Distribution of ABO and RH genes in Nigeria.

Phenotype and gene frequencies of ABO and RH (D) systems were studied in 37,846 random blood donors in five zone of Nigeria (South West) (Yoruba)--Zone A, North West (Hausa-Fulani)--Zone B, Plateau (Birom)--Zone C, South East (Igbo)--Zone D and North East (Kanuri)--Zone E). We assessed the micro differences of genetic markers of ABO and RH blood groups between the ethnic groups in the ABO and RH blood group systems. Gene frequencies were ABO *O = 0.7068, ABO *A = 0.1490, ABO *B = 0.1443, RH *D = 0.8150 and results are similar to those earlier reported. Phenotype frequencies of the blood groups were in agreement with Hardy-Weinberg equilibrium expectations, except in two zones B and C where deviation was thought to be due to a high frequency of blood group AB.

Medical laboratory audit: performance of twelve selected laboratories in metropolitan Enugu, Nigeria.

The abilities of 12 medical diagnostic laboratories situated in Enugu metropolis to estimate haemoglobin concentration accurately and precisely, by the cyanmethaemoglobin photometric method, were assessed. Nine (75%) of these laboratories showed good precision. Three (25%) were imprecise. As assessed by variance index (VI), only 5 (8.3%) of the entire haemoglobin results obtained from the participating laboratories showed good excellent accuracy (VI = 0 < or = 0.5). Conversely, 16 (26.7%), 9 (15%) and 30 (50%) of the entire haemoglobin results were satisfactory (VI > 0.5 - 1), acceptable (VI > 1 - 2) and rejectable (VI > 2) respectively. Furthermore, only 4 (33.3%) of the laboratories produced haemoglobin results that were both accurate and precise. Non-compliance with desirable practices that ensure quality of laboratory determinations were observed as possible contributing factor to this rather poor performance. The latter underscores the need for institution of external quality control laboratories in Nigeria.

IgG2 associated hypergammaglobulinaemia in some Nigerians with HIV infection.

Concentrations of immunoglobulins (IgA, IgG and IgM) were measured in Nigerians with (HIV) infection. Considerable elevations up to two-fold the reference values were observed for IgG and IgM in the patient group as a whole but elevations in IgA concentration were least marked albeit significantly different from the healthy subjects. Elevation of a particular isotype was not always concomitant with elevation of the other major classes in the same patient. Overall, these elevations were observed in both symptomatic and asymptomatic infected subjects. Further analysis of IgG hyperglobulinemia showed that increases in this major class may be due to increased IgG2 subclass concentrations. It is suggested that elevation of IgG2 subclass in Nigerians with HIV infection and not IgG1 or IgG3 may be due to genetic and environmental factors rather than variation in the strain of the virus.

PIP: The major and subclass concentrations of immunoglobulins were examined in 27 Nigerians with HIV infection. 12 had definite HIV-1 infection, 2 had both HIV-1 and HIV-2, and the remaining 15 were included because of the reactivity of their sera. The reference group was drawn from four major Nigerian population groups that were part of a group of 238 healthy Nigerians. Individual increases in IgM and IgG concentrations in the patient group varied and was sometimes up to 7-fold above the mean of those in the control group. Overall, the increases were about twice the mean concentrations found in the reference group. The IgM concentration range was 0.6-9.7 g/l in the HIV group (n = 27) vs. 0.4-4.6 in the reference group (n = 157, p 0.02). The IgG concentration range was 10-70 g/l in the HIV group (n = 27) vs. 10-30 g/l in the reference group (n = 160, p .001). The highest IgG concentrations in cases were found in symptomatic patients, but this relationship was not observed for IgM and IgA. The scattergram of IgA concentrations was the least elevated. The increase was significant when those with HIV-1 infection alone were compared with the healthy subjects (p .05). IgG2 subclass concentrations were determined only in patients of Kanuri and Hausa populations. In comparison to their healthy counterparts, IgG2 concentrations were significantly higher in the patient group (p .001). Other IgG subclasses showed a bimodal distribution in both groups. There was no significant difference in distribution of IgG1, IgG3, and IgG4 concentrations between the reference and the HIV groups. In several ethnic groups polyclonal hypergammaglobulinemia has been reported to be a frequent feature of HIV infection with markedly increased IgA concentrations. The differences observed here do not reflect a variation in the strain of the virus in the Nigerian populations, but may be related to racial and environmental factors.

Serum complement levels in asymptomatic Plasmodium falciparum parasitaemic children.

