The Effect of Levamisole Combined with the Classical Treatment in Chronic Brucellosis

In Vitro and In Vivo IFN-γ and IL-10 Measurement in Experimental Brucella abortus Biotype 1 Infection in Sprague-Dawley Rats

The immune response to Brucella abortus mainly depends on antigen-specific T cell activation, CD4⁺ and CD8⁺ T cells, and Brucella-specific humoral response. Protective immune response against Brucella infection has not been performed in the Sprague-Dawley (SD) rat model. We measured bacterial kinetics in addition to in vivo and in vitro interferon gamma (IFN-γ) and interleukin-10 (IL-10) production against crude Brucella protein in the SD rats at different days of postinfection with B. abortus biotype 1 by indirect enzyme-linked immunosorbent assay. Forty SD rats were inoculated intraperitoneally with 0.1 mL sterile injectable pyrogen-free solution containing 1 × 10¹⁰ colony-forming units/mL of B. abortus biotype 1 obtained from cattle in Korea. Four rats were used as uninfected control. Serum IFN-γ level at 3 and 7 days postinfection were significantly higher (p > 0.001) compared with the IL-10 level. On the contrary, serum IL-10 levels were observed significantly higher at 21 and 28 days postinfection compared with the serum IFN-γ levels (p < 0.001). The production of IFN-γ by spleen cells was significantly higher at 7 and 14 days postinfection compared with IL-10 (p < 0.001). On the contrary, IL-10 productions were found to be significantly higher at 21, 28, 35, and 42 days postinfection compared with IFN-γ (p < 0.001). The presence of B. abortus in blood was marked till 5 weeks of infection, throughout the experiment in case of spleen, and no bacteria were isolated from the kidney and liver at 6 weeks postinfection. The in vivo and in vitro IFN-γ and IL-10 measurement in our study reported that B. abortus infection in rats primarily educe T helper (Th)1-dominant immune response in acute infection accompanied by Th2-dominant immune response in chronic infection.

The current therapeutical strategies in human brucellosis

Prompt and adequate treatment of human brucellosis continues to be the most important strategy in its management, as eradication of animal brucellosis is not possible so far, and there is no adequate vaccine for humans. The goal of antibrucellar treatment is to alleviate and shorten the symptomatic period and reduce complications, relapses, and chronicity. Contemporary trends in the treatment of human brucellosis are postulated on the ability of Brucellae to persist in host macrophages through the inhibition of phagolysosome fusion and to survive for prolonged periods intracellularly without restricting basic cellular functions. As a result of this and despite satisfactory antibiotic treatment, relapses and therapeutical failures are inevitable to a certain degree. The current principles for the treatment of brucellosis advocate for a long enough treatment duration combined with antimicrobial regimens that possess activity in the intracellular acidic environment. In the future, other antimicrobial agents, immunomodulation, decrease in the intracellular acidic environment, or development of agents that would act on well-defined molecular bacterial targets, might be incorporated to improve the therapeutical effects.

The Profile of Immunoglobulin A and Immunoglobulin G Subclasses in Sprague Dawley Rats Experimentally Infected with Brucella abortus Biotype 1

This study measured total serum immunoglobulin A (IgA), immunoglobulin G (IgG)1, IgG2a response against whole cell antigen (WCA), outer membrane protein (OMP), periplasmic protein (PP), cytoplasmic protein (CP), and crude Brucella protein (CBP) of Brucella abortus in experimental brucellosis induced with B. abortus biotype 1 in Sprague Dawley (SD) rats during a 17-week infection period. Six- to 8-week-old SD rats (n = 44) were experimentally infected with 1 × 10⁹ colony forming unit of B. abortus biotype 1 through the intraperitoneal route. Serial serum samples were collected from the rat at 0, 3, 7, 14, 21, 28, 35, 42, 60, 90, and 120 days after inoculation. The sera were tested by enzyme linked immunosorbent assay. We have noticed a very low level and short persistence of IgA antibody in our experiment. The low level and short persistence of IgA antibody suggest that this antibody isotype might not be protective against brucellosis in rats. Both Th1 and Th2 specific immune responses were recorded in our study with the production of IgG1 and IgG2a antibody isotopes, respectively. We noticed significant dominant IgG2a antibody responses over IgG1 responses throughout the experiment (p < 0.001) against WCA and OMP. The mixed Th1 and Th2 dominant immune responses mediated by IgG2a and IgG1 antibody isotypes were observed against CP, PP, and CBP. Data of our study suggest that IgG2a dominant responses in the early stages of disease play the main role in conferring protection against brucellosis and with the progress of disease IgG1 dominant responses were elicited.

