BLOOD GRANULOCYTE KINETICS IN CONDITIONS ASSOCIATED WITH GRANULOCYTOSIS

Neutrophil left shift and white blood cell count as markers of bacterial infection

Neutrophil left shift and white blood cell (WBC) count are routine laboratory tests used to assess neutrophil state, which depends on supply from the bone marrow and consumption in the tissues. If WBC count is constant, the presence of left shift indicates an increase of neutrophil consumption that is equal to an increase of production. A decrease in WBC count indicates that neutrophil consumption surpasses supply. During a bacterial infection, large numbers of neutrophils are consumed. Thus, from onset of infection to recovery, dynamic changes occur in WBC count and left shift data, reflecting the mild to serious condition of the bacterial infection. Although various stimuli in healthy and pathological conditions also cause left shift, a change as sudden and significant is only seen in bacterial infection. Left shift does not occur in the extremely early or late phases of infection; therefore, assessing data from a single time point is unsuitable for diagnosing a bacterial infection. We argue that time-series data of left shift and WBC count reflect real-time neutrophil consumption during the course of a bacterial infection, allowing more accurate evaluation of patient condition.

Combination of white blood cell count and left shift level real-timely reflects a course of bacterial infection

BACKGROUND

The efficacy of white blood cell (WBC) count and left shift in predicting bacterial infections has been controversial. The aim of this study was to prove that WBC count and left shift reflect a course of bacterial infection.

MATERIALS

Six patients in whom the onset of bacterial infection had been determined and successful treatment had been done were selected. Manual 100-cell differential counts were repeated at least every 24 hr.

RESULTS

WBC count and left shift divided a course of bacterial infection into five phases. In the first phase of bacterial infection (0-10 hr after the onset), WBC count decreased to fewer than reference range without left shift. In the second phase (about 10-20 hr), low WBC count continued and left shift appeared. In the third phase (one to some days), WBC count increased above reference range with left shift. In the fourth phase (some to several days), high WBC count continued without left shift. In the fifth phase, WBC count went down into reference range without left shift.

CONCLUSIONS

A combination of WBC count and left shift real-timely reflected a course of bacterial infection from the onset to healing. And we could judge which bacterial infection is adequately treated or not only by the above two routine laboratory tests.

Comprehensive postmortem analyses of intestinal microbiota changes and bacterial translocation in human flora associated mice

Background

Postmortem microbiological examinations are performed in forensic and medical pathology for defining uncertain causes of deaths and for screening of deceased tissue donors. Interpretation of bacteriological data, however, is hampered by false-positive results due to agonal spread of microorganisms, postmortem bacterial translocation, and environmental contamination.

Methodology/Principal Findings

We performed a kinetic survey of naturally occurring postmortem gut flora changes in the small and large intestines of conventional and gnotobiotic mice associated with a human microbiota (hfa) applying cultural and molecular methods. Sacrificed mice were kept under ambient conditions for up to 72 hours postmortem. Intestinal microbiota changes were most pronounced in the ileal lumen where enterobacteria and enterococci increased by 3–5 orders of magnitude in conventional and hfa mice. Interestingly, comparable intestinal overgrowth was shown in acute and chronic intestinal inflammation in mice and men. In hfa mice, ileal overgrowth with enterococci and enterobacteria started 3 and 24 hours postmortem, respectively. Strikingly, intestinal bacteria translocated to extra-intestinal compartments such as mesenteric lymphnodes, spleen, liver, kidney, and cardiac blood as early as 5 min after death. Furthermore, intestinal tissue destruction was characterized by increased numbers of apoptotic cells and neutrophils within 3 hours postmortem, whereas counts of proliferative cells as well as T- and B-lymphocytes and regulatory T-cells decreased between 3 and 12 hours postmortem.

