Immunoglobulin A anti-phospholipid antibodies in Swedish cases of systemic lupus erythematosus: associations with disease phenotypes, vascular events and damage accrual.

Immunoglobulin (Ig) G- and IgM-class anti-cardiolipin antibodies (aCL) and lupus anti-coagulant (LA) are included in the 1997 update of the American College of Rheumatology (ACR-97) systemic lupus erythematosus (SLE) criteria. Despite limited evidence, IgA-aCL and IgA anti-ß2 -glycoprotein-I (anti-ß2 GPI) were included in the 2012 Systemic Lupus International Collaborating Clinics criteria. The present study aimed to evaluate IgG-/IgA-/IgM-aCL and anti-ß2 GPI occurrence in relation to disease phenotype, smoking habits, pharmacotherapy, anti-phospholipid syndrome (APS) and organ damage among 526 Swedish SLE patients meeting ACR-97. Patients with rheumatoid arthritis (n = 100), primary Sjögren's syndrome (n = 50) and blood donors (n = 507) served as controls. Anti-phospholipid antibodies (aPL) were analysed by fluoroenzyme-immunoassays detecting aCL/anti-ß2 GPI. Seventy-six (14%) SLE cases fulfilled the Sydney APS-criteria, and ≥ 1 aCL/anti-ß2 GPI isotype (IgG/IgA/IgM) occurred in 138 SLE patients (26%). Forty-five (9%) of the SLE cases had IgA-aCL, 20 of whom (4%) lacked IgG-/IgM-aCL. Seventy-four (14%) tested positive for IgA anti-ß2 GPI, 34 (6%) being seronegative regarding IgG/IgM anti-ß2 GPI. Six (1%) had APS manifestations but were seropositive regarding IgA-aCL and/or IgA anti-ß2 GPI in the absence of IgG/IgM-aPL and LA. Positive LA and IgG-aPL tests were associated with most APS-related events and organ damage. Exclusive IgA anti-ß2 GPI occurrence associated inversely with Caucasian ethnicity [odds ratio (OR) = 0·21, 95% confidence interval (CI) = 0·06-0·72) and photosensitivity (OR = 0·19, 95% CI = 0·05-0·72). Nephritis, smoking, LA-positivity and statin/corticosteroid-medication associated strongly with organ damage, whereas hydroxychloroquine-medication was protective. In conclusion, IgA-aPL is not rare in SLE (16%) and IgA-aPL analysis may have additional value among SLE cases with suspected APS testing negative for other isotypes of aPL and LA.

Troponin I and echocardiography in patients with systemic sclerosis and matched population controls.

OBJECTIVES: Cardiac manifestations in systemic sclerosis (SSc) are associated with poor prognosis. Few studies have investigated cardiac troponins in SSc. We studied the relationships between echocardiographic abnormalities, cardiac biomarkers, and disease manifestations in a population-based cohort of patients with SSc and controls. METHOD: The study comprised 110 patients with SSc and 105 age- and sex-matched population-based controls. We examined ventricular function, heart valves, and estimated pulmonary arterial pressure (ePAP) by echocardiography in all participants. Disease characteristics, manifest ischaemic heart disease (IHD), and measurements of N-terminal prohormone brain natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin I (hs-cTnI) were tabulated. RESULTS: NT-proBNP and hs-cTnI levels were higher in SSc patients than controls. Both NT-proBNP and hs-cTnI were associated with the presence of echocardiographic abnormalities. Forty-four SSc patients and 23 control subjects had abnormal echocardiograms (p = 0.002). As a group, SSc patients had lower (but normal) left ventricular ejection fraction (LVEF, p = 0.02), more regional hypokinesia (p = 0.02), and more valve regurgitations (p = 0.01) than controls. Thirteen patients and four controls had manifest IHD. Decreased right ventricular (RV) function (n = 7) and elevated ePAP (n = 15) were exclusively detected among SSc patients. CONCLUSIONS: Both NTproBNP and hs-cTnI were associated with echocardiographic abnormalities, which were more prevalent in SSc patients than in controls. Our results thus suggest that hs-cTnI could be a potential cardiac biomarker in SSc. Low RV function and signs of pulmonary hypertension (PH) were uniquely found in the SSc group. SSc patients had more valve regurgitation than controls, an observation that warrants more clinical attention.

Kinetics of the soluble IL-1 receptor type I during treatment with an LCAP filter in patients with inflammatory bowel disease.