Frequencies of CD4+ T Regulatory Cells and their CD25(high) and FoxP3(high) Subsets Augment in Peripheral Blood of Patients with Acute and Chronic Brucellosis

Objectives

Brucellosis remains one of the most common zoonotic diseases worldwide. In humans, brucellosis can be a serious, debilitating, and sometimes chronic disease. Different mechanisms can be postulated as to the basis for the induction of the chronic status of infectious diseases that T regulatory cells are one of the most important related mechanisms. The current study was designed to determine whether percentage of CD4+Treg cells and their CD25^high and FoxP3^high subpopulations in peripheral blood are changed in human brucellosis samples in comparison to a control group.

Methods

In total, 68 brucellosis patients (acute form: n = 43, chronic form: n = 25) and 36 healthy volunteers entered our study. After isolating of peripheral blood mononuclear cells, heparinized venous blood samples were obtained from both patients and healthy donors, CD4, CD25, and FoxP3 molecules were evaluated by two- and three-color flow cytometric methods.

Results

The results revealed a new finding in relation to Treg cells and human brucellosis. The numbers of CD4⁺Treg cells and their CD25^high and FoxP3^high subsets increase significantly in the peripheral blood of acute and chronic forms of brucellosis samples compared with healthy groups, with this increase being greater in the chronic group.

Conclusion

There seems to be a correlation between increase of CD4+Treg cells and their subsets and the disease progress from healthy state to acute and chronic brucellosis.

Antibiotics for treating human brucellosis

BACKGROUND

Brucellosis is the most common zoonotic infection in the world. Several antibiotics, separately or in combination, have been tried for treatment of human brucellosis. The inconsistencies between different treatment regimens warrants the need for a systematic review to inform clinical practice and future research.

OBJECTIVES

To evaluate the effects of various antibiotic regimens, monotherapy or in combination with other antibiotics, for treating human brucellosis.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register, Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, and LILACS until May 2012. We browsed the abstract books of several international infectious diseases conferences. We also checked the reference lists of all studies identified

SELECTION CRITERIA

We included the randomized controlled trials on the pharmaceutical interventions in treatment of acute, chronic, non-complicated, and complicated human brucellosis. The outcomes of interest were relapse, persistence of symptoms at the end of treatment, and adverse drug effects.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the studies for inclusion, risk of bias, and extracted relevant data using pre-designed extraction forms. The findings of homogenous studies were pooled using fixed-effect meta-analysis.

MAIN RESULTS

In total we included 25 studies comparing various antibiotic regimens. Methods of allocation and concealment were inadequately described in half the studies, and only three were blinded. In comparisons of doxycycline plus rifampicin versus doxycycline plus streptomycin we found eight studies with 694 participants. For treatment failure, the doxycycline plus rifampicin regimen was less effective (risk ratio (RR) 1.91, 95% confidence interval (CI) 1.07 to 3.42, seven studies, 567 participants), relapse (RR 2.39, 95% CI 1.17 to 4.86), and minor adverse drug reactions (RR 1.38, 95% CI 0.99 to 1.92). In comparisons of doxycycline plus rifampicin against quinolone (ciprofloxacin or ofloxacin) plus rifampicin we found five studies of 336 participants. The pooled analysis did not demonstrate any significant difference between two regimens in terms of relapse and symptom persistence, but showed a non-significant higher risk of minor adverse reactions in doxycycline plus rifampicin (RR 1.80, 95% CI 0.78 to 4.18). Other comparisons were reported in a few heterogenous studies, and the pooled analyses, where applied, did not show any significant difference.

