A variant form of hairy cell leukemia resistant to alpha-interferon: clinical and phenotypic characteristics of 17 patients.
We describe the clinical and laboratory features of 17 adult patients with a variant form of hairy cell leukemia (HCL-V) studied over the last 7 years. The main findings were: splenomegaly, moderate anemia, thrombocytopenia, and a raised white blood cell count (median 116 x 10(9)/L; range 15 to 482). The circulating lymphoid cells had abundant villous cytoplasm and a round, occasionally bilobed nucleus, with a prominent nucleolus. Monocytopenia, a feature of typical HCL, was not seen; neither was tartrate-resistant acid phosphatase demonstrated in eight cases tested. HCL-V cells had a mature B-cell phenotype: CD19+, CD20+, CD22+, FMC7+, CD11c+, CD10-, CD5-, with light chain isotope restriction in 15 cases. In contrast to typical hairy cells, HCL-V cells were negative with the monoclonal antibodies anti-HC2 and anti-TAC (CD25). Immunoglobulin (Ig) was not detected in two cases and IgG was expressed in the cell membrane of 73% of cases. Bone marrow histology was different from HCL, showing interstitial infiltration by cells clumped together and a moderate amount of reticulin, but the spleen showed the typical red pulp expansion of HCL. HCL-V patients did not respond to splenectomy (5 of 7) or alpha-interferon (7 of 7); 2 of 3 patients had a partial response to 2'deoxycoformycin. The clinical course was benign with 15 patients alive with a median survival greater than 4 years. We confirm that HCL-V is a distinct clinico-pathologic entity with intermediate features between HCL and B-prolymphocytic leukemia.
Sainati
L
L
Academic Department of Haematology and Cytogenetics, Royal Marsden Hospital, London, UK.
Matutes
E
E
Mulligan
S
S
de Oliveira
M P
MP
Rani
S
S
Lampert
I A
IA
Catovsky
D
D
D000368:Aged; D000369:Aged, 80 and over; D004351:Drug Resistance; D005260:Female; D014644:Genetic Variation; D006801:Humans; D007370:Interferon Type I / Q000494:pharmacology* / Q000627:therapeutic use; D015448:Leukemia, B-Cell / Q000188:drug therapy / Q000473:pathology; D007943:Leukemia, Hairy Cell / Q000188:drug therapy / Q000235:genetics*; D015463:Leukemia, Prolymphocytic / Q000188:drug therapy / Q000473:pathology; D008223:Lymphoma / Q000188:drug therapy / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D013160:Splenic Neoplasms / Q000188:drug therapy / Q000473:pathology
D007370:Interferon Type I