Effect of immunosuppression of the virulence of Giardia lamblia cysts.

This study was done to evaluate the pathological effects of Giardia lamblia cysts obtained from immunosuppressed host on the small intestine and liver of immunocompetent hosts. Thirty mice, subdivided into two groups, were infected with G. lamblia cysts in a dose of 5000 cysts/mouse. The first group (10 mice) was inoculated with Giardia cysts obtained from immunocompetent patients and the second group (20 mice) was inoculated with Giardia cysts obtained from already immunosuppressed mice (injected with cyclophosphamide). Stool examination revealed that mice in both groups passed cysts on day 6 +/- 1 after infection. The pathological changes of small intestine in both groups were more or less similar. The changes were in the form of shortening and widening of the villi with cellular inflammatory infiltrate in the lamina propria. The liver of both groups showed no pathological changes. It can be concluded that, although immunosuppression affects the immune system and the defensive mechanism of the host, yet it has no effects on the virulence of the excreted Giardia lamblia cysts.

Immunological changes in opportunistic parasitic infections.

This study was done on 110 patients with different types of malignant diseases and 20 healthy controls. Cases were divided into four groups according to parasitological and serological examination. The first group included 37 patients without any parasitic infection, the second 28 patients with no opportunistic parasitic infection, the third group 33 patients with opportunistic parasitic infection while the fourth included 12 patients with mixed opportunistic and non opportunistic parasites. Immunological status was estimated by carrying out leucocyte migration inhibition test and intradermal skin test for cell mediated immunity and quantitative determination of immunoglobulins IgG, IgM and IgA for humoral immunity testing. It was found that cell mediated immunity was decreased in cancer patients compared with the normal control group. Super added parasitic infections lead to greater decrease. Opportunistic parasitic infection aggravated the condition more. Marked suppression of the cell mediated immunity was found in the group of cancer patients with mixed opportunistic and non opportunistic parasitic infections. IgG and IgA were increased in the first three groups and decreased in the mixed one, IgM was increased in the first and second groups while decreased in groups with opportunistic infections.

The application of S. mansoni adult and soluble egg antigens for the serodiagnosis of schistosomiasis by CIEP, IHA and ELISA.

The sero-reactivity of 82 schistosomiasis infected patients were studied by the use of the CIEP, IHA and ELISA tests using S. mansoni adult worm antigen (AWA) and soluble egg antigen (SEA). CIEP with (AWA) showed a progressive sensitivity decreased with advance of S. mansoni infection, and increased in sensitivity by (SEA). The test was more sensitive in the early cases of S. haematobium infection by (AWA), while by (SEA) it was more sensitive in the late cases. There was no difference in sensitivity of the test with either antigens in mixed bilharzial infection. IHAT with (AWA) showed high sensitivity in the different stages of S. mansoni infection, but sensitivity decreased with the progress of clinical status of S. mansoni if (SEA) was utilized. The test with (AWA) was slightly more sensitive in the early cases of S. haematobium than the late cases, while the same high sensitivity was given by the test with (SEA) in both groups. Also IHAT with (AWA) was more sensitive for the diagnosis of mixed bilharzial infection than with (SEA). ELISA test with (SEA) showed a progressive increase in sensitivity with the advance of S. mansoni. Also the test with (SEA) was more sensitive than with (AWA); and for the diagnosis of cases of mixed bilharzial infection, while S. haematobium infected cases showed a lower sensitivity than S. mansoni or mixed bilharzial infection cases, if the ELISA test is performed with either antigens.

A comparative study between IFAT, COPT, CHR and IDT in the diagnosis of schistosomiasis mansoni.

Human sera were collected from various localities in Egypt from 103 cases of parasitologically confirmed schistosomiasis mansoni and 20 volunteers free from parasitic diseases.

The relation between the two forms of COPT and levels of total IgG and IgM in acute and chronic schistosomiasis mansoni.

COPT was performed on 55 acute and 48 chronic male patients with schistosomiasis mansoni as well as on 20 control normal subject. The percentage of the segmented and the bleb reactions were determined. The total levels of IgG, IgM and IgA were measured. There was no distinct evidence that COPT shows only bleb precipitations in acute cases and only segmented reactions in chronic cases. The total levels of IgG were higher in patients who showed segmented that in those who showed bleb reactions especially in the segmented but not the bleb reactions especially in chronic cases. IgM may be responsible for the bleb reactions in acute cases.

