[Tuberculosis, mycobacterium infection and hairy cell leukemia]

OBJECTIVES

Diagnosis of tuberculosis and/or mycobacteria infection is particularly difficult in immunocompromised patients.

PATIENTS AND METHODS

We examined the clinical presentation, means of diagnosis, treatment and outcome of tuberculosis in a retrospective study of 6 patients among 75 with hairy cell leukemia diagnosed from 1982 to 1995.

RESULTS

Hearlding symptoms of tuberculosis diagnosis were: fever (6/6), weight loss (4/6), pleural effusion (1/6), superficial adenopathy (1/6), persistence of cytopenia or splenomegaly during the treatment of hairy cell leukemia. Pulmonary symptoms were present in only two cases. Diagnosis was obtained by positive culture of mycobacteria in 2 cases (Mycobacterium tuberculosis in pleural effusion, Mycobacterium kansaii in adenopathy). Microbiological diagnosis was never obtained from sputum (6/6). Diagnosis was obtained by histopathology in all cases: from bone marrow (2 cases), lymph nodes (2 cases), liver (1 case), spleen (1 case), umbilical fat (1 case). Tuberculosis was disseminated in all cases. By clinical, biological, microbiological histopathological means and response to treatment, tuberculosis was considered as: hematopoietic in all cases, hepatic (in 4/6), pleural (1/6), pulmonary (1/6). A favorable outcome of tuberculosis was observed in all cases. No death was observed.

CONCLUSIONS

Tuberculosis was found in 8% of hair cell leukemia patients. In hairy cell leukemia, tuberculosis is characterized by few pulmonary symptoms and scarse microbiological documentation. In contrast, histopathology is very interesting to confirm diagnosis. Tuberculosis is in most cases disseminated and in particular hematopoietic diffusions is always present. In spite of existensive localization, the prognosis remains excellent and all patients can be cured. In our opinion, this good prognosis may be linked to the improvement of hairy cell leukemia treatment observed since the advent of interferon pentostatin and 2cdA.

In vitro NCp7 enhancement of ribozyme-mediated cleavage of full-length human IL-6 mRNA

We have previously shown that a ribozyme directed against human interleukin-6 (IL-6) mRNA is efficient in vivo, despite its poor activity in vitro on full-length IL-6 mRNA. We compared the effect of the nucleocapsid protein of HIV-1 (NCp7) on the ribozyme cleavage reaction of a long (1041 nt) and a short (19 nt) substrate IL-6 RNA in vitro. At a one to five molar ratio of the long substrate to ribozyme, almost no cleavage is observed after 30 min at 37 degrees C. The NCp7 protein significantly increases the catalytic activity of the ribozyme on this substrate (from 0 to 53% after 7 min at 37 degrees C), but not on the short one. A kinetic analysis of single turnover reactions performed with ribozyme in at least fivefold molar excess over substrate also lead to a stimulation (70-fold) of the reaction rate with long substrate, but not with the shorter one. Preferential increases of the catalytic activity on the long substrate suggests that the NCp7 protein prevents misfolding of RNAs.

Catalytic activity and stability of hammerhead ribozymes containing 2'-acetamido-2'-deoxyribonucleosides

Hammerhead ribozymes may be of great therapeutic importance, since they can, in theory, be developed to cleave any undesired target RNA. In order to design ribozymes which are stable against endogenous RNases, we incorporated 2'-acetamido-2'-deoxynucleosides in the catalytic core of a hammerhead ribozyme. The 2'-acetamido function has, like the hydroxyl group, both proton donor and proton acceptor capacities, which seem to be crucial for efficient catalytic activity. However, the presence of 2'-acetamido-2'-deoxypyrimidine residues in the catalytic core caused a considerable drop in cleavage rate. Replacement of the purine residues led to complete loss of the catalytic activity. Surprisingly, these 2'-modifications showed no beneficial influence on the stability of the ribozymes against RNases present in cell culture supernatant containing 10% fetal calf serum.

