Seroreactivity to Mycoplasma pneumoniae and Legionella pneumophila: lack of a statistically significant relationship.

We reviewed antibody titers to Mycoplasma pneumoniae and Legionella pneumophila serogroup I in sera from 1,060 cases of acute respiratory infection to determine whether there was an association in seroreactivity to these organisms. Of the 170 serum pairs with antibodies to L. pneumophila (35 seroconversions and 135 with presumptive titers), 32 (18.8%) demonstrated seroreactivity to M. pneumoniae (17 seroconversions and 15 with presumptive titers). This frequency was not significantly greater than the seroreactivity to M. pneumoniae observed in sera without antibodies to L. pneumophila (17.5%) (0.05 less than P less than 0.10), which included 111 seroconversions and 45 sera with presumptive titers.

Isolation of Legionella pneumophila from clinical specimens: salutary effects of lung tissue dilution.

Diagnosis of legionnaires' disease is seldom confirmed by isolation of Legionella pneumophila. In 2 cases, isolates were obtained using inoculums of diluted lung tissue suspension, even though no growth ocurred when undiluted suspensions were used. It is speculated that tissue dilution decreases the concentration of antimicrobial agents and antibacterial properties associated with lung host defense mechanisms, which allows improved recovery rates. This technique is recommended when attempting isolation of L. pneumophila from clinical specimens.

Legionnaires' disease serology. Effect of antigen preparation on specificity and sensitivity of the indirect fluorescent antibody test.

Sera from 31 Legionnaires' disease (LD) survivors of the Philadelphia outbreak, 31 Legionnaire (L) controls, and 300 additional controls were examined for the presence of specific antibodies to five antigen preparations of Legionella pneumophila (serogroup 1) to determine the effect of antigen preparation on the sensitivity and specificity of the indirect immunofluorescence test. Diagnostic levels were determined for each antigen at the upper limit of normal value (ULNV) titre, which established the titre not exceeded by 85% of controls. Antigens were prepared from formalin-killed L. pneumophila suspended in egg yolk sac (EYS) (LPF:EYS) or bovine serum albumin (BSA) (LPF:BSA); and from heat-killed organisms suspended in EYS (LPH:EYS) or BSA (LPH:BSA). Antigen was also supplied by the Center for Disease Control (CDC:AG).Although there was wide variation in the sensitivity of the antigens, at the ULNV level all antigens tested could be used to differentiate LD survivors from L controls (p<0.001; X(2) test). Formalin treatment resulted in the most specific antigen by eliminating titres in L controls. The results of the X(2) test, comparing LD survivors with L controls, ranked the antigens in the following ascending order of sensitivity: LPH:BSA 15.3,

Graft infection or graft reaction?

A perigraft reaction has been described that has been found to be free of infection, with a microscopic picture compatible to an immunologic-like reaction. Varied time intervals between onset of reaction and removal of tissue have allowed for a histopathologic staging. Note is made that four of the five grafts involved were external velour Dacron, with a question remaining as to whether the double velour stimulates an intensified hyperimmune response. Graft replacement by way of new uninvolved plains of tissue has not been necessary. Replacement with polytetrafluoroethylene through the same pathway resulted in prompt healing of wounds with no evidence of recurrent reaction.

Serology of Legionnaires disease: comparison of indirect fluorescent antibody, immune adherence hemagglutination, and indirect hemagglutination tests.

An immune adherence hemagglutination (IAHA) test for the measurement of antibodies to Legionella pneumophila was developed and evaluated for the diagnosis of Legionnaires disease. Its sensitivity was compared to that of the indirect fluorescent antibody (IFA) test and a recently developed indirect hemagglutination (IHA) test. The sensitivity of the three tests appeared to be similar, with the IFA test giving slightly higher titers. Both the IHA and IAHA tests appear useful for the serodiagnosis of Legionnaires disease; the IAHA test has the advantage that it can be used with many other serological antigens.

Legionnaires' disease pneumonia: histopathologic features and comparison with microbial and chemical pneumonias.

