Kikuchi disease presenting as a flu-like illness with rash and lymphadenopathy.

Kikuchi-Fujimoto disease (Kikuchi Disease) is a self-limited and benign systemic lymphadenitis of unknown cause, originally described by Kikuchi and Fujimoto and coworkers in 1972. Although relatively uncommon, it is increasingly discussed in the medical literature. Clinical presentation typically includes adenopathy, particularly cervical, with fever and flu-like symptoms. This constellation of symptoms, in the presence of a characteristic histiocytic necrotizing lymphadenitis, provides the clinicopathologic diagnosis. The immunopathogenesis of Kikuchi disease may lie in a hyperactive response to viral infection. We describe an African American man with Kikuchi disease, unusual in the extent of his rash and debilitation, and in the relapse of his clinical symptoms.

The T cell receptor repertoire of CD8+CD28- T lymphocytes is dominated by expanded clones that persist over time.

The costimulatory molecule CD28 is expressed on almost all CD4+ T cells, but on only a portion of CD8+ T cells in healthy human adults. alpha beta T cells may thus be divided into three phenotypically and functionally different subsets: CD4+, CD8+CD28+ and CD8+CD28-. Using peripheral blood lymphocytes from six healthy adults, we have studied the T cell receptor (TCR) repertoire within these subsets by analysis of the distribution of lengths of the complementarity determining region 3 (CDR3) of the beta variable (BV) transcripts and flow cytometric analysis of TCR V beta usage. Expanded CDR3 lengths were identified in 86% of BV families within CD8+CD28- T cells, but in only 4% within CD4+ T cells, and 35% within CD8+CD28+ T cells (P < 0.01). When sequenced, the majority of expanded peaks were found to be dominated by single clones. Identical expanded clones were found within both CD8+CD28+ and CD8+CD28- subsets, consistent with the belief that CD8+CD28- T cells descend directly from CD8+CD28+ T cells. Greatly expanded CD28- clones were found within both CD8+ and CD4+ subsets and persisted at the same magnitude for up to 4.5 years of observation. The finding of a small proportion of cells expressing Ki-67 showed that some of these clonally expanded cells were in the active stages of the cell cycle, but few of the cells expressed activation markers CD69, CD25, CD71 or CD122. One likely explanation for the persistence of expanded peripheral lymphocyte populations in healthy individuals is the presence of persistent antigen.

Molecular analysis of the complementarity determining region 3 of the human T cell receptor beta chain. Establishment of a reference panel of CDR3 lengths from phytohaemagglutinin activated lymphocytes.

The T cell receptor (TCR) repertoire of a lymphocyte population may be characterized by the distribution of lengths of the hypervariable fragment known as the complementarity determining region 3 (CDR3). Immunological activity leading to clonal predominance will result in an over-representation of given CDR3 lengths and a distortion of the CDR3 length distribution. CDR3 length distribution may be studied by the in vitro amplification of TCRB cDNA followed by gel electrophoresis of the resulting product. We have established a simple, robust method for the evaluation of CDR3 length distribution in human lymphocyte samples. The CDR3 length distribution in phytohaemagglutinin (PHA) activated lymphocytes from a large number of healthy donors was established as a reference panel for each of 22 human TCR beta variable (BV) families. We propose that an abnormal CDR3 length distribution be defined as one in which one or more CDR3 lengths exceed the upper confidence limit (5% significance, one-sided test) given by this PHA reference population. Using this criterion in titration experiments, we were able to identify a clone when it constituted 2% of the cells analyzed. Over-dilution of cellular material or cDNA may produce falsely abnormal CDR3 length distributions. A nested technique using two separate amplification steps was found to yield results comparable in quality to the single amplification technique. When few cells are available, the nested method gives more material for CDR3 length analyses. However, it does not reduce the likelihood of a falsely abnormal distribution being recorded when the cellular material is too scarce.

In vivo expansion coincident with excessive in vitro cell death within the memory subset of CD8+ T cells in HIV type 1 infection.

