A study of allergens in celery with cross-sensitivity to mugwort and birch pollens

Sixty-one sera with positive RAST to mugwort pollen ( Artemisiae vulgaris ) were submitted to RASTs for birch pollen ( Betula verrucosa) and celery ( Apium graveolens ). In 36 cases RAST results were positive for celery. In addition, 23 sera presented specific IgE to birch pollen. The binding of specific IgE to individual allergens in celery, mugwort pollen and birch pollen was studied by the immunoblotting technique. This involved electrophoretic separation of allergenic extracts, electrotransfer of proteins onto nitrocellulose sheets and sensitive immunoenzymatic detection. Eighteen sera had specific IgE binding to two celery components of molecular weight around 15 kD. All these sera also detected a 15 kD allergen in mugwort and two allergens in birch of 14 kD and 16 kD molecular weight. The sera that did not detect the 15 kD bands in celery failed to react with both the 15 kD mugwort component and the 14 and 16 kD birch components. Specific cross-inhibitions of the detection of these allergens on immunoblots were obtained by pre-incubation of the sera with crude extract of the three species. These results strongly suggest that such allergens display some structural identity and that they could be at the origin of some cases of crossed hypersensitivity to celery, mugwort pollen and birch pollen.     

Unclassified Haemolytic Anaemia with Splenomegaly and Erythrocyte Cation Abnormalities – A Disease of the Spleen?

An unclassified case of haemolytic anaemia with voluminous splenomegaly is reported. This anaemia was normocytic without any specific morphologic aspect of red blood cells (RBC); Coombs test was negative; the osmotic fragility was normal; the increased autohaemolysis was not affected by the presence of glucose; Hb studies were normal; no RBC enzyme deficiency was found; RBC lipids and membrane proteins were normal; there was a marked reduction in RBC survival with exclusive splenic uptake of erythrocytes. Before splenectomy, RBC cations and water content were abnormal: 1) the RBC water was decreased moderately; 2) the RBC sodium was about twice the normal mean with an increased ²²Na turn-over; 3) the RBC potassium was markedly reduced and ⁴²K influx was twice the normal mean; 4) the RBC calcium content was increased. Splenectomy was followed by rapid disappearance of haemolysis and RBC water and cation disturbances. Because of this extremely rapid disappearance after splenectomy the authors suggest this case of haemolytic anaemia could be a primary disease of the spleen.     

Revisiting host/parasite interactions: molecular analysis of parasites collected during longitudinal and cross-sectional surveys in humans

This paper summarizes the first conclusions arising from an analysis of parasite diversity in blood samples collected during longitudinal surveys conducted in Senegal. Parasite typing was carried out using a PCR-based molecular analysis of allelic polymorphism. The parasite populations circulating in the village of Dielmo during periods of intense transmission (when the inoculation rate was 0.5–1 infective bite/night) are characterized by a considerable allelic diversity of the MSP-1, MSP-2 and TRAP loci. A large proportion of blood samples contained several MSP-1 or MSP-2 alleles. In asymptomatic carriers, the complexity of the infections (number of alleles and genetic diversity of these alleles) was age-dependent. In children, the trend was for a reduced complexity during clinical episodes. Molecular typing showed that successive clinical episodes experienced by children were caused by genetically distinct parasites. Longitudinal analysis of asymptomatic carriers indicated that in the absence of transmission, the same parasite types were carried for long periods, while rapidly changing profiles were observed during intense transmission season. The consequences of these findings on our understanding of acquired anti-parasite immunity in humans living in endemic are discussed.