The prognostic significance of serum XCL1 concentration in patients with acute lymphoblastic leukemia: a pilot study

There is no information about XCL1 in patients with acute lymphoblastic leukemia (ALL). The objective of this study was to correlate the serum levels of XCL1 and survival in ALL patients. Only ALL patients older than 12 months were considered to participate. Serum XCL1 was measured at diagnosis, end of remission induction, and end of consolidation. Thirty-three ALL patients with median age of 21 years (1-78) were included. Higher XCL1 level (above 50 pg/mL) at ALL diagnosis correlated with higher survival (p = 0.038), whereas XCL1 level at end of induction and consolidation had no significant correlation. Concerning the behavior of serum XCL1 during treatment, higher survival at 5 years was observed in the group with progressively decreased levels of XCL1 (70%) than those with progressively increasing (29%) or no detectable XCL1 (14%). In conclusion, higher serum XCL1 levels at diagnosis and their progressive decline throughout chemotherapy could be correlated with higher survival.

Mycetoma medical therapy

Medical treatment of mycetoma depends on its fungal or bacterial etiology. Clinically, these entities share similar features that can confuse diagnosis, causing a lack of therapeutic response due to inappropriate treatment. This review evaluates the response to available antimicrobial agents in actinomycetoma and the current status of antifungal drugs for treatment of eumycetoma.

Nocardia brasiliensis induces formation of foamy macrophages and dendritic cells in vitro and in vivo

Foamy cells have been described in various infectious diseases, for example in actinomycetoma induced by Nocardia brasiliensis. These cells are generally considered to be macrophages, although they present dendritic cell (DC)-specific surface markers. In this study, we determined and confirmed the lineage of possible precursors of foamy cells in vitro and in vivo using an experimental actinomycetoma model in BALB/c mice. Bone marrow-derived macrophages (BMDM) or DC (BMDC) were infected in vitro with N. brasiliensis or labeled with carboxyfluorescein diacetate succinimidyl ester (CFSE). Both, macrophages and DC, differentiated into foamy cells after in vitro infection. CFSE-labeled BMDM or BMDC were tested for phagocytosis and CD11c/CD11b receptors markers expression before being transferred into the actinomycetoma lesion site of infected mice. In vivo studies showed that BMDM and BMDC were traced at the site where foamy cells are present in the experimental actinomycetoma. Interestingly, many of the transferred BMDM and BMDC were stained with the lipid-droplet fluorophore Nile Red. In conclusion, macrophages and DC cells can be differentiated into foamy cells in vitro and in vivo during N. brasiliensis infection.

Systemic increased immune response to Nocardia brasiliensis co-exists with local immunosuppressive microenvironment

Human diseases produced by pathogenic actinomycetes are increasing because they may be present as opportunistic infections. Some of these microbes cause systemic infections associated with immunosuppressive conditions, such as chemotherapy for cancer, immunosuppressive therapy for transplant, autoimmune conditions, and AIDS; while others usually cause localized infection in immunocompetent individuals. Other factors related to this increase in incidence are: antibiotic resistance, not well defined taxonomy, and a delay in isolation and identification of the offending microbe. Examples of these infections are systemic disease and brain abscesses produced by Nocardia asteroides or the located disease by Nocardia brasiliensis, named actinomycetoma. During the Pathogenic Actinomycetes Symposium of the 16th International Symposium on Biology of Actinomycetes (ISBA), held in Puerto Vallarta, Mexico, several authors presented recent research on the mechanisms by which N. brasiliensis modulates the immune system to survive in the host and advances in medical treatment of human actinomycetoma. Antibiotics and antimicrobials that are effective against severe actinomycetoma infections with an excellent therapeutic outcome and experimental studies of drugs that show promising bacterial inhibition in vivo and in vitro were presented. Here we demonstrate a systemic strong acquired immune response in humans and experimental mice at the same time of a local dominance of anti inflammatory cytokines environment. The pathogenic mechanisms of some actinomycetes include generation of an immunosuppressive micro environment to evade the protective immune response. This information will be helpful in understanding pathogenesis and to design new drugs for treatment of actinomycetoma.

