D.F. van Wichen

T cells in Cardiac Allograft Vasculopathy Are Skewed to Memory Th-1 Cells in the Presence of a Distinct Th-2 Population

Cardiac allograft vasculopathy (CAV) in heart transplantation (HTx) patients remains the major complication for long‐term survival, due to concentric neointima hyperplasia induced by infiltrating mononuclear cells (MNC). Previously, we showed that activated memory T‐helper‐1 (Th‐1) cells are the major component of infiltrating MNC in coronary arteries with CAV. In this study, a more detailed characterization of the MNC in human coronary arteries with CAV (n = 5) was performed and compared to coronary arteries without CAV (n = 5), by investigating MNC markers (CD1a, DRC‐1, CD3, CD20, CD27, CD28, CD56, CD68, CD69, FOXP3 and HLA‐DR), cytokines (IL‐1A, 2, 4, 10, 12B, IFN‐γ, and TGF‐β1), and chemokine receptors (CCR3, CCR4, CCR5, CCR7, CCR8, CXCR3 and CX3CR1) by immunohistochemical double‐labeling and quantitative PCR on mRNA isolated from laser microdissected layers of coronary arteries. T cells in the neointima and adventitia of CAV were skewed toward an activated memory Th‐1 phenotype, but in the presence of a distinct Th‐2 population. FOXP3 positive T cells were not detected and production of most cytokines was low or absent, except for IFN‐γ, and TGF‐β. This typical composition of T‐helper cells and especially production of IFN‐γ and TGF‐β may play an important role in the proliferative CAV reaction.

Stem cell-derived cardiomyocytes after bone marrow and heart transplantation

Cardiomyocytes are a stable cell population with only limited potential for renewal after injury. Tissue regeneration may be due to infiltration of stem cells, which differentiate into cardiomyocytes. We have analysed the influx of stem cells in the heart of patients who received either a gender-mismatched BMT (male donor to female recipient) or a gender-mismatched cardiac transplant (HTX; female donor to male recipient). The proportion of infiltrating cells was determined by Y-chromosome in situ hybridization combined with immunohistochemical cell characterization. In BM transplanted patients and in cardiac allotransplant recipients, cardiomyocytes of apparent BM origin were detected. The proportions were similar in both groups and amounted up to 1% of all cardiomyocytes. The number of stem cell-derived cardiomyocytes did not alter significantly in time, but were relatively high in cases where large numbers of BM-derived Y-chromosome-positive infiltrating inflammatory cells were present. The number of Y-chromosome-positive endothelial cells was small and present only in small blood vessels. The number of BM-derived cardiomyocytes in both BMT and HTX is not significantly different between the two types of transplantation and is at most 1%.

Evidence for heterogeneity of T cell expansion in polymyositis and inclusion body myositis

Vβ usage of muscle-infiltrating T lymphocytes in polymyositis (PM) and sporadic inclusion body myositis (s-IBM) was correlated with clinical and histopathological features. Immunohistochemical analysis was combined with complementarity-determining region 3 (CDR3) length analysis in nine muscle biopsies of eight PM patients and six biopsies of five s-IBM patients. Vβ usage was heterogeneous in seven patients. Four of these patients had definite PM with endomysial located T cell infiltrates, but T cells specifically surrounding and invading individual non-necrotic fibers were not found. In two s-IBM patients, Vβ 2 usage was increased. In one of them, a repeat biopsy showed a heterogeneous Vβ usage. We conclude that clonal expansion of muscle-infiltrating T cells could only be detected in part of the patients. Explanations may be that clonal expansion does not take place in all disease phases and that PM is a heterogeneous disease with respect to pathogenesis.Vbeta usage of muscle-infiltrating T lymphocytes in polymyositis (PM) and sporadic inclusion body myositis (s-IBM) was correlated with clinical and histopathological features. Immunohistochemical analysis was combined with complementarity-determining region 3 (CDR3) length analysis in nine muscle biopsies of eight PM patients and six biopsies of five s-IBM patients. Vbeta usage was heterogeneous in seven patients. Four of these patients had definite PM with endomysial located T cell infiltrates, but T cells specifically surrounding and invading individual non-necrotic fibers were not found. In two s-IBM patients, Vbeta 2 usage was increased. In one of them, a repeat biopsy showed a heterogeneous Vbeta usage. We conclude that clonal expansion of muscle-infiltrating T cells could only be detected in part of the patients. Explanations may be that clonal expansion does not take place in all disease phases and that PM is a heterogeneous disease with respect to pathogenesis.

