Distribution of desmin and fibronectin in chick embryo gonad during testicular cord formation

In order to compare PCR with rapid virus culture for the early detection of CMV in bronchoalveolar lavage (BAL) after bone marrow transplantation, 26 asymptomatic patients were routinely evaluated for the presence of CMV on day 35 using these two techniques. Concurrent blood samples were also analyzed in all cases. CMV was detected synchronously by both culture and PCR in six of 26 (23%) BAL and in five of 26 (19%) blood specimens. Among these positive specimens, three BAL and blood samples were positive in the same patients. Five (19%) BAL and five (19%) blood samples were culture-negative but PCR-positive. No BAL or blood specimens were positive by culture alone. When considering matched BAL-blood samples, five were positive in only one fluid, BAL (n = 3) or blood (n = 2) using culture, while seven were positive in only one fluid, BAL (n = 4) or blood (in = 3) using PCR. Overall, six of 26 (23%) patients had culture-negative but PCR-positive results. Three of these six patients were positive only in BAL and two of them subsequently received antiviral therapy for development of symptoms suggestive of CMV infection. We suggest that asymptomatic patients with negative-culture but PCR-positive results on day 35 in BAL should be subsequently closely monitored for the presence of CMV.     

Cytomegalovirus retinitis in a pediatric AIDS patient

INTRODUCTION: Cytomegalovirus retinitis (CMV) is the most frequently found opportunistic eye infection in adults with AIDS, with mean incidence of 20%-50%. However, only 5% of children with AIDS have this infection. CLINICAL CASE: We present the case of a six year old girl with stage C3 AIDS diagnosed at the age of 20 months, who developed unilateral diffuse retinitis due to CMV. The infection involved the posterior pole of the right eye, with retinal atrophy along the temporal vascular arcodes, and an active advance front in the temporal macula. The optic nerve was not found to be involved although the peripheral areas of the retina were involved leading to rhegmatogenous detachment of the superotemporal retina. In view of the systemic deterioration of the patient, no specific anti-CMV treatment was given. The patient died of respiratory insufficiency a few weeks later. CONCLUSIONS: CMV retinitis in paediatric AIDS patients is usually associated with more severe illness and a poorer general health than the adult population. In view of the absence of symptoms in these patients, periodic ophthalmoscopic examinations should be done in those who have severe immunological deterioration.     

Polymerase chain reaction-based assays of vitreous samples for the diagnosis of viral retinitis. Use in diagnostic dilemmas

OBJECTIVE: This study aimed to review the authors' results using polymerase chain reaction (PCR)-based assays for the diagnosis of viral retinitis. DESIGN: The study design was a retrospective case series. PARTICIPANTS: Thirty-seven patients (38 eyes) with active retinitis from whom vitreous biopsy specimens were received in the authors' laboratory for diagnostic evaluation. INTERVENTION: Vitreous biopsy specimens were evaluated with previously described PCR-based assays for cytomegalovirus (CMV), varicella zoster virus (VZV), and herpes simplex virus (HSV) DNA; clinical histories were reviewed. MAIN OUTCOME MEASURES: Laboratory findings and clinical course were measured. RESULTS: The results of the authors' assays were consistent with the long-term clinical course of each patient. Cytomegalovirus, VZV, or HSV DNA was detected in the vitreous from 24 patients. Cytomegalovirus DNA was detected in vitreous biopsy specimens from 10 patients (11 eyes). Nine patients (ten eyes) with acquired immune deficiency syndrome ultimately were diagnosed with CMV retinitis as they were followed clinically over time. Varicella zoster virus DNA was detected in vitreous biopsy specimens from eight patients; seven adult patients were ultimately diagnosed with acute retinal necrosis or progressive outer retinal necrosis. Herpes simplex virus DNA was detected in vitreous biopsy specimens from six patients; five patients had previous or subsequent herpes encephalitis. No viral DNA was detected in the vitreous from 13 patients; all were ultimately diagnosed with toxoplasmosis, syphilis, Behcet disease, fungal endophthalmitis, or idiopathic inflammation. CONCLUSIONS: These data further support the use of PCR-based assays of vitreous specimens in the diagnostic evaluation of patients with infectious retinitis.     

