C-reactive protein (CRP) levels do not reflect disease status in patients with multiple myeloma

It has recently been suggested that a combination of C-Reactive Protein (CRP) and beta-2-microglobulin (beta 2M) can be used to devise a simple prognostic model for patients with multiple myeloma. In this study we have measured serum beta 2M, CRP and thymidine kinase (STK) in a series of 215 samples to determine their value as a monitor of disease status. A longitudinal study was also performed with 6 individual patients. CRP levels did not correlate with disease status. The mean of the stable (23.62 mg/L) and the progressive disease 23.64 mg/L) groups were almost identical (t = 0.003; p = NS) with ranges of < 5-150 mg/L and < 5-100 mg/L respectively. There was no correlation between CRP and STK (r = 0.11) or CRP and beta 2M (r = 0.05). In longitudinal studies, CRP did not necessarily reflect changes in disease activity. We conclude that CRP measurements are not valuable as a monitor of disease activity in patients with myeloma.

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.

von Willebrand's disease characterized by increased ristocetin sensitivity and the presence of all von Willebrand factor multimers in plasma: a new subtype

The clinical and laboratory features of a patient with a recently recognized new variant of von Willebrand's disease are presented. The importance of this variant is that it is associated with a clinically significant bleeding diathesis but with a normal skin bleeding time, PTTK, factor VIIIc and platelet aggregation with 1 mg/ml ristocetin. The distinctive laboratory features are increased platelet sensitivity to low concentrations of ristocetin, and the presence of all plasma von Willebrand factor multimers, but in reduced amounts. The need for thorough investigation of patients with significant bleeding history despite apparently normal screening tests is emphasized.

Heparin Standardization

Heparin is a major therapeutic item in any hospital and although local supplies are assumed to meet BP criteria, physicians often note differences in clinical results when the source of a supply is altered. BP and USP specifications require testing of heparins using animal blood thromboplastin tests - conditions which may not be particularly relevant to human use. A new method for determining heparin potency relative to a standard involves making equal dilutions of these heparins in several patients’ plasmas and determining the PTTK’s. The ratios of these PTTK’s to the initial PTTK of each plasma, when plotted for one heparin against the other, fall on a straight line and may be treated in the same way as recently proposed for thromboplastin calibration by the WHO. Features of heparin vary in importance depending on the particular application. Heparin used at high levels during bypass should be completely neutralizable by protamine. Mini-dose heparin needs to be standardised in terms of factor xa inactivation rate whereas that used for routine continuous infusion might best be standardised from its effect in vitro on the PTTK of normal plasma. We have recently investigated 3 tests for assessing heparins. 1. effect of their in vitro addition on the PTTK of normal plasma. 2. effect on factor xa inactivation. 3. protamine neutralisability as detected by the PTTK. The latter test was most accurate, demonstrating significant differences between sources of heparin and detecting variations in batch potency previously suspected by clinicians.