Serology Curriculum For Residents Using Online, Case-Based Simulation Modules

Introduction/Objective

Although serology concepts are a frequent exam topic for Pathology trainees, serology education remains challenging, in part, because serologic test performance occurs in different laboratories (immunology, microbiology, or chemistry.) Serology education topics may be eclipsed by larger concerns of the laboratory where serology resides. To evaluate the utility and advantages of online modules as adjuncts to other education modalities used during a standalone serology rotation, we developed a one-week curriculum in which residents were given four case-based vignettes to discuss with faculty, eight online case-based simulation modules, and bench time in the laboratory performing serological tests (RPR, VDRL, hepatitis, and HIV).

Methods

The online modules are housed within an e-learning portal. Residents were asked to print certificate of completion for eight assigned modules. Residents were offered an anonymous survey of the rotation between one week and up to 2 months after completing the rotation.

Results

Twenty-three first-year residents (spanning a 3-year period) completed the online modules, and 10 (43.5%) completed the survey. The average percentage of correct answers ranged from 73% for the HIV module to 88% for the hepatitis B module. The number of residents with scores below 80% was highest for EBV and Cryptococcus modules (8 and 9 scoring <80% respectively) and lowest for hepatitis B and toxoplasmosis modules (2 and 3 respectively). On the survey, residents stated they had repeated the online modules between 1 and 4 times, averaging between 1 and 2 attempts. Although there was no specific module rated as most enjoyable, the toxoplasmosis and EBV modules were picked by 3 out of 10 residents as his or her favorite. There was no consensus on which module was subjectively easiest or most difficult, nor which was least enjoyed. The majority of the residents (7/10) found the modules helpful and all ten residents stated that they “learned more” after completion of the modules because they reinforced (6/10) concepts important to serologic testing.

Conclusion

The online, case-based simulation modules are effective additions to a serology curriculum that includes case-based discussions and time in the laboratory performing tests. The online modules are effective because they provide additional structure and reinforce learning within the serology curriculum.

Comparison of Schistosoma mansoni irradiated cercariae and Sm23 DNA vaccines

Immunization with defined antigens is generally less effective at inducing host protection against experimental infection with Schistosoma mansoni than vaccination with attenuated infective cercariae. We predicted that quantitative and/or qualitative differences existed between the immune responses generated to attenuated cercariae and those induced by defined antigens. Thus, we compared immune responses typically associated with protection in the murine model between animals vaccinated with attenuated cercariae and mice immunized with DNA encoding Sm23, a schistosome integral membrane protein that has previously been shown to confer protection. Mice vaccinated three times with attenuated cercariae demonstrated higher levels of protection than Sm23-vaccinated animals but spleen cells from Sm23 DNA vaccinated mice produced significantly higher levels of schistosome antigen-specific IFN-gamma. Both vaccines induced similar levels of Sm23-specific antibody and post-challenge dermal inflammation. However, the pulmonary inflammatory responses following challenge were much less pronounced in DNA immunized animals compared to those receiving irradiated cercariae. Thus, although Sm23 DNA vaccination effectively induced parasite-specific IFN-gamma and antibody responses, it failed to evoke other critical responses needed for optimal vaccine efficacy.

Evaluation of synthetic, M type-specific peptides as antigens in a multivalent group A streptococcal vaccine

The recent development of emm gene sequence-based typing methodology has allowed group A streptococci (GAS) M serotype prevalence data to be determined. This information has been used to identify the components of a multivalent M protein peptide vaccine that could theoretically prevent most of the GAS-mediated diseases in the USA. In this study, we have evaluated in mice the immunogenicity and protective ability of multiple synthetic, M type-specific peptides, derived from the N-termini of three prevalent GAS serotypes (three peptides per serotype, total of nine peptides). At least one peptide, representing each of the three M types tested, was immunogenic. Five of the nine synthetic peptides tested, elicited an immune response in mice, and sera raised against four of the peptides, all possessed functional activity as demonstrated in a bactericidal assay. In vivo nasopharyngeal challenge experiments were carried out with peptides from the M1 (peptide M1-3) and M3 (peptide M3-2) proteins induced in vivo immune protection by reducing intranasal carriage. Reduction in colonization for M1-3 and M3-2 was 90% (P=0.02) and 66% (P<0.17), respectively. A reduction in colonization of 67% (P=0.03) was observed for M3-2 immunized mice when M43, a heterologous serotype, was used as the challenge strain. These results show the utility of synthetic, M type-specific peptides as antigens in a multivalent GAS vaccine.

Standardizing Chlamydia pneumoniae assays: recommendations from the Centers for Disease Control and Prevention (USA) and the Laboratory Centre for Disease Control (Canada)

Chlamydia pneumoniae has been associated with atherosclerosis and several other chronic diseases, but reports from different laboratories are highly variable and "gold standards" are lacking, which has led to calls for more standardized approaches to diagnostic testing. Using leading researchers in the field, we reviewed the available approaches to serological testing, culture, DNA amplification, and tissue diagnostics to make specific recommendations. With regard to serological testing, only use of microimmunofluorescence is recommended, standardized definitions for "acute infection" and "past exposure" are proposed, and the use of single immunoglobulin (Ig) G titers for determining acute infection and IgA for determining chronic infection are discouraged. Confirmation of a positive culture result requires propagation of the isolate or confirmation by use of polymerase chain reaction (PCR). Four of 18 PCR assays described in published reports met the proposed validation criteria. More consistent use of control antibodies and tissues and improvement in skill at identifying staining artifacts are necessary to avoid false-positive results of immunohistochemical staining. These standards should be applied in future investigations and periodically modified as indicated.

Mouse model for Chagas disease: immunohistochemical distribution of different stages of Trypanosoma cruzi in tissues throughout infection

Different stages of Trypanosoma cruzi are seen during mammalian infection. Histologic sections of infected hearts have shown amastigotes and, when using immunohistochemistry (IHC), parasite antigens; however, demonstration of trypomastigotes in these tissues has proven elusive. Using a mouse strain that develops chagasic cardiomyopathy (histologically similar to human infection) 70 days after injecting T. cruzi-Brazil strain, we studied the distribution of parasite stages and the extent of inflammation. All organs had varying amounts of mononuclear inflammation by day 10, which peaked between day 20 and day 30, and decreased by day 50. Amastigotes were detected in myocytes, histiocytes, acinar pancreatic cells, astrocytes and ependymal cells by day 10, and the number of amastigotes peaked on day 30. Immunohistochemistry demonstrated trypomastigotes in sinusoids, vessels and interstitial tissues of several organs between day 15 and 50. Abundant parasite antigens (granular staining) were detected in connective tissues throughout the infection. The burden of amastigotes and trypomastigotes during the acute phase seems to correlate with the degree of inflammation and granular staining in the chronic stage.

