Arnaldo Leprini

A lymphoproliferative disorder of the large granular lymphocytes with natural killer activity

This paper reports the case of a patient with an abnormally expanded population of circulating lymphoid cells displaying the features of the so-called large granular lymphocytes (LGL). These cells were peroxidase negative and nonphagocytic, formed rosettes with sheep erythrocytes, had receptors for IgG, and contained azurophilic (electron-dense) granules. Like normal LGL, the patient cells were positive for two acid hydrolases (acid phosphatase and β-glucuronidase) but did not stain for α-naphthyl acetate esterase (ANAE), which is present in normal LGL. Ultrastructural studies revealed that the patient cells were rich in Golgi-derived vesicles, coated vesicles, multivesicular bodies, and immature granules, indicating that, unlike normal LGL, they were engaged in granulogenesis. These features, together with the absence of ANAE activity, are suggestive of some degree of cell immaturity. The patient cells displayed natural killer (NK) and antibody-dependent cellular cytotoxicity (ADCC) activities comparable to those of normal peripheral blood mononuclear cells, or even higher, and did not respond to T-cell mitogens or allogeneic cells. Furthermore, they were incapable of suppressing normal T-cell proliferation or pokeweed mitogen-induced B-cell differentiation. Analysis of the NK activity at the single-cell level revealed that a large proportion of the patient cells bound to the K562 target cells but could not accomplish the entire lytic process. This finding supports further the possibility that the patient cells were immature LGL. The surface phenotype of the patient cells (as defined by a battery of monoclonal antibodies) was somewhat different from that usually observed in the majority of the normal LGL because, in addition to the HNK-1 marker, the cells were OKT3+, aLeul+, aLeu4+, OKT8+, aLeu2a+, and 3A1+ but were OKM1− and 4F2−. This phenotype could correspond to that of maturing LGL.

In situ lung perfusion with cisplatin an experimental study

Background. This research work was planned to evaluate the soundness of in situ lung perfusion as a regional administration modality of chemotherapeutic agents.

Receptors for the Third Complement Component on a Proportion of Large Granular Lymphocytes from Human Peripheral Blood

Large granular lymphocytes (LGL) are nonadherent cells with cytoplasmic azurophilic granules, avid receptors for the Fc portion of IgG, and a paranuclear localization of alpha‐naphthyl acid esterase or acid phosphatasc. LGL constitute the bulk of TG cells (cells with receptors for sheep erythrocytes and for IgG molecules) and null cells (non‐T, non‐B cells). In the present study we demonstrate that 20–33% of the circulating human LGL express receptors for the third complement component (C3R). When TG cell or null cell fractions from normal individuals or non‐T cells from a patient with infantile agammaglobulinaemia (which contained almost exclusively LGL) were rosetted with erythro cytes coated with antibody and complement, a variable number of C3R‐bearing cells were detected. Such cells were isolated and analysed further; the great majority of them displayed the cytochemical and ultrastructural features of LGL.

Complement Receptor Distinguishes between Two Subsets of Large Granular Lymphocytes with Different Natural Killer Activity and Cytochemical and Ultrastructural Features

Human peripheral blood large granular lymphocytes (LGL)—that is, cells with intracytoplasmic azurophilic (electron‐dense) granules, with a positiviiy for the cytochemical localization of certain acid hydrolascs, and with avid surface receptors for the Fc portion of IgG—have been purified on Percoll density gradients. Approximately 30% of these cells expressed receptors for the third complement component (C3R). They were separated into C3R‐positive and C3R‐negative cells. C3R− cells had a significantly greater natural killer (NK) activity against K562 target cells than C3R+ cells. This difference was unrelated to the presence in the C3R+ cells of a contaminant cell type incapable of NK activity, since cytochcmical and ultrastructural analysis revealed that C3R+ and CR− fractions contained comparable LGL numbers. Agarose cytotoxicity assays at the single‐cell level demonstrated that C3R + LGL contained a large number of cells that bound to but did not lyse the target. The remaining fully cytotoxic C3R+ LGL had, however, the same killing and recycling properties as the cells from the OR fraction. Electron microscopy and cytochcmical studies showed that C3R+cells had fewer electron‐dense granules than C3R cells and stained more faintly for the localization of α‐naphtyl acetate eslerase. In contrast to C3R cells. C3R+ LGL displayed morphological features suggesting that an active process of granule formation was taking place. Taken together, the data indicate that C3R+ cells represent a discrete subset or a maturationsl stage of LGL.

