Laboratory detection of strongyloidiasis: IgG-, IgG4 - and IgE-ELISAs and cross-reactivity with lymphatic filariasis.

Enzyme-linked immunosorbent assays (ELISAs) were developed for the detection of IgG, IgG4 and IgE antibodies against Strongyloides stercoralis. A commercial ELISA (IVD Research, USA) was also used, and the sensitivities and specificities of the four assays were determined. Serum samples from 26 patients with S. stercoralis infection and 55 patients with other infections or no infection were analysed. Sensitivities of the IgG4 , IgG, IgE and IgG (IVD) assays were 76.9%, 84.6%, 7.7% and 84.6%, respectively, while the specificities were 92.7%, 81.8%, 100% and 83.6%, respectively. If filariasis samples were excluded, the specificities of the IgG4 -ELISA and both IgG-ELISAs increased to 100% and 98%, respectively. A significant positive correlation was observed between IgG- and IgG4 -ELISAs (r = 0.4828; P = 0.0125). IgG- and IgG- (IVD) ELISAs (r = 0.309) were positively correlated, but was not significant (P = 0.124). Meanwhile there was no correlation between IgG4 - and IgG- (IVD) ELISAs (r = 0.0042; P = 0.8294). Sera from brugian filariasis patients showed weak, positive correlation between the titres of antifilarial IgG4 and the optical densities of anti-Strongyloides IgG4 -ELISA (r = 0.4544, P = 0.0294). In conclusion, the detection of both anti-Strongyloides IgG4 and IgG antibodies could improve the serodiagnosis of human strongyloidiasis. Furthermore, patients from lymphatic filariasis endemic areas who are serologically diagnosed with strongyloidiasis should also be tested for filariasis.

Effects of feeding and induction strategy on the production of BmR1 antigen in recombinant E. coli.

AIM: To investigate the effects of feeding and induction strategies on the production of BmR1 recombinant antigen. METHODS AND RESULTS: Fed-batch fermentation was studied with respect to the specific growth rate and mode of induction to assess the growth potential of the bacteria in a bioreactor and to produce high yield of BmR1 recombinant antigen. Cells were grown at a controlled specific growth rate (mu(set)) during pre-induction, followed by constant feeding postinduction. The highest biomass (24.3 g l(-1)) was obtained during fed-batch process operated at mu(set) of 0.15 h(-1), whereby lower mu(set) (0.075 h(-1)) gave the highest protein production (9.82 mg l(-1)). The yield of BmR1 was increased by 1.2-fold upon induction with 1 mmol l(-1) IPTG (isopropyl-beta-d-thiogalactoside) compared to using 5 mmol l(-1) and showed a further 3.5-fold increase when the culture was induced twice at the late log phase. CONCLUSIONS: Combination of feeding at a lower mu(set) and twice induction with 1 mmol l(-1) IPTG yielded the best result of all variables tested, promising an improved method for BmR1 production. SIGNIFICANCE AND IMPACT OF THE STUDY: This method can be used to increase the production scale of the BmR1 recombinant antigen to meet the increasing demand for Brugia Rapid(), a commercial diagnostic test for detection of brugian filariasis.

Symptomatic chronic strongyloidiasis in children following treatment for solid organ malignancies: case reports and literature review.

Strongyloidiasis is an infection caused by the intestinal nematode Strongyloides stercoralis. Infected healthy individuals are usually asymptomatic, however it is potentially fatal in immunocompromised hosts due to its capacity to cause an overwhelming hyperinfection. Strongyloidiasis could be missed during routine screening because of low and intermittent larval output in stool and variable manifestations of the symptoms. We present two cases of strongyloidiasis occurring in children with solid organ malignancies suspected to have the infection based on their clinical conditions and treatment history for cancer. Both patients were diagnosed by molecular and serological tests and were successfully treated. Thus, strongyloidiasis in patients undergoing intensive treatment for malignancies should be suspected, properly investigated and treated accordingly.

Fatal septicemic shock associated with Strongyloides stercoralis infection in a patient with angioimmunoblastic T-cell lymphoma: a case report and literature review.

INTRODUCTION: Strongyloides stercoralis infection can persist in the host for several decades, and patients with cancer and other clinical conditions who are exposed to immunosuppressive therapy are at risk of developing hyperinfection. CASE REPORT: This is a case of angioimmunoblastic T-cell lymphoma (AITL) in a patient with lymphadenopathy and bulky neck mass. Severe sepsis and episodes of diarrhea were observed upon the first cycle of cyclophosphamide, doxorubicin, oncovin (vincristine) and prednisone (CHOP) regime chemotherapy preceded by high dose of dexamethasone. There was Klebsiella pneumoniae bacteremia and moderate eosinophilia. Rhabditiform S. stercoralis larvae were observed in the stool, and this was confirmed by real-time PCR. Strongyloides-specific IgG and IgG4 were also positive. The patient was treated with oral albendazole (400mg/day) for 3 days and intravenous tazocin (4.5gm/6 hours) for 5 days; however he succumbed following multi-organ failure. CONCLUSION: This is likely a case of Strongyloides hyperinfection with secondary bacteremia.