Leukocyte apheresis primarily used for treatment of inflammatory diseases such as inflammatory bowel disease (IBD). Beside an effect of the apheresis column, the plastic lines in the apheresis system might also have an effect due to interaction between the plastic surfaces and circulating leukocytes and plasma proteins. We recently reported generation of LL-37 in the plastic lines during leukocyte adsorbing apheresis. This generation might have a positive impact on the immunologic tolerance and therefore be one operational mechanism by which the apheresis treatment executes its effect. In the present study, we report a significant generation of sIL-1RI in the apheresis lines that is initially absorbed by the LCAP device. This finding, together with our previous data on IL-1Ra indicate that important members of the IL-1 family are significantly altered during the LCAP treatment of patients with IBD. Since IL-1 and its antagonists are important for regulation of inflammatory processes in IBD, we speculate that the LCAP related changes in sIL-1RI and IL-1Ra might impact the clinical outcome. These findings have to be taken into consideration when designing new apheresis techniques as well as sham-controlled studies.

A high incidence of disease flares in an open pilot study of infliximab in patients with refractory inflammatory myopathies.

OBJECTIVE: To investigate the effect of the tumour necrosis factor (TNF) blocking agent infliximab in patients with treatment-resistant inflammatory myopathies. METHODS: A total of 13 patients with refractory polymyositis (PM), dermatomyositis (DM), or inclusion body myositis (IBM) were treated with 4 infliximab infusions (5 mg/kg body weight) over 14 weeks. Outcome measures included myositis disease activity score with improvement defined according to The International Myositis Assessment and Clinical Studies Group (IMACS), and MRI. Repeated muscles biopsies were investigated for cellular infiltrates, major histocompatibility complex (MHC) class I and II, TNF, interleukin (IL)1alpha, IL6, high mobility group box chromosomal protein 1 (HMGB-1), interferon gamma (IFNgamma), myxovirus resistance protein A (MxA) and membrane attack complex (MAC) expression. Type I IFN activity was analysed in sera. RESULTS: Nine patients completed the study. Three patients discontinued due to adverse events and one due to a discovered malignancy. Three of the completers improved by >or=20% in three or more variables of the disease activity core set, four were unchanged and two worsened >or=30%. No patient improved in muscle strength by manual muscle test. At baseline, two completers had signs of muscle inflammation by MRI, and five at follow-up. T lymphocytes, macrophages, cytokine expression and MAC deposition in muscle biopsies were still evident after treatment. Type I IFN activity was increased after treatment. CONCLUSIONS: Infliximab treatment was not effective in refractory inflammatory myopathies. In view of radiological and clinical worsening, and activation of the type I IFN system in several cases, infliximab is not an alternative treatment in patients with treatment-resistant myositis.

Aerosolized pentamidine as primary prophylaxis for Pneumocystis carinii pneumonia: efficacy, mortality and morbidity.

OBJECTIVE: Primary prophylaxis against Pneumocystis carinii pneumonia (PCP) for patients with HIV infection has been recommended by the Centers for Disease Control and Prevention. We evaluated alternatives to routine primary PCP prophylaxis with aerosolized pentamidine. METHODS: A total of 121 HIV-infected patients with CD4+ cell counts < or = 200 x 10(6)/l or an AIDS diagnosis were enrolled in a controlled study of aerosolized pentamidine as primary PCP prophylaxis. Patients were randomly assigned to treatment (n = 61) with aerosolized pentamidine once every month or to no treatment (n = 60). Patients were evaluated for PCP, mortality, morbidity and progression of HIV disease. Morbidity was estimated from the number of days patients were unable to work due to illness, number of days hospitalized and AIDS events. RESULTS: Baseline characteristics were similar in the treatment and control groups and mean CD4+ cell counts were 116 and 107 x 10(6)/l, respectively. Eight incidents of PCP and 19 deaths were observed in the treatment group during a median follow-up of 16.4 months (range, 2.3-32.4 months). Nineteen incidents of PCP and 13 deaths, of which one was related to an acute episode of PCP, were noted in the control group. Median follow-up of controls was 18.5 months (range, 3.1-32.9 months). Patients in the treatment group were unable to work 19% of the observation time and were hospitalized for 4.3% of that time. Corresponding figures were 20 and 3.0%, respectively, in the control group. CONCLUSIONS: Aerosolized pentamidine had significant prophylactic efficacy, but we could not detect any major effect on mortality and morbidity. The overall mortality and morbidity were not markedly influenced by PCP. Clinical check-ups and treatment of acute PCP could be a justifiable alternative to drug prophylaxis with aerosolized pentamidine in selected patients.

