process of detachment via antiadhesion molecules and attachment and migration through adhesion. In the prostate, androgens are generally thought to contribute to the development and progression of prostate cancer by promoting cell proliferation and survival through poorly defined mechanisms. We have reported previously that PC-3 prostate cancer cells, which are unresponsive to androgens, show androgen-dependent detachment and ultimately apoptosis when stably transfected with a full-length human androgen receptor (AR) cDNA. We now demonstrate that treatment of these cells with 5alpha-dihydrotestosterone (DHT) for 24 or 48 h increased the expression of antiadhesion mucin MUC-1 at the cell surface as detected by flow cytometry with two independent antibodies. This increase in protein was concordant with up-regulation of MUC-1 mRNA in the AR-transfected PC-3 sublines, as determined by quantitative RT-PCR. Treatment with DHT for 48 h also down-regulated the cell surface expression of alpha2beta1-integrin but having little effect on the levels of alpha3beta1- and alpha5beta1-integrins. Androgen also decreased, in a dose-dependent manner, the adhesion of AR-transfected PC-3 cells to collagen type I, which was shown to be specifically inhibited by blocking antibody to alpha2beta1-integrin. The present data demonstrate that DHT can modulate expression of adhesion and antiadhesion molecules and suggest that this effect of androgen might contribute to prostate cancer progression.     

Myelodysplastic features in visceral leishmaniasis

We have detected trilineage myelodysplasia in two children recently diagnosed to have visceral leishmaniasis (V.L.), which led us to investigate retrospectively available peripheral blood and bone marrow aspirate smears of 5 children previously diagnosed as V.L. We saw that they also had trilineage myelodysplasia. We postulate that elevated levels of tumor necrosis factor-alpha (TNFalpha) may cause trilineage myelodysplasia in the patients with V.L. This nonclonal myelodysplasia may be responsible for pancytopenia along with hypersplenism, hemolysis and reticuloendothelial hyperplasia causing abnormal retention of iron in V.L.     

Mechanisms for segregating T cell receptor and adhesion molecules during immunological synapse formation in Jurkat T cells

T cells interacting with antigen-presenting cells (APCs) form an "immunological synapse" (IS), a bull's-eye pattern composed of a central supramolecular activation cluster enriched with T cell receptors (TCRs) surrounded by a ring of adhesion molecules (a peripheral supramolecular activation cluster). The mechanism responsible for segregating TCR and adhesion molecules remains poorly understood. Here, we show that immortalized Jurkat T cells interacting with a planar lipid bilayer (mimicking an APC) will form an IS, thereby providing an accessible model system for studying the cell biological processes underlying IS formation. We found that an actin-dependent process caused TCR and adhesion proteins to cluster at the cell periphery, but these molecules appeared to segregate from one another at the earliest stages of microdomain formation. The TCR and adhesion microdomains attached to actin and were carried centripetally by retrograde flow. However, only the TCR microdomains penetrated into the actin-depleted cell center, whereas the adhesion microdomains appeared to be unstable without an underlying actin cytoskeleton. Our results reveal that TCR and adhesion molecules spatially partition from one another well before the formation of a mature IS and that differential actin interactions help to shape and maintain the final bull's-eye pattern of the IS.     

Cryoglobulinemic purpura in visceral leishmaniasis

Visceral leishmaniasis may present with cytopenias along with the formation of many autoantibodies and, rarely, with the presence of mixed cryoglobulinemia, type II, resembling an autoimmune disease. The syndrome of mixed cryoglobulinemia is characterized by the triad of purpura, arthralgias, and asthenia, in conjunction with cryoglobulins in the serum. In this article mixed cryoglobulinemia, type II, was diagnosed in a negative for hepatitis B or C patient suffering from visceral leishmaniasis. Antimicrobial therapy against leishmania eliminated the cryoglobulin titer, as well as the clinical manifestations of cryoglobulinemia. The role of the immune system and the type of immune response for the formation of cryoglobulins are discussed.     

新疆喀什地区再度流行内脏利什曼病

喀什地区位于新疆南部边陲 ,辖 12县、市。早在 2 0世纪3 0年代 ,该地即有内脏利什曼病 (visceralleishmaniasis ,VL)的报道 ,5 0年代初确定当地为VL疫区 ,70年代中期在疏附三角洲 (喀什、疏附和疏勒三县市 )VL曾一度流行 ,年发病人数在2 0 0例左右 ,经 1977～ 1983年反复防治 ,至 1989年新发病人数降至 11例 ,基本控制了当地VL的流行。当前 ,除泽普、叶城和塔什库尔干 3县尚未发现该病外 ,其余 9县市 (包括喀什、疏附、疏勒、巴楚、英吉沙、麦盖提、伽师、岳普湖、莎车 )均有VL发生。2 0 0 3年 8月 ,作者对该地区VL的流行状况进行了短…