Antineutrophil cytoplasm autoantibodies in patients with tuberculosis are directed against bactericidal/permeability increasing protein and are detected after treatment initiation

OBJECTIVES

To determine the prevalence of antineutrophil cytoplasm autoantibodies (ANCA) and its antigenic specificities in sera of patients with pulmonary tuberculosis (Tb) before and after treatment.

PATIENTS AND METHODS

Sixty-eight patients with culture-proven Tb were studied for the presence of ANCA, both by indirect immunofluorescence (IIF) and ELISA against proteinase-3 (PR3), myeloperoxidase (MPO) and bactericidal/permeability increasing protein (BPI). They were sought before treatment and in 52 of them also after therapy for the infection. High sensitivity C-reactive protein (CRP) was also measured at both times.

RESULTS

ANCA by IIF were found in 3/68 (4.4%) sera prior to treatment, one C-ANCA and two P-ANCA, all recognizing BPI. After treatment, this increased to 15/52 (28.8%), 3 C-ANCA and 12 P-ANCA, the majority directed against BPI (11/15, 73%). BPI-ANCA were positive in 6/68 (8.8%) and 15/52 (28.8%) before and after Tb after treatment initiation (p=0.003). PR3-ANCA and MPO-ANCA were negative in all Tb sera. A positive ANCA test correlated with CRP as inflammatory marker (p=0.001).

CONCLUSIONS

The prevalence of ANCA in culture positive Tb patients is modified by Tb chemotherapy. BPI is the main target antigen for ANCA in tuberculosis and BPI-ANCA increase after treatment.

Expression of Nocardia brasiliensis superoxide dismutase during the early infection of murine peritoneal macrophages

Nocardia brasiliensis is the main agent of actinomycetoma in Mexico, but little is known about its virulence and molecular pathogenic pathways. These facultative intracellular bacteria are able to survive and divide within the host phagocytic cells, in part by neutralizing the reactive oxygen intermediates. Superoxide dismutase (SOD) participates in the intracellular survival of several bacterial species and, in particular, constitutes one of Nocardia asteroides virulence factors. To clarify SOD participation in the N. brasiliensis early infective process, we report its isolation and the consequent comparison of its transcript level. A 630 bp polymerase chain reaction fragment that included most of the coding sequence of N. brasiliensis sodA was cloned. A competitive assay was developed, allowing comparison of bacterial sod expression in exponential culture and 1 h after infecting peritoneal macrophages from BALB/c mice. At that time, there were viable bacteria in the macrophages. The intracellular bacteria presented a clear decrease in their sod transcript amount, although their 16S rRNA (used as an internal control) and hsp levels were maintained or slightly increased, respectively. These results indicate that sodA transcription is not maintained within the SOS bacterial response induced by phagosomal conditions. Further kinetics will be necessary to precisely define sod transcriptional regulation during N. brasiliensis intra-macrophage growth.

Mycetoma

Mycetoma is a granulomatous infection affecting mainly the feet and lower extremities. It can be caused either by aerobic, branched actinomycetes or by eumycetes. Most cases are found in tropical and subtropical regions. The infection is usually produced by the introduction of the etiologic agents through minor wounds caused by thorns and wood splinters. Clinically the disease begins as small, firm nodules that can enlarge to form extensive lesions with fistulae and abscesses with pus containing granules of the causative microorganisms. Antimicrobials and surgery are used in the management of mycetoma. The actinomycetomas generally respond well to antimicrobials. For eumycetomas, surgery may be required. New therapeutic options for drug-resistant cases are discussed.