Pneumocystis carinii is not a major cause of pneumonia in HIV infected patients in Lusaka, Zambia.

The clinical occurrence of Pneumocystis carinii and Mycobacterium tuberculosis was investigated in patients infected with human immunodeficiency virus (HIV) who had clinical pneumonia of unknown aetiology in Lusaka, Zambia. The results were compared with a similar group of patients in Stockholm, Sweden. Induced sputum samples were stained for Pneumocystis by indirect immunofluorescence using monoclonal antibody 3F6 and toluidine blue O. Mycobacterial culture and acid fast stain were performed on the specimens from Lusaka. P. carinii cysts were detected in none of 27 Lusaka patients, compared to 10 of 33 Stockholm patients. M. tuberculosis was identified in 11 of 22 Lusaka patients tested. In conclusion, P. carinii could not be incriminated as the aetiological agent of HIV-associated pneumonia in Zambia in contrast to the situation in Sweden, where Pneumocystis is the dominating aetiological agent.

Pneumocystis carinii pneumonia: detection of parasites in sputum and bronchoalveolar lavage fluid by monoclonal antibodies.

Diagnosis of pneumocystis pneumonia is based on identifying Pneumocystis carinii cytochemically in material from the lung. The silver methenamine staining methods most commonly used are technically difficult and lack specificity. The diagnostic value of immunocytological identification of the parasite was evaluated by using mouse monoclonal antibody 3F6, specific for human pneumocystis, to identify P carinii in bronchoalveolar lavage fluid and sputum by immunofluorescence and was compared with that of other variables. Bronchoalveolar lavage was performed on 25 patients positive for HIV antibody with clinically suspected pneumocystis pneumonia and 40 patients negative for HIV antibody who presented with interstitial disorders of the lung. Lavage fluid showed pneumocystis only in the patients positive for antibody, the parasite being detected in 19 by immunofluorescence and in 17 by a modified silver methenamine staining method. Chest x ray films obtained at the time of bronchoscopy showed interstitial or alveolar shadowing in 17 of the 19 patients, but clinical symptoms and the presence of antibodies to pneumocystis did not seem to be predictive. Sputum samples were collected during 43 episodes of clinically suspected pneumocystis pneumonia in patients positive for HIV antibody. Pneumocystis was detected consistently more commonly by immunofluorescence than the silver strain in sputum collected routinely and induced by inhalation of saline. In 17 patients bronchoalveolar lavage followed sputum collection, and the sensitivity of detection of pneumocystis in immunofluorescence in sputum compared with lavage fluid was 57% (8/14). Immunofluorescence was suitable for specimens fixed in ethanol and seemed highly specific and more sensitive than the standard cytochemical methods for identifying pneumocystis.

[Pneumocystis carinii is still a dangerous opportunist. The infection is continuously a threat to immunocompromised patients]. / Pneumocystis carinii fortfarande en svår opportunist. Infektionen ett ständigt hot mot immundefekta patienter.

Despite recent decrease in the incidence of Pneumocystis carinii pneumonia (PCP) among patients infected with HIV (human immunodeficiency virus), PCP remains a threat to other categories of immunocompromised patients. The article provides an outline of recent, mainly molecular genetic, findings in P. carinii research, including its new classification as a primitive fungus, host specificity and verified de novo infection in HIV-infected subjects. As the pathogen still defies propagation in vitro, laboratory diagnosis is dependent on microscopic demonstration of the organism. Diagnostic specificity can be enhanced by generating specific PCR (polymerase chain reaction) products which can be sequenced for genotyping. Findings in animal studies and epidemiological observations (e.g., in outbreaks of PCP among immunocompromised hospital patients), suggest transmission of PCP infection to be airborne. Genetic methods have been used to study the mode of P. carinii transmission. Nucleic acids of the human form of P. carinii (P. carinii f. sp. hominis) have been detected in the air of hospital wards, indicating susceptible patients to be at risk. By contrast, findings obtained with the same methods in studies of person-to-person transmission of P. carinii among clustered cases of PCP in hospitals suggest infection to be environmentally acquired. Thus, many questions remain to be answered regarding the occurrence and transmission of P. carinii infection.

