Human schistosomiasis haematobium: effective diagnosis of active infection using a pair of monoclonal antibodies against soluble egg antigen

Lab-scale production of anti-Schistosoma monoclonal antibodies by hybridoma culturing in serum free medium: Enhancement of growth, cryopreservation survival rate, and diagnostic accuracy

This study was performed to evaluate the effect of two commercially available serum-free culture media; serum free medium (SFM) and chemically defined medium (CDM), on the growth rate, antibody productivity and post adaptation cryopreservation and revival reactivity of hybridoma cells compared to the conventional serum based medium (SBM). In addition, the diagnostic efficacy of MAbs secreted in each culture medium was evaluated by testing their performance in sandwich ELISA for antigen detection. Anti- Schistosoma mansoni soluble egg antigen hybridoma cell line (7A/8F) secreting previously characterized IgG Kappa mAbs, were retrieved and propagated in each of the three aforementioned media. Growth rate and viability were assessed post culturing in each media. The data collected from this study indicated that MAbs secreted from hybridoma cells cultured in SFM were the most abundant, easiest to purify, and the most effective in antigen detection by sandwich ELISA, in comparison to those produced in the other two media. Moreover, combination of fresh and conditioned medium with DMSO 7.5% was the most promising formulation for the cryopreservation of hybridoma cells cultivated in serum independent media (SFM or CDM).

Application of urine antigen assay to evaluate outcomes of praziquantel treatment and reinfection in opisthorchiasis in northeast Thailand

Background

A urine antigen assay was applied to evaluate chemotherapeutic outcomes and reinfection patterns of opisthorchiasis in Thailand.

Methods

We used a prospective study design by following opisthorchiasis subjects at baseline and post-treatment using a urine antigen assay and faecal examination by the formalin–ethyl acetate concentration technique (FECT).

Results

The antigen of Opisthorchis viverrini in urine diminished within 4 weeks after praziquantel treatment. Concurrent faecal examinations by FECT showed that faecal eggs were negative at 4 weeks after treatment. In a subsequent study, reinfection rates and intensity patterns of O. viverrini were evaluated at 48 weeks after praziquantel treatment. Within a group of subjects with curative treatment (n=137), 16.8% became reinfected according to FECT and 27.7% according to the urine antigen assay (p<0.05). There were significant correlations in intensity of infection between pretreatment and at 48 weeks post-treatment in both faecal egg counts and antigen levels in urine.

Conclusions

The results suggested that in addition to screening, the urine antigen assay is an efficient tool for monitoring outcomes of drug treatment and reinfection in opisthorchiasis. Due to the ease of urine sample collection and handling, the urine assay becomes an alternative method to faecal examination for diagnosis and monitoring of opisthorchiasis.

Case Report of Urinary Schistosomiasis in a Returned Traveler in Korea

A 23-year-old Korean woman with a residence history in Kenya and Malawi for about 2 years presented with gross hematuria for 1 month. Blood tests were within normal range except eosinophilia. Asymmetrically diffuse wall thickening and calcification were observed at the urinary bladder on CT. Multiple erythematous nodular lesions were observed in the cystoscopy and transurethral resection was done. Numerous eggs of Schistosoma haematobium with granulomatous inflammation were observed in the submucosal layer of the bladder. The patient was diagnosed with schistosomiasis-related cystitis and treated with praziquantel (40 mg/kg/day) twice before and after transurethral resection. This case suggests that S. haematobium infection should be considered as a cause of hematuria in Korea when the patient had a history of traveling endemic areas of schistosomiasis.

Impact of density of schistosomal antigen expression in urinary bladder tissue on the stratification, cell type, and staging, and prognosis of carcinoma of the bladder in Egyptian patients

BACKGROUND

Infection with urinary schistosomiasis and its severity are oncogenic factors for developing carcinoma of the bladder, whether it is urothelial carcinoma (UC) of a transitional cell type (TCC) or non-urothelial of squamous cell carcinoma (SCC). In UC it is not defined whether it is schistosomal or not. This led to controversial results in expression of tumour markers, tumour prognosis, and response to therapy.

