Pulmonary shunts in severe hepatosplenic schistosomiasis: Diagnosis by contrast echocardiography and their relationship with abdominal ultrasound findings

Characteristics of peripheral lymphocyte subsets in patients with different stages of schistosomiasis japonica

Immune cells are important for the development of schistosomiasis japonica and are also critical for the treatment of schistosomiasis. The immune cells in the peripheral blood help assess the immune state. The peripheral lymphocytes in schistosomiasis mansoni were well studied; however, immune cells in patients with different stages of schistosomiasis japonica are not well analysed. Here, we performed a preliminary study to explore characteristics of peripheral lymphocyte subsets in patients with different stages of schistosomiasis japonica. 135 patients with Schistosoma japonicum infection and 25 healthy volunteers were included in this study, including 84 patients with chronic S. japonicum infection and 51 patients with advanced S. japonicum infection. Flow cytometry analysis was performed to evaluate peripheral lymphocytes including T cells, B cells, and natural killer (NK) cells. Blood routine and liver function test data were analysed. Ultrasound examination was used to access liver fibrosis according to the World Health Organization standard about ultrasound in schistosomiasis. Demographic data analysis suggested there was no difference in age and gender in patients with S. japonicum infection and health control group. Liver function tests showed that patients with advanced schistosomiasis had a higher incidence of liver function abnormality and blood lipid than those with chronic schistosomiasis. Blood routine results reflected that haemoglobin, red blood cells, platelets, as well as lymphocytes in the advanced group were significantly less than that in the chronic group. Furthermore, flow cytometry analysis indicated that the percentage of CD4+ T cells was lower in the advanced group, but the percentage of CD19+ B cells was higher in the advanced group. In addition, the number of CD3+ T cells, CD3+ CD4+ T cells, CD3+ CD8+ T cells, and NK cells was less in the advanced group when compared with those in the chronic group. In addition, there was a correlation between the decrease in CD4+ T cells and more severe fibrosis on ultrasound images. Our results indicated that the immune state in the peripheral is different in different stages of S. japonicum infection. Lymphocyte subset analysis has potential to facilitate differential diagnosis of different stages of schistosomiasis japonica and even to be a prognostic factor.

Schistosomiasis Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a disease of the lung blood vessels that results in right heart failure. PAH is thought to occur in about 5% to 10% of patients with hepatosplenic schistosomiasis, particularly due to S. mansoni. The lung blood vessel injury may result from a combination of embolization of eggs through portocaval shunts into the lungs causing localized Type 2 inflammatory response and vessel remodeling, triggering of autonomous pathology that becomes independent of the antigen, and high cardiac output as seen in portopulmonary hypertension. The condition is likely underdiagnosed as there is little systematic screening, and risk factors for developing PAH are not known. Screening is done by echocardiography, and formal diagnosis requires invasive right heart catheterization. Patients with Schistosoma-associated PAH show reduced functional capacity and can be treated with pulmonary vasodilators, which improves symptoms and may improve survival. There are animal models of this disease that might help in understanding disease pathogenesis and identify novel targets to screen and treatment. Pathogenic mechanisms include Type 2 immunity and activation and signaling in the TGF-β pathway. There are still major uncertainties regarding Schistosoma-associated PAH development, course and treatment.

Tropical Lung Diseases

Lung disease is common in the tropics; lower respiratory tract infections are a major cause of mortality, especially in children under 5 years of age. The World Health Organization has launched strategies to tackle this killer of children. Infections, including tuberculosis and drug-resistant tuberculosis, find vulnerable hosts in the tropics where human immunodeficiency virus co-infection is widespread, especially in India and sub-Saharan Africa. Parasitic infections can cause pulmonary manifestations (e.g., pleural effusion and cavitary lesions). Blood and pulmonary eosinophilia are common in such infections. Non-communicable lung disease such as chronic obstructive pulmonary disease and lung cancer associated with tobacco use, contribute to mortality, particularly where there is poor access to health structures.

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Pneumonia is a major cause of death in the tropics, especially in children under 5 years old.

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Symptoms and physical examination determine care-seeking behaviors and clinical management.

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Most new tuberculosis cases occur in the tropics, often with human immunodeficiency virus (HIV) co-infection.

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Parasitic infections can manifest as wheezing, eosinophilic pneumonia, pleural effusion, and cavitary lesions.

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The impact of non-communicable disease (e.g., chronic obstructive pulmonary disease [COPD] and lung cancer) on mortality is projected to rise in low- and middle-income countries.