Serum adenosine deaminase and procalcitonin concentrations in neutropenic febrile children with acute lymphoblastic leukaemia.

Neutropenia as a state of immunosuppression is probably the major problem in patients suffering from acute lymphoblastic leukaemia undergoing intensive chemotherapy. Fever is frequent in neutropenic patients and often related to infection. Clinically, the presence of infection in patients with neutropenia may be difficult to establish, because there are usually few signs of infection. The aim of this work was to study sensitive markers for early diagnosis of microbial infection in neutropenic children undergoing intensive chemotherapy as a treatment for acute lymphoblastic leukaemia. The study included three groups (A, B and C) of children with acute lymphoblastic leukaemia and neutropenia. Group A consisted of 29 children with febrile neutropenia and microbial infection, aged 1-14 years (5.8+/-2.9), 11 boys and 18 girls; Group B of 38 children with febrile neutropenia without microbial infection, aged 2-14 years (6.8+/-3.1), 14 boys and 24 girls; and Group C of 53 children with neutropenia without fever and without infection, aged 1-14 years (5.9+/-2.1), 21 boys and 32 girls. Blood samples were collected upon admission and before the start of any antimicrobial treatment. The samples were used for blood culture, serological tests, leukocyte count and analysis of levels of C-reactive protein, procalcitonin, total adenosine deaminase (ADA) activity and its isoenzymes, ADA-1 and ADA-2. According to our results the procalcitonin levels and total ADA activity discriminated best between neutropenic febrile (Groups A and B) and neutropenic afebrile episodes (Group C). In conclusion, this study suggests procalcitonin and total ADA activity as two easily measurable and cost effective markers for the assessment of immune response in febrile neutropenic patients with acute lymphoblastic leukaemia.

Response of ADA and its isoenzymes in mice infected by Trichinella spiralis and treated with mimosine.

Infections caused by the nematode Trichinella spiralis (T. spiralis) are characterized by an inflammatory response in the host. The aim of this study was to identify and evaluate markers for monitoring mice infected with T. spiralis and treated with or without mimosine. The markers that have been used were total and differential white blood cell counts, subpopulations of lymphocytes, serum tADA and its isoenzymes ADA1 and ADA2 activity. The study included 3 groups of BALB/c mice. Group A consisted of 16 healthy mice, Group B of 16 mice infected with T. spiralis and treated with saline, and Group C of 16 mice infected with T. spiralis and treated with mimosine. The measurements were made once per week for the first six weeks continuously following the infection. According to our results, leukocytosis, lymphocytosis and increased percentages of adhesion molecules and CD4 lymphocytes were present in groups B and C one week post-infection. Total ADA activity as well as ADA1 and ADA2 was higher in groups B and C versus group A from the first week post-infection. The levels of tADA activity, ADA1 and ADA2 were higher in group B compared to those of group C and the difference was statistically significant (p<0.05) during the 4th week post-infection. The majority of tADA activity, essential for an efficient immune response, was derived from ADA1 which may have been produced by infected tissues. The elevated activities of tADA and ADA1 may be sensitive markers for infection of T. spiralis and for monitoring the course of the infection.

Serum procalcitonin, adenosine deaminase and its isoenzymes in the aetiological diagnosis of pneumonia in children.

A prospective study was undertaken to assess the usefulness of leukocyte count, serum C-reactive protein (CRP), procalcitonin (PCT), and the activities of total adenosine deaminase (tADA) and its isoenzymes ADA1 and ADA2, in the aetiological diagnosis of pneumonia in children. The study included three groups. Group A consisted of 23 children with bacterial pneumonia, group B of 50 children with viral and mycoplasmal pneumonia and group C of 46 healthy children. On the first day of admission in the clinic, blood samples were collected before the start of antimicrobial treatment, for culture, serological tests, leukocyte count and for the determination of CRP and PCT levels as well as tADA activity and its isoenzymes ADA1 and ADA2. According to our results, the mean leukocyte count and the mean concentrations of PCT and CRP were significantly higher in the children of group A than those in groups B and C. The admission serum PCT concentration has a higher sensitivity, specificity and positive predictive value for bacterial pneumonia than either CRP or the leukocyte count. The mean serum tADA, ADA1 and ADA2 activity in children of group A was not significantly different from those in group C, while the difference between groups B and C was statistically significant. In conclusion, we found that CRP is a good marker for screening various infectious diseases, but it cannot be used to distinguish between bacterial and viral infections. Serum PCT measurement might be a useful tool for the physician for the aetiological diagnosis of pneumonia in children. Measurements of serum tADA and ADA2 activity may provide useful additional diagnostic information on the aetiology of pneumonia so that appropriate antibiotic therapy can be given promptly. Further studies with larger patients groups are required to confirm our results.

Adenosine deaminase activity and its isoenzyme pattern in patients with juvenile rheumatoid arthritis and systemic lupus erythematosus.

Adenosine deaminase (ADA) is involved in purine metabolism and plays a significant role in the mechanisms of the immune system. The aim of this study was to investigate the activity of total ADA (tADA) and its isoenzymes ADA1 and ADA2 in serum and peripheral blood lymphocytes (PBLs) of children with juvenile rheumatoid arthritis (JRA) and systemic lupus erythematosus (SLE) in different phases of the diseases. The study comprised 34 patients with rheumatic disease, 24 with JRA and 10 with SLE, and 64 healthy controls. The tADA activity and its isoenzymes were measured in serum and PBLs of all patients by the method of Giusti and by the presence or absence of EHNA (erythro-9-(2-hydroxy-3-nonyl)adenine) during the active phase of the disease (before treatment), as well as during remission and relapse. Our data show that increased tADA activity in the serum and PBLs of patients with JRA and SLE is correlated mainly to increased levels of ADA2 activity in serum and ADA1 activity in PBLs. It also closely correlates with clinical disease activity and relapse. The cause of this increased tADA/ADA2 activity in serum and tADA/ADA1 activity in PBLs in JRA and SLE remains to be elucidated. Nevertheless, it may be noted that the measurement of tADA activity, together with ADA2 activity in serum and tADA with ADA1 activity in PBLs, could offer a biochemical approach to the assessment of the pathophysiology of JRA and SLE. Also, tADA and its isoenzymes could be used as alternative parameters representing disease activity.