Hairy cell leukemia: an ultrastructural study of hairy cells before and after interferon therapy.
OBJECTIVE
To test the diagnostic relevance of the presence of ribosome-lamellae complexes (RLC) in 18 hairy cell leukemia (HCL) cases, and to correlate clinical response to interferon (IFN) therapy with hairy cell ultrastructural modifications in 5 of these cases.


METHODS
Peripheral blood samples of 18 HCL patients were studied by transmission electron microscopy. Five of these patients received IFN treatment and subsequently were evaluated at different intervals for ultrastructural modifications of the peripheral blood.


RESULTS
RLC were observed in 66.66% of our 18 HCL patients, but in less than 1% of all the cases contained in the files (consisting of over 8,000 cases) of our Electron Microscopy Unit. The microvilli disappeared after IFN therapy in the patients who did not display RLC before therapy (2 cases), whereas they were fewer, shortened and blunted, but still evident, in the cases where RLC had been observed before therapy (3 cases). Moreover, in the HCL cases with pretherapy RLC, neoplastic cells still synthesized RLC after IFN treatment, but their morphologic aspect was immature.


CONCLUSIONS
Our study suggests that: 1) the presence of RLC, when associated to the hairy aspect of the cells, has considerable diagnostic value even though RLC are observed in other rare neoplastic and non-neoplastic conditions; 2) HCL cases with pre-therapy RLC exhibited a morphologic response to IFN therapy different from that of cases without pre-therapy RLC; 3) the quantitative and qualitative modifications of RLC following IFN treatment, as yet unexplained, are probably related to IFN action, in line with a previous report.
Institute of Normal Human Morphology, Faculty of Medicine, University of Ancona - U.S.L. 12, Italy.
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Morroni
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Cinti
D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D016898:Interferon-alpha / Q000627:therapeutic use*; D007943:Leukemia, Hairy Cell / Q000188:drug therapy* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D012270:Ribosomes / Q000648:ultrastructure*; D013997:Time Factors
D016898:Interferon-alpha