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Serum levels of tumor necrosis factor alpha/cachectin (TNF alpha) were studied in a group of adult patients with sickle cell disease (SCD), which include 31 patients with homozygous SS hemoglobinopathy and 10 patients bearing double heterozygous SC hemoglobinopathy and in their matched normal controls. All patients tested did not show any form of crisis for at least 4 weeks prior to the extraction of the sample. The amount of TNF alpha in serum was quantitated by means of an immunoenzymatic assay with a lower limit of detection of 25 pg/ml. The percentage of sera with detectable levels of TNF alpha was significantly increased in SCD patients as compared with the normal controls. Mean TNF alpha values in individuals with detectable levels of the cytokine were also significantly higher in the whole group of SCD patients and in patients bearing either SS or SC hemoglobinopathies than in the control group. An inverse correlation was observed between the percentages of Hb F and the levels of TNF alpha found in the sera from the patients.

To study the capacity of peripheral blood mononuclear cells (PBMC) from patients with sickle cell disease to synthesize antibodies in vitro, the levels of IgM, IgG, and IgA were quantitated in supernatants of cultured PBMC from a group of asymptomatic adults with sickle cell disease and from normal controls. The rates of spontaneous synthesis of IgM were similar in nonstimulated cultures of PBMC from patients and controls, whereas the amounts of IgG and IgA produced spontaneously by nonstimulated lymphocytes from the patients were significantly greater than those from controls. Similar levels of IgM, IgG, and IgA were detected in the supernatants of cultures stimulated with pokeweed mitogen from patients and controls. Thus, the capacity of PBMC to respond in vitro to pokeweed mitogen was preserved in the patients. The enhanced spontaneous synthesis of IgG and IgA suggests the presence of chronic polyclonal activation of B cells and/or defective regulation of the production of antibodies.

A mild anemia (hemoglobin 9 g/dl) was found in a patient from Seville (Spain) with marked morphological abnormalities in the peripheral blood smear. The red cell osmotic fragility showed a mild resistance curve with a mean cell fragility (MCF) of 0.375% NaCl (normal = 0.450). Chemical Chemical and thermal instability test and search for inclusion bodies gave positive results. Hemoglobin electrophoresis at pH 8.9 revealed absence of Hb A, a major component of fast mobility (94%), and increased Hb F and Hb A2 levels (1.5% and 4.6%, respectively). The fast fraction, isolated and purified by means of cellulose acetate electrophoresis, precipitated in acid acetone and treated with urea 8 M and mercaptoethanol, revealed an anomalous beta chain. Trypsin-digested globin peptides were separated by high-voltage electrophoresis at pH 6.4 and ascendant chromatography. With differential staining, an extra peptide was detected in an unusual site, more anodic than alpha Tp4 but in lower position. Peptide map of the fast beta chain, stained with ninhydrin, and also for Tyr, confirmed the position of the new peptide and the absence of the usual beta Tp13. The new peptide, separated by high-voltage electrophoresis at pH 3.5, revealed absence of Val and the presence of an additional Glu residue, which should appear only in position beta 126. The diagnosis of Hb Hofu (alpha 2 beta 2 126 Val----Glu; H4) was reached, thus interpreting its increase and the absence of Hb A, as an association with beta o-thalassemia, producing a mild hemolytic anemia. Evidence was obtained that Hb Hofu is a mild unstable hemoglobin variant.