Leptospirosis mimicking acute cholecystitis among athletes participating in a triathlon

Leptospirosis, a disease acquired by exposure to contaminated water, is characterized by fever accompanied by various symptoms, including abdominal pain. An acute febrile illness occurred in athletes who participated in an Illinois triathlon in which the swimming event took place in a freshwater lake. Of 876 athletes, 120 sought medical care and 22 were hospitalized. Two of the athletes had their gallbladders removed because of abdominal pain and clinical suspicion of acute cholecystitis. We applied an immunohistochemical test for leptospirosis to these gallbladders and demonstrated bacterial antigens staining (granular and filamentous patterns) around blood vessels of the serosa and muscle layer. Rare intact bacteria were seen in 1 case. These results show that leptospirosis can mimic the clinical symptoms of acute cholecystitis. If a cholecystectomy is performed in febrile patients with suspicious environmental or animal exposure, pathologic studies for leptospirosis on formalin-fixed, paraffin-embedded tissues may be of great value.

Gastrointestinal basidiobolomycosis in Arizona: clinical and epidemiological characteristics and review of the literature

Gastrointestinal basidiobolomycosis (GIB) is an unusual fungal infection that is rarely reported in the medical literature. From April 1994 through May 1999, 7 cases of GIB occurred in Arizona, 4 from December 1998 through May 1999. We reviewed the clinical characteristics of the patients and conducted a case-control study to generate hypotheses about potential risk factors. All patients had histopathologic signs characteristic of basidiobolomycosis. Five patients were male (median age, 52 years; range, 37--59 years) and had a history of diabetes mellitus (in 3 patients), peptic ulcer disease (in 2), or pica (in 1). All patients underwent partial or complete surgical resection of the infected portions of their gastrointestinal tracts, and all received itraconazole postoperatively for a median of 10 months (range, 3--19 months). Potential risk factors included prior ranitidine use and longer residence in Arizona. GIB is a newly emerging infection that causes substantial morbidity and diagnostic confusion. Further studies are needed to better define its risk factors and treatment.

Genotypic, clinical, and demographic characteristics of children infected with Helicobacter pylori

Helicobacter pylori isolates vary between geographic regions. Certain H. pylori genotypes may be associated with disease outcome. Thirty-eight children underwent diagnostic upper endoscopy at four medical centers and were retrospectively analyzed to determine if H. pylori virulence genes were associated with endoscopic disease severity, histologic parameters, and host demographics. The H. pylori virulence genotype was analyzed by a reverse hybridization line probe assay and type-specific PCR. Endoscopic ulcers or erosions were found in 17 (45%) patients, with 13 (34%) of these patients having antral nodularity. Histological gastritis, of varying severity, was present in all children. Four patients harbored more than one H. pylori strain: one subject had both cagA(+) and cagA-negative strains, while three patients harbored either two different cagA-negative strains (two children) or two cagA(+) strains (one child). There were 28 (74%) cagA(+) isolates; 19 were associated with the vacA s1b genotype, 7 were associated with the vacA s1a genotype, 1 was associated with the vacA s1c genotype, and 1 was associated with the s2 genotype. Of 14 cagA-negative isolates, 6 were vacA s2 genotype, 4 were vacA s1b, 3 were vacA s1a, and 1 was vacA s1c. Nine of ten (90%) Hispanics had similar H. pylori strains (vacA s1b,m1), and all Asian-Canadian children were infected by strains with vacA s1c genotype. No correlation between H. pylori strain and endoscopic or histopathologic abnormalities was found. This study provides a baseline framework of North American children and their H. pylori strains, serving as a powerful epidemiological tool for prospective investigations to better understand the transmission and evolution of diverse disease outcomes.

Screening markers for chronic atrophic gastritis in Chiapas, Mexico

Intestinal-type gastric adenocarcinomas usually are preceded by chronic atrophic gastritis. Studies of gastric cancer prevention often rely on identification of this condition. In a clinical trial, we sought to determine the best serological screening method for chronic atrophic gastritis and compared our findings to the published literature. Test characteristics of potential screening tests (antibodies to Helicobacter pyloni or CagA, elevated gastrin, low pepsinogen, increased age) alone or in combination were examined among consecutive subjects enrolled in a study of H. pylori and preneoplastic gastric lesions in Chiapas, Mexico; 70% had chronic atrophic gastritis. English-language articles concerning screening for chronic atrophic gastritis were also reviewed. Sensitivity for chronic atrophic gastritis was highest for antibodies to H. pylori (92%) or CagA, or gastrin levels >25 ng/l (both 83%). Specificity, however, was low for these tests (18, 41, and 22%, respectively). Pepsinogen levels were highly specific but insensitive markers of chronic atrophic gastritis (for pepsinogen I <25 microg/l, sensitivity was 6% and specificity was 100%; for pepsinogen I:pepsinogen II ratio <2.5, sensitivity was 14% and specificity was 96%). Combinations of markers did not improve test characteristics. Screening test characteristics from the literature varied widely and did not consistently identify a good screening strategy. In this study, CagA antibodies alone had the best combination of test characteristics for chronic atrophic gastritis screening. However, no screening test was both highly sensitive and highly specific for chronic atrophic gastritis.

Gastric atrophy and extent of intestinal metaplasia in a cohort of Helicobacter pylori-infected patients

Atrophy and intestinal metaplasia (IM) are preneoplastic gastric lesions associated with Helicobacter pylori infection. Atrophy and IM are usually found together; however, the association between increasing degrees of severity of both atrophy and IM has not been evaluated completely. Two pathologists graded atrophy and IM using the visual analog scale of the Sydney classification in gastric biopsies from 368 H pylori-infected patients. Extent of IM also included determining the number of specimens affected. We then correlated the degree of atrophy with the degree and number of specimens affected with IM by calculating relative risks (RR) and 95% confidence intervals (95% CI). The mean number of biopsies examined from each patient was 6.5. Atrophy and IM were found more frequently in the antrum (85% and 75% of biopsies, respectively). One hundred thirty-eight patients had a combination of atrophy and IM, 48 had IM only, and 89 had atrophy only. Fifty-three subjects had mild atrophy and IM (RR = 1.57; 95% CI 1.2-2.1), 69 had moderate atrophy and IM (RR = 1.86; 95% CI 1.9-2.4), and 16 had marked atrophy and IM (RR = 2.47; 95% CI 1.8-3.3). The median number of biopsy specimens with IM increased from 0 in subjects with no atrophy to 3 in subjects with severe atrophy. The degree of IM correlated with the degree of atrophy; the median degree was 0.6 in subjects with no atrophy and increased to 2.32 in those with severe atrophy. Our data suggest that higher degrees of IM in an individual specimen and increasing number of specimens with IM are associated with moderate or severe degrees of atrophy.

