Objectives-To provide preliminary evidence that the currently employed semiquantitative method of screening for glucose-6-phosphate dehydrogenase (G6PD) deficiency can only detect infants who are totally deficient for G6PD and misses all cases of partial G6PD deficiency. Setting-General population: 2150 randomly selected blood samples from the Blood Donation Department, Speliopouleion General Hospital, Athens, Greece. Neonate population: 2000 samples from neonates (50% male; 50% female) in maternity hospitals in the greater Athens area. High risk population: a total of 545 individuals from 133 families in the Athens area, the minimum acceptance criteria being the parents and any brother or sister. Method-Blood specimens from neonates or adults were collected and either spotted and dried on special filter paper (Schleicher and Schull 2992, Darmstadt, Germany) or used in tubes after being heparinised. For the quantitative evaluation of G6PD enzyme activity, the Quantase G6PD screening kit (Quantase Limited, Perth, UK) was used. Quantase G6PD controls (Quantase Limited) were used at three levels of G6PD. These controls are rated at 24, 30, and 37°C. Alternatively, we used the Sigma G6PDH controls (Sigma Chemical Company, St Louis, USA) which are rated at 30 and 37°C. The assay was performed according to the instructions included in the kit with the modification for haemoglobin normalisation. Results-General population: 36 females who were classified as having normal enzymatic activity with the semiquantitative test, were classified as partially deficient with the quantitative test. Neonate population: using the quantitative test, the percentage of G6PD deficient neonates in this population was 5.5%, compared with 3.17% reported in routine screening using the semiquantitative method. High risk population: the quantitative method detected 28 cases of total or partial G6PD deficiency in sisters of males with known total deficiency. The semiquantitative method only detected 32% (nine out of 28) of these cases.Conclusions-A considerable amount of partially G6PD deficient female neonates (heterozygotes) are undetected and classified as having normal enzymatic activity using the semiquantitative method, which uses a cut oV of 2.1 U/g haemoglobin (Hb). The use of a fully quantitative G6PD screening kit is proposed, employing the automated haemoglobin normalisation and a cut oV of 6.4 U/g Hb. Any neonate with an activity below this mark should be regarded as G6PD deficient, and all preventive measures should be taken. (J Med Screen 2000;7:46-51)

Background. Human natural killer (NK) cells mediate spontaneous cytotoxicity against tumor cells and represent the main precursors of lymphokine‐activated killer (LAK) cell activity. A comparison of some aspects of NK and LAK cell activity was undertaken in 85 preoperative patients with breast cancer and 75 healthy donors. Methods. NK cell activity (tested in 18‐hour cultures of effector peripheral blood mononuclear cells [PBMC] with K562 or MOLT‐4 tumor target cells) was significantly diminished in these patients as it was the fully mature LAK cell activity (i.e., interleukin‐2 (IL‐2)‐in‐duced cytotoxicity in PBMC) against NK resistant target cells. Using immunoenzymatic methods we showed that the reduced NK cell activity was due to abnormally high levels of prostaglandin E2 (PGE2) produced by monocytes in culture. Results. PGE2 was found to suppress the production of IL‐2 in these cultures. Removal of monocytes from PBMC restored to almost normal levels the deficient NK and LAK cell activity in patients with breast cancer and was also associated with a normalization in the levels of PGE2 and IL‐2. Indomethacin and gamma‐interferon (IFN‐γ) increased the NK and LAK cell activity in these patients up to the levels of healthy donors. When highly purified CD56+ cells (obtained by an immunomagnetic isolation technique) were used as effector cells, no differences in LAK cell activity could be noticed between healthy donors and patients with cancer. FACS and northern blot analyses demonstrated a PGE2‐mediated down‐regulation of IL‐2 receptor (IL‐2R) expression on CD56+ cells that correlated with reduced LAK cell activity. This inhibitory effect of PGE2 was noticeable in long‐term LAK cultures and was abrogated in the presence of IFN‐γ or indomethacin. Conclusion. This study may have important implications in the potentiation of NK and LAK cell activity for immunotherapeutic protocols in patients with breast cancer.

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Prothymosin alpha(Prot alpha), an immunologically active polypeptide derived initially from rat thymus, and now pig thymus, was tested for its effect on autoantigen-induced human T cell proliferation in vitro. Pig ProT alpha was found to enhance the autologous mixed lymphocyte response (auto-MLR). Optimum enhancement was achieved at doses which varied among different donors. Treatment of the stimulatory monocytes with ProT alpha resulted in considerably higher auto-MLR responses as compared to those with non treated monocytes. ProT alpha was without effect on T lymphocytes. In contrast, T lymphocytes exhibited enhanced proliferative activity when treated with ProT alpha in the environment of autologous monocytes. Moreover, supernatants from cultures of monocytes incubated with ProT alpha (ProT alpha-sup) were also shown to enhance the human auto-MLR either after addition in cultures or after preincubation with responder T lymphocytes. In addition, ProT alpha-sup did not demonstrate any detectable interleukin 1 (IL 1) or interleukin 2 (IL 2) - like activity. Furthermore, ProT alpha-sup induced an increase in IL 2 production in auto-MLR cultures. The enhancement of T-cell proliferation and IL 2 production by ProT alpha-sup was maximal when this material was added at the beginning of the auto-MLR, and no effect of ProT alpha-sup was seen if the latter was added 3 days after initiation of the culture. Finally, Prot alpha-sup was also shown to increase the expression of IL 2 receptors on T lymphocytes activated in the auto-MLR. These studies suggest that ProT alpha enhances the human auto-MLR through ProT alpha-sup which is released after interaction of monocytes with ProT alpha ProT alpha-sup then increases directly T lymphocyte proliferation by elevating IL 2 production and expression of IL 2 specific receptors on autoactivated T lymphocytes.