Effect of ecological factors in an industrial city on the health of students

PURPOSE: To determine the prevalence of cytomegalovirus retinitis after cardiac transplantation. METHODS: Records of patients who had cardiac transplantation at Jackson Memorial Hospital between November 1986 and November 1994 were reviewed. Patients who had not previously had ophthalmic evaluation after transplantation were invited for retinal examination. RESULTS: Eighty-two patients had cardiac transplantation during the study period. One to 68 months (mean, 24.5 months) after transplantation, ophthalmoscopic examination was performed in 41 patients. Six (14.6%) of 41 patients had healed scars consistent with cytomegalovirus retinitis or active cytomegalovirus retinitis. CONCLUSIONS: Cytomegalovirus retinitis lesions were found in six (14.6%) of 41 patients. If remaining patients were unaffected and no patient developed cytomegalovirus retinitis after ophthalmoscopic examination, the prevalence would be 7.3% (6/82). We recommend ophthalmic screening of all patients 3 to 4 months after cardiac transplantation with repeat examinations yearly or as ocular symptoms occur.     

Spatiotemporal dynamics of intracellular calcium in the mouse egg injected with a spermatozoon

The purpose of this study was to assess the cytological composition of bronchoalveolar lavage (BAL) fluid in allogeneic BMT patients without lung complications and compare it with that obtained from healthy volunteers. During the first 6 months post-BMT we studied the differential cell counts of 98 BALs from 56 patients as well as the total cell count of 44 BALs from 27 patients. The BAL cellular composition in BMT patients was clearly different from that of healthy subjects: there was a marked increase in alveolar neutrophils (in 82% of the patients when sequential BALs were performed) and an increase in lymphocytes, with a lower percentage of macrophages and similar numbers of eosinophils. A greater variation in cellular populations was found without an evident cause. The total number of cells per ml of fluid recovered appeared similar to that of healthy volunteers. A high frequency of neutrophilic alveolitis was found in patients with asymptomatic CMV on BAL. Owing to the variability of BAL cellular composition in asymptomatic BMT patients and its difference from that in healthy volunteers, great caution should be taken when interpreting the BAL composition data from patients with lung complications. In order to avoid drawing wrong conclusions these data should be compared with those obtained from a control group of BMT patients without lung complications and not from healthy volunteers.     

Cytomegalovirus retinitis in patients with AIDS in Europe. AIDS in Europe Study Group

The incidence of cytomegalovirus (CMV) retinitis and risk factors associated with the condition were studied in patients with the acquired immune deficiency syndrome (AIDS) in a multicenter retrospective cohort study of 6458 patients from 52 centers in 17 countries in Europe. Cytomegalovirus retinitis was diagnosed in 154 patients (2.4%) at the time of AIDS diagnosis, the probability of this diagnosis being significantly higher for those with CD4+ cell counts of < 100/mm3 (3.4%) than with counts of 100-200/mm3 (1.3%) or > 200/mm3 (0.8%). The rate of developing CMV retinitis after AIDS diagnosis was 9.4 per 100 patient years of follow-up. Multivariate analysis showed that risk behavior was significantly associated with the risk of developing CMV retinitis: lower for intravenous drug users [relative risk (RR) 0.47] and those engaged in "other risk behavior" (RR 0.58) than for homosexual men. The risk of developing CMV retinitis after AIDS diagnosis was significantly associated with CD4+ cell count at the time of AIDS diagnosis: for counts < 100/mm3 (RR 2.90) and from 100 to 200/mm3 (RR 2.13), there was a higher risk than for counts > 200/mm3. Patients with Pneumocystis carinii pneumonia, toxoplasmosis, or extraocular CMV infection at time of AIDS diagnosis exhibited an increased risk of developing CMV retinitis. Patients treated with zidovudine exhibited an increased rate of CMV retinitis: RR was 1.75 during and 2.87 after the second year of treatment as compared to those who had not received zidovudine. Median survival after CMV retinitis at time of AIDS diagnosis was eight months.     

CMV-specific immune responses and HLA phenotypes of AIDS patients who develop CMV retinitis. HNRC Group. HIV Neurobehavioral Research Center