[Anti-Nocardia brasiliensis antibodies in patients with actinomycetoma and their clinical usefulness]

Anti-Nocardia brasiliensis antibodies quantification and its clinical utility was confirmed in this study. A protein cellular extract from a N. brasiliensis strain named HUJEG-1 and registered at the ATCC # 700358 was used in a western blot assay to identify the immunodominant antigens. The protein P24 was selected to set up an ELISA test because it exhibit no cross-reaction with sera from tuberculosis and leprosy patients. A purified protease was also used as antigen in the ELISA test to compare its utility. Sera from N. brasiliensis mycetoma persons gave absorbance values above 0.3 when the disease was active using the P24 as antigen, these values decreased after patients completed their medical treatment. Anti-protease antibodies showed great variation and absorbance values similar to the healthy controls. We confirmed the clinical usefulness of the ELISA test both in serodiagnosis and in assessing the response to medical treatment. This is the first sensitive and specific serologic test for routine clinical laboratory.

Nocardia brasiliensis: from microbe to human and experimental infections

Nocardia brasiliensis is a Gram-positive bacterium that lives as a saprophyte in soil. In this article the physical properties, chemical composition and taxonomic position of this species is reviewed. Human infections and an experimental model of actinomycetoma in BALB/c mice as well as the host-immune response is described.

Distribution of a Nocardia brasiliensis catalase gene fragment in members of the genera Nocardia, Gordona, and Rhodococcus

An immunodominant protein from Nocardia brasiliensis, P61, was subjected to amino-terminal and internal sequence analysis. Three sequences of 22, 17, and 38 residues, respectively, were obtained and compared with the protein database from GenBank by using the BLAST system. The sequences showed homology to some eukaryotic catalases and to a bromoperoxidase-catalase from Streptomyces violaceus. Its identity as a catalase was confirmed by analysis of its enzymatic activity on H2O2 and by a double-staining method on a nondenaturing polyacrylamide gel with 3,3'-diaminobenzidine and ferricyanide; the result showed only catalase activity, but no peroxidase. By using one of the internal amino acid sequences and a consensus catalase motif (VGNNTP), we were able to design a PCR assay that generated a 500-bp PCR product. The amplicon was analyzed, and the nucleotide sequence was compared to the GenBank database with the observation of high homology to other bacterial and eukaryotic catalases. A PCR assay based on this target sequence was performed with primers NB10 and NB11 to confirm the presence of the NB10-NB11 gene fragment in several N. brasiliensis strains isolated from mycetoma. The same assay was used to determine whether there were homologous sequences in several type strains from the genera Nocardia, Rhodococcus, Gordona, and Streptomyces. All of the N. brasiliensis strains presented a positive result but only some of the actinomycetes species tested were positive in the PCR assay. In order to confirm these findings, genomic DNA was subjected to Southern blot analysis. A 1.7-kbp band was observed in the N. brasiliensis strains, and bands of different molecular weight were observed in cross-reacting actinomycetes. Sequence analysis of the amplicons of selected actinomycetes showed high homology in this catalase fragment, thus demonstrating that this protein is highly conserved in this group of bacteria.

Immune response to Nocardia brasiliensis antigens in an experimental model of actinomycetoma in BALB/c mice

Nine- to twelve-week-old BALB/c mice were injected in footpads with 10(7) CFU of a Nocardia brasiliensis cell suspension. Typical actinomycetoma lesions, characterized by severe local inflammation with abscess and fistula formation, were fully established by day 28 after infection. These changes presented for 90 days, and then tissue repair with scar formation slowly appeared, with complete healing after 150 days of infection. Some animals developed bone destruction in the affected area. Histopathology showed an intense inflammatory response, with polymorphonuclear cells and hyaloid material around the colonies of the bacteria, some of which were discharged from draining abscesses. Sera from experimental animals were analyzed by Western blotting, and immunodominant antigens P61 and P24 were found as major targets for antibody response. Anti-P24 immunoglobulin M (IgM) isotype antibodies were present as early as 7 days, IgG peaking 45 days after infection. Lymphocyte proliferation with spleen and popliteal lymph node cells demonstrated thymidine incorporation at 7 days after infection, the stimulation index decreasing by day 60. Levels of interleukin-1 (IL-1), IL-2, IL-4, IL-6, tumor necrosis factor alpha, and gamma interferon (IFN-gamma) were determined by enzyme-linked immunosorbent assay in the sera of infected animals. The circulating levels of IFN-gamma increased more than 10 times the basal levels; levels of IL-4, IL-6 and IL-10 also increased during the first 4 days of infection.