Bioterrorism-related inhalational anthrax: the first 10 cases reported in the United States

From October 4 to November 2, 2001, the first 10 confirmed cases of inhalational anthrax caused by intentional release of Bacillus anthracis were identified in the United States. Epidemiologic investigation indicated that the outbreak, in the District of Columbia, Florida, New Jersey, and New York, resulted from intentional delivery of B. anthracis spores through mailed letters or packages. We describe the clinical presentation and course of these cases of bioterrorism-related inhalational anthrax. The median age of patients was 56 years (range 43 to 73 years), 70% were male, and except for one, all were known or believed to have processed, handled, or received letters containing B. anthracis spores. The median incubation period from the time of exposure to onset of symptoms, when known (n=6), was 4 days (range 4 to 6 days). Symptoms at initial presentation included fever or chills (n=10), sweats (n=7), fatigue or malaise (n=10), minimal or nonproductive cough (n=9), dyspnea (n=8), and nausea or vomiting (n=9). The median white blood cell count was 9.8 X 10(3)/mm(3) (range 7.5 to 13.3), often with increased neutrophils and band forms. Nine patients had elevated serum transaminase levels, and six were hypoxic. All 10 patients had abnormal chest X-rays; abnormalities included infiltrates (n=7), pleural effusion (n=8), and mediastinal widening (seven patients). Computed tomography of the chest was performed on eight patients, and mediastinal lymphadenopathy was present in seven. With multidrug antibiotic regimens and supportive care, survival of patients (60%) was markedly higher (<15%) than previously reported.

A cluster of fulminant myocarditis cases in children, Baltimore, Maryland, 1997

The true incidence of myocarditis in children is difficult to estimate because many mild cases go undetected. This study describes an unusual cluster of myocarditis cases that occurred in young children living in the greater Baltimore area between May and October 1997. A search of multiple comprehensive databases and interviews with area pediatric cardiologists were conducted to identify unreported cases and determine the background rate of myocarditis in the area. Seven cases of myocarditis were found as well as two with a similar clinical picture and myocardial fibrosis on tissue examination. Six case patients with active myocarditis and one child with fibrosis died. The case children were predominantly black (eight of nine) and male (seven of nine), with no identifiable risk factors. The disease was characterized by a fulminant course with malignant arrhythmias. The greatest number of pediatric myocarditis deaths reported in 1 year prior to 1997 was three. Myocardial tissues were examined using immunohistochemistry, in situ hybridization, and polymerase chain reaction but no etiologic agent was identified. This outbreak is unusual because of both the number of cases and the fulminant course of the disease in this group of children.

Maternal and congenital syphilis in Bolivia, 1996: prevalence and risk factors

OBJECTIVES

The present study was carried out in seven maternity hospitals to determine the prevalence of maternal syphilis at the time of delivery and the associated risk factors, to conduct a pilot project of rapid syphilis testing in hospital laboratories, to assure the quality of syphilis testing, and to determine the rate of congenital syphilis in infants born to women with syphilis at the time of delivery--all of which would provide baseline data for a national prevention programme in Bolivia.

METHODS

All women delivering either live-born or stillborn infants in the seven participating hospitals in and around La Paz, El Alto, and Cochabamba between June and November 1996 were eligible for enrolment in the study.

FINDINGS

A total of 61 out of 1428 mothers (4.3%) of live-born infants and 11 out of 43 mothers (26%) of stillborn infants were found to have syphilis at delivery. Multivariate analysis showed that women with live-born infants who had less than secondary-level education, who did not watch television during the week before delivery (this was used as an indicator of socioeconomic status), who had a previous history of syphilis, or who had more than one partner during the pregnancy were at increased risk of syphilis. While 76% of the study population had received prenatal care, only 17% had syphilis testing carried out during the pregnancy; 91% of serum samples that were reactive to rapid plasma reagin (RPR) tests were also reactive to fluorescent treponemal antibody-absorption (FTA-ABS) testing. There was 96% agreement between the results from local hospital laboratories and national reference laboratories in their testing of RPR reactivity of serum samples. Congenital syphilis infection was confirmed by laboratory tests in 15% of 66 infants born to women with positive RPR and FTA-ABS testing.

CONCLUSION

These results indicate that a congenital syphilis prevention programme in Bolivia could substantially reduce adverse infant outcomes due to this disease.

Pathologic studies of fatal cases in outbreak of hand, foot, and mouth disease, Taiwan

In 1998, an outbreak of enterovirus 71-associated hand, foot, and mouth disease occurred in Taiwan. Pathologic studies of two fatal cases with similar clinical features revealed two different causative agents, emphasizing the need for postmortem examinations and modern pathologic techniques in an outbreak investigation.

Influenza A virus infection complicated by fatal myocarditis

Influenza virus typically causes a febrile respiratory illness, but it can present with a variety of other clinical manifestations. We report a fatal case of myocarditis associated with influenza A infection. A previously healthy 11-year-old girl had malaise and fever for approximately 1 week before a sudden, witnessed fatal collapse at home. Autopsy revealed a pericardial effusion, a mixed lymphocytic and neutrophilic myocarditis, a mild lymphocytic interstitial pneumonia, focal bronchial/bronchiolar mucosal necrosis, and histologic changes consistent with asthma. Infection with influenza A (H3N2) was confirmed by virus isolation from a postmortem nasopharyngeal swab. Attempts to isolate virus from heart and lung tissue were unsuccessful. Immunohistochemical tests directed against influenza A antigens and in situ hybridization for influenza A genetic material demonstrated positive staining in bronchial epithelial cells, whereas heart sections were negative. Sudden death is a rare complication of influenza and may be caused by myocarditis. Forensic pathologists should be aware that postmortem nasopharyngeal swabs for viral culture and immunohistochemical or in situ hybridization procedures on lung tissue might be necessary to achieve a diagnosis. Because neither culturable virus nor influenza viral antigen could be identified in heart tissue, the pathogenesis of influenza myocarditis in this case is unlikely to be the result of direct infection of myocardium by the virus. The risk factors for developing myocarditis during an influenza infection are unknown.