In HIV-1-infected individuals the CD8+ T cell subset is considerably expanded. This has been shown to be caused predominantly by an increase in the number of CD8+CD28- T cells. To characterize further the subsets of CD8+ T cells, we have performed analyses of cell surface phenotype, T cell receptor Vbeta usage, and ability to survive in unstimulated cultures. CD8+CD28- T cells frequently expressed CD45RA. Nonetheless, coincident expression of CD95 (Fas) and high levels of integrins suggested that these cells were immunologically experienced. Contrary to what has been observed in CD8+CD28- T cells from uninfected individuals, a common hierarchy of Vbeta usage was found in CD8+CD28- T cells from HIV-1-infected individuals, which was adhered to by all the study participants, and which was shown to be similar to that observed within CD8+CD28+ T cells. Cells from the memory subsets of CD8+ T cells showed a high incidence of spontaneous death in unstimulated cultures, indicating that these cells have received signals for death by apoptosis in vivo. In contrast, most naive CD8+CD28+CD45RA+ cells survived. The CD8+CD28- memory subset is expanded in vivo despite evidence for coincident excessive cell death in vitro. Our results are consistent with the notion that frequent transitions occur from the memory CD8+CD28+CD45RA- T cell subset to the end-stage CD8+CD28- subset during HIV-1 infection.

Normal CD4 T-cell receptor repertoire in tonsillar tissue despite perturbed repertoire in peripheral blood in HIV-1 infected individuals.

OBJECTIVE: To compare the T-cell receptor (TCR) repertoire of T-cell subsets in peripheral blood and lymphoid tissue from HIV-1 infected individuals. DESIGN: Biopsies of tonsillar tissue and samples of peripheral blood were obtained from 10, mostly treatment-naive, HIV-1-infected individuals. CD4 and CD8 T-cell subsets were quantified, the TCR repertoire was analysed within 'naive' and 'memory' subsets, and results compared between identical subsets in tonsillar tissue and blood. METHODS: Cell subsets were quantified by flow cytometry. CD4 T cells and CD8 T cells were isolated by immunomagnetic beads. Populations were in most cases further subdivided by immunomagnetic selection on the basis of CD45RO expression. TCR repertoire was studied by spectratyping of the TCR beta variable (BV) complementarity determining region 3 (CDR3) transcripts. RESULTS: Amongst CD4 T cells, an abnormal TCR repertoire was found in median 25% (range, 0-88%) of BV families in peripheral blood, but in 0% (0-7%) in tonsillar tissue (P<0.05). Large peaks suggestive of expanded clones were common within CD8 T-cells, both in peripheral blood and tonsillar tissue. However, the expanded clones were rarely identical in the two compartments. Expanded CDR3 peaks, suggesting the presence of clonally expanded cells, were observed within both CD45RO+ and CD45RO- cells from all T-cell subsets, but, again they were mainly of different lengths. CONCLUSION: CD4 T cells were preserved in number and TCR repertoire in tonsillar tissue compared with blood in HIV-1 infected individuals. T-cells collected from the peripheral blood may not be representative of those residing in lymphoid tissue.

Demonstration of identical expanded clones within both CD8+CD28+ and CD8+CD28- T cell subsets in HIV type 1-infected individuals.

In HIV-1-infected individuals, the CD8+CD28- T cell subset is considerably expanded and is frequently the largest subset of T cells found in peripheral blood. It has been assumed, but not proven, that CD8+CD28- T cells derive from CD8+CD28+ T cells in vivo. To further study the ontogeny of CD8+CD28- T cells, we have performed analyses of the complementarity determining region 3 (CDR3) of the TCRB of CD8+CD28+ and CD8+CD28- T cells from the peripheral blood of HIV-1-infected individuals. When cells from the same individual were compared, expanded peaks in CDR3 length analysis within a given BV family were frequently observed at the same location in both CD8+ subsets (p < 0.001). Sequencing of cDNA corresponding to dominant peaks revealed the presence of identical expanded CD8+ T cell clones within both the CD28+ and CD28- subsets on eight of nine attempts. Our results show that CD8+CD28+ and CD8+CD28- T cells are phenotypic variants of the same lineage, most likely evolving from CD8+CD28+ to end-stage CD8+CD28- T cells.