HLA phenotype and immune responses to CMV were studied to determine whether the subset of AIDS patients who developed CMV retinitis were immunogenetically or immunologically predisposed. CMV retinitis develops in approximately 28-35% of AIDS patients and CMV encephalitis develops in 40% of those with retinitis, often leading to death. T-cell proliferation responses to CMV and HIV were assayed prospectively in individuals enrolled in a longitudinal study at the HIV Neurobehavioral Research Center (HNRC) in San Diego. Seventy-three participants, at various stages of disease, have been HLA typed and followed, clinically and immunologically, for up to 5 years. Six HIV infected individuals who eventually developed CMV retinitis, and were assayed prospectively, had a history of low T-cell proliferation to CMV antigens before they were profoundly immunosuppressed. All 10 individuals with CMV retinitis had at least one of three HLA alleles (or combinations): A2B44 (p = 0.02), B51(p = 0.02), or DR7 (p = 0.01) (collective p value = 0.007). Three of the 10 had two or more of these alleles. Of AIDS patients with CD4 counts below 100 and actively at risk for retinitis, 7/15 with A2B44,51, or DR7 have developed retinitis compared to 0/13 without these HLA alleles (relative risk = 23.8). All 4 patients with these alleles who have died, had retinitis. These results suggest that HIV infected individuals with HLA phenotypes A2B44, B51, and DR7 have low T-cell immune responses to CMV and are predisposed to CMV retinitis and encephalitis as immunodeficiency progresses.     

Increasing breast and cervical cancer screening in low-income women

Active cytomegalovirus (CMV) retinitis in patients with acquired immunodeficiency syndrome (AIDS) was treated with an intraocular sustained-release ganciclovir implant. A total number of 19 implants were performed in 15 eyes of 9 AIDS patients. The intraocular sustained-release ganciclovir was effective in preventing reactivation of CMV retinitis in 15 of the 19 implants, ineffective in 3, and undetermined in 1. All ineffective cases had been resistant to ganciclovir therapy before the implants. Vision after the therapy was maintained at better than 0.5 except for one eye. There were no serious ocular complications caused by the therapy. Among 5 patients with unilateral CMV retinitis, 2 unaffected eyes developed CMV retinitis during this therapy. In addition, another patient developed presumed CMV infection in other systemic organs. Based on these data, the intraocular sustained-release ganciclovir implant was considered to be useful for the treatment of CMV retinitis in AIDS.     

Anterior uveitis in HIV-infected patients. 3 cases in patients treated with an antiprotease

OBJECTIVES: Uveitis is an ocular manifestation rarely observed in HIV-infected patients. We observed three cases of anterior uveitis without progressive retinitis in HIV patients receiving antiprotease treatment. CASE REPORT: The first patient developed a first episode of uveitis during ritonavir therapy. Two other episodes occurred with indinavir. The second patient developed uveitis when treated with indinavir. In the third patient, the first episode developed with indinavir and a second with a ritonavir-saquinavir combination. Uveitis was unilateral in 4 episodes. Clinical manifestations were red irritable eyes and, in 2 episodes, reduced visual acuity. The antiprotease was interrupted in 4 of the 6 episodes and clinical course was rapidly favorable. DISCUSSION: Pure anterior uveitis should suggest drug induction in HIV infected patients; rifabutin is often the cause. Infectious causes predominate in case of total uveitis associating choroid and retinal involvement. Cytomegalovirus, herpes zoster, syphilis, and toxoplasmosis have been incriminated. Antiproteases would appear to be a new cause of anterior uveitis in HIV-infected patients.     

Viral lesions of the eye in human immunodeficiency virus infection]

HIV infection destroying cellular immunity system creates prerequisites for herpesvirus involvement of the anterior and posterior segments of the eye. A total of 370 HIV-infected patients were examined. Ocular diseases were detected in 53 (14.35%). The most prevalent conditions were retinal angiopathy (most often with cotton-like foci--in 7.3% and cytomegalovirus (CMV) retinitis in 4.1%). Cotton-like foci in the presence of CMV activation (evidenced by high level of CMV DNA in peripheral blood) are a sign of probable CMV infection manifesting by retinitis or involvement of other organs. Intravenous gancyclovir in a dose of 7.5 mg/kg twice a day and its combination with interferon inductor poludan are effective methods for therapy of CMV infection, preventing blindness or poor vision. Moreover, combination of chemotherapy with interferon inductors cured involvement of the anterior segment of the eye--herpetic keratitis and iridocyclitis, which sometimes develop in the presence of HIV infection.     

