Robert W. Schroff

Pneumocystis carinii Pneumonia and Mucosal Candidiasis in Previously Healthy Homosexual Men

Four previously healthy homosexual men contracted Pneumocystis carinii pneumonia, extensive mucosal candidiasis, and multiple viral infections. In three of the patients these infections followed prolonged fevers of unknown origin. In all four cytomegalovirus was recovered from secretions. Kaposis sarcoma developed in one patient eight months after he presented with esophageal candidiasis. All patients were anergic and lymphopenic; they had no lymphocyte proliferative responses to soluble antigens, and their responses to phytohemagglutinin were markedly reduced. Monoclonal-antibody analysis of peripheral-blood T-cell subpopulations revealed virtual elimination of the Leu-3 / helper/inducer subset, an increased percentage of the Leu-2 + suppressor/cytoxic subset, and an increased percentage of cells bearing the thymocyte-associated antigen T10. The inversion of the T/ helper to suppressor/cytotoxic ratio suggested that cytomegalovirus infection was an important factor in the pathogenesis of the immunodeficient state. A high level of exposure of male homosexuals to cytomegalovirus-infected secretions may account for the occurrence of this immune deficiency.

Immunological studies of homosexual men with immunodeficiency and Kaposi's sarcoma☆

Acquired immunodeficiency and Kaposis sarcoma are epidemic among homosexual men in the United States. We have identified three clinically distinct disease syndromes in homosexually active men: a syndrome of severe cellular immunodeficiency including infection with Pneumocystis carinii and other opportunistic pathogens, a syndrome of chronic benign lymphadenopathy without severe opportunistic infections, and Kaposis sarcoma. All 46 patients which we have studied with these three disease syndromes shared a common immune abnormality, that being a reduction in the circulating T-lymphocyte subpopulation bearing the Leu-3/OKT-4 antigen. The second major T-lymphocyte subpopulation, which bears the Leu-2/OKT-8 antigen, was numerically normal in all the disease syndromes, but increased as a percentage of all circulating lymphocytes. These abnormalities resulted in an inversion of the normal ratio of these two lymphocyte subpopulations. A similar, but less pronounced imbalance in circulating T-lymphocyte subpopulations was observed in a group of healthy homosexual men. The immune deficiency in these patients was most evident in the T-cell component of the immune system. Percentages of B cells, circulating immunoglobulin levels, and natural killer (NK) and antibody-dependent cell-mediated cytoxic (ADCC) functions were normal. Proliferative responses to antigen and mitogen were typically decreased in patients with the acquired immunodeficiency syndrome and some Kaposis sarcoma patients, but not those with the prolonged lymphadenopathy syndrome or a control group of healthy homosexual men. Possible causes or factors contributing to the immunodeficiency and interrelationships among the three disease manifestations are discussed.

Radioimmunodetection of cutaneous T-cell lymphoma with 111In-labeled T101 monoclonal antibody

T101 monoclonal antibody recognizes a pan-T-cell antigen present on normal T cells and also found in high concentrations in cutaneous T-cell lymphoma. We used this antibody, radiolabeled with 111In, in gamma-camera imaging to detect sites of metastatic cutaneous T-cell lymphoma in 11 patients with advanced disease. In all patients, [111In]T101 concentrated in pathologically or clinically detected nodes, including those in several previously unsuspected nodal regions. Concentrations (per gram of tissue) ranged from 0.01 to 0.03 percent of the injected dose and were consistently 10 to 100 times higher than previously reported on radioimmunodetection. Focal uptake was seen in skin tumors and heavily infiltrated erythroderma but not in skin plaques. The specificity of tumor targeting was documented by control studies with [111In]chloride or [111In]9.2.27 (anti-melanoma) monoclonal antibody. Increasing the T101 dose (1 to 50 mg) altered distribution in nontumor tissues. These studies suggest that imaging with [111In]T101 may be of value in identifying sites of cutaneous T-cell lymphoma. In contrast to the targeting of solid tumors, the mechanism of localization appears to be related to binding to T cells, which can then carry the radioactivity to involved sites.