Function of mechanically lengthened jejunum after restoration into continuity.

PURPOSE: Distraction enterogenesis is a potential treatment for patients with short bowel syndrome. We previously demonstrated successful lengthening of jejunum using a degradable spring device in rats. Absorptive function of the lengthened jejunum after restoration into intestinal continuity needs to be determined. METHODS: Encapsulated polycaprolactone springs were placed into isolated jejunal segments in rats for four weeks. Lengthened segments of jejunum were subsequently restored into intestinal continuity. Absorption studies were performed by placing a mixture of a non-absorbable substrate and glucose into the lumen of the restored jejunum. RESULTS: Restored jejunal segments demonstrated visible peristalsis at specimen retrieval. Compared to normal jejunal controls, restored segments demonstrated equal water absorption and greater glucose absorption. Restored segments had thicker smooth muscle, increased villus height, increased crypt depth, and decreased sucrase activity compared to normal jejunum. The density of enteric ganglia increased after restoration to near normal levels in the submucosa and to normal levels in the myenteric plexus. CONCLUSION: Jejunum lengthened with a degradable device demonstrates peristaltic and enzymatic activity as well as glucose and water absorption after restoration into intestinal continuity. Our findings further demonstrate the therapeutic potential of a degradable device.

Down-regulation of interferon-gamma parallels clinical response to selective leukocyte apheresis in patients with inflammatory bowel disease: a 12-month follow-up study.

BACKGROUND & AIMS: Pilot studies have indicated a therapeutic role for an apheresis device (Adacolumn) that selectively adsorbs leukocytes in patients with inflammatory bowel diseases. It may also exert immunoregulatory effects contributing to its clinical efficacy. This study aimed to correlate the clinical response to leukocyte apheresis with the expression of key cytokines in mucosal tissue, in peripheral leukocytes, and in plasma. METHODS: Ten patients (seven with Crohn's disease and three with ulcerative colitis, median age: 31 years) with mild to moderately chronic activity were recruited to an open study. Patients were refractory to or had a relapse despite conventional treatment including azathioprine. Leukocyte apheresis was performed once a week for five consecutive weeks. Clinical efficacy was assessed on week 7 and after 12 months. Colonoscopy with multiple biopsies was performed at the start of the study and after 7 weeks for semiquantitative immunohistochemical analyses of cytokines. Cytokine levels in blood and the proportion of cytokine producing CD4+ and CD8+ lymphocytes were determined. RESULTS: The apheresis procedures were well tolerated and no major adverse events were encountered. The median clinical activity score decreased from 12 to 7 on week 7 (P=0.031, n=9) and to 4 after 12 months (P=0.004, n=9). Five patients were in clinical remission at the 12th month. Tissue interferon (IFN)-gamma-positive T-cells decreased in clinical responders (P=0.027) after apheresis. In parallel, significantly lower levels of IFN-gamma-producing lymphocytes were detected in peripheral blood. IFN-gamma-positive cells in pretreatment biopsies completely disappeared or decreased in posttreatment biopsies sampled on week 7 in responders (P=0.027) and appeared to predict the maintenance of long-term remission or response after 12 months. CONCLUSIONS: Leukocyte apheresis is a novel and safe nonpharmacological adjunct therapy that may prove useful in steroid refractory or dependent patients when conventional drugs have failed. Down-regulation of IFN-gamma in mucosal biopsies and in peripheral leukocytes may be a predictive marker for sustained, long-term response.

Allergen challenge alters intracellular cytokine expression.

The pathophysiology of asthma is complex and engages cascades of events in the cytokine network. We, therefore, investigated the impact of bronchial allergen challenge in humans on the cytokine profile of circulating lymphocytes. Peripheral blood samples from 10 patients with allergic asthma were collected before and 24 h after allergen provocation. Patients who mounted a late-phase reaction were designated dual responders opposite to single responders. Whole blood cells were stimulated by mitogen and intracellular interleukin (IL)-4 and interferon (IFN)-gamma were detected by flow cytometry. The allergen challenge induced a decrease in IL-4+CD4+ cells in the patients (P = 0.05), and a significant decrease (P < 0.05) in IFN-gamma+CD4+ cells was noted in single, but not dual, responders. In addition, there was a significant difference (P < 0.01) with respect to the changes in the IFN-gamma+CD4+ cells comparing dual and single responders. No corresponding changes were observed in CD8+ cells. The data suggest a possible on-going traffic of IFN-gamma and IL-4+CD4+ lymphocytes into the bronchial mucosa in relation to an allergen challenge and generate the hypothesis that a difference exists between single and dual responders in this respect. Because the CD4+IFN-gamma-producing cells have the capacity to downregulate the T-helper type 2 response, a reduced capacity in this aspect might contribute to the pathophysiology in dual responders.

