Gamma irradiation of HIV-1.

The potential for transmission of human immunodeficiency virus (HIV) type 1 has created serious concern for the continued clinical use of bone and soft-tissue allografts. Tissue banks have employed 1.5-2.5 Mrad for sterilization of bone and tendon allografts, which, according to the current literature, approaches the level at which the tissue quality is adversely affected for implantation. Our working hypothesis was that gamma irradiation at increasing doses can proportionately inactivate HIV type 1. The objective of this study was to inactivate HIV type 1 by irradiation, as determined by its capacity to infect human T-lymphocytes and established cell lines in vitro. The replicative competence of HIV type 1 was also assessed by the presence of reverse transcriptase activity, enzyme-linked immunoadsorbent assay (ELISA), immunofluorescence assays for p24 viral core antigen, and the formation of syncytia induced by HIV type 1 in the cultures inoculated with irradiated virus. The results demonstrated the presence of active viral replication in previously noninfected cells in the supernatant samples that were exposed to as much as 5.0 Mrad. The data for the 10-Mrad sample were indeterminate due to cellular damage. These data suggest that gamma irradiation (1.5-2.5 Mrad) does not constitute a virucidal dose for HIV type 1. Current technologies for screening have greatly improved, and the surgeon should rely on tissue bank screening procedures and other methods of preparation rather than sterilization by gamma radiation techniques in choosing allograft material.

Dynamics of Pneumocystis carinii-specific immune complexes in AIDS patients with P. carinii pneumonia.

Pneumocystis carinii-specific immune complexes were detected by immunoblot and enzyme-linked immunosorbent assay (ELISA) in 53% of sera from Acquired Immunodeficiency Syndrome (AIDS) patients with P. carinii pneumonia (PCP). Resolution of glycoprotein antigenemia (50-55 kd = dominant species) appears to correlate with successful PCP drug therapy and recovery. An epitope map has been constructed from immunoblots of P. carinii hydrolysates and from human and murine serum containing P. carinii antigens.

A fifteen-year perspective on the in vitro culture of Pneumocystis carinii.

The in vitro cultivation of Pneumocystis carinii in chick lung cell culture made it possible to observe the organism proceeding through its life cycle. It provided the foundation for extensive seroepidemiologic studies, for in vitro drug screening, and for essential biological, metabolic, and morphologic research. In vitro culture made possible the discovery of P. carinii antigenemia, its biochemical nature, and its relevance to subclinical and clinical infection. Its utility in the presumptive diagnosis of P. carinii pneumonia and in monitoring responses to drug therapy illustrate the value and clinical application of basic research.

Pneumocystis carinii serologic study in pediatric acquired immunodeficiency syndrome.

Pneumocystis carinii antigen and IgG antibody profiles were prepared on 17 pediatric patients with acquired immunodeficiency syndrome (AIDS) with pneumonia who were examined by a variety of invasive methods for P carinii organisms. Overall, the accuracy of the antigen assay in invasively examined pediatric patients with AIDS with pneumonia was 94% (sensitivity, 100%; specificity, 90%), as antigen and invasive test results agreed in 16 of 17 patients. No statistically significant differences in IgG titer were observed between controls and patients invasively examined for P carinii, whether the organism was observed in the specimen or not. Since 38% of all serum samples referred were derived from "blood-borne" cases of AIDS, including patients who contracted AIDS as a result of both transfusion and hemophilia A, this suggests that P carinii pneumonia or P carinii pneumonia- like pneumonias may be more common in these individuals.

Borderline immunodeficiency in male homosexuals: is life-style contributory?

Results of our study suggest that white Southern male homosexuals without clinical evidence of AIDS who patronize "gay bars" may have significant zinc deficiency and moderately depressed T-helper/T-suppressor cell ratios. No single causative factor could be identified to explain the significantly low zinc and elevated copper levels measured in whole blood, as well as the depressed OKT4/OKT8 cell ratios. Seventy-four percent of the homosexual male subjects were "recreational" drug abusers, 81% used inhalant nitrites routinely, and 41% routinely treated themselves with antibiotics. Eighty-one percent practiced active and/or passive penile-oral insertion, and 55.5% practiced both active and passive anal intercourse. Of the latter, 19% reported anal bleeding. Clinically inapparent, though statistically significant, borderline immunodeficiency and aberrant zinc and copper levels may be a consequence of multiple factors comprising the gay bar life-style.