Conclusions/Significance

We conclude that kinetics of ileal overgrowth with enterobacteria and enterococci in hfa mice can be used as an indicator for compromized intestinal functionality and for more precisely defining the time point of death under defined ambient conditions. The rapid translocation of intestinal bacteria starting within a few minutes after death will help to distinguish between relevant bacteria and secondary contaminants thus providing important informations for routine applications and future studies in applied microbiology, forensic pathology, and criminal medicine.

Granulocyte transfusion: a review

Neutrophils are the body's main defence against invasion by bacteria and fungi and, below a level of 1 x 10(9)/l, there is a direct relationship between their circulating number and the risk of systemic infection. Despite advances in supportive care, such as improved broad-spectrum antibiotics and the haemopoietic growth factors, neutropenia following myelosuppressive chemotherapy for malignant disease remains the most important cause of treatment-related morbidity and mortality and its most important dose-limiting toxicity. Although there is clear theoretical, experimental and anecdotal clinical evidence supporting the use of transfused granulocytes to prevent and treat infection in neutropenia, early attempts at exploiting this clinically were unsuccessful, mainly because of difficulties in collecting a sufficient number of cells. Improvements in the technology of collection, including the use of red cell sedimenting agents, glucocorticoids and, more recently, granulocyte-colony-stimulating factor, now allow granulocyte doses within the therapeutic range to be routinely collected. Preliminary evidence suggests clinical efficacy. However, well-designed trials with clinically relevant end-points will be required before granulocyte transfusion can become part of routine clinical practice.

The measurement of granulocyte kinetics

Studies using 3H-TdR, DF32P or 51Cr have all contributed important information concerning neutrophil kinetics in normal and abnormal conditions. Recent evidence, however, suggests that DF32P underestimates, and 51Cr overestimates, the blood neutrophil T1/2 and that both isotopes overestimate the TBNP, compared with 3H-TdR-derived data. The differences are quantitative and not qualitative, and the principles of blood neutrophil kinetics defined by DF32P studies are still valid. 3H-TdR studies are impractical for general use, and clinical measurement of neutrophil kinetics will have to continue to rely on the use of either DF32P or 51Cr. Comparison of abnormal findings with normal values obtained using the same isotope is probably valid for either technique. Changes in neutrophil kinetics leading to a neutrophil leucocytosis in different situations are fairly predictable from published data. In neutropenias, however, kinetic studies might be needed to delineate the relative contributions of under-production, shortened survival and excessive margination in the individual patient.

[Kinetics and regulation of granulocytopoiesis (author's transl)]

The present survey of the development of the granulocytes consists of two parts. In the first section the different stages of granulopoiesis are discussed with special regard to the stem cells. In the second one the regulation of the granulopoiesis and the different factors taking part in the homeostasis of the granulocytes are examined. Emphasis is placed upon the colony stimulating activity" (CSA) previously tested in different situations of stress in relationship to the granulopoietic system. In a separate chapter some marked clinical syndromes are discussed which accompany disorders of granulocyte-homeostasis. The pathogenesis of leukaemia is reviewed.

Neutrophil kinetics in acute infection

Neutrophil kinetics of acute experimental infection were studied with diisopropylfluorophosphate-(32)P labeling in 31 dogs inoculated intrabronchially with pneumococci. In vitro neutrophil labeling indicated a rapid transit time through the blood in early infections, with an elevated marginal granulocyte pool sometimes preceding an elevation of the circulating granulocyte pool. 13 hr after infection, the circulating and total blood granulocyte pools were increased but the rate of neutrophil transit through the blood was normal. During the recovery from infection there was a marked prolongation of neutrophil blood transit time, suggesting virtually complete cessation of bone marrow release of neutrophils into the blood. Labeling of neutrophils in vivo indicated an increased rate of emptying of the bone marrow storage pool proportional to the severity of infection as measured by the fever index. The change in the blood ratio of nonsegmented to segmented neutrophils was a much more accurate index of the severity of infection than the blood granulocyte concentration, correlating significantly with the fever index.