Morphology cytochemical features and membrane phenotype of hla dr + interstitial cells in the human pancreas

The morphology, histological distribution, surface, and enzymatic phenotype of pancreatic HLA-DR+ cells were studied on seven human pancreata, removed from cadaver donors. Frozen and paraffin-embedded pancreas sections were stained with a battery of monoclonal antibodies by indirect immunofluorescence, immunoperoxidase, and immunophosphatase techniques. Two types of cells were found to express HLA-DR surface molecules: endothelial cells and nonfibroblastic non-B and non-T interstitial elements. The latter cells, which were localized both in the exocrine and endocrine portions of the organ, were distinguished in two main families (macrophagic and dendritic) according to their morphology, surface phenotype, and lysosomal enzymatic activities. The phenotype of cells belonging to macrophagic cell family was the following: Leu M1+, Leu M2+, Leu M3+, OKM1+, and OKT6−. In addition these cells were positive for the expression of lysosomal enzymes such as alpha-naphthyl acetate esterase (ANAE) and acid phosphatase (AP). The “dendritic” cell family comprised, among others, cells that were characterized by the presence of numerous finger-like projections, the absence of Leu M1, Leu M2, Leu M3, OKM1, OKT6 surface antigens, and by the negativity for ANAE and AP. These “dendritic looking cells” (DLC) constituted the most represented DR+ cell type within pancreatic islets. The demonstration of dendritic cells within human islets may justify, in humans also, in vitro procedures of intra-islet dendritic cell removal prior to transplantation, in the attempt of islet rejection prevention.

Expression of a receptor for sheep erythrocytes by B lymphocytes from a chronic lymphocytic leukemia patient

A patient with a B-cell chronic lymphocytic leukemia, whose lymphocytes also formed rosettes with sheep red cells, is described. The B-cell nature of the malignant lymphocytes was determined by surface marker analysis, and cytochemical and ultrastructural studies. The lymphocyte membrane immunoglobulin (IgG1K) did not have anti-sheep red cell activity and was not responsible for the binding of sheep erythrocytes to the leukemic cells as shown by (i) the failure to inhibit rosette formation with anti-immunoglobulin reagents and (ii) the different sensitivity to proteolysis of the membrane immunoglobulin and the sheep erythrocyte receptor. The malignant lymphocytes expressed a receptor for sheep erythrocytes similar to that of normal T cells since they stained with monoclonal antibodies directed against the sheep red cell receptors. Furthermore these antibodies blocked rosette formation. Endogenous labeling experiments demonstrated that the patients cells produced IgG both of the membrane and of the secretory type. The latter molecular form was also actively secreted. Ultrastructural studies demonstrated that the malignant clone comprised cells at different maturational stages and with different secretory properties. These findings were confirmed by the analysis of intracytoplasmic acid hydrolases, which are normally expressed at late maturational stages. These data are consistent with the hypothesis that a process of maturation was occurring within the malignant clone.

Immunofluorescent and ultrastructural analysis of plasma cell degeneration in the chicken Harder's gland

In this study we describe some aspects of plasma cell degeneration in the chicken Harders gland. The immunofluorescent patterns of cytoplasmic immunoglobulin (cIg) localization have been studied in relation to the ultrastructure of maturing and degenerating B cells. It appears that Russell body formation through the accumulation of Ig within the cisternae of the rough endoplasmic (RER) does not represent the only mechanism for the formation of cytoplasmic vacuoles. Mitochondrial swelling and disruption or dilation of Golgi cisternae, often preceding alterations of the RER, may be the origin of some vacuoles. It also appears that, in the Harders gland, degeneration may occur not only in mature plasma cells but also in maturing B cells at a stage when only clusters of polyribosomes are found in the cytoplasm and no RER is yet developed. These observations are relevant to some immunofluorescence and ultrastructural patterns observed in human B-cell pathology.