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Biomedical subjects

J H Joncas

Publications and source records attributed to J H Joncas.

At least 37 records · Page 2Linked to original sources
PubMed1984

A familial syndrome of susceptibility to chronic active Epstein-Barr virus infection.

In two members of a family (daughter and father) active Epstein-Barr virus (EBV) infections persisted over periods of 4 and 3 years respectively (possibly 10 years in the father). Both had persistent splenomegaly and occasional bouts of unexplained fever but lived otherwise normal lives. The other members of the family (mother and son) were healthy. The titres of antibody to the EBV viral capsid antigen (VCA) and early antigen (EA) were extremely high in the daughter's blood, whereas the titres of antibody to the Epstein-Barr nuclear antigen were low in the daughter's blood and undetectable in the father's. Target cells of the EBV infection that were obtained from the daughter's blood were established in culture with great difficulty and showed increased expression of VCA and EA. Other immunologic investigations in the two patients revealed that the ratio of helper to suppressor T lymphocytes was inverted, natural killer-cell activity was abnormally low, lymphocyte responses to certain mitogens were depressed and there was a serum factor blocking mitogen-induced transformation. The possibility that the patients' unusual susceptibility to EBV infection represented an inherited syndrome (perhaps X-linked) is discussed.

Antibodies, Viral↗
PubMed1984

A comparison of ampicillin-cefotaxime and ampicillin-chloramphenicol in childhood bacterial meningitis: an experience in 55 patients.

Ampicillin-cefotaxime was tested as initial therapy of presumptive bacterial meningitis in 55 children greater than or equal to 2 months of age at our hospital. During the first year of this ongoing trial, 11 patients, 10 whose CSF yielded ampicillin-resistant Haemophilus influenzae type b (MIC greater than 16 mg/l, beta-lactamase +) and one, indole-negative proteus (MIC 4 mg/l), were begun on ampicillin-cefotaxime and then continued on cefotaxime alone. All did well clinically except one who convulsed briefly but recovered without sequelae. The cefotaxime MICs/MBCs of the beta-lactamase-positive H. influenzae isolates (less than or equal to 0.007 to 0.03/less than or equal to 0.007 to 0.12) and the proteus isolate (0.03/0.12) were significantly lower than chloramphenicol MICs/MBCs (0.25 to 1.0/0.5 to 1.0 and 8/greater than 16). We followed 44 other children with meningitis due to ampicillin-sensitive organisms who were treated with ampicillin or penicillin after 1 or 2 days of ampicillin-cefotaxime. Aetiological agents included ampicillin-sensitive H. influenzae (25), pneumococci (9), meningococci (8), Strept. MG (1) and Listeria monocytogenes (1). 40/44 recovered uneventfully. There were 4 neurological complications: the streptococcal meningitis sustained a brain abscess and the three others were motor incoordination (sensitive haemophilus), hearing loss and subdural effusion (2 pneumococci). There were no deaths. 18/48 children managed initially with ampicillin-chloramphenicol during the same 12-month period one year earlier had significant neurological complications and/or sequelae and there was one death; aetiological agents included sensitive H. influenzae (30), pneumococci (9), ampicillin-resistant haemophilus (5), meningococci (3) and pneumococci plus strept. MG (1). The two groups were comparable except for the number of resistant haemophilus and meningococcal strains and underlying disease more frequent in the ampicillin-cefotaxime group. A significant reduction of neurological morbidity (5/55 or 9.1% vs. 18/48 or 37.5%:P less than 0.001) was therefore associated with the ampicillin-cefotaxime schedule in the initial treatment of proven bacterial meningitis. A prolonged hospitalization (greater than 15 days) was less frequent (P less than 0.01) in the ampicillin-cefotaxime group (3/55 or 5.5% vs. 13/48 or 27.1%). The results of the trial to date are considered to be very promising.

Adolescent↗
PubMed1984

Giant cell pneumonia due to respiratory syncytial virus. Occurrence in severe combined immunodeficiency syndrome.

A 6-month-old male infant with a severe combined immunodeficiency syndrome was hospitalized for progressive respiratory distress. Examination during hospitalization disclosed widespread pulmonary infiltrates that did not respond to intensive therapy. The patient died eight days after admission. Autopsy disclosed Pneumocystis carinii pneumonia and widespread giant cell pneumonia. Respiratory syncytial virus (RSV) was grown from a lung specimen obtained at autopsy. Specific immunofluorescent staining of the cytoplasm of alveolar lining cells with RSV antiserum was demonstrated. The electron microscopic appearance of giant cells was compatible with RSV infection. The RSV should be added to the list of viruses causing giant cell pneumonia.

Humans↗
PubMed1981

Epstein-Barr virus antibodies in patients with ataxia-telangiectasia and other immunodeficiency diseases.