Construction of a ribozyme directed against human interleukin-6 mRNA: evaluation of its catalytic activity in vitro and in vivo

We have designed a ribozyme (Rz) that cleaves human interleukin-6 (IL-6) mRNA in vivo. This Rz was tested in vitro, and was found to give expected size fragments. It was then incorporated into a mammalian expression vector containing the constitutive cytomegalovirus (CMV) immediate early promoter and transfected into human U amniotic cells (UAC). Cell clones that stably express this catalytic RNA have been obtained. Some of them displayed a marked reduction of tumor necrosis factor (TNF)-induced IL-6 production. Their reduced ability to express IL-6 was related to the amount of Rz they produced and to the extent of IL-6 mRNA cleavage as observed by a ribonuclease protection assay. These data provide a method to study further the role of IL-6 production in various biologic situations, and suggest the feasibility of developing Rzs directed against various cytokines to study their biologic role and mechanism of action.

[Spondylodiscitis disclosing bacterial endocarditis. Apropos of a case. Review of the literature]

The authors report a case of infectious spondylodiscitis revealing a staphylococcal endocarditis in a patient with a Carpentier aortic heterograft. This case, along with 60 descriptions from the literature, has enabled them to specify the characteristics of occurrence of endocarditis during a spondylodiscitis. The clinical factors in favor of this association are: a pre-existing cardiopathy, an oral port of entry, occurrence of other rheumatoid manifestations, even more the presence of complications of endocarditis. The laboratory factors in favor of an association are: discovery of an inflammatory anemia, of circulating immune complexes, of a cryoglobulinemia, of a rheumatoid factor, of hematuria. But it is mostly the demonstration of streptococcus in blood cultures and other samples that should be an indication to search for an endocarditis, the course of which dominates the prognosis.

[Circulating anticoagulants excluding hemophilia. Multicenter survey undertaken under the aegis of the French National Society of Internal Medicine apropos of 207 cases]

A retrospective multicentre study, undertaken under the aegis of the French National Society of Internal Medicine, involved 200 subjects with acquired circulating anticoagulants; 130 were female and 77 were male; mean age was 45 +/- 23 years (range: 10 months to 80 years). Mean duration of follow-up was 23 months. In 130 subjects the anticoagulants were detected as a result of a systematic screening examination. The main overt clinical manifestations were haemorrhages, venous or arterial thrombosis and spontaneous abortion. Typing of the anticoagulant, performed in 166 cases, showed the presence of an antiprothrombinase in 141; this enzyme is not responsible for severe bleeding unless it is associated with other disorders of coagulation; less frequent were an anti-factor VIIIc (n = 16) and an anti-factor V (n = 2) anticoagulants. An underlying pathology was found in 172 subjects, including systemic lupus erythematosus (n = 60), induced lupus (n = 11), discoid lupus (n = 3), infection (n = 23), blood disease (n = 19), cancer (n = 15) and vasculitis (n = 15); other factors were pregnancy (n = 5) and medicines (n = 6). The anticoagulant disappeared spontaneously in 10 cases and in 33 of the 115 subjects treated. In subjects with lupus and in children under twelve years of age, an antiprothrombinase was regularly identified at typing.

Effect of surgical trauma on various aspects of the immune response in rats

The effects of a standard laparotomy on different aspects of the immune response were studied in Wistar R/A rats. When the antigen was administered at the time of operation, antibody synthesis against sheep red blood cells (SRBC), a thymo-dependent antigen was significantly stimulated. The same phenomenon was observed when a soluble antigen extracted from SRBC was injected during the surgical procedure. On the contrary, late antibody production induced by formalinized Salmonella enteritidis or Escherichia coli lipopolysaccharide, two thymo-independent antigens, was reduced in operated animals. Cell-mediated immunity against SRBC was investigated by the radiometric ear index test described by Kostiala in 1977. Surgery did not alter the induction phase but suppressed the expression of the cellular immune response. Carrageenin-induced edema was inhibited in operated rats. These results show that surgical trauma acts differently on the various aspects of the immune response.

Effect of surgical trauma on delayed type hypersensitivity

There is no general agreement in the literature concerning the effects of surgery on delayed type hypersensitivity (DTH). Therefore, the effect of a standard laparotomy on DTH was studied in rats and measured by the ear index method of Kostiala. Surgery depresses significantly the ear index in animals challenged at the time of operation (2.35 +/- 0.24 vs 6.30 +/- 1.26) or 24 hr later (2.69 +/- 0.21 vs 4.34 +/- 0.64). There is no late rebound of the immune response. The reduction of ear index is not due to a delayed response of operated rats but is really a decrease of the peak response. Surgery seems to act on the early phase of the immune response.