Nocardia, nocardiosis and mycetoma

The recent emergence of invasive infections due to Nocardia spp., including nosocomial outbreak, is now evident. Newer molecular diagnostic and typing methods are developed. Although sulfonamide-based therapy is generally effective, optimal treatment may be guided by antimicrobial susceptibility testing of isolates. The improved classification of nocardiae and other related genera such as actinomadurae, using the 16S ribosomal RNA sequencing, provide a sound basis for improved diagnostic methods for the identification of members of clinically significant species. The commonest cause of eumycetoma in Sudan is Madurella mycetomatis, and Streptomyces somaliensis and Actinomadura madurae for actinomycetoma. The humoral immunity response in actinomycetoma patients and in experimental mice was measured and significant titre of anti-P24 antibody was demonstrated.

Monoclonal antibodies to P24 and P61 immunodominant antigens from Nocardia brasiliensis

We prepared a Nocardia brasiliensis cell extract and purified two immunodominant antigens with molecular weights of 61,000 and 24,000. The isolated proteins were shown to be reasonably pure when analyzed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (8 to 18% polyacrylamide gradient) and stained with Coomassie blue and silver nitrate. By using an immunoelectrotransfer blot method (Western blotting), we demonstrated that these two purified proteins reacted strongly with serum from N. brasiliensis-infected mycetoma patients. To obtain anti-P61 and anti-P24 monoclonal antibodies (MAbs), we used an N. brasiliensis cell extract as the antigen for the first immunization; 2 weeks later female mice were reimmunized with a semipurified antigen containing the P24 or P61 fraction. A booster injection was given 3 days before the fusion was carried out. Two hybrids that reacted strongly with P24 were cloned by limiting dilution, the generated MAbs were analyzed for isotyping, and their specificity was tested in a Western blot assay with cell extracts from Nocardia asteroides and Mycobacterium tuberculosis cultures. Anti-P24 MAbs were shown to be specific for N. brasiliensis HUJEG-1 and did not cross-react with either the N. asteroides or M. tuberculosis strains used. However, additional studies with several N. asteroides and N. brasiliensis strains are needed to investigate whether there are cross-reactions between strains or species when these MAbs are used. The anti-P61 and anti-24 MAbs were used to locate the antigen in N. brasiliensis cells by immunofluorescence. The lack of reaction with intact cells suggests that the P24 and P61 antigens are not exposed in the complete bacterial cell surface or that the recognized epitopes are different. Only one anti-P61 MAb that reacted specifically with the N. brasiliensis cell extract was obtained.

Enzyme-linked immunosorbent assay for serological diagnosis of Nocardia brasiliensis and clinical correlation with mycetoma infections