Evidence for depressed humoral immunity to Pneumocystis carinii in homosexual males, commercial plasma donors, and patients with acquired immunodeficiency syndrome.

Heterosexual controls were found to have significantly higher titers of immunoglobulin G antibody to Pneumocystis carinii than did patients with the acquired immunodeficiency syndrome (AIDS) and P. carinii pneumonitis, human immunodeficiency virus (HIV) antibody-positive or -negative homosexual male "gay bar" patrons, and HIV antibody-positive or -negative commercial plasma donors. The T-helper/T-suppressor lymphocyte ratios of HIV antibody-negative homosexual male gay bar patrons were slightly depressed (mean = 1.31 +/- 0.54) compared with those of heterosexual controls (mean = 1.79 +/- 0.32). In addition to other recognized factors, preexisting humoral as well as cell-mediated immune deficits before infection with HIV may help to explain the prevalence of and morbidity and mortality associated with P. carinii pneumonitis in AIDS patients.

Preliminary studies on the development of a vaccine for Pneumocystis carinii. I. Immunological and biochemical characterization.

Initial progress has been made toward the development of an experimental vaccine or immunostimulant for Pneumocystis carinii. Antigen derived from cell culture propagated P. carinii proved to be a potent immunogen in the rabbit and antibody thus produced demonstrated identity with intact murine and human lung-derived P. carinii organisms. Reactivity of the antibody with P. carinii soluble antigen in the blood of rats and human subjects with P. carinii pneumonitis (PCP) was demonstrated by the Ouchterlony technique, by counterimmunoelectrophoresis (CIE) and by latex particle agglutination (LPA). Murine-derived P. carinii antigen was utilized in an enzyme-linked immunosorbent assay (ELISA) for anti-P. carinii IgG and IgM produced in immunized rabbits and for human IgG antibody against P. carinii. Preliminary biochemical analysis of whole and solubilized cysts has been carried out, as well as slab gel electrophoresis and immunoblot profiling of solubilized organisms and naturally-occurring P. carinii antigen(s) in the blood of humans and rats with PCP. These studies represent an initial step toward the development of a vaccine or immunostimulant against PCP.

Antibody to the retrovirus associated with the acquired immunodeficiency syndrome (AIDS). Presence in presumably healthy San Franciscans who died unexpectedly.

We performed autopsies and serologic tests in 189 subjects (152 men and 37 women) between 20 and 50 years of age with no history of immunosuppression who died unexpectedly and whose bodies were referred to the San Francisco coroner's office. Forty-eight of the 88 single men for whom addresses were available lived in areas of the city with a high incidence of the acquired immunodeficiency syndrome (AIDS). In addition, 36 of the subjects (30 men) were intravenous drug abusers. Antibody to the retrovirus associated with AIDS was present in 23 (18%) of the 121 subjects whose sera were tested. However, neither pathologic nor laboratory manifestations of AIDS were present in any of the 189 subjects who underwent autopsy. These results suggest that antibody to the retrovirus is common but subclinical manifestations of AIDS are uncommon in San Francisco, a city where the incidence of clinical AIDS is high.

Pneumonia associated with infection with pneumocystis, respiratory syncytial virus, chlamydia, mycoplasma, and cytomegalovirus in children in Papua New Guinea.

Paired serum samples were collected from 94 children with pneumonia admitted to Goroka Hospital, Papua New Guinea. All but three of the children were aged 1-24 months. Only nine children were malnourished, with weight for age less than 70% of the Harvard median (three had weight for age less than 60% of the Harvard median). Pneumocystis carinii antigen was detected in the serum of 23 children. Twenty two children had serological evidence of recent infection with respiratory syncytial virus. Five children were probably infected with Chlamydia trachomatis at the time of the study, and there was less convincing serological evidence of current infection in a further 11 children. Five children showed a fourfold rise in antibody to Mycoplasma pneumoniae. Although only one child showed a fourfold rise in antibody to cytomegalovirus, 86 children had this antibody. No child showed a fourfold rise in antibody to Ureaplasma urealyticum or Legionella pneumophila. P carinii, respiratory syncytial virus, C trachomatis, M pneumoniae, and cytomegalovirus may be important causes of pneumonia in children in developing countries.