Sensitivity of crude and purified Fasciola antigens in immunological diagnosis of human fascioliasis.

A study has been done to find the effect of purification of crude antigens, extracted from adult Fasciola gigantica and Fasciola hepatica worms on the sensitivity of some serological techniques in diagnosis of fascioliasis. Using C.I.E.P. test, the partially purified antigens of both Fasciola species were less sensitive than their corresponding crude ones. Using I.H.A., the difference between results of crude and partially purified antigens for the two species were statistically insignificant, both (P greater than 0.05). So in applying this test, there is no need for the partially purification of antigen. On using E.L.I.S.A. the partially purified antigens showed higher sensitivities for detection of fascioliasis than their corresponding crude ones. Partially purified F. gigantica and F. hepatica antigens gave nearly the same results whether using C.I.E.P., I.H.A. or E.L.I.S.A. However, E.L.I.S.A. was the most sensitive technique followed by I.H.A. then C.I.E.P.

Opportunistic parasitic infections in immunocompromised hosts.

Parasitological and serological examination was done for 111 cases with various types of malignancies under immunosuppressive therapy and another 20 apparently healthy individuals as a control group to determine the prevalence of opportunistic parasitic infections among immunocompromised patients. Single examination showed that 74 (66.7%) harboured infection with different parasites: Strongyloides stercoralis infection was found in 4 (3.64%) cases; 3 cases (2.7%) had Pneumocystis carinii infection. No Cryptosporidium oocysts were detected; IFAT for toxoplasmosis was positive in 40 cases (36%) with titres ranging from 1/16 - 1/256 but IFAT-IgM was negative. The control group did not show any parasitic infection except that IFAT was positive in 4 out of 20 (20%) with titres ranging from 1/16 to 1/128 but IFAT-IgM was also negative. Although Toxoplasma infection was higher among patients the difference was insignificant. Generally the percentages recorded for the different parasites were found to be within the expected prevalence. One case report of concomitant opportunistic Pneumonocytis and Toxoplasma infection is reviewed.

The immunodiagnosis of Schistosoma mansoni infection in the different clinico-parasitological stages.

A total of 52 bilharzial mansoni patients were examined, 20 patients with early intestinal infection with living ova in stools, 20 patients with hepatosplenomegaly but without ascites, also with viable ova in stools, and 12 patients with hepatosplenomegaly and ascites without ova in stools; but in the rectal snip. Also 20 normal persons were examined. An IDT test was performed by S. mansoni adult worm antigen. S. mansoni adult worm and egg antigen extracts were used for performing CIEP, IHAT and ELISA tests showed statistically the same high sensitivity. In cases with hepatosplenomegaly whatever the clinical (with or without ascites) or the parasitological status (passing or not passing ova in stools) of the patients, the ELISA test with egg antigen is found to be a highly sensitive and a specific test.

The immune defensive mechanism in parasitic infection with eosinophilia.

This study was attempted to assess the extent of stimulation of the immune system in some patients suffering from parasitic infection with eosinophilia. Eighty-eight cases were selected, they included 10 apparently healthy, 10 suffering from different atopic disorders associated with eosinophilia and free from parasitic infections and 68 patients suffering from different parasitic infections associated with marked eosinophilia. The results showed a highly significant increase in the absolute eosinophil count in the atopic group while the parasitized group showed a moderate increase. The IgE serum level was increased in both atopic and parasitized groups. The cellular immunity expressed by phagocytic power of neutrophils was more depressed in parasitized than atopic group.

Effect of immunomodulation on experimental hymenolepiasis nana in mice.

Oral infection of cortisone treated and diabetes induced groups of mice (immunosuppressed) with H. nana eggs, whether before or after infection, showed persistent hyperinfection of the gut with H. nana worms and cysticercoids, dissemination of cysticercoids to the liver and marked degenerative changes in the intestinal mucosa and liver. BCG treated groups (immunostimulated) whether before or after infection, showed no significant changes compared to the control group. Subcutaneous infection of mice resulted in severe localized cellular reaction around and infiltrating the injected H. nana eggs in BCG treated and control groups. BCG did not inhibit larval development, as cysticercoids were found in the injected sites. In cortisone treated and diabetic groups, mild cellular reaction was observed.