We previously identified three immunodominant antigens obtained from a Nocardia brasiliensis cell extract and recognized by sera from mycetoma patients (M. C. Salinas-Carmona, L. Vera, O. Welsh, and M. Rodríguez, Zentralbl. Bakteriol. 276:390-397, 1992). In the present work, we obtained a crude extract from a mass culture of N. brasiliensis HUJEG-1 and purified two immunodominant antigens, the 26- and 24-kDa proteins, by using simple physiochemical techniques. With these antigens, we developed a conventional solid-phase enzyme-linked immunosorbent assay and tested 30 serum samples from mycetoma patients, 29 from tuberculosis patients, 24 from a leprosy group, and 31 from healthy individuals. Our results show for the first time statistically significant differences in serology among these groups. All mycetoma patients with a positive culture for N. brasiliensis had absorbance values higher than 0.3. On the other hand, the mycobacterium-infected patients as well as the healthy individuals all had absorbance values below that level. Moreover, we found a close correlation between the clinical condition of the mycetoma patients and the anti-26- and anti-24-kDa protein antibody concentrations. We therefore propose the use of this assay in routine clinical laboratories to confirm the diagnosis of N. brasiliensis infection in human mycetoma cases. In addition, the possible application of this assay in the serodiagnosis of Nocardia asteroides infection is also discussed.

Isolation and purification of two immunodominant antigens from Nocardia brasiliensis

Two immunogenic proteins from a crude extract of Nocardia brasiliensis were purified to homogeneity. A 61-kDa protein (P61) was isolated from a 50% ammonium sulfate precipitate in two steps. Initially, P61 was obtained by electroelution in a 10% nondenatured preparative polyacrylamide gel electrophoresis (PAGE). In a second step, the eluate from the nondenatured gel was run in a 12% sodium dodecyl sulfate (SDS) preparative polyacrylamide gel. After elution, a single band was demonstrated by SDS-PAGE and Western blot (immunoblot). Also, a 24-kDa immunogenic protein (P24) was isolated by gel filtration in a Sephadex G-100 column and then by electroelution in a 12% nondenatured polyacrylamide gel. In a previous paper, we showed by Western blot assays that these proteins are recognized by the sera of mycetoma patients and not by sera from mycobacterial-infected or healthy individuals. We consider these proteins to be good candidates for the study of the host-parasite relationship in nocardial infections. The possible clinical application of these purified antigens in a serological diagnosis is discussed.

Antibody response to Nocardia brasiliensis antigens in man

A crude extract from N. brasiliensis cells grown in brain heart infusion culture was analyzed. It showed a complex mixture of at least 37 bands when resolved with the discontinuous buffer system of Laemmli in a gradient SDS-PAGE. Western blot analysis of 16 sera from N. brasiliensis-infected individuals always showed the recognition of six bands of 61, 49, 45, 42, 26, and 24 kilodaltons (kDa). Some other bands also reacted but with less intensity. Sera from tuberculosis and leprosy patients reacted strongly with the 49, 45, and 42 kDa bands but weakly or not at all with the 61, 26, and 24 kDa. Sera from healthy control volunteers reacted with some bands but little or not at all with those three identified by the sera from mycetoma patients. These three immunodominant antigens (61, 26 and 24 kDa) may be of clinical value in the serodiagnosis of mycetoma by N. brasiliensis.

[Antibodies against human T-cell lymphotropic viruses in subjects at high risk for HIV in Monterrey]

HIV and HTLV-1 are retrovirus that can produce human disease. It is known that HTLV-1 is associated to the adult T cell leukemia and to the spastic tropical paraparesis. AIDS is now a pandemic infection and HTLV-1 has a high endemicity in the Caribbean region and Japan, whereas the south of the United States has a low endemicity. In Mexico there is little information on HTLV-1 incidence. In the present work we looked for anti HTLV-1 antibodies in one hundred persons that belong to the high risks AIDS population in the city of Monterrey, Mexico. We found that 93 sera were positive for anti HIV antibodies in a ELISA test and seven were negative. All 93 sera were also positive in the Western Blot assay. In the confirmatory test two out of the seven negative sera were classified as indeterminate and five as negative. We also included in this study 50 sera from healthy control volunteers that did not belong to the high risk AIDS population and resulted negative in the HIV and HTLV-1 test. Anti HTLV-1 antibodies were determined by using an agglutination test with gelatin particles covered with HTLV-1 and confirmed by a Western Blot assay. We found that only three sera resulted positive in this agglutination test, but were negative by the Western Blot technique.

