T-cell subset counts and serum immunoglobulin concentrations in patients with chronic renal failure at the Kenyatta National Hospital.

This study was designed to determine whether there was any difference in the T-cell subset counts and serum immunoglobulin concentrations in patients with chronic renal failure as compared to normal controls. Ninety individuals participated in the study. These were divided into three groups as follows; (i) 30 subjects with normal renal function; (ii) 30 subjects with chronic renal failure (CRF)(creatinine clearance 10-50 mls/min), not requiring haemodialysis and; (iii) 30 subjects with end stage renal disease (creatinine clearance < 10 mls/min) on haemodialysis. The subjects in the three groups were matched for age and sex. In addition, it was ascertained that none of the subjects was on any medication or suffered from any ailment known to interfere with the immune system. The T-cell subset counts were carried out using flow cytometry while the serum concentration of immunoglobulins was measured using the radio-immunodiffusion method. Patients with CRF, whether on haemodialysis or not, had significantly lower lymphocyte counts as a proportion of total white cell count (19% and 19.2% respectively versus 39%) and low absolute CD4 cell counts per mm3 (337 +/- 94 and 449 +/- 116 respectively versus 891 +/- 360) and CD8 cell counts per mm3 (437 +/- 234 and 490 +/- 176 respectively versus 644 +/- 228) as compared to normals, with no statistically significant difference between the two groups with CRF. The CD4: CD8 ratios in the three groups studied were 1.487 +/- 0.233, 0.961 +/- 0.326 and 0.751 +/- 0.167 respectively, being significantly higher in normal controls than in any of the groups with CRF (p < 0.05) and in the group with CRF not requiring dialysis than in those requiring it (p < 0.05). The serum concentration of immunoglobulins in the two groups with CRF were similar to those in the group with normal renal function. It is concluded that CRF represents a state of immunodeficiency not significantly corrected by haemodialysis.

Vaccination of the vervet monkey (Cercopithecus aethiops) against infection with Schistosoma mansoni.

Pilot experiments were carried out to assess the immunizing potential of radiation-attenuated cercariae of S. mansoni. Groups of 4 monkeys each were vaccinated 4-5 times at 3-5-week intervals using cercariae which had received 10, 20, 40 or 60 krad of gamma radiation. Animals were vaccinated with 1000 or 2000 cercariae per kilogram of body weight. Overall the difference in worm burdens between the vaccinated and unvaccinated groups was highly significant (P greater than 0.01). The highest level of protection achieved was 44.4%. This was in monkeys which were immunized five times with 2000, 20-krad cercariae at 3-4-week intervals. Protection levels of 33.3%, 36.6% and 37.0% were achieved in groups which had received, respectively, 1000 20-krad cercariae, 1000 10-krad cercariae, 2000 40-krad cercariae and 2000 60-krad cercariae. Vaccination reduced faecal egg counts markedly and intestinal tissue egg counts by 20-40%. Antischistosomular antibody was detectable in vitro 3 weeks after the first vaccination. Schistosomule kill rates of up to 60% were observed in vitro.