AUTHORS' CONCLUSIONS

Doxycycline (six weeks) plus streptomycin (two or three weeks) regimen is more effective regimen than doxycycline plus rifampicin (six weeks) regimen. Since it needs daily intramuscular (IM) injection, access to care and cost are important factors in deciding between two choices. Quinolone plus rifampicin (six weeks) regimen is slightly better tolerated than doxycycline plus rifampicin, and low quality evidence did not show any difference in overall effectiveness.

Cell-mediated immunity in human brucellosis

Brucella can parasitize within human antigen-presenting cells modifying phagocytosis, phagolysosome fusion, antigen presentation, cytokine secretion, and apoptosis. Subversion of innate immune mechanisms by Brucella leads to defective Th1 immune responses and T-cell anergy in chronic brucellosis patients. This review summarizes the cellular immune responses in brucellosis, based on data derived exclusively from human cells or cell lines.

Clinical manifestations and complications in 1028 cases of brucellosis: a retrospective evaluation and review of the literature

INTRODUCTION

Brucellosis is the most prevalent bacterial zoonosis worldwide. In this study, we aimed to compare our 1028 brucellosis cases with other big series in the literature in view of epidemiological, clinical, and laboratory findings and therapeutic features.

METHODS

A total of 1028 brucellosis cases admitted to the Department of Infectious Diseases and Clinical Microbiology over a 10-year period were included in the study. A retrospective analysis was undertaken and patient files were reviewed for history, clinical and laboratory findings, and therapeutic features, as well as complications.

RESULTS

Of the 1028 patients, 539 (52.4%) were female and 489 (47.6%) were male. The mean age of patients was 33.7+/-16.34 years and 69.6% of cases were aged 13-44 years. Four hundred and thirty-five cases (42.3%) had a history of raising livestock and 55.2% of the cases were found to have no occupational risk for brucellosis. Six hundred and fifty-four of the cases (63.6%) had a history of raw milk and dairy products consumption. The most frequently seen symptoms were arthralgia (73.7%) and fever (72.2%), while the most common clinical findings were fever (28.8%) and hepatomegaly (20.6%). The most frequent laboratory finding was a high C-reactive protein level (58.4%). The standard tube agglutination (STA) test+Coombs STA test was positive in 1016 cases (98.8%). Focal involvement was present in 371 (36.1%) cases. The most frequent involvement was osteoarticular involvement with 260 cases (25.3%). The overall relapse rate for patients with brucellosis was 4.7%. The highest relapse rate, 8.5%, was observed in the group of patients with osteoarticular involvement. Regimens including doxycycline and streptomycin with or without rifampin appeared more effective than other regimens in osteoarticular involvement.

CONCLUSIONS

In humans, brucellosis may lead to serious morbidity, and it continues to be a major health problem in Turkey. There is no recommended treatment protocol for complicated brucellosis. Large multicenter studies are needed to determine the most appropriate treatment choices and durations in complicated brucellosis.

Brucellosis: a retrospective evaluation of 99 cases and review of brucellosis treatment

This retrospective study was performed in two university hospitals between January 2002 and 2006. Ninety-nine brucellosis patients were included in the study. These patients were classified as acute (91), chronic (4) and relapse (4) according to their clinical presentations and serological tests. Brucella bacteria were isolated in the blood of 17 (17.2%) cases. The most frequent symptom and clinical sign was fever. The osteoarticular complications were found in 17 patients (17.2%). Four of them were complicated with epidural abscess the same time. Two (2.2%) had meningitis, two (2.2%) had epididymoorchitis, three (3.3%) had skin rashes and one (1.1%) had hepatitis. Three of the acute brucellosis patients were pregnant. Rifampin and doxycycline combination therapy had been administered to most of the patients with acute and relapse brucellosis. However, complicated and chronic brucellosis cases were given different treatment combinations. This study reviews brucellosis therapy choices.

