Background: Schistosomiasis is a major tropical disease with significant morbidity and mortality in
several developing countries. Hence, searching for a new immunomodulating supportive aid for the sole
drug of choice, praziquantel (PZQ), is an important target.
Objective: The aim of the present work is to assess the immunomodulatory effect of Kalobin (Pelargonium
reinforme/sidoides extract) on schistosomiasis mansoni in vivo.
Material and Methods: Swiss albino mice were infected with S. mansoni cercariae and were divided into
two major categories, immunocompetent (IC) and immunosuppressed (IS). Immunosuppression was
performed 14 successive days prior to infection. Kalobin and PZQ, either individually or combined, were
given orally seven weeks post infection (wpi). Only in IC mice, both drugs were given in a combination of
100 mg/kg seven wpi for five consecutive days as a preliminary trial. Other groups were treated with PZQ
(IC2, 50 mg/kg and IC1, 200 mg/kg) or Kalobin (IC3, 200 mg/kg) or combined PZQ-Kalobin treatment (IC4,
50 mg/kg each) for five consecutive days. This regimen was administered to both IC and IS subgroups and
compared to the negative uninfected non-treated control subgroup and the two corresponding positive
infected non-treated control CIC and CIS subgroups. All mice were sacrificed 9 wpi for assessment of
parasitological parameters including total worm burden (TWB), tissue egg load, oogram pattern, and
measurement of hepatic granuloma number and size. Immunohistochemical procedure was employed
to assess the expression of vascular endothelial growth factor (VEGF) in both hepatocytes and sinusoids.
Results: Therapy with combined treatment (IC5, 100 mg/Kg each) proved to be superior to the sole PZQ
treatment (IC1, 200 mg/kg and IC2, 50 mg/kg) as shown by its effect on TWB and oogram pattern and
greater reduction in intestinal and hepatic egg counts in IS groups. Combined PZQ-Kalobin therapy (IC4,
50 mg/kg each) approached the higher individual PZQ dose (IC1, 200 mg/kg) in reducing the granuloma
number. The highest reduction in the expression of VEGF in hepatocytes and sinusoids was recorded in the
combined PZQ-Kalobin (IC4 and IS4, 50 mg/kg each) followed by subgroup IC3 (Kalobin 200 mg/kg) then
IC1 (PZQ 200 mg/kg). Moreover, as regards the IS subgroups; IS4, PZQ-Kalobin 50 mg/kg combination and
IS3, Kalobin 200 mg/kg showed better results than all IC subgroups. Individual Kalobin in (IS3) subgroup < br />showed better response than in IC3 subgroup using the same dose of 200 mg/kg.
Conclusion: Our study highlighted the immunopotentiating outcome for Kalobin whether in combination
with PZQ or individually on schistosomiasis mansoni in vivo.