Quantitative cytomegalovirus DNA level in the blood and its relationship to cytomegalovirus retinitis in patients with acquired immune deficiency syndrome

OBJECTIVE: A pilot study was performed to determine whether relationships exist between changes in a quantitative solution hybridization assay for cytomegalovirus (CMV) DNA in the blood and development of CMV retinitis, development of nonocular CMV disease, or reactivation of pre-existing CMV retinitis lesions. DESIGN: Observational case series. PARTICIPANTS: Two groups of human immunodeficiency virus-infected patients: 10 CMV antibody-positive patients with CD4+ T-lymphocyte counts of less than 50 ml and no CMV disease at baseline and 11 patients with CMV retinitis but no extraocular CMV disease at baseline. INTERVENTION: Quantitative changes in leukocyte-associated CMV DNA levels were observed over time. Anti-CMV therapies were based on clinical findings only. MAIN OUTCOME MEASURES: Development of CMV end-organ disease or change in activity of pre-existing CMV retinitis lesions was measured. RESULTS: Among patients with no CMV disease at baseline, four had CMV disease develop during follow-up (three cases of CMV retinitis, one case of presumed CMV esophagitis); all had CMV DNA levels greater than 5000 genomes/ml before the onset of CMV disease. The remaining six patients had levels less than 5000 genomes/ml throughout follow-up (P = 0.05). Among patients with CMV retinitis at baseline, all whose CMV DNA blood levels rose more than tenfold had extraocular CMV disease or reactivation of CMV retinitis develop. Raised CMV DNA blood levels were not seen in every patient with clinical reactivation of CMV retinitis. CONCLUSION: Elevated or rising CMV DNA blood levels appear to be associated with the development of CMV disease in individuals with low CD4+ T-lymphocyte counts. In patients with CMV retinitis, rising levels appear to be associated with the development of extraocular CMV disease or reactivation of CMV retinitis. Conversely, reactivation of CMV retinitis also may occur in the absence of changes in CMV DNA blood levels. Further studies are warranted to determine whether changes in CMV blood levels can be used as a guide for preemptive therapy to prevent reactivation of CMV retinitis lesions or to help choose between local and systemic therapy for management of reactivations.     

Relation between polymerase chain reaction findings and morphological changes during cytomegalovirus infection in transplanted lung

Cytomegalovirus (CMV) can be present as a latent or productive infection resulting in disease. The polymerase chain reaction (PCR) is a sensitive technique to document the presence of CMV (DNA). Negative reactions are indicative of its absence. The presence of CMV (DNA) was assessed longitudinally in 261 transbronchial lung biopsy (TBB) specimens from 37 patients over a 6-month period. The TBB specimens from six serologically CMV-negative recipients who received lungs from serologically CMV-negative donors never showed a positive CMV-PCR(DNA) reaction during the study. Based on a study of their TBB specimens, 10 serologically CMV-positive recipients who received lungs from serologically CMV-negative donors all developed a CMV-PCR(DNA)-positive reaction and five (50%) morphologically manifested CMV disease. The remaining 21 serologically CMV-positive recipients who received lungs from serologically CMV-positive donors all developed a CMV-PCR(DNA)-positive reaction and 15 (71%) developed CMV pneumonitis. The data show that development of a positive CMV-PCR(DNA) reaction in a TBB sample within the first month after transplantation indicates a greatly increased risk of developing CMV disease. In addition, a positive CMV-PCR(DNA) reaction preceded morphologically manifest disease on average by 2 weeks. Comparisons between TBB and bronchoalveolar lavage show the former to provide a more dependable template.     

Is routine post-operative surveillance for cytomegalovirus infection following heart transplantation necessary?

OBJECTIVE: Cytomegalovirus infection (CMV) is an important cause of morbidity and mortality following cardiac transplantation. The purpose of the present study was to ascertain whether routine post-operative screening for CMV infection influenced clinical management. METHODS: Laboratory and case notes of 220 patients who received cardiac transplantation between November 1986 and October 1996 were reviewed. The range of follow-up was one to 120 (median 36) months. CMV surveillance involved blood tests for early antigen detection weekly for the first 6 post-operative weeks, fortnightly thereafter until the end of the third post-operative month and every 6 weeks to the end of the first post-operative year. Otherwise monitoring was performed if the patients had clinical symptoms suggestive of CMV infection. CMV sero-negative IgG recipients (R) of sero-positive IgG donor (D) organs and/or blood products received hyper-immune gammaglobulin for the first three post-operative months. Four patient groups were noted, namely R+D+ (59 patients), R+D- (70 patients), R-D+ (35 patients) and R-D- (56 patients). RESULTS: CMV antigenaemia was present in 40% (89) of patients and 48% (43) of these patients developed clinical features of CMV infection and received ganciclovir therapy. The distribution of clinical CMV infection requiring treatment was 25% (9/35) in the R+D- group, 50% (16/32) in the R+D+ group and 85% (18/22) in the R-D+ group. None of the patients in the R-D- group developed CMV antigenaemia. Forty six (52%) patients who were CMV antigen positive but who did not develop symptoms were not treated with ganciclovir and have remained well. CONCLUSION: Our results suggest that routine screening for CMV following cardiac transplantation is unnecessary. Surveillance did not result in the instigation of treatment for CMV unless there were associated clinical features of CMV infection.     