[The association between Helicobacter pylori and gastric neoplasia. Epidemiologic evidence]

Helicobacter pylori (HP) causes chronic gastritis and, together with non-steroidal anti-inflammatory drugs, is considered the most frequent etiologic agent of peptic ulcer. Since there are numerous epidemiologic and pathogenesis studies that demonstrate an association between infection by HP and gastric neoplasias, the World Health Organization declared, in 1994, HP infection a Group 1 carcinogen (a definitive cause of human neoplasias, similar to tobacco). This article reviews the epidemiological evidence supporting the association between HP infection and two gastric neoplasias: adenocarcinoma and B cell lymphoma associated to mucosas (MALT). This article also presents preliminary results of a project performed in the mountainous region of Chiapas, Mexico, in which the decrease of precancerous gastric lesions were studied one year after treatment for HP infection.

Helicobacter pylori gastritis in children and adults: comparative histopathologic study

The inflammatory response to Helicobacter pylori in adults has been well characterized. In children, studies of H. pylori gastritis have been based on small numbers of patients and have used loose definitions of the inflammatory components. Comparative study of the inflammatory response to H. pylori in children and adults can help our understanding of the natural history of this infection. Using the Updated Sydney Classification, we performed a retrospective, blinded pathology review of gastric biopsy specimens from 42 children and 40 adults with H. pylori infection, and we quantified each inflammatory cell separately (neutrophils, lymphocytes, plasma cells, and eosinophils). Differences in inflammatory cell components of children and adults were assessed by logistic regression analysis. More children had marked amounts of H. pylori (P = .05) and mild degree of neutrophils (P = .02), plasma cells (P = .005), and eosinophils (P = .0001) compared with adults. No differences existed when quantifying mononuclear cells or atrophy. Ulcers and intestinal metaplasia were present only in adults. We found that the numbers of inflammatory cells present in H. pylori-infected biopsy specimens is different in children and adults. We hypothesize that these differences demonstrate how H. pylori infection evolves from an acute childhood infection to an adult chronic disease.

A comprehensive review of the natural history of Helicobacter pylori infection in children

Across populations of children, Helicobacter pylori prevalence ranges from under 10% to over 80%. Low prevalence occurs in the U.S., Canada, and northern and western Europe; high prevalence occurs in India, Africa, Latin America, and eastern Europe. Risk factors include socioeconomic status, household crowding, ethnicity, migration from high prevalence regions, and infection status of family members. H. pylori infection is not associated with specific symptoms in children; however, it is consistently associated with antral gastritis, although its clinical significance is unclear. Duodenal ulcers associated with H. pylori are seldom seen in children under 10 years of age. H. pylori-infected children demonstrate a chronic, macrophagic, and monocytic inflammatory cell infiltrate and a lack of neutrophils, as compared with the response observed in adults. The effect of H. pylori infection on acid secretion in children remains poorly defined. The events that occur during H. pylori colonization in children should be studied more thoroughly and should include urease activity, motility, chemotaxis, adherence, and downregulation of the host response. The importance of virulence determinants described as relevant for disease during H. pylori infection has not been extensively studied in children. Highly sensitive and specific methods for the detection of H. pylori in children are needed, especially in younger pediatric populations in which colonization is in its early phases. Criteria for the use of eradication treatment in H. pylori-infected children need to be established. Multicenter pediatric studies should focus on the identification of risk factors, which can be used as prognostic indicators for the development of gastroduodenal disease later in life.

Immunohistochemical and in situ hybridization studies of influenza A virus infection in human lungs

Influenza viruses are responsible for acute febrile respiratory disease. When deaths occur, definitive diagnosis requires viral isolation because no characteristic viral inclusions are seen. We examined the distribution of influenza A virus in tissues from 8 patients with fatal infection using 2 immunohistochemical assays (monoclonal antibodies to nucleoprotein [NP] and hemagglutinin [HA]) and 2 in situ hybridization (ISH) assays (digoxigenin-labeled probes that hybridized to HA and NP genes). Five patients had prominent bronchitis; by immunohistochemical assay, influenza A staining was present focally in the epithelium of larger bronchi (intact and detached necrotic cells) and in rare interstitial cells. The anti-NP antibody stained primarily cell nuclei, and the anti-HA antibody stained mainly the cytoplasm. In 4 of these cases, nucleic acids (ISH) were identified in the same areas. Three patients had lymphohistiocytic alveolitis and showed no immunohistochemical or ISH staining. Both techniques were useful for detection of influenza virus antigens and nucleic acids in formalin-fixed paraffin-embedded tissues and can enable further understanding of fatal influenza A virus infections in humans.

An outbreak of plague including cases with probable pneumonic infection, Ecuador, 1998

During February and March of 1998, 12 sudden deaths were reported among residents of a high-Andean community in Ecuador. All 12 fatalities were members of the same extended family and some had apparent exposure to sick guinea-pigs. Following an initial investigation by public health officials, an additional death was reported in a nearby community in April, also associated with exposure to sick guinea-pigs. Blood samples from humans, dogs, and a rodent were tested for antibody to the F1 antigen of Yersinia pestis by passive haemagglutination assay. Tissue from rodents was subjected to direct fluorescent antibody staining using fluorescein-labelled monoclonal antibody to Y. pestis F1 antigen. Formalin-fixed specimens from the 2 autopsies were evaluated using a 2-step alkaline phosphatase immunoassay with a monoclonal antibody to Y. pestis F1 antigen, and tissues that had not been embedded in paraffin were tested for the presence of DNA encoding the F1 structural antigen by polymerase chain reaction. Serological evaluation of close contacts of the fatalities revealed positive titres to F1 antigen of Y. pestis, the aetiological agent of plague, in 3 contacts from the first community and 1 from the second. Immunohistochemical staining of tissues collected from 2 of the fatalities provided evidence that both had pneumonic plague. Five of 14 dogs found in the communities were seropositive for plague antibody, providing evidence of a recent epizootic plague in the area.