Pneumocystis Carinii Pneumonia and Mucosal Candidiasis in Previously Healthy Homosexual Men. Evidence of a New Acquired Cellular Immunodeficiency

Four previously healthy homosexual men contracted Pneumocystis carinii pneumonia, extensive mucosal candidiasis, and multiple viral infections. In three of the patients these infections followed prolonged fevers of unknown origin. In all four cytomegalovirus was recovered from secretions. Kaposis sarcoma developed in one patient eight months after he presented with esophageal candidiasis. All patients were anergic and lymphopenic; they had no lymphocyte proliferative responses to soluble antigens, and their responses to phytohemagglutinin were markedly reduced. Monoclonal-antibody analysis of peripheral-blood T-cell subpopulations revealed virtual elimination of the Leu-3 / helper/inducer subset, an increased percentage of the Leu-2 + suppressor/cytoxic subset, and an increased percentage of cells bearing the thymocyte-associated antigen T10. The inversion of the T/ helper to suppressor/cytotoxic ratio suggested that cytomegalovirus infection was an important factor in the pathogenesis of the immunodeficient state. A high level of exposure of male homosexuals to cytomegalovirus-infected secretions may account for the occurrence of this immune deficiency.

HLA studies in acquired immune deficiency syndrome patients with Kaposi's sarcoma

To investigate the possible contribution of genetic susceptibility to Kaposis sarcoma associated with acquired immune deficiency syndrome (AIDS-KS), 21 patients were typed for HLA-A, B, C, and DR antigens. Significantly increased frequencies of HLA-Aw23, and HLA-Bw49 antigens were observed in the Caucasian AIDS-KS group. In this same group, the frequencies of HLA-DR5 and HLA-Bw44 antigens were increased at the P less than 0.1 level. Increased frequencies of HLA-A29 and HLA-Cw4 antigens and a decreased frequency of HLA-B8 antigen were also noted, but with P greater than 0.1, in the Caucasian AIDS-KS group.

Cell mediated inhibition of erythropoiesis and megaloblastic anemia in T-cell chronic lymphocytic leukemia

A patient with T‐cell chronic lymphocytic leukemia presented with severe megaloblastic anemia with normal serum folic acid and cobalamin concentrations. BFU‐E could not be cultured from the patients peripheral blood unless T‐lymphocytes were removed by E‐rosette formation. Inhibitory activity by the patients T‐cells was restricted to autologous BFU‐E. After cyclic chemotherapy the anemia and megaloblastic changes resolved, peripheral blood BFU‐E could be cultured from unfractionated peripheral blood and the T‐cell inhibitory activity could no longer be demonstrated. The anemia in this patient is probably due to the neoplastic expansion of a suppressor T‐lymphocyte population.

Immunoregulatory T cells in men with a new acquired immunodeficiency syndrome.

We have evaluated the functional properties of the OKT8+/OKT4+ T-cell subpopulations in nine patients with a new syndrome of acquired immune deficiency (AIDS). Despite polyclonal hypergammaglobulinemia in the sera of these patients, their peripheral blood lymphocytes (PBL) produced negligible quantities of immunoglobulin (Ig) when culturedin vitro for 8 days in the presence of pokeweed mitogen (PWM). Patient B cells, however, synthesized normal quantities of immunoglobulin when cocultured with T cells from healthy donors, indicating preservation of B-cell function. Unfractionated PBL or T cells of patient origin mediated marked suppression of pokeweed mitogen-driven immunoglobulin production by T and B cells from healthy donors. The suppressive activity was contained within the population of T cells bearing the OKT8 antigen and was sensitive toin vitro irradiation. On a per-cell basis, patient OKT8+ cells appeared to have greater suppressive activity than normal control OKT8+ cells. In addition, OKT4+ cells from patients had less helper activity for induction of immunoglobulin synthesis than control OKT4+ cells. Increased T suppression and reduced T help are probably a consequence of one or more viral infections and may contribute to progressive immune deficiency and susceptibility to malignancy in patients with the acquired immuno deficiency syndrome.

Human melanoma-associated antigens: analysis of antigenic heterogeneity by molecular, serologic and flow-cytometric approaches.

