The immature reticulocyte fraction: a negative predictor of the harvesting of CD34 cells for autologous peripheral blood stem cell transplantation

The optimal time for the harvesting of peripheral blood stem cells following chemotherapy and growth factors for autologous transplantation is based on the CD34 cell count. In this study, 51 patients having 59 stem cell mobilizations were assessed for the timing of the harvest by a CD34 cell count and an immature reticulocyte fraction (IRF). Results from 272 preharvest tests showed that when the CD34 cells were not harvestable, defined as a CD34 cell count of < 15 cells/microl, the IRF was always < or = 0.2. A low IRF resulted in a negative predictive value of 1 for the harvesting of stem cells. The IRF is therefore a valuable negative predictor of the timing of autologous stem cell harvesting.

An A gamma globin promoter (four base-pair deletion) mutant shows linked polymorphic changes throughout the A gamma gene

The A gamma fetal globin genes from a large Australian kindred with nondeletional A gamma hereditary persistence of fetal hemoglobin (HPFH) were cloned and sequenced. The -198 T----C mutation (British type HPFH) was demonstrated upstream of the A gamma gene on one allele. On the other allele, a 4-deletion was identified -222 to -225 bp upstream from the cap site. The 4-bp deletion allele was associated with a number of variations in the A gamma gene sequence: anA gamma T transition, in the second exon (T----C at +402 relative to the cap site); a HindIII polymorphism in the second intron; and a G gamma-like sequence in the 3' untranslated region (TCAC in place of CTCT, creating a SacI site). An association between the -222 to -225 deletion, the A gamma T polymorphism, and the second intron HindIII polymorphism has previously been reported. In addition, linkage of the HindIII polymorphism with the G gamma-like sequence in the 3' untranslated region of A gamma has also been described. The case described here is unique, with all four changes present in the one A gamma gene. It is also noteworthy because there is simultaneous occurrence of high (HPFH) and low (-222 to -225 deletion) expression mutants in the same patient. Despite the presence of the 4-bp deletion, the resulting hematological phenotype remained that of HPFH. When the 4-bp deletion promoter was studied in a K562-cell transient expression assay, there was found to be no statistically significant reduction in activity compared to the control A gamma promoter. The possible reasons for the observed differences between the in vivo and in vitro activity of this mutation are discussed.

Neonatal alloimmune thrombocytopenia caused by an antibody to the Bak(a) antigen

A 31 year old woman was assessed following delivery of her second child affected by neonatal alloimmune thrombocytopenia (NAIT). Antiplatelet antibodies with specificity for Bak(a) were identified in the woman's serum and her platelets were typed as Bak(a) negative whilst her husband's were Bak(a) positive. Unlike the majority of reported anti-Bak(a) antibodies in the literature, this patient's serum contained no contaminating anti-HLA antibodies. This is the first report of NAIT caused by an anti-Bak(a) without co-existing anti-HLA antibodies. An anti-Bak(a) antibody has not previously been reported in Australia. The current status of this antigen system is reviewed.

Recurrent epistaxis, chronic pancytopenia and nasal mycosis

A 52-year-old man with chronic, profound pancytopenia associated with a four-year history of Waldenstrom's macroglobulinemia refractory to chemotherapy began to experience major epistaxes requiring hospital admission for control. A diagnosis of invasive Aspergillus was made on nasal mucosal biopsy. A regimen of bi-weekly intravenous and sixth-hourly topical amphotericin B drops with adjuvant rifampicin successfully eradicated local nasal pain as well as the epistaxis. Resolution of infection was documented by gallium scan. It is suggested that, in addition to the aggressive craniofacial mycoses already described, lower grade nasal mycoses occur. The roles of biopsy and gallium scan in immunocompromised hosts with epistaxis are discussed.

Fine needle aspiration sampling of bone marrow for DNA flow cytometric analysis

Fine needle aspiration (FNA) was used to obtain bone marrow samples from 57 patients with a variety of hematologic disorders, and from three normal subjects. We confirm that the technique is well tolerated and show that reliable cytokinetic and cell differential data can be obtained provided marrow fragments are isolated for analysis. This requires aspiration of a larger volume of marrow than originally described but this can still be achieved with minimal discomfort to the patient. The technique thus provides a means by which marrow samples could be obtained at frequent intervals in the monitoring of chemotherapy.