The care available for SCD in Nigeria is still suboptimal and there is an urgent need for concerted effort to tackle the problem, but to make a significant impact on the burden of the disease would require more focus at the primary care level. Some steps to achieving this are outlined.

Sickle cell disease (SCD) is characterized by recurrent vaso-occlusive crisis (VOC). Patients with SCD have impaired immunity and are thus predispose to infections. The vast majority of SCD patients live in underdeveloped nations with high prevalence and transmission rates of infections. This makes the SCD patients prone to infections, which frequently precipitate VOC. We reviewed the role of infection in the pathogenesis of VOC, taking into consideration all potential mechanisms from previous studies and hypothetical perspectives. The potential mechanisms through which infections may lead to VOC involve several pathological changes including pneumonitis, pyrexia, acute phase reaction, hypercoagulability, neutrophilia, eosinophilia, thrombocytosis, bronchospasm, red cell cytopathic and membrane changes, auto-antibodies mediated red cell agglutination and opsonization, diarrhoea and vomiting, which may act singly or in concert to cause red cell sickling. These changes can induce sickling directly or indirectly through their adverse effects on Hb oxygenation and polymerization, hydration, blood viscosity, red cell metabolism, procoagulant activation, intercellular adherence and aggregation, culminating in VOC. There is therefore the need to ameliorate the burden of infection on SCD through immunization, prophylactic and therapeutic use of antimicrobials, barrier protection and vector control in communities with high prevalence of SCD.

BACKGROUNDPriapism was associated with certain hematological parameters in sickle cell anemia (SCA) patients in one report but not in another. We studied differences in haematological parameters between SCA patients with and without priapism.PATIENTS AND METHODSEighteen patients with SCA who presented with acute priapism during the years 2001–2004 were compared with age- and sex-matched SCA patients without priapism with respect to hematocrit, reticulocyte count, level of irreversibly sickled cells (ISC), percentage of haemoglobin F (Hb F), total leukocyte and platelet counts.RESULTSSCA patients with priapism had a mean hematocrit of 0.28 L/L, which was significantly higher than the mean hematocrit value of 0.24 L/L (P<0.05) in patients without priapism. The mean reticulocyte count of 8% in patients with priapism was significantly lower than mean reticulocyte count of 12% (P<0.05) in patients without priapism. The level of ISC of 3% in patients with priapism was significantly lower than the level of 6.5% (P<0.05) in patients without priapism. There was no statistically significant difference in the mean levels of Hb F (7% vs. 6%). Patients with priapism had a mean leukocyte count and mean platelet count that did not significantly differ from values in patients without priapism.CONCLUSIONSSCA patients with priapism had a lower rate of hemolysis, resulting in a higher hematocrit and greater blood viscosity, which increased the risk of corpora cavernosal sickling and blockade. Hence, a relatively high hematocrit is a risk factor for the development priapism in patients with sickle cell anemia.

Nigeria has the fourth highest prevalence of TB and the highest prevalence of Sickle cell anaemia (SCA) in the world. SCA patients have impaired immunity and are vulnerable to TB. Hence, we studied the haematological indices of SCA patients with TB in Nigeria. A total of 23 SCA patients with TB were studied in parallel with equal number of age and sex matched SCA patients without TB. SCA patients with TB had significantly lower haematocrit, higher level of circulating sickle cells (CSCs) and similar level of reticulocyte count in comparison to patients without TB. SCA patients with TB had significantly higher mean WBC count associated with higher frequency of neutrophilia in comparison to those without TB. Monocytosis and eosinopenia were exclusively found in SCA patients with TB at frequencies of 52% and 65% respectively. Lymphocyte and basophil counts were normal in all patients with and without TB. Mean platelet counts were high in both patient groups but the frequency of thrombocytosis was significantly higher in patients with TB. SCA patients with TB had significantly higher mean ESR than their counterparts without the infection. The findings of this study revealed that TB in SCA patients was associated with rising level of CSCs, falling level of haematocrit, sub-optimal reticulocytosis, neutrophilia, monocytosis, thrombocytosis, eosinopenia and rising level of ESR. Hence, SCA patients presenting with these haematological indices should be investigated for TB.

. One thousand nine hundred and twenty nine voluntary group "O" blood donors (1609 males and 320 females, median age 26 years ± 7.6 SD) were screened for alpha-(anti-A) and beta-(anti-B) haemolysins using the standard tube technique at 37 degrees C for 1 hour. All samples showing haemolysis were titrated for anti-A and anti-B haemolysins. Results. The overall prevalence of haemolysins in group O donors was 55.4%. Prevalence of alpha-and beta-haemolysins only was 10.3% and 12.6%, respectively, while that of donors having both alpha-and beta-haemolysins in their sera was 32.5%. Visual titre of 8 was seen in 0.4% of lytic alpha-haemolysin and 0.2% of lytic beta-haemolysin whereas donors with both alpha-and beta-haemolysins had a titre of 1.8%. Lytic titre of 16 and 32 was very low in our donor population. Conclusion. This study has shown that although the prevalence of haemolysins is high in our voluntary group "O" donor population, the strength of the lytic antibodies is low. Therefore, despite the labour intensiveness of our haemolysis titration technique and the frequent transfusion of group O blood to certain recipients of blood group A, B, and AB in our environments, there is the need to routinely screen our donors for haemolysins in order to identify those posing the greatest risk to recipients. Further studies to determine episodes of clinically significant haemolysis in recipients of blood group O may be necessary.