Historical aspects of chronic lymphocytic leukaemia

CD5‐negative chronic lymphocytic leukemia: Does this entity really exist?

“…And, to muddy the waters, as appropriately asserted by Terence John Hamblin, "most of the large series of patients with CLL published before 1990 were contaminated with diseases that we would now recognize as not being CLL." (Hamblin, 2000). 3 In the end, the issue can be summed up by the statement that "diagnosis is an act of categorization, and as our understanding of categorization has evolved, our understanding of the diagnostic process has evolved right along with it."…”

“…In the early days of lymphoma classification, the diagnosis of CLL (at that time, initially designated by the term "lymphocytic lymphoma") (Gall & Mallory, 1942) was based exclusively on nodal histology. In the 1970s, a set of articles identified B-cells in the blood of CLL patients (Hamblin, 2000;Rai, 1993), but even in 1978, Karl Lennert's classification system (Kiel classification) was still heavily based (although not exclusively) on cytomorphology (peripheral blood) and histology (lymph node and bone marrow) to define what was then known as "chronic lymphocytic leukemia, B-cell type" (Lennert & Mohri, 1978). In the ensuing years, it is true that a set of new immunological markers were added to the diagnostic armamentarium.…”

“…It is worth noticing that smudge cells are not useful to differentiate CLL from other mature B-cell neoplasms(Matos et al, 2009).3 In addition, Hamblin considers that "other cases of this disease [scil.splenic marginal zone lymphoma] may not have very obvious villi and may constitute what has become known as CD5-negative CLL. "(Hamblin, 2000).4 Indeed, tuberculosis is monothetic on the etiological axis (M. tuberculosis), but polythetic on the symptoms/signs axis. Smallpox is a better example of a "pure" monothetic disease: etiological axis (the poxvirus) and symptoms/signs.…”

“…3 3 In addition, Hamblin considers that “other cases of this disease [ scil . splenic marginal zone lymphoma] may not have very obvious villi and may constitute what has become known as CD5‐ negative CLL.” (Hamblin, 2000). …”