Follicular Dendritic Cells and Infection by Human Immunodeficiency Virus Type 1—A Crucial Target Cell and Virus Reservoir

Even before human immunodeficiency virus type 1 (HIV-1) was recognized as the causative agent of the acquired immunodeficiency syndrome (AIDS), generalized persistent lymphadenopathy was considered as one of the symptoms in this condition. The atypical histologic features of the lymph nodes, mainly the hyperplasia of follicles, were also identified at that time. After the discovery of HIV-1 and the introduction of serology to assess the status of infection, clinicopathologic evaluations could be performed. Schuurman etal. (1985) differentiated three main stages in lymph node abnormalities, which were similar to stages described by Baroni and Uccini (1990) , Biberfeld etal. (1985), Burns etal. (1985) , Garcia etal. (1986) , Janossy etal. (1985), Ost etal. (1989) , Porwit et al. (1989), RAcz et al. (1986,1990) , and Wood (1990) (Fig. 1): 1. Persistent generalized lymphadenopathy develops in the first phase after infection, either as the only symptom or in combination with constitutional symptoms such as persistent fever, weight loss, night-sweat, and diarrhea. Open image in new window Histology of the swollen lymph nodes shows hyperplasia of the follicles. The follicles not only are large with pronounced germinal centers, but also often show obizarre shape ofgerminal centers with indentations andfragrnentetono ofLhefollicular dendh1iocell (FDC)meshwork. These indentations and fnogmentations are visible in the histologio section as these show the accumulation of small-sized lymphocytes, and not the pale-staining large germinal center cells (Fig. 1 a). The mantle of the follicles is of variable size, and individual follicles can vary from almost absent to quite large. The interfollicular areas in the swollen nodes do not manifest major abnormalities, but can manifest vascular endothelial oeUprolifenstion like that seen inangioirnmunoblestiolymphadenopethy. According to the disease classification by the CENTERS FOR DISEASE CONTROL (CDC; 1988)follicle hyperplasia occurs in either CDC group III (persistent generalized lymphadenopathy) orCDCVA. 2. In the subsequent stage, lymphadenopethy is less pronounced. In histology, follicles show a larger extent of fragmentation and degeneration. Some resemblance with angioimrnunoblastiolyrnphedenopathycanbe more evident during the process offollicle degeneration, as visualized byvascular proliferation lymphocyte depletion, end emergence of blastoid cells (Fig. 1b). In CDC subgroups of COC IV when patients have neurologic disease, opportunistic infections, or neoplasia associated with the diagnosis AIDS, lymph nodes show either follicular hyperplasia or follicular degeneration. 3. In the last stage, lymph nodes become very small. Histologically, there is follicle atrophy with hyalinizedremnants of the original architecture. Thenode is often depleted of lymphocytes in this terminal stage; plasma cells form one of the main lymphocyte subsets still present inthis stage. Lymph node atrophy is mainly seen in the terminal phase of AIDS.

Expression of CD64 (FcγRI) in skin of patients with acute GVHD

GVHD remains a major problem in allo-SCT. We explored the presence of APC in skin biopsies of GVHD patients, using the IgG receptor CD64 expression as a hallmark for activated APC. By immunohistochemistry we demonstrated CD64 to be upregulated on host APC in skin biopsies of patients with acute GVHD and, less prominently, in chronic GVHD. Double staining for CD32 polymorphism revealed CD64-positive cells to be mainly of host origin. The majority of CD64-positive cells coexpressed CD68, indicating a macrophage phenotype. Given its very restricted cellular distribution, CD64 may represent an excellent target for APC-directed therapies in GVHD.