H.D. Alexander

Changes in natural killer cells, the CD57CD8 subset, and related cytokines in healthy aging.

Aging has been shown to be accompanied by various changes in the lymphocyte subset distribution in the elderly. We have investigated more fully, and in a large number of subjects, age-related changes within several subpopulations bearing natural killer (NK) cell-associated surface antigens and changes in several cytokines involved in NK cell expansion. A total of 229 healthy subjects from all decades of life from 20 to 98 years of age was included in this cross-sectional study. A significant increase with age was found in both the absolute counts and the proportions of CD3−CD(16+56)+, CD3+CD(16+56)+, CD57+CD8+, CD57+CD8(low)+, and CD57+CD8− cells, whereas the CD57+CD8(high)+ subset, which may represent the cytolytic T cell population more precisely, showed less change with age. Some evidence is also provided to suggest that these expanded NK cell populations are in an activated state. Soluble IL-2 receptor levels were also found to increase significantly with age and correlated with certain NK cell subsets. Although the functions of some of these subsets remain to be elucidated, their expansion in the elderly may represent a remodeling of the immune system with increasing age, with an increase in non-MHC-restricted cells perhaps compensating for the previously reported decline in T and B cells in the elderly. Alternatively, increased numbers of these cells may be a direct result of cytokine dysregulation or increased antigenic or neoplastic cell challenge.

A whole blood method for measurement of intracellular TNF-α, IFN-γ and IL-2 expression in stimulated CD3+ lymphocytes: differences between young and elderly subjects

Abstract Cytokines, the central regulators of leucocyte growth and differentiation, are produced by a wide variety of cell types, target various cell subsets and exhibit numerous biological activities. Cytokine dysregulation is believed to play a role in the remodelling of the immune system in old age, however, previous reports of cytokine levels in elderly subjects have been conflicting, possibly due to methodologies employed. We used the relatively new technique of intracellular cytokine detection by flow cytometry to measure cytokine production in CD3+ lymphocytes from young and elderly subjects, but applied it to whole blood, thereby eliminating the need for laborious cell separation techniques and maintaining cells in their normal physiological environment. We found the assay to be very reproducible with acceptable intra- (2.9%) and inter- (6.3%) assay CVs. The percentages of CD3+ cells producing TNF-α and IFN-γ were significantly higher in elderly compared to young people (p=0.0049; p=0.0026, respectively) after stimulation with PMA and ionomycin. Absolute counts of CD3+IFN-γ+ and CD3+TNF-α+ cells were also significantly higher in the elderly group (p=0.039; p=0.051) respectively. There was no significant difference between the age groups for the percentage or numbers of IL-2-producing CD3+ cells on stimulation. CD3+ cells expressing TNF-α were highly associated with CD3+ cells expressing IFN-γ in both elderly and young people. In contrast, IL-2 secreting CD3+ cells were associated with TNF-α and IFN-γ producing CD3+ cells in young but not elderly subjects providing further evidence for the remodelling of the cytokine network associated with old age.

Plasma levels of the immunomodulatory cytokine interleukin-10 during normal human pregnancy: a longitudinal study.

Pregnancy is proposed to be a Th2 phenomenon, where Th2 cytokines inhibit Th1 responses to improve foetal survival. The importance of interleukin-10 (IL-10), an immunomodulatory cytokine produced by Th2 cells, in the maintenance of normal pregnancy is becoming increasingly apparent. In a longitudinal case-control study, the physiological effect of pregnancy on plasma IL-10 was investigated. The plasma concentration of IL-10 was determined using an ELISA technique in 99 pregnant women sampled at 12, 20 and 35 weeks of gestation, 38 non-pregnant control subjects sampled in parallel and in a subgroup of women sampled at 3 days post-partum (n, pregnant 21, non-pregnant 21). Plasma IL-10 was significantly higher in pregnant women at 12, 20 and 35 weeks of gestation (p<0.05, p<0.01 and p<0.0001, respectively), and in mothers post-delivery (p<0.01) when compared to non-pregnant control subjects. Furthermore, there was no significant effect of gestational time on IL-10 concentration. Results from the current study suggest that elevated IL-10 is a physiological consequence of normal healthy pregnancy. These findings help clarify previous conflicting results and establish a range for plasma levels of IL-10 in normal healthy pregnancy.