Comparison of polyvinyl alcohol fixative with three less hazardous fixatives for detection and identification of intestinal parasites

Polyvinyl alcohol (PVA) containing the fixative mercuric chloride is considered the "gold standard" for the fixation of ova and parasites in the preparation of permanently stained smears of stool specimens. However, mercuric chloride is potentially hazardous to laboratory personnel and presents disposal problems. We compared three new alternative, nontoxic fixatives with PVA, analyzing ease of sample preparation and quality of smears. Sixty-eight fresh stool specimens were divided into aliquots and placed in each of four different fixatives: PARASAFE (PS) (Scientific Devices Laboratory, Inc., Des Plaines, Ill.), ECOFIX (EC) (Meridian Diagnostics, Inc., Cincinnati, Ohio), Proto-Fix (PF) (Alpha-Tec Systems, Inc., Vancouver, Wash.), and low-viscosity PVA fixative (PVA) (Meridian). Specimens were processed and stained according to each manufacturer's directions. Parasites were found in 31 of 68 slide preparations with PVA, 31 with PF, 30 with EC, and 30 with PS. Blastocystis hominis and Iodamoeba bütschlii were preserved in a readily identifiable state by all methods of fixation. However, some parasites were more easily identified with some of the fixatives because of differences in parasite distortion. For example, Entamoeba histolytica (Entamoeba dispar) was detected in 13 stools fixed with PF, 7 with PVA, and 6 with EC but none with PS. Likewise, Chilomastix mesnili was identified in 13 specimens fixed with PF, 8 with EC, and 5 with PVA but only 1 with PS, while Entamoeba coli was seen much less frequently with PS than with the other three fixatives. A dirty background was observed in 41% of specimens prepared with PS, whereas background quality was acceptable with other fixatives. Sample preparation was most rapid with PS, although the EC method involved the fewest steps. In conclusion, PVA and PF produced the least parasite distortion, while PS proved unsatisfactory for the identification of E. histolytica, E. coli, and C. mesnili. Both PF and EC appear to be acceptable, environmentally safe substitutes for PVA.

The role of pathology in an investigation of an outbreak of West Nile encephalitis in New York, 1999

An outbreak of encephalitis occurred in New York City in late August 1999, the first caused by West Nile virus in North America. Histopathologic and immunopathologic examinations performed on human autopsy materials helped guide subsequent laboratory and epidemiologic investigations that led to identification of the etiologic agent.

Testing umbilical cords for funisitis due to Treponema pallidum infection, Bolivia

To establish the frequency of necrotizing funisitis in congenital syphilis, we conducted a prospective descriptive study of maternal syphilis in Bolivia by testing 1,559 women at delivery with rapid plasma reagin (RPR). We examined umbilical cords of 66 infants whose mothers had positive RPR and fluorescent treponemal antibody absorption tests. Histologic abnormalities were detected in 28 (42%) umbilical cords (seven [11%] had necrotizing funisitis with spirochetes; three [4%] had marked funisitis without necrosis; and 18 [27%] had mild funisitis), and 38 [58%] were normal. Of 22 umbilical cords of infants from mothers without syphilis (controls), only two (9%) showed mild funisitis; the others were normal. Testing umbilical cords by using immunohistochemistry is a research tool that can establish the frequency of funisitis due to Treponema pallidum infection.

Interobserver variability in application of the revised Sydney classification for gastritis

The Sydney classification for gastritis provides guidelines for histological grading of gastric biopsies. In an ongoing study of gastric preneoplastic lesions in Chiapas, Mexico, 7 biopsies from 150 patients (4 from the antrum and 3 from the body) were obtained during endoscopy and studied histologically. The first 74 endoscopy specimens were read independently by 2 general surgical pathologists. We assessed diagnostic concordance using kappa statistics. The 2 pathologists then jointly reviewed biopsies about which they had disagreed to reach a final diagnosis. A second group of 76 endoscopies was subsequently evaluated independently by the 2 pathologists, and concordance was again assessed. In the first group of biopsies, we found low concordance rates (Heliobacter pylori 0.59, acute inflammation 0.22, intestinal metaplasia 0.60, and atrophy 0.04). In the second group, of independently reviewed cases, there was better concordance (H pylori 0.77, acute inflammation 0.50, intestinal metaplasia 0.70, and atrophy 0.64). We presumed that use of the Sydney classification would result in minimal interpretational differences achieving ideal kappas greater than 0.80. Because pathology results are based on subjective interpretation of this classification, complete diagnostic agreement is practically impossible. Concordance by general surgical pathologists after joint review of cases was similar to that obtained by gastrointestinal pathologists.

Congenital syphilis in a newborn: an immunopathologic study

A 3-week-old girl presented to the emergency room with respiratory distress and generalized maculopapular rash. The newborn was hospitalized with a presumptive diagnosis of congenital syphilis, but she died after 2 days of therapy. Tissue from the gastrointestinal tract, brain, liver, spleen, and lung was studied by using direct fluorescent antibody and immunohistochemical analysis (IHC) for Treponema pallidum. The inflammatory infiltrate was characterized by using IHC against CD3, CD20, CD68, and smooth muscle actin. The diagnosis of congenital syphilis was confirmed by demonstrating spirochetes in tissues with IHC and direct fluorescent antibody examination. IHC showed abundant treponemes in the small intestine and liver and occasional spirochetes in the meninges. Bacteria were seen as intact spirochetes, granular staining, or large extracellular collections of antigen. A constant pathologic feature throughout the tissues was concentric macrophage (CD68-positive) infiltrate around vessels, giving an onion-skin appearance. IHC identified the macrophages as the prime immune response in congenital syphilis.

Cytokine mRNA levels in the hearts of inbred mice that develop different degrees of cardiomyopathy during infection with Trypanosoma cruzi

Profiles of cytokine mRNA expression were examined by semiquantitative RT-PCR in the hearts of DBA/2 (pathopermissive) and B10.D2 (pathoresistant) mice during infection with the Brazil strain of Trypanosoma cruzi. The levels and time-course profiles of IFNgamma, IL-1beta and IL-10 mRNA expression were similar in each strain. TNFalpha, iNOs, and IL-13 mRNA expression peaked at comparable levels and times after infection in each strain, but declined more rapidly in B10.D2 than in DBA/2 mice. Peak IL-2 mRNA levels were also similar between the two strains, but occurred earlier in DBA/2 than in B10.D2 mice. Levels of IL-4, IL-6 and IL-12 mRNA were significantly higher in DBA/2 than in B10.D2 mice from day 10 through day 50 of infection. With the exception of IL-1beta, which was expressed constitutively in both strains, the levels of mRNA of all other cytokines examined reached their peak no later than day 20 and declined significantly by day 50 after infection. The inflammatory infiltrate paralleled the latter cytokines; starting at day 10 in DBA/2 mice and at day 15 in the B10.D2 s, peaking between days 20 and 30 in both strains, decreasing to minimal levels by day 50 in the pathoresistant mice, but maintaining a mild amount through day 70 in the pathopermissive strain. The inflammation was composed mostly of lymphocytes and histiocytes throughout the entire process. These data demonstrate differences in the profiles of cytokine mRNA that may be related to the differential degree of cardiac pathology that develops in these two strains of mice upon infection with T. cruzi.

