Israel Medical Association Journal

Background: Monitoring the rate of infections in individual centers that treat patients with hematological malignancies is of major importance. However, there are no uniform guidelines for infection surveillance.

Objectives: To describe the epidemiology of bacterial and fungal infections in a single hematology ward and to compare methods for reporting surveillance and infection rates in other centers in Israel.

Methods: We conducted a prospective surveillance of all patients admitted to our hematology ward, applying standard definitions for invasive fungal infections and adapting definitions for non-fungal infections. Incidence rates were calculated using patients, admissions, hospital days and neutropenia days. We performed a search for other reported surveillance studies in Israel.

Results: We detected 79 infectious episodes among 159 patients admitted to the hematology ward during 1 year. Using neutropenia days as the denominator for calculation of incidence discriminated best between patients at high and low risk for infection. The incidence of invasive fungal infections was 7, 10 and 18 per 1000 neutropenia days, among all patients, those with acute leukemia and those with acute leukemia undergoing induction therapy, respectively. Only 10 reports from Israel were identified, 6 of which were prospective. Our data could not be compared to these reports because of the varying definitions and denominators used.

Conclusions: Hematology centers should monitor infection rates and report them in a uniform methodology.
 

Objectives: To evaluate immunologic parameters in B-CLL[1] associated with autoimmune disorders. As a hypothesis we postulated that in those cases, the malignant B cells might disclose an activated phenotype pattern leading to the production of autoantibodies.

Methods: In the Registry of the Israel Study Group on CLL that includes 964 patients, we found 115 cases showing a single or a complex of autoimmune disorders. We evaluated the lymphocyte morphology, immunoglobulin G and beta-2-microglobulin serum levels and positivity of the CD38 and FMC7 markers, and compared these values with those of a matched CLL population without autoimmune disorder. 

Results: The main autoimmune disorders encountered were autoimmune hemolytic anemia (55 patients), Evan's syndrome (n=7), Hashimoto's thyroiditis (n=15), vasculitis (n=5) and rheumatoid arthritis (n=4). We found atypical prolymphocytic morphology in 22%, high expression of the activation antigens CD38 and/or FMC7 in 30%, and high level of immunoglobulin G (> 1000 mg/dl) and beta-2-microglobulin in 57% and 78% respectively. When compared with a matched CLL population without an autoimmune disorder, these values were statistically significant.

Conclusions: Our data, which show activated lymphocyte morphology, high levels of IgG[2] and beta-2-microglobulin, and increased expression of CD38 and/or FMC7 in a significant number of cases, suggest that some degree of activation of B cells may lead to the occurrence of an autoimmune disorder in CLL.

Background: The highly tissue-specific trafficking of normal and malignant lymphocytes to particular organs is mediated by adhesion molecules, or “homing receptors.” Among our patients with B cell chronic lymphocytic leukemia 15% demonstrate predominantly splenic manifestations and are classified as stage II(S).

Objective: To investigate whether expression of cell surface adhesion molecules can distinguish stage II(S) patients from stage 0 or stage 0 and I CLL[1] patients.

Methods: Expression of adhesion molecules belonging to different families was studied in CD19-positive cells isolated from the blood of 42 patients by dual color flow cytometry. The families included: immunoglobulin superfamily (CD54, CD58), integrin family (β1, β2 and β3 chains, CD11a, CD11c CD49d), selectin family (L-selectin), and lymphocyte homing receptor family (CD44).

Results: The average percentage of leukemic cells expressing CD11c in the 23 patients with stage II(S) was 25.7 compared with 13.2% in the 14 patients with stage 0 disease (P = 0.047). The average percentage of leukemic cells expressing CD44 in patients with stage II(S) was 90.5 compared with 77.2% in patients with stage 0 (P = 0.007) and 80% in patients with stages 0 and I together (n=19, P = 0.008). Other adhesion molecules tested did not show a statistically significance difference in expression between the different disease stages.

Conclusions: The higher expression of CD44 and CD11c in cells of CLL patients with predominantly splenic manifestations may account for the tendency of their lymphocytes to home to the spleen.

In recent years, umbilical cord blood has emerged as an alternative source of hematopoietic progenitors (CD34+) for allogeneic stem cell transplantation, mainly in patients who lack an human leukocyte antigen-matched marrow donor. Since 1998, about 2,500 patients have received UCB[1] transplants for a variety of malignant and non-malignant diseases. The vast majority of recipients were children with an average weight of 20 kg, however more than 500 UCB transplantations have already been performed in adults. The “naive” nature of UCB lymphocytes may explain the lower incidence and severity of graft versus host disease encountered in UCBT[2] compared to the allogeneic transplant setting. Furthermore, UCB is rich in primitive CD16^-CD56⁺⁺ natural killer cells, which possess significant proliferative and cytotoxic capacities and can be expanded using interleukin-12 or 15, so as to mount a substantial graft versus leukemia effect. The major disadvantage of UCB is the low yield of stem cells, resulting in higher graft failure rates and slower time to engraftment compared to bone marrow transplantation. A rational approach thus involves ex vivo expansion of UCB-derived hematopoietic precursors.