Predictive value of cord blood hematological indices and hemoglobin Barts for the detection of heterozygous alpha-thalassemia-2 in an African-Caribbean population.

BACKGROUND: Cord blood hemoglobin Barts (HbBarts) and hemocytometric indices may be used for classification of newborns into those without alpha-thalassemia-2 (alphaalpha/alphaalpha) and with heterozygous alpha-thalassemia-2 (-alpha(3.7)/alphaalpha). We investigated by logistic regression analysis whether the combination of HbBarts and hemocytometric indices improves classification compared with classification based on a single analyte. METHODS: HbBarts percentages and hemocytometric indices were determined in cord blood of 208 consecutive newborns in Curaçao (Netherlands Antilles). Of these, 157 had alphaalpha/alphaalpha and 51 had -alpha(3.7)/alphaalpha, as established by DNA analysis. RESULTS: Between-group differences were significant for erythrocytes, mean cell volume, mean cell hemoglobin (MCH), mean cell hemoglobin concentration, platelets, hemoglobin F(0) (HbF(0)), and HbBarts. The Logit equation of the logistic regression model, using MCH (pg) and HbBarts (%), was: 42.7164 + 5.7916(HbBarts) - 1.3110(MCH). A sensitivity of 100% was reached at a Logit value of -3.70. The corresponding specificity was 62.2%, and the predictive value of a positive test (PV+) was 46.3% (95% confidence interval, 37.0-55.7%). The relative information gains were as follows: 88% for the HbBarts-MCH combination, 26% for MCH (not significant), and 0% for HbBarts compared with the 24.6% -alpha(3.7)/alphaalpha prevalence. CONCLUSION: Combined use of cord blood HbBarts and MCH improves classification compared with classification based on single hemocytometric indices.

Functional properties of neoplastic T cells in adult T cell lymphoma/leukemia patients from the Caribbean.

The neoplastic T cells from five patients with adult T cell lymphoma/leukemia (ATLL), born in the Caribbean, were studied with respect to immunoregulatory activity on pokeweed mitogen (PWM) driven immunoglobulin (Ig) synthesis as well as surface-marker phenotypes with monoclonal antibodies. The neoplastic T cells in all patients had an OKT1+4+8-11+M1-I1-3A1- phenotype, but differed in the reactivity with OKT3. None of the patients' cells exerted helper activity on PWM-induced Ig synthesis. The neoplastic cells of three patients had suppressor activity on PWM-induced Ig synthesis. All patients were positive for human T cell leukemia/lymphoma virus (HTLV) or had antibodies against HTLV antigens. It has previously been shown that the neoplastic cells in Japanese ATLL patients and in patients from the Caribbean are indistinguishable by morphology and marker phenotype. We now show them to be also similar with respect to their functional properties.