Therapeutic options for human brucellosis

Worldwide, human brucellosis is the most common zoonotic disease and it has gained increasing interest because of the potential use of Brucella as a biological weapon. Monotherapy for brucellosis is associated with a high relapse rate and dual therapy in different combinations is more efficacious. The combination regimen of intramuscular streptomycin with an oral tetracycline resulted in fewer relapses than the doxycycline-rifampin combination in meta-analysis and prospective studies, although the use of doxycycline and rifampin is a reasonable choice in certain conditions. Longer duration and triple antimicrobial therapy appear to improve outcome and prevent relapses, especially in patients with focal disease. Recently, the use of gentamicin-loaded microparticles and the use of new antibiotics, such as tigecycline, may hold future promise. In addition, there are a few studies of the enhanced effect of immune response stimulators, such as levimasole and IFN-2, in the treatment of brucellosis. The development of an effective subcellular Brucella vaccine would be an important step forward to curtail the disease. However, currently and for the near future, only the control of animal disease is possible using vaccine strategies.

Human brucellosis

Human brucellosis still presents scientists and clinicians with several challenges, such as the understanding of pathogenic mechanisms of Brucella spp, the identification of markers for disease severity, progression, and treatment response, and the development of improved treatment regimens. Molecular studies have shed new light on the pathogenesis of Brucella spp, and new technologies have permitted the development of diagnostic tools that will be useful in developing countries, where brucellosis is still a very common but often neglected disease. However, further studies are needed to establish optimum treatment regimens and local and international control programmes. This Review summarises current knowledge of the pathogenic mechanisms, new diagnostic advances, therapeutic options, and the situation of developing countries in regard to human brucellosis.

Future trends in human brucellosis treatment

The global burden of human brucellosis remains enormous. Existing treatment options, largely based on experience gained > 30 years ago, are adequate but not optimal. The evolving understanding of the pathophysiology of the disease may augment in designing and evaluating alternative approaches that may prove to be superior. Current alternative approaches such as co-trimoxazole-containing regimens, should be widely evaluated as being more cost-effective. New methods of delivery such as gentamicin-loaded microparticles, neutralisation of the environment where Brucella resides and use of novel antibiotics such as tigecycline may be of importance in the future. The role of immunomodulation, widely but inconsistently applied in 'chronic' brucellosis, should be further evaluated in all disease stages to define if it is of any use. The development of a subcellular vaccine would be an important step forward although one has to take into account the multiple interactions between Brucella and the immune system, various technical problems and the lack of funds. Reviewing existing attempts at the development of such a vaccine, the authors conclude that a trivalent subcellular vaccine may be needed for adequate efficacy.

Diminished percentage of CD4+ T-lymphocytes expressing interleukine-2 receptor alpha in chronic brucellosis

OBJECTIVES AND METHODS

Despite the treatment, a considerable proportion of brucellosis patients develop chronic disease, characterized by atypical clinical picture and/or relapses. Th1 cytokines are critical for the clearance of Brucella infection and diminished production of IL-2 in response to PHA, has been described in chronic brucellosis. In order to investigate the role of IL-2R alpha (CD25) in disease outcome, we evaluated the ex vivo and PHA-induced percentage of peripheral CD4+ T-lymphocytes expressing CD25 in 13 acute brucellosis patients (AB), 22 chronic brucellosis patients (CB), 11 "clinically cured" subjects and 15 healthy volunteers (controls). Simultaneously, CD3+, CD4+ and CD8+ T-lymphocytes subsets were measured.

RESULTS

The ex vivo percentage of CD4+/CD25+ T-cells was significantly higher in AB patients compared to "clinically cured" subjects (p=0.005) and controls (p=0.006). By contrast, CD4+/CD25+ T-cells were significantly lower in CB patients (p=0.001). T-lymphocytes subsets did not significantly differ between the groups. After PHA stimulation, CD4+/CD25+ T-cells remained significantly lower in CB and specifically in the relapsing form of chronic disease compared to AB (p=0.044, 0.023). Additionally, CD8+ T-lymphocytes were found to be significantly increased in CB and mainly in the relapsing subgroup of CB patients compared to AB (p=0.044, 0.011).

CONCLUSION

Diminished percentage of peripheral CD4+ T-lymphocytes expressing IL-2R alpha is associated with chronic relapsing brucellosis.