Laboratory diagnosis and occurrence of Pneumocystis carinii.

Pneumocystis carinii is an opportunistic pathogen causing life threatening pneumonia (PCP) in immunosuppressed patients and particularly among AIDS patients. Whether the infection results from reactivation or reinfection is debated. Since methods for in vitro cultivation still are not successful, the diagnosis is dependent on direct demonstration of the organism in respiratory specimen. In this thesis laboratory diagnostic methods in terms of staining, sampling, antibody detection and DNA amplification are evaluated. Furthermore, the occurrence of the organism in the Western world versus Africa, and in symptomatic and asymptomatic HIV infected patients is studied and discussed. The use of a monoclonal antibody (MAb), 3F6 in an indirect immunofluorescence assay (IFL) was compared to the two most commonly used chemical stains, silver methenamine and toluidine blue. The IFL method detected both cyst and trophozoite stages of P. carinii and was more sensitive than the chemical stains when applied to sputum samples. Among commercialised MAbs for P. carinii detection by IFL, only the indirect tests were readily applicable to ethanol treated HIV inactivated samples. In contrast to the MAb 3F6, (Dakopatts), the MAb from Northumbria stained only a selection of the cysts and no trophozoites. The relative sensitivity of IFL in detecting the organism in sputum samples compared to bronchoalveolar lavage (BAL) samples was estimated to be at least 70%. The polymerase chain reaction (PCR), which can amplify specific DNA fragments, was used for the demonstration of P. carinii in sputum and BAL specimens. The PCR was shown to be specific and more sensitive than IFL. However, P. carinii DNA was found in a few patients without clinical evidence of present, past or future PCP. Thus the possibility of PCR to detect colonization must be considered. Detection of antibodies to P. carinii by indirect IFL was studied in HIV versus non-HIV patients. A titer rise was seen in 45% of non-HIV patients versus only 3% in HIV patients during a PCP episode. No humoral response was seen in AIDS patients, whereas the serology did support the clinical PCP diagnosis in a proportion of the otherwise immunosuppressed patients. Serology may however not be of help in the acute setting. In the beginning of 1988 PCP had not yet been reported from Central Africa where the AIDS epidemic by then was growing fast. The occurrence of P. carinii in Central Africa was evaluated by a comparative study on induced sputum samples from HIV infected patients with pulmonary infection in Stockholm, Sweden and Lusaka, Zambia.(ABSTRACT TRUNCATED AT 400 WORDS)

Application and staining patterns of commercial anti-Pneumocystis carinii monoclonal antibodies.

Commercially available monoclonal antibodies to Pneumocystis carinii were compared with respect to immunofluorescence staining patterns of human immunodeficiency virus-inactivated smears. Only the indirect staining kits were suitable for application to ethanol-inactivated samples. When antibodies from Dakopatts and Northumbria were compared, the staining of cysts and trophozoites showed different patterns.

Detection of Pneumocystis carinii DNA in sputum and bronchoalveolar lavage samples by polymerase chain reaction.

A polymerase chain reaction (PCR)-based assay was developed for the detection of Pneumocystis carinii DNA in induced sputum and bronchoscopic alveolar lavage samples. The primer pair was selected from the published sequence of the thymidylate synthase gene of P. carinii derived from infected rats. The amplified DNA fragment of 403 bp was detected by agarose gel electrophoresis and by Southern and slot blot hybridization. No positive reaction was seen with DNA from different microorganisms typically found in the respiratory tract. P. carinii DNA was demonstrated in 30 of 42 sputum samples from immunosuppressed patients, whereas 21 of 42 sputum samples were positive by indirect immunofluorescence (IFL). Among the 42 patients, 14 were receiving prophylactic chemotherapy. In that group, PCR detected P. carinii in nine sputum samples, whereas IFL detected P. carinii in only four sputum samples. A positive PCR result was also seen in 5 of 43 IFL-negative bronchoscopic alveolar lavage samples from patients with respiratory symptoms. The PCR assay detected 10 copies of the target DNA, which corresponds to 10(-18) g of the specific P. carinii sequence. The results indicate that PCR amplification in combination with DNA hybridization is specific and is a more sensitive diagnostic method than IFL for the detection of P. carinii.