[Zidovudine plus didanosine in HIV infected asymptomatic patients previously treated with zidovudine]

OBJECTIVE

To evaluate if the combination of AZT/ddl offered any advantages in surrogate markers among HIV infected asymptomatic patients previously treated with AZT for at least six months.

METHODS

We used a prospective cohort of 269 asymptomatic HIV patients with CD4+ cell counts between 200 and 500 cells/microL. They were given didanosine (ddl 400 mg/d) in addition to AZT (500 mg/d) and had received AZT monotherapy for an average of 20 months. End points were progression to AIDS, death, or toxicity.

RESULTS

Median CD4+ cell count at the start of the combination therapy was 339 cells/microL which increased at three months to 451 and subsequently declined at 6, 12 and 18 months of followup (medians of 392, 360, 307 cells/microL respectively). Five patients progressed to AIDS, six developed toxicity (myelosuppression, hepatitis or pancreatitis) and 26 had minor side effects that required only dose reduction.

CONCLUSIONS

The addition of ddl to patients with prolonged ZDV monotherapy can be useful. CD4+ T cell counts showed a significant increase at 3 months with a gradual subsequent decline to below baseline at 18 months. Adverse effect of the drugs, although frequent, did not stop therapy in most patients.

Ca 15.3 in breast cancer: comparison of two assays and validation in a Mexican population

Ca 15.3 is a tumor marker used for breast carcinoma, since one epitope is an antigen present in milk fat globules. Serum from 171 patients with breast cancer upon initial presentation was studied for Ca 15.3. In the first 72 cases, the authors compared RIA vs. ELISA using a simple linear regression. On the following 99, only ELISA was performed. With all 171 patients, a clinical association between Ca 15.3 measurement and age, stage and hormone receptors was carried out. Correlation coefficient between RIA and ELISA was 0.85. Of 104 patients below 50 years of age, 88 had normal Ca 15.3 and 16, elevated; 67 were older than 50 years, 46 had normal Ca 15.3 and 21, elevated (p=0.022). Ca 15.3 was elevated in 11% of patients with clinical stages I/II, and 89% in stages III/IV (p=0.0001). The association of Ca 15.3 with hormone receptors was not significant. In conclusion, ELISA and RIA measure Ca 15.3 with comparable results, the first method has the advantage of not using radioactivity. The authors found higher probability of elevated Ca 15.3 in older patients and in those with advanced disease.

CD4+ T-lymphocyte variations in patients with advanced human immunodeficiency virus infection and counts below 100 cells per microliter

Variability in CD4+ T-lymphocyte measurements has been described for both normal and human immunodeficiency virus (HIV)-infected persons. Clinical protocols use CD4+ cell counts as surrogate markers for disease progression or response. In this study, we determined the variability of CD4+ T-lymphocytes below 100 cells/microl when measured less than 7 days apart. Two consecutive lymphocyte subset measurements were performed in 55 patients using CD3/CD4 antibodies in a flow cytometer (Epics Profile II). Specimens were collected between 8:00 and 10:00 am within the same week. Data from the first and second measurements were compared. The average total lymphocyte count on the first measurement was 1,064 (360-2,853), and on the second 1,162 (320-2,223; P = 0.07); the percentage CD4 was 1.76 (0-8) on the first, and on the second 1.98 (0-9; P = 0.3); the absolute CD4 cell count on the first measurement was 16.6 (0-57) and on the second 22.8 (0-93; P = 0.01). Statistically significant differences were found between the first and second absolute CD4 T-lymphocytes but not in the CD4 percentage. These differences probably are due to variations in total lymphocyte count. For research protocols, repeating CD4+ cell determinations within a short period is advisable, to ensure a homogeneous population. On the other hand, for day-to-day patient follow-up, a combination of clinical criteria and both percentage and absolute CD4+ cell counts should be used to make treatment decisions, because repeating CD4 cell measurements can be very costly.

Frequency of intestinal parasites in adult cancer patients in Mexico

Approximately 28% of the Mexican population has intestinal parasites. Oncologic patients receiving chemotherapy should have a coproparasitoscopic study to avoid disseminated parasitic infections. The frequency of intestinal parasites, including Cryptosporidium and Isospora, was evaluated in 100 diarrheic (DS) and 100 formed stools (FS) from adult patients recently diagnosed with cancer, using wet mounts stained with Kinyoun, saccharose and ZnSO4 procedures stained with Lugol's iodine. Seven patients with DS and three with FS had more than one parasite. Pathogenic intestinal parasites were seen in 26% of DS and 15% of FS. Of the frequent parasites, Entamoeba histolytica was found in 12 DS and in 2 FS (p = 0.01), Giardia lamblia in three DS and six FS and Hymenolepis nana in eight DS and 10 FS. Other pathogenic parasites were found only in DS: Cryptosporidium sp. in five patients, Ascaris lumbricoides in two, Strongyloides stercoralis in two and Isospora sp. in one. Cryptosporidium and Isospora were only identified by wet mounts stained with Kinyoun while other parasites were identified by flotation procedures. Since six (3%) of our patients had coccidia, the laboratory must perform special techniques for their detection. In epidemiologic settings where there is a high prevalence of intestinal parasitic infections the coproparasitoscopic studies should be performed and antiparasitic treatment provided before starting chemotherapy.