Age-related reference intervals for lymphocyte subsets in whole blood of healthy individuals.

Enumeration of various lymphocyte subsets is used widely in the diagnosis and monitoring of various disease states. With the development of flow cytometric technology and whole blood analysis, methodologies have become more sensitive. It is therefore important to establish reference intervals in normal, healthy individuals using these techniques to give a better indication of the border between health and disease. Since some lymphocyte subpopulations are known to change with age, we have enumerated common subsets in healthy individuals from all decades of adult life, including nonagenarian subjects. We report reference intervals for these subsets in each age group, which will be of use in diagnosis and disease monitoring, particularly in elderly subjects, the most rapidly expanding group within the population today.

ABCB1 (MDR1) rs1045642 is associated with increased overall survival in plasma cell myeloma

Multi-drug resistance (MDR) may compromise the successful management of haematological malignancies, impairing the effectiveness of chemotherapy. The P-glycoprotein (P-gp) drug efflux pump, encoded by the gene ABCB1 (MDR1), is the most widely studied component in MDR. A single nucleotide polymorphism (SNP) has been identified within ABCB1, rs1045642 (C3435T), which may alter P-gp substrate specificity and have an impact on the effectiveness of treatment, and hence overall survival (OS). We estimated the frequency of this SNP in the Northern Irish population and investigated its impact on the OS of patients with plasma cell myeloma (PCM). There was no significant difference in the frequency of rs1045642 between the PCM cohort and an age- and gender-matched control population. Findings within the PCM cohort suggest that rs1045642 genotype influences OS (p = 2 × 10−2). If confirmed in larger studies, these results suggest that genotyping rs1045642 may be a useful predictor of outcome in PCM and could indicate modified treatment modalities in certain individuals.

Immunoglobulin Gene Rearrangement Investigations in the Diagnosis of Lymphoid Malignancies from Formaldehyde-fixed Biopsies

Determination of the biologic potential of lymphoid proliferations in biopsies can be difficult by standard histological or even immunohistochemical examination. Polymerase chain reaction (PCR) has been used with increasing frequency to detect clonal rearrangements of the immunoglobulin heavy chain (IgH) in formaldehyde fixed, paraffin wax embedded tissues. Sensitivity ranges between 50 and 80%, and therefore at least 20% of neoplasms remain undetected by these approaches. Few investigators have attempted to detect immunoglobulin light chain (IgL) gene rearrangements by PCR using paraffin wax embedded samples. We studied 29 cases of B-cell neoplasms, along with 21 cases with equivocal histology and 4 reactive biopsies, using degenerate oligoprimers to amplify Ig κ and Ig   light chain genes, along with IgH (Fr 1, 2 and 3) gene rearrangement analysis. The combination of these methods detected clonality in 93% of cases (27/29) with histological diagnosis of B-NHL. Fr2 and Fr3 primers detected clonality in 79% (23/29) of cases. IgL chain rearrangements detected 4 cases (14%), negative for IgH rearrangements, improving sensitivity from 79 to 93%. Clonality was detected in 52% (11/21) of histologically equivocal lymphoid proliferations, including one case detected by IgL rearrangements which was negative for IgH rearrangements. Archival material from 4 cases with reactive histology produced polyclonal results. These results confirm that PCR based immunoglobulin gene rearrangement is a sensitive and specific method for demonstrating B-cell clonality in paraffin-wax embedded sections. The addition of IgL analysis to the IgH assay allows the detection of greater than 90% of B-cell lymphoproliferative disorders from routine histological specimens with poor preservation of genomic DNA.

Red Cell Aplasia Due to Erythrovirus Parvovirus B19 Infection in a Jehovah's Witness with Post-transplant EBV-induced Aggressive Lymphoma: Management Considerations

The refusal of Jehovahs Witnesses to accept blood and blood products often poses a clinical dilemma to present day medicine. We present a case of a Jehovahs Witness who had undergone renal transplantation, only to develop an Epstein-Barr virus associated aggressive lymphoma post-transplant. His condition was further complicated by erythrovirus (parvovirus) B19 infection resulting in red cell aplasia and severe anemia. The management of this difficult clinical situation is discussed together with a review of recommendations for chemotherapy treatment in Jehovahs Witnesses.