OBJECTIVES

We assessed the application by immunohistochemistry method (IHC) for detection of schistosomal antigen in bladder cancer tissue samples to differentiate UC associated with or without schistosomiasis. Urothelial carcinoma stage, grade, and progression were correlated with the density, intensity, and index of schistosomal antigen expression. Follow up was done for 2-5 years.

DESIGN AND PARTICIPANTS

Archival tissue samples of 575 patients were studied: 515 urothelial carcinoma, 30 patients with SCC associated with schistosomiasis, and a control group of 30 patients without schistosomiasis.

MEASUREMENTS

Expression of schistosomal antigen in tissue was done by IHC using monoclonal antibodies (MAbs) against schistosomal antigens (SA). Correlation of intensity of antigen expression to clinical and pathological data was analysed.

RESULTS AND LIMITATIONS

We identified 3 parameters of antigen expression: density, intensity and index with 4 grades for each. SCC-group was 100% positive. UC was positive in 61.4% distributed as follows: Ta: 37.5%, T1: 62%, and muscle invasive T2-4 were 64%. Upstaging, metastases and recurrence were correlated with high index in T1 and T2-4 tumours.

CONCLUSION

Urothelial carcinoma associated with schistosomiasis was defined by the positive expression of schistosomal antigens in tissues detected by lHC using MAbs against schistosomal haematobium. Upstaging and progression of T1 and T2-4 were correlated with high density, intensity, and index of antigen expression. Non-schistosomal UC had negative expression for schistosomal antigen, which was detected in 36.5% of cases. These results would be of significance in differentiating schistosomal from non-schistosomal bladder cancer of UC and would predict the prognosis in T1, T2-3 tumours. Implementation of IHC using MAbs against SA in UC would help in planning the proper therapy. Schistosomiasis should be considered as an oncogene for UC in endemic areas.

Asymptomatic Schistosoma haematobium infection in a traveler with negative urine microscopy and late seroconversion presumably linked to artemisinin

We describe a Schistosoma haematobium infection with asymptomatic eosinophilia, persistently negative urine microscopy, and late seroconversion (7.5 months) in a traveler returning from Mali. After initial negative parasitological tests, travel history led to diagnostic cystoscopy, allowing final diagnosis with urine microscopy after the bladder biopsy. The patient was successfully treated with praziquantel. Difficulties in making the diagnosis of schistosomiasis in asymptomatic returning travelers are discussed; we propose a trial treatment in these cases.

Monoclonal antibody-based dipstick assay: a reliable field applicable technique for diagnosis of Schistosoma mansoni infection using human serum and urine samples

A field applicable diagnostic technique, the dipstick assay, was evaluated for its sensitivity and specificity in diagnosing human Schistosoma mansoni infection. A monoclonal antibody (mAb) against S. mansoni adult worm tegumental antigen (AWTA) was employed in dipstick and sandwich ELISA for detection of circulating schistosome antigen (CSA) in both serum and urine samples. Based on clinical and parasitological examinations, 60 S. mansoni-infected patients, 30 patients infected with parasites other than schistosomiasis, and 30 uninfected healthy individuals were selected. The sensitivity and specificity of dipstick assay in urine samples were 86.7% and 90.0%, respectively, compared to 90.0% sensitivity and 91.7% specificity of sandwich ELISA. In serum samples, the sensitivity and specificity were 88.3% and 91.7% for dipstick assay vs. 91.7% and 95.0% for sandwich ELISA, respectively. The diagnostic efficacy of dipstick assay in urine and serum samples was 88.3% and 90.0%, while it was 90.8% and 93.3% for sandwich ELISA, respectively. The diagnostic indices of dipstick assay and ELISA either in serum or in urine were statistically comparable (P>0.05). In conclusion, the dipstick assay offers an alternative simple, rapid, non-invasive technique in detecting CSA or complement to stool examinations especially in field studies.