Quantitative polymerase chain reaction to predict occurrence of symptomatic cytomegalovirus infection and assess response to ganciclovir therapy in renal transplant recipients

Cytomegalovirus (CMV) DNA levels were measured by quantitative-competitive polymerase chain reaction (PCR) in weekly leukocyte samples from 50 renal transplant recipients, including 23 with symptomatic and 27 with asymptomatic CMV infection. Peak and week 4 CMV DNA levels were higher in symptomatic subjects (P = .07 and .02, respectively). In a logistic regression model, the logarithm of the week 4 level independently predicted symptomatic infection (odds ratio, 1.78 for a 1 log10 increase; 95% confidence interval, 1.14-2.78; P = .01). All subjects whose week 4 level exceeded 1000 copies/100,000 leukocytes developed symptoms. In subjects with adequate samples for analysis, CMV levels declined exponentially with ganciclovir treatment, with an average half-life of 3.3 days. Levels exceeding 10,000 copies were associated with prolonged time to clearing of CMV DNA. Potential clinical applications of quantitative CMV PCR include predicting occurrence of symptomatic first episodes after transplantation and individualizing duration of antiviral therapy.     

AIDS: infections of the retina and choroid

Various viral, bacterial, parasitic and fungal agents have been found to cause infections of retina and choroidea in HIV-infected patients. Usually these infections are opportunistic infections caused by the profound immunodeficiency, which is a result of the decay of lymphocytes by HIV. Before the HIV epidemic only rare cases of cytomegalovirus (CMV) retinitis were known in the literature. Now CMV retinitis has become the most common infection of the eye in AIDS patients. Ocular toxoplasmosis in HIV-infected patients can have a severe clinical appearance without treatment. Spontaneous recovery, as it usually occurs in otherwise healthy patients, does not take place in HIV-infected patients, so that a lifelong maintenance therapy is mandatory. Pneumocystis carinii chorioiditis was unknown before the HIV epidemic. In 1987 Pneumocystis carinii were found in the choroidea and two years later the clinical appearance could be described. Infections of choroidea and retina associated with AIDS may not be seen as isolated diseases. Commonly other organs are infected by the same or another organism. In case of AIDS-associated eye infections other organs should be checked for opportunistic disease. Diagnosis can be difficult. Because most of all intraocular infections associated with AIDS are CMV retinitis, an effective therapy can be initiated in most cases and in the follow-up a diagnosis can finally be made. Serological testing may be inconclusive because of occasional false-negative findings. Treatment often only suppresses the infections and so ongoing maintenance therapy may be necessary, as in the cases of CMV retinitis and Toxoplasma retinochorioiditis. A variety of different diseases, which can be treated by a multitude of different substances with a lot of adverse effects and contraindications, can complicate the therapeutic modalities used for the management of each individual disorder. Additionally HIV-infected patients suffer from at least two or three different diseases and must be treated lifelong with plenty of substances, which often are given with higher doses than usual. Only by cooperation of HIV-experienced doctors of different specialities in hospitals and offices the complex subject of HIV infection can be managed.     

Treatment of cytomegalovirus retinitis with an intraocular sustained-release ganciclovir implant. A randomized controlled clinical trial

BACKGROUND AND METHODS: We performed a randomized controlled clinical trial to assess the safety and efficacy of a 1 microgram/h ganciclovir implant for the treatment of newly diagnosed cytomegalovirus (CMV) retinitis in patients with the acquired immunodeficiency syndrome (AIDS). Patients with previously untreated peripheral CMV retinitis were randomly assigned either to immediate treatment with the ganciclovir implant or to deferred treatment. Standardized fundus photographs were taken at 2-week intervals and analyzed in a masked fashion. The study end point was progression of retinitis based on the photographic assessment. RESULTS: Twenty-six patients (30 eyes) were enrolled. The median time to progression of retinitis was 15 days in the deferred treatment group (n = 16) vs 226 days in the immediate treatment group (n = 14) (P < .00001, log-rank test). During the study, 39 primary implants and 12 exchange implants were placed in immediate-treatment eyes, deferred-treatment eyes that progressed, or contralateral eyes that developed CMV retinitis. Postoperative complications in the total series included seven late retinal detachments and one retinal tear without detachment. Final visual acuity was 20/25 or better in 34 of 39 eyes. The estimated risk of developing CMV retinitis in the fellow eye was 50% at 6 months. Biopsy-proven visceral CMV disease developed in eight (31%) of 26 patients. The median survival was 295 days. CONCLUSION: The ganciclovir implant is effective for the treatment of CMV retinitis. Patients with unilateral CMV retinitis treated with the implant are likely to develop CMV retinitis in the fellow eye, and some patients will develop visceral CMV disease.     

