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.