Heartworm disease caused by Dirofilaria immitis affects canine and feline hosts, with infections occasionally being reported in humans. Studies have shown that both dirofilarial antigens and those derived from its bacterial endosymbiont Wolbachia, interact with the host organism during canine, feline and human infections and participate in the development of the pathology and in the regulation of the host's immune response. Both innate and acquired immune responses are observed and the development of the acquired response may depend on the host and, or on its parasitological status. This review aims at illustrating current research on the role of both D. immitis and Wolbachia, in the immunology and immunopathology of dirofilariosis.

Summary. Central nervous system (CNS) leukaemia is still a matter of debate and new technologies are required to improve the classic morphological definition. One hundred and sixty-eight cerebrospinal fluid (CSF) samples from 31 patients with acute leukaemia were analysed by flow cytometry and conventional cytology. Concordant positive and negative findings were found in 158 samples but 10 produced discrepant results. Cytology seemed to offer more precise information in one CSF sample and flow cytometric accuracy could be demonstrated in five samples. We conclude that flow cytometry is of great help in confirming CNS leukaemia and eliminating other conditions. Therefore, leukaemic patients can benefit from double cytological and flow cytometric CSF studies.

Low volume and few cells have hampered the use of flow cytometry for studying cerebrospinal fluid (CSF) in routine clinical practice, although information about the cellular phenotypes present in this type of sample is of great value in many diseases. We developed a novel flow cytometric strategy capable of identifying total CSF T lymphocytes and the CD4+ subset, even in CSF samples with as few as 1 leukocyte per 3 microL of sample. We also showed that identification of CD8+ T cells could be achieved in most samples, while B lymphocytes are detectable only in samples with more than 5 cells per microliter. These findings demonstrate the reliability of this method to improve the diagnostic accuracy of classic cytologic studies in many neurologic disorders.

Clinically significant endogenous circulating heparin-like anticoagulant activity has been associated with hematological malignancies, liver damage, and other pathological conditions. The source of high plasma concentrations of endogenous heparin-like anticoagulants is poorly understood. We report three cases of circulating heparin-like anticoagulants in three patients with hematological malignancies: CLL, multiple myeloma, and T-prolymphocytic leukemia. The severity of bleeding in our patients ranged from severe epistaxis and deep-site hematoma to bleeding of biopsy site and occasional ecchymosis.