Guidelines for the treatment of cytomegalovirus diseases in patients with AIDS in the era of potent antiretroviral therapy: recommendations of an international panel. International AIDS Society-USA

OBJECTIVE: To provide recommendations for the treatment of acquired immunodeficiency syndrome-related cytomegalovirus (CMV) end-organ diseases, including retinitis, colitis, pneumonitis, and neurologic diseases. PARTICIPANTS: A 17-member panel of physicians with expertise in clinical and virological research and inpatient care in the field of CMV diseases. EVIDENCE: Available clinical and virological study results. Recommendations are rated according to the quality and strength of available evidence. Recommendations were limited to the treatment of CMV diseases; prophylaxis recommendations are not included. PROCESS: The panel was convened in February 1997 and met regularly through November 1997. Subgroups of the panel summarized and presented available information on specific topics to the full panel; recommendations and ratings were determined by group consensus. CONCLUSIONS: Although the epidemiological features of CMV diseases are changing in the setting of potent, combination antiretroviral therapy, continued attention must be paid to CMV diseases in patients infected with the human immunodeficiency virus to prevent irreversible endorgan dysfunction. The initial and maintenance treatment of CMV retinitis must be individualized based on the characteristics of the lesions, including location and extent, specific patient factors, and characteristics of available therapies among others. Management of relapse or refractory retinitis must be likewise individualized. Ophthalmologic screening for patients at high risk for retinitis or who have a prior diagnosis of extraretinal disease is recommended. Recommendations for gastrointestinal, pulmonary, and neurologic manifestations are included.     

Varicella-zoster virus is strongly associated with atypical necrotizing herpetic retinopathies

Aqueous humor samples from nine patients with atypical necrotizing retinopathies of suspected viral origin, six with acute retinal necrosis syndrome (ARN), and 17 with active cytomegalovirus (CMV) retinitis underwent amplification for viral DNA of herpes simplex virus type 1 (HSV-1), varicella-zoster virus (VZV), and human CMV. VZV DNA was detected in seven of the nine aqueous humor samples from patients with atypical necrotizing retinopathies of suspected viral origin and in four of the six samples from individuals with ARN; of the two other samples from patients with ARNS, no viral DNA was found in one, and both CMV DNA and HSV-1 DNA, but not VZV DNA, were detected in one (this patient presented with bilateral ARNS 2 months after being successfully treated for CMV retinitis). Thus, VZV is likely to be the main pathogen of atypical necrotizing herpetic retinopathies. DNA amplification may be used to establish an early, sensitive, and reliable diagnosis of any form of necrotizing retinopathy in 80% of cases, irrespective of viral etiology.     

Serum concentrations of nitrite in patients with HIV-1 infection

AIMS: To measure circulating concentrations of nitrite in patients with HIV-1 infection. METHODS: Nitrite concentrations were measured using the Griess reaction adapted to microtitre plates in the serum of 10 asymptomatic HIV-1 positive patients, 33 patients with AIDS with cerebral disorders, 17 patients with AIDS with pulmonary involvement, and in eight patients with AIDS with other disorders. Nitrite concentrations were also measured in bronchoalveolar lavage (BAL) fluid and cerebrospinal fluid (CSF) of patients with AIDS with pulmonary involvement and cerebral disorders, respectively. RESULTS: Increased serum concentrations of nitrite were observed in patients with pulmonary involvement, and in particular in serum and in BAL samples of patients with interstitial pneumonia (36.2 (26.2) mumol/l and 0.3 (0.4) mumol/l, respectively). Increased serum concentrations of nitrite were also noted in patients with retinitis caused by infection with cytomegalovirus. Serum nitrite concentrations were also raised in patients with cerebral toxoplasmosis, whereas normal serum concentrations were found in patients with HIV-1 encephalopathy and cryptococcal meningitis. Nitrite concentrations in CSF were not raised in patients with cerebral disorders. CONCLUSIONS: These results suggest that production of nitrite in patients with AIDS with concomitant opportunistic infections may be part of the host defense against opportunistic organisms.