The histopathologic findings in lung tissue are reported from five cases of Philadelphia Legionnaire's Disease and the results are compared to pneumonias caused by other microbial and chemical agents. Histopathology of lung tissue was similar in all cases, despite the fact that death occurred between the fourth and 14th day of clinical illness. The inflammatory response was almost totally limited to the lower respiratory tract and primarily involved respiratory bronchioles, alveolar ducts and alveoli. Major bronchial branches and pulmonary interstices showed little or no involvement. There was considerable variation in the extent and nature of the consolidation, but the overall reaction pattern was highly characteristic of diffuse alveolar damage. Most involved areas showed intra-alveolar, fibrinocellular mononuclear cell predominant exudates, associated with pneumonocytic hyperplasia and slough. These findings plus the presence of erythroleucophagocytosis by macrophages and paucity of polymorphonuclear leucocytes are commonly associated with psittacine pneumonia, and much less so with classic patterns of bacterial, viral, fungal or rickettsial pneumonias. Of the toxic inhalants, nickel carbonyl, phosgene, nitrous oxide, cadmium oxide and some halogenated hydrocarbons have been associated with this tissue reaction pattern. Bacteria were notably absent in lung tissue stained by methods used to demonstrate the Legionnaires' Disease agent.

The Philadelphia epidemic of Legionnaire's disease: clinical, pulmonary, and serologic findings two years later.

Clinical, pulmonary, and serologic findings in Legionnaires who attended the 1976 American Legion Convention in Philadelphia were studied 2 years after the Legionnaires' disease epidemic there. All 31 survivors of Legionnaires' disease studied became ill within 2 weeks after the convention, and 18 had not fully recovered 2 years after the epidemic. Twenty-five (28%) of 90 additional Legionnaires exposed at the convention but not diagnosed as having Legionnaires' disease became ill during the same time interval; five of these had symptoms during the next 2 years. Survivors had decreased diffusion capacities measured by the carbon monoxide single-breath method. These differences could not be accounted for by ventilation abnormalities or concurrent illness. Significant levels of IgG or IgM antibodies persisted in 94% of survivors of Legionnaires' disease and in 53% of Legionnaires exposed at the convention, which suggests a high prevalence of subclinical infection. Persistence of IgM antibody raises the question of latency or subclinical infection as part of the natural history of Legionnaires' disease.

Diagnostic specificity of immunoglobulin M (IgM) response in differentiation Legionnaires' disease from psittacosis.

Specific IgM and IgG antibody responses to Legionella pneumophila (LDB) and Chlamydia psittaci (PSI) in serum specimens from 22 cases of Legionnaires' Disease (LD) were examined by micro-immunofluorescence (IF) tests to explore the diagnostic significance of the IgM antibody response. Serial samples from 5 patients with LD showed greater than or equal to 4-fold changes in IgG antibody against LDB and PSI. All 5 patients possessed IgM antibodies against LDB but not against PSI. In single convalescent serum samples from 17 additional cases, 16 exhibited IgG and 15 showed IgM antibodies against LDB; all 17 exhibited IgG but not IgM antibodies against PSI. The IgM antibody response appears more specific than the corresponding IgG response in the serodiagnosis of LD, and may be valuable in differentiating LDB infections from those due to PSI.

Legionnaires' disease. Clinical findings and one-year follow-up.

The cases of six patients with Philadelphia Legionnaires' disease were studied during the acute phase and throughout the following year. This multisystems disease process developed abruptly with symptoms of chills, fever, myalgias, and headache. The unusual clinical association of fever with relative bradycardia was noted frequently. Pneumonia developed after the first few days and rapidly progressed to life-threatening respiratory failure despite penicillin and cephalosporin therapy. Improvement occurred within 48 hours after tetracycline or chloramphenicol was administered. No permament sequelae were noted on the one-year follow-up examination, and no secondary cases of infection occurred.

Legionnaires' disease: antigenic peculiarities, strain differences, and antibiotic sensitivities of the agent.

Paired sera from victims of Legionnaires' disease showed, in many cases, significant rises in immunoglobulin G antibodies to both the causative agent (LA) of Legionnaires' disease and Chlamydia psittaci, but concurrent rises in immunoglobulin M antibodies only against LA. Guinea pigs experimentally infected with LA likewise responded with antibodies to both C. psittaci and LA. Guinea pigs infected with LA also reflected significant differences in antigenic makeup and in pathogenicity among four strains of LA examined. In antibiotic studies, rifampin was 200 times more effective than erythromycin and 17,000 times more effective than tetracycline in plaque reduction tests of LA in monolayer cultures of primary chick embryo cells. An isolate of LA recovered from a healthy person was compared with three isolates from persons with fatal infections.