Twenty-eight (42%) of 67 afebrile children (mean age 6.3 +/- 3.6 years) undergoing various minor elective surgeries were slide positive for malaria parasitaemia. All infected subjects were given oral chloroquine therapy before and after blood samples were collected. Pre- and post-treatment complement (C4, C3, Bf and CH50 levels were evaluated in 15 of the subjects who had parasite densities > or = 500/microliter. These were compared with the levels in 15 age/sex-matched children who had acute malaria, as well as with the levels in 15 age/sex matched, non-infected controls. Significant consumption of C4 was observed in both the asymptomatic (p < 0.05) and symptomatic (p < 0.05) subjects. The mean serum levels of C4 were significantly higher in the asymptomatic, when compared with the symptomatic subjects (p < 0.01), and the healthy controls (p < 0.05). The distribution of classical pathway complement haemolytic titres in the groups studied was the same as that of the C4 levels. It is concluded that the forth component of the classical complement pathway may play a protective role in asymptomatic malaria.

The profile of C-reactive proteins in functional psychotic states in a cohort in Nigeria.

Based on the findings of previous work involving the measurement of 8 acute-phase proteins in 8 subjects receiving electroconvulsive therapy, we assayed the levels of C-reactive proteins (CRP) in 40 functional psychotic subjects, 37 of whom were consecutive admissions at the psychiatric ward. From 16 subjects, a second sample of blood for assay of CRP was collected 6 weeks after discharge from hospital, when the patients were no longer experiencing psychotic symptoms. The patients and controls were screened for tissue injury, inflammatory conditions and other diseases. We found that 14 (35%) of the psychiatric patients and only one (2%) of 50 normal control subjects had detectable levels of CRP. At follow-up, none of the 7 patients in whom CRP had been earlier detectable had measurable levels of CRP in the non-psychotic state. The presence of CRP was not related to biochemical indexes of nutritional status (total proteins and albumin), nor did clinical variables such as type of psychosis, pacing in acutely disturbed patients, use of intramuscular injections or diet and drugs distinguish the two groups of patients. It is suggested that the presence of CRP in the psychotic state is probably a state-dependent expression of nonspecific humoral immune alteration in subjects in whom more specific tests could reveal some immune alteration.

Acute phase reactants and severity of homozygous sickle cell disease.

Serum concentrations of seven acute-phase reactants: albumin, transferrin (Tf), alpha-1-antitrypsin (AIAT), caeruloplasmin (Cp), alpha 2-macroglobulin (alpha 2-MG), haptoglobin (hp) and C-reactive protein (CRP) were determined in 73 subjects with varying severities of homozygous sickle cell (HbSS) disease. Fifty healthy subjects of comparable sex, age and socio-economic class distributions as the HbSS subjects served as controls. Albumin and alpha 2-MG were comparable in all the subject groups. Tf and hp levels were significantly reduced in the HbSS groups relative to the control group. Conversely, AIAT, CRP and CP were significantly elevated. However only Tf and CRP manifested significant correlations with any of the indices of disease severity employed. Transferrin and CRP are suggested as plasma proteins worthy of further evaluation as indicators of severity in homozygous sickle cell disease.

Serum immunoglobulin (G, A and M) classes and IgG subclasses in sickle cell anaemia.

Serum concentrations of immunoglobulins G, A, M and IgG subclasses were determined by single radial immunodiffusion assay in a population of sickle cell anaemia patients resident in the tropics. Fifty apparently healthy subjects of haemoglobin genotype AA, of comparable age, sex and socioeconomic status (SES), and in the same environment as the patients, were included as controls. Three indices of morbidity in SCA, namely frequency of crisis, degree of anaemia and the number of organ complications, were used to derive a severity score for each patient; and thus categorize the subjects into severity groups. Immunoglobulin levels were then correlated with the indices of morbidity as well as the derived severity score. IgG, IgA, IgM, IgG1 and IgG3 levels were significantly raised in the SCA subjects when they were compared as a group with the controls. When separated into disease severity groups, the mildly affected patients were found to have virtually normal levels of immunoglobulins. Total IgG concentration and level of the IgG3 subclass showed significant positive correlation with frequency of crisis and derived severity score. Markedly raised levels of IgG and IgG3 may be predictive of severity in sickle cell anaemia.

Foetal haemoglobin levels in Nigerians with sickle cell anaemia. A revisitation.

Foetal haemoglobin (HbF) levels were estimated by the alkali denaturation method in 73 Nigerians with sickle cell anaemia (SCA). Subjects were studied during their asymptomatic periods and were divided into three groups based on HbF levels. Group I: HbF levels < 10%; group II: HbF levels > or = 10% but < 15%; group III: HbF levels > or = 15%. Mean crises per year, number of organ (system) complications, degree of anaemia, as well as total severity scores derived from these three parameters did not vary significantly in the three groups. Similarly, HbF levels failed to manifest significant correlation between either frequency of crises, occurrence of complications, degree of anaemia or the derived total severity scores. It is probable that in Nigerian SCA subjects whose HbF concentrations are mostly < 20%, other variables apart from HbF may influence the severity of their disease.