[Immunoelectroblotting in Mexican subjects at high risk for infection with human immunodeficiency virus (HIV)]

Sera from 124 persons in high risk groups were analyzed including homosexuals, blood recipients, and spouses or siblings from AIDS patients. In this study, 118 individuals had a positive ELISA for anti-HIV antibodies. Six persons had a complete immunodeficiency syndrome and a negative ELISA test. In the Western blot, 111 sera were positive, four negative, and nine scored indeterminate; four of the latter converted to positive when retested three months later. Antibodies present in the positive sera were directed against the HIV gp 41 kD in 100% of the cases and against the gp 120 kD in 82%. Frequency of recognition of p55 kD was 96% but p18 kD was only 42%.

Modulation of experimental autoimmune uveitis with cyclosporin A

Cyclosporin A has been shown to be an effective inhibitor of T cell-mediated diseases. We show here that cyclosporin A was capable of totally preventing the clinical appearance of experimental autoimmune uveitis in Lewis rats, even when administered on an every-other-day schedule (10 mg/kg) or when begun seven days after immunization (40 mg/kg). At lower doses of the drug, a modulation of the disease was seen with evidence of a more chronic, granulomatous process. A long-lasting unresponsive state to the immunizing antigen was not uniformly induced with cyclosporin A if therapy was begun seven days after S antigen immunization. Because of cyclosporin A's effective control of this experimental model that is induced by an antigen to which certain patients with uveitis demonstrate cell-mediated immune responses, cyclosporin A may be an effective mode of therapy for T cell-mediated intraocular inflammatory disease.

Experimental autoimmune uveitis in the athymic nude rat

A single injection of the retinal soluble antigen (S-Ag, 30 micrograms) to the Lewis or the heterozygous (rnu/+) rats induces a severe bilateral uveitis, characterized initially by infiltration of the retina with inflammatory cells. The athymic nude rat (homozygous rnu/rnu), which lacks the thymus gland and T cell-mediated functions, does not develop ocular inflammatory disease, clinically of histologically, after repeated challenges with S-Ag. Circulating anti-S-Ag antibodies were found in S-Ag-immunized Lewis rats and in the heterozygous, but not the athymic nude rats. Good proliferative responses to concanavalin A, S-Ag and purified protein derivitive of tuberculin (PPD) were found in lymphocyte cultures prepared from the draining lymph nodes of immunized heterozygous rats, but not when lymphocytes from the athymic nude rats were used. Uveitis could be induced in the athymic nude rat when lymphocytes from S-Ag-immunized heterozygous rats were transferred to them. By stimulating the donor lymphocytes in vitro with S-Ag before transfer, the number of recipients that developed uveitis was increased. On the other hand, it was impossible to transfer disease with hyperimmune serum alone. The possible role of T lymphocytes in the induction of experimental autoimmune uveitis with S-Ag is discussed.

Cyclosporin a. Inhibition of experimental autoimmune uveitis in Lewis rats

Cyclosporin A (CS-A), a selective inhibitor of T lymphocytes, is reported here to prevent S antigen (S-Ag) induced uveitis in Lewis rats. The S-Ag, found in all mammalian retinas, is uveitogenic under experimental conditions and patients with certain uveitic entities demonstrate cell mediated responses to this antigen. Daily treatment with CS-A (10 mg/kg) begun on the same day as S-Ag immunization totally inhibited the development of the uveitis in this experimental autoimmune model. Moreover a greater CS-A dose (40 mg/kg) efficiently prevented the disease process when therapy was started 7 d after S-Ag immunization. Anti-S-Ag antibody titers were observed to be similar in rats either protected or not protected with CS-A. Our data support strongly the need for T cell participation in this disease model. Since ocular inflammatory disease is an important cause of visual impairment, the data further suggest that CS-A may be useful in the treatment of patients with intractable uveitis.