SummarySystemic lupus erythematosus (SLE) patients are characterized by a low lymphocyte count, which is considered a specific disease marker and is related to disease activity. The membrane bound molecules CD25 and CD27 are expressed and released in a soluble CD25 (sCD25) and soluble CD27 (sCD27) form by activation of predominantly T cells. In previous studies it was claimed that sCD25 as well sCD27 might be used as parameters for activation of the immune system; a correlation between the sCD25 profile with the disease course in SLE patients was also shown. To assess the relationship between lymphocyte count and these T cell activation markers, we performed a cross-sectional and a longitudinal study. In the longitudinal study three SLE patients who were known for a long time at our outpatient clinic were studied. Both T cell markers strongly correlated with each other and formed a reflection of the disease course. In all 7 periods of exacerbation, which we observed in the 3 investigated patients, both levels increased preceding this period; however, no correlation was found with the lymphocyte count. In the cross sectional study of 69 patients with SLE, sCD25 and sCD27 levels were correlated with defined disease manifestations; sCD25 was elevated in all periods of increased disease activity. The same holds true for sCD27, with the exception of patients with nephritis in which the highest levels were observed. Both profiles of sCD25 and sCD27 were strongly correlated during the whole disease course. Our data prove that in the pathogenesis of SLE an active recruitement of unprimed and primed T cells takes place.

Previously, we have shown that the monomeric-sugar composition of cell-surface-associated glycoconjugates of two strains of Chlamydomonas eugametos, of different mating type, differs strikingly (Gerwig et al. 1984, Carbohydr. Res. 127, 245-251). Besides the common occurrence of various pentoses and hexoses, the glycoconjugates of one strain contain 4-O-methyl xylose, a 2-O-methyl pentose (probably 2-O-methyl arabinose) and 3-O-methyl galactose, whereas those of the other strain contain 6-O-methyl mannose and 3-O-methyl glucose. In order to investigate whether these differences are relevant to the mating process of this organism, the sugar composition of the sexual progeny of these strains was analyzed. The ability to produce 4-O-methyl xylose, 2-O-methyl pentose and 3-O-methyl galactose on the one hand, and the ability to produce 6-O-methyl mannose and 3-O-methyl glucose on the other hand, appear to be genetically linked. However, the ability to produce either set of O-methyl sugars was inherited independently of mating type. O-Methylated sugars do not occur in the cell wall of C. eugametos, or in the cell-free medium, but only in surface-membrane-associated glycoconjugates, extractable with salt or detergent solutions.

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