SPONTANEOUS AND ACTIVATION-INDUCED APOPTOSIS OF PERIPHERAL BLOOD MONONUCLEAR CELLS FROM PATIENTS WITH SCHISTOSOMA MANSON/INFECTION

Abstract

• Schistosomiasis is the second extensively studied human parasitic infection next to malaria: This disease remains a public health problem in Egypt, which contributes to death of over half a million people yearly, despite the continuous control efforts.

The main pathology associated with schistosomiasis is the host granulomatous and fibrosing inflammatory reactions against the deposited parasite eggs deposition, which in case of species S. mansoni takes place in the liver and small intestines.

. It has been clea-rly- de. mo+n trated .,that

.g• ranu.loma.

form. ation and its r. e. gu.lation is

depe deD:_t on activation of CD4 Th1ymphoc)'tes and chronic-stage down-modulation of inflammatory response. This down-modulation process known as immuno-modulation has received considerable attention and is thought to be mediate by a number of different mechanisms, including CD4+ Th lymphocyte unresponsiveness, anti-inflammatory cytokines and apoptosis.

It is well established that programmed cell death (apoptosis) is an important regulator of host responses during infection with a variety of parasites. Parasitic pathogens have evolved diverse strategies to induce or inhibit host cell death, thereby modulating the host immune response.

The role of apoptotic mechanisms as immuno-regulator related to schistosome infection is still unclear and complex, especially in human model of schistosomiasis.

Consequently, the present work aimed at assessment of spontaneous and in vitro PHA-induced apoptosis in lymphocytes isolated from patients with chronic S. mansoni. In addition, cell death data was further correlated to degree of lymphoproliferation in response to PHA as well as to the serum anti-bilharzia!antibody titer in order to gain an insight into the role played by apoptotic mechanisms in the immunomodulation during the chronic stage of S. mansoni infection.

To achieve this goal, 20 Egyptian pure S.mansoni infected patients chosen from those admitting the outpatient clinic of the Medical research Institute, parasitology department, Alexandria University. They were seronegative for hepatitis B surface antigen and/or hepatitis C virus antibodies and free from other parasitic disease. In addition, 10 healthy subjects of comparable age and sex were included in the study as negative controls.

The male to female ratio among infected patients included in our study was 11 males (55%) and 9 females (45%), and among the healthy subjects was 7 males (70%) and 3 females (30%). The mean age of controls was 28.8 ± 1.10 years ranging from 25-36 while that of patients was 23.85 ± 2.38 years ranging from 10-49 years.