Chronic myelocytic leukemia in accelerated phase with i(17) (q10) and loss of p53 gene. Case report

Chronic myelogenous leukemia (CML) is a clonal disorder that presents with a stable period followed by an accelerated phase. The most frequent chromosomal abnormality described is t(9;22). Alterations of chromosome 17, where p53 is located, have been described during transformation. We studied a 23-year-old male who presented with chronic myelogenous leukemia. The karyotype demonstrated 46,XY,t(9;22) (q34;q11) in 12% of mitoses and hyperdiploidy in 43%. Forty-six months later the patient suffered a blast crisis characterized by absolute basophilia; the cytogenetic study demonstrated 48,XY,+8,t(9;22) (q34;q11), +der(22)t (9;22) (q34;q11), +i(17)(q10) in 18% of the mitoses, 46,XY, t(9;22) (q34;q11) in 34% and hyperdiploidy in 23%. Since there was i(17)(q10) during this stage, a retrospective DNA study of the biopsy material before and after the transformation was performed. In the chronic phase, p53 was present in normal amounts, during transformation there was loss of genetic material from the p53 region. The protein product of suppressor gene p53 normally works holding the proliferation of cells. When there is the formation of an isochromosome, genetic material is lost; thus, in this patient, p53 was deleted upon the observation of i(17). Lastly, this case shows how DNA can be extracted from slides; this technique is novel and can be used for retrospective studies when paraffin blocks or fresh tissue are not available.

Chemotherapy-associated oral mucosal lesions in patients with leukaemia or lymphoma

In order to determine the incidence rate of oral lesions associated with chemotherapy, as well as well as its association with clinical and laboratory parameters and potential risk factors, 50 in-patients with non-Hodgkin's lymphoma or leukaemia under chemotherapy were followed from January 1993 to May 1994. Basal and weekly oral examinations were performed. Clinical and laboratory data were registered. Wilcoxon's rank sum test, chi square test, univariate and multivariate logistic regression analyses were used, 36 individuals with leukaemia and 14 with non-Hodgkin's lymphoma were followed for 158 weeks; mean age was 33 years (range 15-85). Oral lesion incidence rate was 45/100 patients-week. Exfoliative cheilitis and infections (herpes and candidosis) were the most common oral complications, followed by haemorrhagic lesions and mucositis. Haemorrhagic lesions correlated with thrombocytopenia (RR = 30.5). Etoposide administration (RR = 8.6), alkylating agents (RR = 15.6), a prior course of chemotherapy (RR = 23.2) and neutropenia (RR = 4.16) were predictors of mucositis. Oral lesions were a common complication in this study, and a possible association of mucositis with several factors is suggested.

[Simplified CD4+ T-lymphocyte count in patients with HIV/AIDS in Mexico]

OBJECTIVE

To study the correlation between ALC and CD4 cell counts and to find alternative ways of counting CD4+ T-lymphocytes.

MATERIAL AND METHODS

The double positivity for CD3/CD4 antibodies was measured in 175 consecutive HIV-positive patients using flow cytometry; in these cases a difference was made between counting cells that were positive for both antibodies vs those that were positive only to CD4. ALC and CD4 counts were also compared among 500 subjects infected with HIV, using linear regression analysis and comparing the number of dissimilar cases for counts below 200 cells/microliters and ALC counts lower than 1 500 and 2000 cells/microliters.

RESULTS

In the 175 cases measured by the CD3/CD4 antibody combination the mean percent was 13.8% and for total CD4 cells 14.2% (p = NS); the mean difference was 0.4% and the median 0.2%. For the 500 patients the mean ALC was 1 700 cells/microliters and the mean CD4 count was 219 cells/microliters; the correlation coefficient was 0.59.

CONCLUSIONS

These data suggest a poor correlation of ALC and CD4 cell counts, thus it is impossible to predict CD4 on the basis of ALC. This is the reason why it is necessary to measure CD4 cells separately. The difference between measuring double positive CD3/CD4 cells vs only CD4 positive cells was not significant. Our data suggest that the use of a single CD4 antibody may cut costs and still produce clinically useful information.

[Algorithm management for detection of monoclonal gammopathies in serum. Experience of the Instituto Nacional de Cancerología in México]

BACKGROUND

Most patients with multiple myeloma have an abnormal band in the gamma region of protein electrophoresis.

AIM

To correlate the clinical diagnosis with patterns of protein electrophoresis.

METHODS

Retrospective analysis of all protein electrophoresis or immunoglobulin quantification requested during 1992 and review of clinical charts of patients.

RESULTS

During 1992, 553 protein electrophoresis were requested. Of these, 344 were repetitions and 209 came from patients seen for the first time. Among the latter, we found a monoclonal component in 40. Of these 40 patients, 35 had a multiple myeloma, one had a plasmocytoma and four a non-Hodgkin lymphoma. Fourteen patients with diagnosis of myeloma did not have a monoclonal component in protein electrophoresis. These figures resulted in a 71% sensitivity and 97% specificity for monoclonal components in the diagnosis of multiple myeloma. The monoclonal component of patients with myeloma was characterized as IgG in 29 (60%), IgA in 5 (10%) and IgM in one.

CONCLUSIONS

A monoclonal component present in a protein electrophoresis has a high diagnostic accuracy for multiple myeloma.

[Productivity before and after installing a computerized system in a clinical laboratory]

A laboratory information system was installed on January 1991 in the clinical laboratory of the Instituto Nacional de Cancerologia. Our main objective was to speed up the administrative work and integrate its operations under one management. We evaluated the productivity before (1990) and after installing the system (1992), using the parameters proposed by the College of American Pathologists. In 1990 there were 30,764 patients who underwent 191,070 laboratory studies, resulting in 131 tests/clerk/day and 21 patients/clerk/day. In 1992 these figures were 43,679 patients, 245,280 tests, 168 tests/clerk/day and 30 patients/clerk/day. The productivity indexes showed a 41% increase in the number of patients and of 28% in the number of tests. In addition, the laboratory personnel started activities in teaching and research which had been non existent before, i.e. in 1992 they started three research projects and participated in three national or international scientific meetings. In summary, no additional personnel was required even though there was an increase in the workload, basically due to a more efficient organization of the work when using a computerized system.

Mammary Paget's disease and associated carcinoma. An immunohistochemical study

Mammary Paget's disease has been said to result from epidermal spread by contiguity of primary intraductal carcinoma. To assess similar identity, we immunostained Paget's cells and underlying intraductal and/or invasive mammary carcinoma in 20 cases for cytokeratins, epithelial membrane antigen, gross cystic disease fluid protein-15, lysozyme, carcinoembryonic antigen, S100 protein, kappa-casein, and alpha-lactalbumin. Steroid receptor immunostain was positive in only one (5%) of the cases of Paget's disease and in two and four (approximately 15%) (for estrogen and progesterone receptor, respectively) of the cases of ductal carcinoma. In 18 patients (90%), the immunohistochemical profile was identical in Paget's cells and associated carcinoma for seven or more antigens. In one patient, there was a definite disparity in the antigenic profile; in another patient, this was dissimilar because of very focal staining in one site. The antigenic similarity between Paget's cells and underlying carcinoma in 18 (90%) of the cases of mammary Paget's disease suggested in favor of their common origin, ie, probably intraepidermal spread of ductal carcinoma. Origin from apocrine/eccrine structures, or multipotent cells in the epidermis, was suggested in a minority.

