Case Studies

 Case 6.1 Acute leukaemia (common type)

A 7-year-old boy presented with malaise and lethargy of 6 months' duration. He had become inattentive at school, anorexic and had lost 3kg in weight. On examination he was thin, anxious and clinically anaemic. There was mild, bilateral, cervical lymphadenopathy and moderate splenomegaly.

On investigation, his haemoglobin (80g/l) and platelet count (66 x 10⁹/l) were low, but the white-cell count was high (25 x 10⁹/l). The blood film showed that most leucocytes were blasts; the red cells were normochromic and normocytic. Bone marrow examination showed an overgrowth of primitive white cells with diminished numbers of normal erythroid and myeloid precursors. Acute leukaemia was diagnosed.

The circulating blast cells were typed by immunological methods: they did not react with monoclonal antibodies to human T-cell precursor antigens (CD2, CD7) but they were positive for major histocompatibility complex class II (DR), common acute lymphoblastic leukaemia (CD10) and B-cell precursor (CD19) antigens, and contained the enzyme terminal deoxynucleotidyl transferase (Tdt) (Table C6.1; see Fig. 6.4). The phenotype of the blasts was that of acute leukaemia of early precursor B cells (see Fig. 6.3), and the prognosis in this child is relatively good.

Table C6.1 Immunophenotyping in Case 6.1.

CD antigens are defined by monoclonal antibodies (see Chapters 1 and 19). ALL, acute lymphoblastic leukaemia; CIg, cytoplasmic immunoglobulin; MHC II, major histocompatibility antigens class II (DR); SIg, surface immunoglobulin; Tdt, terminal deoxynucleotidyl transferase.