Pneumocystis carinii antigenemia in adults with malignancy, infection, or pulmonary disease.

A counterimmunoelectrophoresis test for Pneumocystis carinii antigenemia was employed to assess the extent of subclinical infection or colonization with this agent in adults with infection, pulmonary disease, or malignancy and in healthy homosexual men. Antigenemia was detected in 6 of 208 (3%) of normal controls, 3 of 28 (11%) of patients with pulmonary infection, 3 of 33 (9%) of those with chronic lung disease, 1 of 36 (3%) of patients with lung cancer, 7 of 271 (3%) of afebrile subjects with malignancy, 6 of 19 (32%) of febrile patients with malignancy, 2 of 22 (9%) of those with nonpulmonary infection, and 0 of 21 (0%) of healthy young homosexual men. These data suggest that P. carinii is a common commensal or saprophyte that becomes clinically significant only when host defenses are impaired. Antigenemia may occur intermittently during various disease states in the absence of positive clinical signs and should alert the physician to subacute infection or colonization. Treatment appears advisable when clinical data and counterimmunoelectrophoresis results concur.

Incidence of Pneumocystis carinii antigenemia in ambulatory cancer patients.

Although the existence of subclinical Pneumocystis carinii infection in pediatric patients with solid tumors or hematologic malignancies has been documented, similar data are lacking in adults. In addition, data are needed to define the epidemiology of this agent in adult malignancies to assess the validity of the methodology employed in antigen detection, and to elucidate the value of these methods in the diagnosis, prophylaxis, and prognosis of P carinii infection in adults with cancer. The study was designed to determine the incidence of P carinii antigenemia in ambulatory patients with solid tumors or hematologic malignancies. The authors also sought to determine if antigenemia as detected by a counterimmunoelectrophoresis test correlated with any clinical parameter. Patients included in the study were ambulatory, asymptomatic, afebrile, adult cancer patients seen in the clinic for follow-up or treatment. Coded sera were electrophoresed against high-titered rabbit antiserum to P carinii organisms. Two hundred forty-seven patients were studied, including 172 hematologic malignancies (average age, 57 years), 109 men and 63 women; 75 solid tumors (average age, 55 years), 39 women and 36 men. One hundred three healthy adults served as controls. Only five patients had positive antigen (2%). All of these patients had hematologic malignancies and were women. None of the control sera were antigen-positive. We conclude that the incidence of P carinii antigenemia in asymptomatic adults with neoplastic disease is extremely low. A positive P carinii antigen in the absence of clinical symptoms most likely represents subclinical infection. Positive antigen does not always indicate active disease, but probably reflects mobilization of antigen during generalized inflammatory response or possible pulmonary insult. In making the decision to treat consideration should be given to clinical presentation and history.

Pneumocystis carinii infection in germ-free rats: implications for human patients.

Pneumocystis carinii infections have been detected both serologically and histologically in untreated, germ-free and conventional rats killed immediately upon arrival from two commercial sources. Pneumocystis antigenemia was detected by counterimmunoelectrophoresis (CIE) and antibody was titered by indirect immunofluorescence. The data suggest that 1) P. carinii is enzootic in certain rat colonies; 2) in utero transmission is a distinct possibility; and 3) paucity of cysts does not rule out P. carinii, as trophozoites predominate in early or sub-clinical infections. Histologic data support the validity of CIE for noninvasive detection of P. carinii antigen. Infection with this agent may be missed by basing diagnosis upon the presence of cyst forms alone, and it may be more common than previously supposed. These data have significant implications for the natural history, diagnosis, and epidemiology of P. carinii with regard to the human host.

Biological profile and response to anti-pneumocystis agents of Pneumocystis carinii in cell culture.

Although the growth characteristics of Pneumocystis carinii have been described in several cell culture systems, the response of this organism to the drugs of choice, trimethoprim-sulfamethoxazole and pentamidine isethionate, have not been described in vitro. The effect of various concentrations of drugs against P. carinii on the growth of this potentially hazardous opportunistic organism as well as the methodology for in vitro assay of these agents have been detailed. Fluorescence profiles illustrating size ranges of trophozoites and cysts derived from cell culture are described.