No evidence of nosocomial Pneumocystis carinii infection via health care personnel.

Clusters of Pneumocystis carinii pneumonia (PCP) in immunocompromised settings suggest person-to-person transmission. We examined whether personnel in a ward for HIV-infected patients were carriers of P. carinii. None of 29 sputum samples from 19 personnel caring for HIV-infected patients had detectable amounts of P. carinii DNA, as determined by the two PCR methods used. Two of 26 personnel were found, by an immunofluorescence assay, to have serum antibodies for P. carinii. The results do not support the hypothesis that personnel represent major vectors or transient reservoirs for spreading P. carinii infection to immunocompromised hosts.

Natural history of asymptomatic and symptomatic pneumocystis carinii infection in HIV infected patients.

The natural appearance of Pneumocystis carinii in induced sputum samples was studied in 60 HIV-infected patients with severe immunodeficiency and without a history of P. carinii pneumonia (PCP). The patients were prospectively evaluated for occurrence of P. carinii in induced sputum samples, PCP diagnosis and CD4+ cell counts during observation periods of 2 to 31 months. P. carinii was detected in 16 patients all of whom developed clinical PCP. In 5 patients P. carinii was detected 3 weeks to 8 months prior to clinical symptoms. Immunofluorescence using monoclonal antibody 3F6 was more sensitive than toluidine in detecting P. carinii in sputum samples (p < 0.05). In the patients who developed PCP a drop of the mean CD4 count to 40-50 x 10(6)/l was observed 200 days before diagnosis. However, out of 13 patients with CD4 counts of 0-20 x 10(6)/l only 7 developed PCP during 200 days of observation. The results do not support the suggested reactivation of a latent infection present in the vast majority of adults. PCP may instead result from exposure to the organism or presence of an unknown cofactor. We conclude that P. carinii is present in some asymptomatic HIV patients and that the detection of the organism in sputum should be regarded as pathological and prophylaxis or treatment inserted. The risk of transmission of P. carinii to patients with severe immunodeficiency should be seriously considered.

Transmission of Pneumocystis carinii from patients to hospital staff.

BACKGROUND: An extrahuman reservoir of human pathogenic Pneumocystis carinii remains unknown. Host to host transmission has been described in animal studies and in cluster cases among immunodeficient patients. P carinii DNA has recently been detected in air filters from inpatient and outpatient rooms in departments of infectious diseases managing patients with P carinii pneumonia (PCP), suggesting the airborne route of transmission. Exposure of staff to P carinii may occur in hospital departments treating patients with PCP. METHODS: Exposure to P carinii was detected by serological responses to human P carinii by ELISA, Western blotting, and indirect immunofluorescence in 64 hospital staff with and 79 staff without exposure to patients with PCP from Denmark and Sweden. DNA amplification of oropharyngeal washings was performed on 20 Danish staff with and 20 staff without exposure to patients with PCP. RESULTS: There was no significant difference in the frequency or level of antibodies to P carinii between staff exposed and those unexposed to patients with PCP. None of the hospital staff had detectable P carinii DNA in oropharyngeal washings. CONCLUSIONS: There is no difference in antibodies and no detectable P carinii DNA in oropharyngeal washings, which suggests that immunocompetent staff treating patients with PCP are not a potentially infectious source of P carinii for immunocompromised patients.

Genotypes of clustered cases of Pneumocystis carinii pneumonia.

Reports of outbreaks of Pneumocystis carinii pneumonia (PCP) among human immunodeficiency virus-negative immunocompromised patients have suggested a person-to-person transmission of P. carinii. In this study, 17 bronchoalveolar lavage isolates from patients in 3 PCP outbreaks were genotyped, 2 in renal transplant recipients and 1 outbreak among patients with haematological disorders. Genotypes in the P. carinii sp. f. hominis (P. carinii f.sp. hominis) mt large subunit ribosomal RNA site 85 were detected by 2 methods: direct sequencing and 3 different allele-specific polymerase chain reaction assays. Although limited data on patient contacts were available, the detected P. c. hominis genotypes do not support person-to-person transmission as the predominant transmission route of P. carinii in humans.