To elucidate whether the fraction of CD28(-) T cells within the CD4(+) T-cell population is a major source of Th1-like and proinflammatory cytokine production driving Wegener's granulomatosis (WG) granuloma formation, we analyzed the phenotype and functional characteristics of peripheral blood CD4(+)CD28(-) T cells and of T cells in granulomatous lesions of 12 patients with active WG. Surface markers and intracytoplasmic cytokine and perforin expression were assessed by flow cytometry. Cytokine secretion was measured by enzyme-linked immunosorbent assay. Immunohistological studies demonstrated interferon-gamma and tumor necrosis factor-alpha cytokine positivity attributable to CD4(+)CD28(-) T cells in granulomatous lesions. Peripheral blood CD4(+)CD28(-) T cells expressed CD57, also found on natural killer cells, and intracytoplasmic perforin. They were generally CD25 (interleukin-2 receptor)-negative. CD18 (adhesion molecule beta(2)-integrin) was strongly up-regulated on CD4(+)CD28(-) T cells, whereas only a minority of CD4(+)CD28(+) T cells expressed CD18. CD4(+)CD28(-) T cells appeared as a major source of interferon-gamma and tumor necrosis factor-alpha. In contrast, CD4(+)CD28(+) T cells were able to produce and secrete a wider variety of cytokines including interleukin-2. One-quarter of CD4(+)CD28(+) T cells expressed the activation marker CD25, but they lacked perforin. Thus, CD4(+)CD28(-) T cells appeared more differentiated than CD4(+)CD28(+) T cells. They displayed Th1-like cytokine production and features suggestive of the capability of CD4(+) T-cell-mediated cytotoxicity. CD4(+)CD28(-) T cells may be recruited into granulomatous lesions from the blood via CD18 interaction, and may subsequently promote monocyte accumulation and granuloma formation through their cytokine secretion in WG.

On a global basis, ticks transmit a greater variety of pathogenic microorganisms, protozoa, rickettsiae, spirochaets, and viruses than any other arthropods and are among the most important vectors of diseases affecting livestock, humans, and companion animals. Ticks and tick-borne diseases (TTBDs) affect 80% of the world cattle population and are widely distributed throughout the world, particularly in tropical and subtropical countries including India, Pakistan, and Bangladesh. Ticks and tick-transmitted infections have coevolved with various wild animal hosts, which constitute the reservoir hosts for ticks and tick-borne pathogens of livestock, pets, and humans. In this region, the livestock sector is suffering from a number of disease problems caused by bacteria, viruses, fungi, and parasites. Among the parasitological problems, the damage caused by TTBDs is considered very high, and the control of TTBDs has been given priority.

LPS (endotoxins) activate cells of the human immune system, among which are monocytes and macrophages, to produce endogenous mediators. These regulate the immune response, but may also cause severe harm leading to septic shock. The activation of monocytes/macrophages by LPS is mediated by a membrane-bound LPS receptor, mCD14. As mCD14 lacks a transmembrane domain, a further protein is required for the signal transducing step to the cell interior. Here we show, using excised outside-out membrane patches, that activation of a high-conductance Ca2+- and voltage-dependent potassium channel is an early step in the transmembrane signal transduction in macrophages. The channel is activated by endotoxically active LPS in a dose-dependent manner. Channel activation can be completely inhibited by LPS antagonists and by anti-CD14 Abs. Activation of the channel is essential for LPS-induced cytokine production as shown by its inhibition by selective K+ channel blockers.

Polymorphisms in the tumor necrosis factor and interleukin-10 genes, linked to cytokine inducibility, may influence the inflammatory response to infection. We studied the biallelic interleukin-10-1082 promoter, the tumor necrosis factor-alpha-308 promoter, and the lymphotoxin-alpha polymorphisms with regard to the development of septic shock in pneumococcal infection. Sixty-nine patients with pneumococcal disease (61 patients with community-acquired pneumonia, 5 patients with meningitis, and 3 patients with pneumonia and meningitis) and 50 age-matched control subjects were included. The polymorphisms were determined by the polymerase chain reaction. In patients with pneumococcal disease, the lipopolysaccharide-stimulated tumor necrosis factor and interleukin-10 release from whole blood were measured by ELISA. Sepsis severity was documented according to standard criteria. No significant genotypic differences were seen between patients and control subjects. Thirteen of 69 patients with pneumococcal disease developed septic shock. Interleukin-10 allele G homozygous patients had the highest risk for septic shock (odds ratio of 6.1; 95% confidence interval, 1.4-27.2; corrected p = 0.024). The stimulated interleukin-10 release was highest in interleukin-10 G homozygous patients (p = 0.04). In conclusion, interleukin-10 polymorphism, associated with high interleukin-10 inducibility, might influence the outcome of pneumococcal infection via induced immunosuppression and impaired bacterial clearance.

SummaryAnaplasma species are obligate intracellular rickettsial pathogens transmitted by ticks with an impact on human and animal health. Anaplasma ovis infects sheep and goats in many regions of the world, and it can be diagnosed by different methods like Giemsa staining, PCR or competitive ELISA. In this study, a PCR based on the gene coding for major surface protein 4 (MSP-4) was used to examine field samples collected from sheep in different countries. Altogether, 1161 blood samples from Turkey (n = 830), Iraq (n = 195), Sudan (n = 96) and Portugal (n = 40) were examined, of which 31.4%, 66.6% 41.6% and 82.5%, respectively, were positive. This indicates high prevalence of A. ovis in the countries under investigation, and it can be assumed that the situation in other areas of the world might be similar. Thus, A. ovis should be considered as an important constraint of livestock production, and further efforts are needed to better understand the epidemiology and to implement suitable control measures.

No abstract

(Thorax 2001;56:751-757)

A fatal disease of sheep and goats in the northwestern part of China has in the past been reported to be due to Theileria lestoquardi. However, some characteristics of the causative agent are not in accordance with attributes ascribed to this parasite. We therefore determined the nucleotide sequence of the 18 small subunit ribosomal RNA (18S rRNA) gene of T. lestoquardi and the parasite identified in China and compared it with that of other Theileria and Babesia species. In the inferred phylogenetic tree, the 18S rRNA sequence of the Chinese parasite falls inside the clade consisting of Theileria species evidencing that it belongs to this genus. The 18S rRNA sequence of the Chinese parasite was found to be most closely related to Theileria buffeli and clearly divergent to T. lestoquardi, suggesting that it was a yet unrecognized Theileria species. The phylogenetic relationship of Theileria species infecting sheep and goats on the basis of their 18S rRNA gene structure was addressed. We report on the existence of at least two additional ovine and caprine piroplasm species, designated T. luwenshuni and T. uilenbergi.