The association of Helicobacter pylori with gastric cancer and preneoplastic gastric lesions in Chiapas, Mexico

BACKGROUND

Helicobacter pylori recently was identified as a risk factor for gastric cancer. Its association with preneoplastic conditions of the stomach, however, is undocumented.

METHODS

Gastric biopsy specimens from 245 symptomatic patients were examined for neoplastic and preneoplastic lesions and for gastric H. pylori infection. The sera of 183 subjects were tested by enzyme-linked immunosorbent assay (ELISA) for anti-H. pylori immunoglobulin G.

RESULTS

Histologic H. pylori infection, usually accompanied by acute and chronic gastritis, was found in 85.7% of patients. There was a strong association between H. pylori in the tissue and atrophy (relative risk, 15.0; 95% confidence interval, 4.2-56.6), intestinal metaplasia (relative risk, 5.7; 95% confidence interval, 1.9-16.8), and dysplasia or cancer (relative risk, 4.0; 95% confidence interval, 1.1-14.8). The ELISA was 93.2% sensitive and 57.1% specific for histologic infection with a positive predictive value of 96.1%. The overall seroprevalence rate was 86.1%, with no significant difference in rates between patients with cancer precursors and those with normal stomachs.

CONCLUSIONS

In this high-risk population, precursor lesions for adenocarcinoma were associated universally with H. pylori infection.

The association of Helicobacter pylori with gastric cancer and preneoplastic gastric lesions in Chiapas, Mexico

BACKGROUND

Helicobacter pylori recently was identified as a risk factor for gastric cancer. Its association with preneoplastic conditions of the stomach, however, is undocumented.

METHODS

Gastric biopsy specimens from 245 symptomatic patients were examined for neoplastic and preneoplastic lesions and for gastric H. pylori infection. The sera of 183 subjects were tested by enzyme-linked immunosorbent assay (ELISA) for anti-H. pylori immunoglobulin G.

RESULTS

Histologic H. pylori infection, usually accompanied by acute and chronic gastritis, was found in 85.7% of patients. There was a strong association between H. pylori in the tissue and atrophy (relative risk, 15.0; 95% confidence interval, 4.2-56.6), intestinal metaplasia (relative risk, 5.7; 95% confidence interval, 1.9-16.8), and dysplasia or cancer (relative risk, 4.0; 95% confidence interval, 1.1-14.8). The ELISA was 93.2% sensitive and 57.1% specific for histologic infection with a positive predictive value of 96.1%. The overall seroprevalence rate was 86.1%, with no significant difference in rates between patients with cancer precursors and those with normal stomachs.

CONCLUSIONS

In this high-risk population, precursor lesions for adenocarcinoma were associated universally with H. pylori infection.

Non-Hodgkin's lymphomas in patients with human immunodeficiency virus infection. Presence of Epstein-Barr virus by in situ hybridization, clinical presentation, and follow-up

The authors studied all patients with serologic evidence of human immunodeficiency virus (HIV) infection and malignant non-Hodgkin's lymphoma (NHL) that presented at a single hospital from 1982 to 1989. Sixteen patients were identified, all white homosexual men with a mean age of 38.2 years. Lymphoma was the initial presentation of HIV infection in 37.5%. Sixty-two percent of the cases had a high-grade NHL, 31% had intermediate-grade, and 6% (one patient) had a low-grade lymphoplasmacytoid lymphoma. Extranodal involvement was present in 43.7%, with the gastrointestinal tract and liver being the most common sites. Actuarial survival was increased by treatment with methotrexate, doxorubicin, cyclophosphamide, vincristine, prednisone, and bleomycin (MACOP-B). Colorimetric in situ hybridization identified Epstein-Barr virus (EBV) in nine of the 14 cases hybridized. A statistically significant association of EBV with diffuse small noncleaved type (i.e., Burkitt's-like) (six of six) compared with other morphologic types (three of eight) was found (P = 0.025).

Association of Epstein-Barr virus in epithelioid angiomatosis of AIDS patients

Epithelioid angiomatosis, hemangioma-like vascular proliferations recently described in AIDS patients, has been associated with the cat scratch disease bacillus. Other vascular lesions present in AIDS patients, in particular Kaposi's sarcoma, have been associated with cytomegalovirus (CMV). We investigated the possibility of viral association with epithelioid angiomatosis by analyzing two such lesions, as well as unrelated concurrent skin lesions, for the presence of viral genetic information. Colorimetric in-situ hybridization was performed on formalin-fixed, paraffin-embedded sections using cloned biotinylated probes for CMV, herpes simplex virus, human immunodeficiency virus, and Epstein-Barr virus (EBV). The only virus demonstrated was EBV, and this was only in the two epithelioid angiomatosis lesions. Hybridization signal for EBV was present in the nuclei of endothelial cells and occasional histiocytes. Bacilli were demonstrated within one of the lesions by silver stain. This is the first report associating EBV with this entity, and the first-time demonstration of EBV genetic information in endothelial cells. Our data suggest that these vascular lesions may represent a nonspecific response to infection by many different agents, and that EBV may be involved in the pathogenesis of some of these lesions.

Composite Hodgkin's and non-Hodgkin's lymphoma in a patient with acquired immune deficiency syndrome. In-situ demonstration of Epstein-Barr virus

A 44-year-old man infected with human immunodeficiency virus had Hodgkin's disease, mixed cellularity, and malignant non-Hodgkin's lymphoma, diffuse large cell type. Colorimetric in-situ hybridization showed the Epstein-Barr virus (EBV) genome in the cells of the large cell non-Hodgkin's lymphoma and in the Reed-Sternberg cells and reactive lymphocytes of the Hodgkin's lymphoma. These results suggest that EBV may play a similar causative role in both neoplasms. This colorimetric method of hybridization, yielding results within 8 hours, is applicable to archival material and will be useful in further epidemiologic work associating EBV and lymphoid proliferations and malignancies.