Feline leishmaniasis in an animal shelter in northeastern Brazil: Clinical aspects, coinfections, molecular detection, and serological study of a new recombinant protein

Infection and clinical cases of leishmaniasis caused by Leishmania infantum in cats have been increasingly reported in several countries, including Brazil. In this study, we used an enzyme-linked immunosorbent assay (ELISA) and an immunochromatographic test (ICT) based on a recombinant antigen (rKDDR-plus) to detect anti-Leishmania antibodies in cats from an animal shelter in northeastern Brazil. We compared the results with an ELISA using L. infantum crude antigen (ELISA-CA). We also investigated the presence of Leishmania DNA in blood or ocular conjunctival samples as well as the association between Leishmania PCR positivity and serological positivity to feline immunodeficiency virus (FIV), feline leukemia virus (FeLV) and Toxoplasma gondii. Concerning serological assays, a higher positivity was detected using the ICT-rKDDR-plus (7.5%; 7/93) as compared to ELISA-rKDDR-plus (5.4%; 5/93) and ELISA-CA (4.3%; 4/93). Upon PCR testing, 52.7% (49/93) of the ocular conjunctival swabs and 48.3% (44/91) of the blood samples were positive. Together, PCR and serological testing revealed overall positivities of 73.1% (68/93) and 12.9% (12/93), respectively. Among PCR-positive samples, 45.5% (31/68) showed co-infection with FIV, 17.6% (12/68) with FeLV, and 82.3% (56/68) with T. gondii. More than half of the PCR-positive cats showed at least one clinical sign suggestive of leishmaniasis (58.8%; 40/68) and dermatological signs were the most frequent ones (45.5%; 31/68). Both tests employing the recombinant antigen rKDDR-plus (i.e., ICT-rKDDR-plus and ELISA-rKDDR-plus) detected more positive cats than the ELISA-CA but presented low overall accuracy. PCR testing using either blood or ocular conjunctival samples detected much more positive cats than serological tests.

[Cloning expression and serological evaluation on Mycobacterium tuberculosis four new antigens]

Objective: To evaluate the serological diagnostic value of Mycobacterium (M.) tuberculosis four new antigens Rv0432, Rv0674, Rv1566c and Rv1547. Methods:Rv0432, Rv0674, Rv1566c and Rv1547 were amplified from M. tuberculosis strain H37Rv genomic DNA by using PCR, among which Rv1547 was divided into two segments for amplification (Rv1547-1 and Rv1547-2). The segments were cloned into expression vector PET-32a while the recombinant proteins were purified by affinity chromatography. Serums were incubated with BL21 (DE3) proteins. Antibodies IgG against M. tuberculosis were tested with 151 serum samples (41 healthy people and 110 TB patients) by using ELISA. The diagnostic efficiency of antigens was analyzed by means of receiver operating characteristic curve. Difference of the objective proteins in TB patients and healthy controls was compared by t-test. Results: Recombinant antigens Rv0432, Rv0674, Rv1566c, Rv1547-1 and Rv1547-2 were successfully expressed and purified. Results from ELISA showed that the sensitivity, specificity, positive predictive value, negative predictive value, Youden index and area under the curve of Rv0432, Rv0674, Rv1566c, Rv1547-1 and Rv1547-2, as 43.64%-92.73%, 80.49%-92.68%, 0.92-0.94, 0.38-0.80, 0.363-0.732 and 0.649-0.915. All the objective proteins showed significantly higher antibody levels in TB patients, when compared to the healthy controls (P<0.000 1). Conclusion: The newly identified antigens Rv0432, Rv0674, Rv1566c, Rv1547-1 and Rv1547-2 all performed well when being used for TB serological diagnosis, thus were expected to be new candidate antigens used for TB diagnosis.

Immunological diagnosis as an adjunctive tool for an early diagnosis of tuberculous meningitis of an immune competent child in a low tuberculosis endemic country: a case report

BACKGROUND

Pediatric tuberculous meningitis is a highly morbid, often fatal disease. Its prompt diagnosis and treatment saves lives, in fact delays in the initiation of therapy have been associated with high mortality rates.

CASE PRESENTATION

This is a case of an Italian child who was diagnosed with tuberculous meningitis after a history of a month of headache, fatigue and weight loss. Cerebrospinal fluid analysis revealed a lymphocytic pleocytosis with predominance and decreased glucose concentration. Microscopy and conventional diagnostic tests to identify Mycobacterium tuberculosis were negative, while a non classical method based on intracellular cytokine flow cytometry response of CD4 cells in cerebral spinal fluid helped us to address the diagnosis, that was subsequently confirmed by a nested polymerase chain reaction amplifying a 123 base pair fragment of the M. tuberculosis DNA.

CONCLUSIONS

We diagnosed tuberculous meningitis at an early stage through an innovative immunological approach, supported by a nested polymerase chain reaction for detection of M. tuberculosis DNA. An early diagnosis is required in order to promptly initiate a therapy and to increase the patient's survival.

Rocket and Two Dimensional Immunoelectrophoresis in Diagnosis of Caprine Brucellosis

BACKGROUND

Brucellosis is a major bacterial zoonosis of global importance with the causative organisms of Gram-negative facultative intracellular pathogens. The aims of this study were to standardize two immunoelectrophoretic techniques, rocket and cross immunoelectrophoresis, and compare their results with other conventional serodiagnostic tests.

METHODS

Sera from 15 sheep, without any history of brucellosis vaccination, infected with Brucella melitensis M16 subcutaneously, were employed in a comparison of culture, precipitating, and immunoelectrophoretic tests. A 125 days serologic follow-up was performed after the infection was started. As a reference, these tests also done in the five healthy sheep.

RESULTS

The results obtained with the rocket immunoelectrophoresis test correlated very well with those of the cross immunoelectrophoresis, whereas results of other tests such as culture, Rose Bengal, standard tube agglutination and 2-mercaptoethanol seruagglutination tests were inferior.

CONCLUSION

As agglutination test shows cross reaction and a prozone phenomenon, and in blood culture, the bacteria is not always detectable, so they are time consuming rocket and cross immunoelectrophoresis are recommended because their results can be obtained in a shorter time.

Immune profiling in patients with recurrent miscarriage

The central role of the maternal immune system for successful and disturbed pregnancies such as recurrent miscarriage (RM) is apparent. Recent studies have increased understanding of the complex interaction of the different immunological players and the adaptation of the maternal immune system to the semi-allogeneic embryo. There is growing evidence for immunological abnormalities in RM patients, including autoimmune and allogeneic factors. However, the question remains unsolved whether these changes represent the cause or the consequence of RM. As in half of the RM patients the underlying mechanism remains unknown, further diagnostic methods are urgently needed. Within this review we summarize (recent) literature on the immunological diagnosis in RM patients to find out current trends and to identify potential targets of therapy. As the exact mechanisms of feto-maternal tolerance have not yet been determined we suggest that the immunological diagnosis should be implemented only in well-designed clinical trials in specialized centers to establish a standardized immunological work-up in RM patients.

Immunological diagnosis of Giardia lamblia infection

Giardia lamblia infection causes diahrea in human beings and other mammalians, and it is attracting more and more attention in recent years. In this article, we reviewed immunological methods for the diagnosis of Giardia lamblia infection, compared the advantages and disadvantages of several diagnostic approaches, and briefly introduced some commercial kits, which would bring lots of conveniences to clinical diagnosis, therapy, and prognosis of Giardiasis.