An unusual antibody response to the Epstein-Barr virus (EBV) has been noted in patients with ataxia-telangiectasia. Of a group of 16 such patients 8 were found to have antibodies in their serum to the EBV viral capsid antigen (VCA), and 4 of them also had antibodies to the EBV early antigen (EA); antibodies to the nuclear antigen (EBNA), however, were absent in 3 of the 8. The antibody pattern persisted for more than 2 years in the patients available for follow-up study. In comparison, of 24 patients with various other immunodeficiency syndromes 9 were found to have EBV-VCA antibodies in their serum, but none of the 9 had EA antibodies and 3 lacked EBNA antibodies. Two other groups of subjects, all of whom had EBV-VCA and EBNA antibodies in their serum late after an EBV infection, were also studied; 82 had infectious mononucleosis and 55 were healthy and had no such history. EA antibodies were detected in 45 of the first group during the acute phase of the illness but persisted in only 6 of the 68 who were followed up for more than 2 years, and they were detected in only 7 of the second group.All eight lymphoblastoid cell lines established from the peripheral blood of the four patients with ataxia-telangiectasia who are still available for follow-up study express EBV-VCA, whereas most similar cell lines established from normal individuals express only EBNA. In two of these patients cell-mediated immunity, as assessed from lymphocyte transformation induced by mitogens, was markedly decreased but autologous cell-mediated immune regression of EBV-induced transformation of B (bone-marrow-derived)-lymphocytes was normal. The percentage of T (thymus-derived)-helper cells was greatly decreased in two of the three patients in whom it was measured, and the percentage of T-suppressor cells was greatly increased in one of them, but the percentage of total T-lymphocytes was within normal limits in all three.The possible significance of these findings - in particular, the persistence of EA antibodies and the diminished restriction of expression of EA - in the late development of tumours after an EBV infection in patients with ataxia-telangiectasia deserves careful attention. Finally, the apparent correlation between immunoglobulin deficiency and poor or absent EBNA antibody response warrants further study.

Antibodies, Viral↗
PubMed1981

Relative lack of Epstein Barr virus (EBV) receptors on B cells from persistently EBV seronegative adults.

Viral receptors are essential for the entry of the virus into the cell. EBV receptors can be detected on fresh lymphocytes by a technique that uses EBV-coupled tanned red blood cells that form rosettes with lymphocyte-bearing receptors. This technique was found to detect viral receptors only and not surface immunoglobulins. T cell depletion of the lymphocyte population showed that these receptors were present on B lymphocytes. Study of the presence of these EBV receptors on the surface of fresh lymphocytes from 66 subjects (age 2 to 66), selected out of a group of over 2000 individuals, showed that the majority of these donors had receptors for the virus. However, a few of these adults persistently failed to develop anti-EBV antibodies, even if they were in close contact with the infectious agent. The lymphocytes of 11 such individuals were found to be lacking EBV receptors. Transformation assay of these lymphocytes did not give rise to lymphoblastoid cell lines whereas lymphocytes from 4 individuals, who were EBV seropositive or seronegative but receptor positive, yielded permanent lymphoblastoid cell lines. This would suggest that a few EBV seronegative adults (less than 0.5%) display natural resistance to EBV transformation of their lymphoid cells as a result of absolute or relative lack of EBV receptors on these cells.

Adolescent↗
PubMed1981

Epstein-Barr virus in a malignant lymphoproliferative disorder of B-cells occurring after thymic epithelial transplantation for combined immunodeficiency.

A fatal disseminated polyclonal malignant lymphoproliferative disorder of B-cells (immunoblastic sarcoma) developed shortly after a second thymic epithelial peritoneal implant in a 5-yr-old girl with combined immunodeficiency. The immunodeficiency was characterized by low T-cell numbers and function, very low levels of thymic hormone, dysgammaglobulinemia, and an inability to mount a primary antibody or cell-mediated response to new antigens. At necropsy, the thymus fulfilled morphological criteria for thymic dysplasia. Epstein-Barr virus (EBV) antigen and DNA were identified in neoplastic infiltrates in the lymph nodes and thymus by immunofluorescence for the EBV nuclear antigen and by EBV-specific complementary RNA/DNA hybridization. No antibodies to nuclear antigen, early antigen, or viral capsid antigen of EBV were identified in the serum. The concurrence of these events suggests that the thymic epithelial implant itself may have been instrumental in the pathogenesis of this neoplasm. It is proposed that the thymus may have provided factors which indirectly potentiated the proliferation of EBV-infected B-cells, possibly by induction of nonspecific T-helper cells and perhaps through other thymic humoral factors. It is suggested that some forms of immunoblastic sarcoma, even when polyclonal, and especially those which arise in immunocompromised hosts, may, in some instances, represent an opportunistic form of EBV-induced B-cell neoplasia.

Antibodies, Viral↗
PubMed1978

Persistence of both human cytomegalovirus and Epstein-Barr virus genomes in two human lymphoblastoid cell lines.

By DNA-DNA reassociation kinetic analysis, less than one genome equivalent per cell of human CMV-DNA was found in two lymphoblastoid cell lines, one derived from the peripheral blood of a congenitally infected male infant at the age of 21 months (D4 cell line), the other obtained by co-cultivation of lethally X-irradiated cells from the 9-month lymphoblastoid cell line previously described by Joncas et al. (1975) with cord blood leukocytes of a female newborn (M1 cell line). Human CMV antigens could not be detected and virus could not be rescued from these cells by co-cultivation with fully permissive human fibroblasts. It may be that the CMV-DNA is defective. Epstein-Barr virus DNA as well as EBNA and EBV-EA antigens were present in these cell lines. Both lines express surface markers characteristic of thymus-independent, B lymphocytes. The CMV-DNA of the CMV-DU strain, isolated from this infant's urine five times successively from the age of 1 day to 30 months, appears to be closely related to the DNA of the AD-169 strain by reciprocal hybridization and by electrophoretic pattern analysis of the restriction enzyme cleavage products. Experimental attempts to transform cord blood leukocytes with this urine strain of CMV before or after u.v. irradiation have so far failed.

Cell Line↗