The relationship of antigenic heterogeneity to the epitope recognized by an antibody was examined with monoclonal antibodies to human melanoma-associated antigens. Expression of the human melanoma-associated antigens, 250-Kd glycoprotein/proteoglycan and p97, was examined quantitatively by flow cytometry on fresh cell suspensions of human melanoma. Percent positive cells and mean fluorescence intensity were consistently higher with antibody 9.2.27 to the 250-Kd glycoprotein/proteoglycan than with antibody to p97. In addition, assessment of percent positive cells in multiple skin lesions biopsied from individual patients indicated that in 26 of 30 lesions, greater than 90% of the cells stained positively with 9.2.27. This relative lack of antigenic heterogeneity with antibody 9.2.27 contrasted with previous reports which showed considerable antigenic heterogeneity with other antibodies to the 250-Kd glycoprotein/proteoglycan. The explanation for this distinction was sought by quantitative flow cytometric and sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) techniques. Comparison by flow cytometry and immunoperoxidase of three antibodies, which recognized distinct epitopes of the 250-Kd glycoprotein/proteoglycan, indicated that 9.2.27 reacted more intensely with cultured cells and tissue sections than other antibodies to the same antigen. Examination by SDS-PAGE indicated that 9.2.27 could immunoprecipitate a larger proportion of 250-Kd glycoprotein molecules than other antibodies. In addition, immunodepletion experiments in gels indicated that the 9.2.27 determinant was present on a higher proportion of 250-Kd glycoprotein molecules than PG-2 antibody to a separate determinant. It is likely that 9.2.27 antibody displays less antigenic heterogeneity because its epitope is represented on a higher proportion of the antigen molecules. Thus, not only the nature of the antigen but also the epitope recognized by an antibody influences the degree of antigenic heterogeneity.

Human Immune Responses to Murine Monoclonal Antibodies

Monoclonal antibodies have great potential for the diagnosis, staging, and therapy of human tumors. As reviewed in the preceding chapters, over a dozen different monoclonal antibodies have been employed for the treatment of advanced malignant diseases since the first clinical trial was reported in 1980 (1). Since all of the monoclonal antibodies utilized to date have been derived from mice, it was expected that perhaps certain hypersensitivity reactions to xenogeneic proteins might occur when they were injected into humans, as was found in earlier clinical trials with crude heterologous antisera (2). While the experiences of investigators in this field are still too limited to provide exact estimates of the frequency of hypersensitivity reactions to monoclonal antibodies, it does not appear that these types of immune responses will pose insurmountable obstacles to the clinical use of monoclonal antibodies. Information is now being acquired on hypersensitivity reactions to murine monoclonal antibodies in humans, and it is this subject which will be reviewed in this chapter.

Monoclonal antibody characterization of plasmacytoma cells associated with T lymphocytes with a suppressor phenotype

Abstract A panel of monoclonal antibodies was used to characterize the cells from a soft-tissue plasmacytoma removed from the mediastinum of a 47-year-old male. The tumor secreted a κ light chain, and there was no evidence of disseminated disease. A single-cell suspension was prepared, and three distinct populations were identified morphologically. The majority of cells (>90%) were very large plasma cells, with a single nucleolus and abundant cytoplasm. The small cells, representing less than 10% of the total population, were composed of 80% mature lymphocytes and 20% small, normal-appearing plasma cells. The cells were studied by indirect immunofluorescence using monoclonal antibodies that identify various T and B lymphocyte antigens and heteroantisera that identify immunoglobulin heavy and light chains. The large plasma cells were 92 and 62% reactive with κ and γ heteroantisera, respectively, and 100% stained intensely with OKT10. All of the small cells reacted with the OKT10 antibody. Eighty percent of the small cells reacted with the pan-T antibody anti-Leu-1 and the cytotoxic/suppressor-associated antibody anti-Leu-2, and 50% reacted with the pan-T antibody OKT3 and the HLA-DR antibody. Immunoperoxidase staining of tissue sections demonstrated that the small plasma cells had λ light chain in their cytoplasm, indicating that they were not derived from the same clone as the large plasma cells. This case demonstrates four interesting points: (1) All of the plasma cells and lymphocytes in this tumor stained intensely with OKT10, (2) the large plasma cells expressed κ and γ light and heavy chains, respectively, on their surface membrane, and secreted a κ light chain, while the small plasma cells had λ light chains in their cytoplasm, (3) all of the T lymphocytes that infiltrated this tumor had a suppressor T lymphocyte phenotype, (4) the T65 antigen identified by the anti-Leu-1 and T101 antibodies, and found on normal and malignant T lymphocytes and some malignant B lymphocytes, was not found on these malignant plasma cells.