ßS-Haplotypes in sickle cell anemia patients from Salvador, Bahia, Northeastern Brazil

BetaS-Globin haplotypes were studied in 80 (160 betaS chromosomes) sickle cell disease patients from Salvador, Brazil, a city with a large population of African origin resulting from the slave trade from Western Africa, mainly from the Bay of Benin. Hematological and hemoglobin analyses were carried out by standard methods. The betaS-haplotypes were determined by PCR and dot-blot techniques. A total of 77 (48.1%) chromosomes were characterized as Central African Republic (CAR) haplotype, 73 (45.6%) as Benin (BEN), 1 (0.63%) as Senegal (SEN), and 9 (5.63%) as atypical (Atp). Genotype was CAR/CAR in 17 (21.3%) patients, BEN/BEN in 17 (21.3%), CAR/BEN in 37 (46.3%), BEN/SEN in 1 (1.25%), BEN/Atp in 1 (1.25%), CAR/Atp in 6 (7.5%), and Atp/Atp in 1 (1.25%). Hemoglobin concentrations and hematocrit values did not differ among genotype groups but were significantly higher in 25 patients presenting percent fetal hemoglobin (%HbF) > or = 10% (P = 0.002 and 0.003, respectively). The median HbF concentration was 7.54+/-4.342% for the CAR/CAR genotype, 9.88 3.558% for the BEN/BEN genotype, 8.146 4.631% for the CAR/BEN genotype, and 4.180+/-2.250% for the CAR/Atp genotype (P = 0.02), although 1 CAR/CAR individual presented an HbF concentration as high as 15%. In view of the ethnic and geographical origin of this population, we did not expect a Hardy-Weinberg equilibrium for CAR/CAR and BEN/BEN homozygous haplotypes and a high proportion of heterozygous CAR/BEN haplotypes since the State of Bahia historically received more slaves from Western Africa than from Central Africa.

Variation of cytokine patterns related to therapeutic response in diffuse cutaneous leishmaniasis

Diffuse cutaneous leishmaniasis is a rare entity characterized by disseminated cutaneous nodules associated with specific anergy to leishmanial antigens. A low but not absent IFN-gamma expression by cells present in cutaneous lesions has been documented during the active phase of diffuse cutaneous leishmaniasis. In this study we confirm this observation, and extend it by showing a similar pattern in peripheral blood mononuclear cells and the variation of mRNA cytokine expression pattern during different stages of the disease. During active disease, patients did not express mRNA for IFN-gamma, while expressing mRNA for IL-2, IL-4, and IL-10. In contrast, an expression of IFN-gamma and low IL-10 was observed after treatment-induced transient healing of cutaneous lesions. In three patients we have been able to analyze a third PBMC sample obtained after clinical relapse, documenting in all of them decreased IFN-gamma expression with no expression of IL-10. Although there was an association between the appearance of IFN-gamma expression and clinical improvement, with marked expression of IFN-gamma mRNA and decreased expression of mRNA for IL-10 after treatment, this was not sufficient to prevent relapse in these patients. Therefore, it is possible that factors other than the cytokines characteristic of the Th1 and Th2 balance are implicated in the inability of diffuse cutaneous leishmaniasis patients to mount an anti-Leishmania immune response causing clinical improvement.

Lymphadenopathy as the first sign of human cutaneous infection by Leishmania braziliensis

This paper describes the presence of transitory lymphadenopathy as an initial sign of cutaneous leishmaniasis, and sometimes the only manifestation of Leishmania braziliensis infection. Ten patients with lymphadenopathy living in an area of L. braziliensis transmission had Leishmania cultivated from their lymph nodes previous to any other manifestation of cutaneous leishmaniasis. Seven of the 10 developed leishmanial ulcers later in the course of infection, whereas lymphadenopathy regressed in three cases and no other sign of infection developed. Results of tests for anti-Leishmania antibodies and an intradermal skin test were positive in four and five patients, respectively, at the time of the diagnosis. The documentation of Leishmania amastigotes in the lymph nodes before any clinical evidence of cutaneous disease indicates that early spread of L. braziliensis from the skin to lymph nodes occurs before a local lesion develops. All medical doctors examining patients coming from endemic areas of leishmaniasis should be aware that lymph node enlargement, even in the absence of a typical ulceration, may be indicative of leishmanial infection and warrants further investigation.

Cloning of an M. tuberculosis DNA fragment associated with entry and survival inside cells

Mycobacterium tuberculosis infects one-third of the world's human population. This widespread infection depends on the organism's ability to escape host defenses by gaining entry and surviving inside the macrophage. DNA sequences of M. tuberculosis have been cloned; these confer on a nonpathogenic Escherichia coli strain an ability to invade HeLa cells, augment macrophage phagocytosis, and survive for at least 24 hours inside the human macrophage. This capacity to gain entry into mammalian cells and survive inside the macrophage was localized to two distinct loci on the cloned M. tuberculosis DNA fragment.