Janice Wheeler

Community acquired pneumonia—a prospective UK study

BACKGROUND There are few data on paediatric community acquired pneumonia (PCAP) in the UK. AIMS To investigate the aetiology and most useful diagnostic tests for PCAP in the north east of England. METHODS A prospective study of hospital admissions with a diagnosis of PCAP. RESULTS A pathogen was isolated from 60% (81/136) of cases, and considered a definite or probable cause of their pneumonia in 51% (70/136). Fifty (37%) had a virus implicated (65% respiratory syncytial virus) and 19 (14%) a bacterium (7% group A streptococcus, 4% Streptococcus pneumoniae), with one mixed infection. Of a subgroup (51 patients) in whom serum antipneumolysin antibody testing was performed, 6% had evidence of pneumococcal infection, and all were under 2 years old. The best diagnostic yield was from paired serology (34%, 31/87), followed by viral immunofluorescence (33%, 32/98). CONCLUSION Viral infection accounted for 71% of the cases diagnosed. Group A streptococcus was the most common bacterial infective agent, with a low incidence of bothMycoplasma pneumoniae andS pneumoniae. Pneumococcal pneumonia was the most common bacterial cause of pneumonia in children under 2 years but not in older children. Inflammatory markers and chestx ray features did not differentiate viral from bacterial pneumonia; serology and viral immunofluorescence were the most useful diagnostic tests.

Renal allograft rejection--in situ demonstration of cytotoxic intratubular cells.

A nonisotopic in situ hybridization method to detect perforin mRNA was developed in cytospin preparations of IL-2-stimulated normal human lymphocytes and applied to formalin-fixed acutely rejected renal transplant material. Individual cells expressing perforin mRNA were localized in severely damaged tubular areas, and a number of these cells appeared to be located inside the tubular basement membrane in close association with tubular epithelial cells. Immunoperoxidase staining in acetone-fixed cryostat sections of acutely rejected kidney confirmed that a considerable proportion of infiltrating cells was CD8+; many of these were in an intratubular location. In addition, perforin protein was identified in individual cells in similar locations to perforin mRNA-positive cells. Again, some intratubular cells were identified. Our findings illustrate that these cells can be fully activated with definite cytotoxic potential. Previously we have demonstrated that T lymphocytes proliferate within the tubular compartment during tubulitis, a characteristic condition in acute renal allograft rejection, and that there is associated tubular epithelial cell proliferation. In this study we think that we have further clarified the consequences of invasion of tubules by lymphoid cells. Our in situ hybridization method in rapid and convenient and may be applied to archival material.

Detection of pneumolysin in sputum.

Western blot detection of the species-specific pneumococcal product, pneumolysin (SPN), was shown to be almost as sensitive as PCR for the non-cultural detection of pneumococci in 27 Streptococcus pneumoniae culture-positive sputa from patients stated to have chest infections. Both techniques were considerably more sensitive than counter-current immuno-electrophoresis for pneumococcal capsular polysaccharide antigens (CPS-CIE) on the same specimens. Sensitivities for PCR, SPN-immunoblotting and CPS-CIE were 100%, 85% and 67%, respectively. In 11 S. pneumoniae culture-negative sputa taken from patients receiving antibiotics, but with proven recent pneumococcal infection, PCR and SPN-blot were positive in six (in two of which CPS-CIE was also positive), PCR alone was positive in one and SPN-blot alone was positive in one. In 11 S. pneumoniae culture-negative samples from patients not receiving antibiotics, all three tests were negative in eight, PCR was positive in three (in one of which CPS-CIE was also positive), but SPN-blot was negative in all 11. In 16 S. pneumoniae culture-negative samples from patients receiving antibiotics and with no known recent pneumococcal infections, one or more non-cultural test was positive in 11. Although further evaluation is required to assess the significance of pneumolysin detection in relation to carriage and infection and to devise a more suitable test format, these preliminary studies suggest that pneumolysin detection is a promising new approach to the non-cultural diagnosis of pneumococcal chest infection.

β-chemokine expression and distribution in paraffin-embedded transplant renal biopsy sections: analysis by scanning laser confocal microscopy

Abstract Previous immunohistochemical and in situ hybridisation studies have shown that, in tubulitis associated with acute cellular rejection of human renal allografts, intratubular T cells proliferate and are fully activated in situ. In the immunohistochemical study reported here we have attempted to establish some understanding of the involvement of the β-chemokines RANTES, MCP-1, MIP-1α and MIP-1β in recruiting T cells to the intratubular site. Paraffin-embedded routine biopsy sections were treated for conventional indirect immunofluorescence to detect the selected chemokines. Scanning laser confocal microscopy was used to provide a measure of fluorescence intensity resulting from binding of FITC-labelled secondary antibody. Cells expressing chemokines could be identified and, within the limits of the staining method, it was possible to obtain a semi-quantitative assessment of individual chemokine activity at different points in biopsy sections by constructing a profile of fluorescence intensity. High concentrations of chemokines (especially RANTES, MIP-1β and/or MIP-1α) were localised to the basolateral surface of tubular epithelial cells (TEC). MCP-1 was also consistently present but at a lower level than RANTES except in one case identified as BANFF category 3. There was diffuse distribution of chemokines in the interstitial matrix and low intensity fluorescence outlined some endothelial cells of peritubular venules and interstitial fibroblast-like cells. Our results suggest a mechanism for specific chemotactic recruitment of inflammatory cells by TEC-produced chemokines.

LightCycler-Based Quantitative PCR for Detection of Cytomegalovirus in Blood, Urine, and Respiratory Samples

In response to a recently published article by Schaade et al. ([12][1]) describing the value of LightCycler technology for quantitative analysis of cytomegalovirus (CMV) in clinical material, we wish to add our experience. Using a different LightCycler (LC; Idaho Technology Inc., Idaho Falls, Idaho

Detection of circulating tumour necrosis factor-α after elective cardiopulmonary bypass

Plasma samples for the assay of tumour necrosis factor-a (TNF) were obtained prior to operation, during perfusion and at hourly intervals during the first 24 hours after operation from five consecutive patients undergoing elective coronary artery bypass grafting. TNF was detected in high concentration (>10 000pg/ml) in one patient and in low levels (approximately 1 00pg/ml) in two other patients during the first 1-6 hours after removal of the aortic crossclamp at the end of perfusion. All other samples were negative. The results support the hypothesis that TNF is transiently released as a response to the endotoxaemia known to occur towards the end of bypass. The significance of these findings in relation to the development of adult respiratory distress syndrome and multiple organ failure in unstable patients undergoing open-heart surgery is discussed briefly.