Human circulating specific antibody-forming cells after systemic and mucosal immunizations: differential homing commitments and cell surface differentiation markers

Circulating spontaneous antibody-secreting cells (ASC) induced by mucosal and systemic immunizations in human volunteers have been characterized with respect to differentiation stage and homing commitments. Irrespective of the immunization route, the large majority of ASC co-expressed CD19 and HLA-DR, which are normally lost during the transition of plasmablasts to plasmocytes, as well as CD38, a marker of activated B cell blasts, expressed also by plasmocytes. However, these cells expressed neither CD28, a molecule acquired by plasmocytes, nor CD22 and CD37, which are lost during the transition of plasmablasts to plasmocytes. Therefore, the large majority of ASC found in peripheral blood after oral and parenteral immunizations are terminally differentiated B cells, but not fully differentiated plasmocytes. As a whole, the mucosally derived ASC population seemed to be more homogenously differentiated. CD25 was detected on few ASC, whereas ASC expressing CD71 were more numerous, especially among systemically derived ASC. Almost all ASC expressed the adhesion molecules CD44 and α4-integrins, irrespective of immunization route. However, virtually all systemically derived ASC expressed L-selectin, recognizing the peripheral lymph node addressin, whereas only a minority of mucosally induced blood ASC expressed L-selectin. These studies are the first to demonstrate in humans that circulating precursors of mucosal B cell immunoblasts utilize organ-specific recognition mechanisms distinct from those of corresponding systemic B cells and appear to be more advanced in the B lineage maturation pathway. Specialization of receptor expression could explain both the unification of immune responses in diverse mucosal sites and the physiologic segregation of mucosal from non-mucosal immune mechanisms in humans.     

Variations in helminth faecal egg counts in Kato-Katz thick smears and their implications in assessing infection status with Schistosoma mansoni

Examination of stool specimens by Kato-Katz (K-K) thick smears is the standard method recommended by the WHO for field diagnosis of intestinal schistosomiasis. However, there is increasing concern that this technique has low diagnostic sensitivity. In 326 study subjects, we compared the diagnostic yield of examining one, three or five Kato-Katz thick smears prepared from one stool specimen using 41.7 mg templates. In a subset of 169 subjects who had no demonstrable Schistosoma mansoni eggs in their first three Kato-Katz thick smears, we assessed the comparative advantage of examining an additional three Kato-Katz thick smears from another stool specimen, taken four weeks later, to that of cumulative yield obtained by examining all five Kato-Katz thick smears derived from the first stool specimen. For all helminth infections, single Kato-Katz thick smear-based prevalence estimates were significantly lower than those obtained from triplet or quintet Kato-Katz thick smears. Prevalence of S. mansoni infection based on single, triplet and quintet Kato-Katz thick smears from one stool specimen were 31.3%, 45.7% and 52.1%, respectively. Prevalence estimate of S. mansoni based on quintet Kato-Katz thick smears from the first day stool specimens was not different from cumulative estimate obtained with two triplet Kato-Katz thick smears from two stool specimens, 52.1% and 52.8%, respectively. In conclusion, either examination of quintet Kato-Katz thick smears from one stool specimen using 41.7 mg template or initial triplet Kato-Katz thick smears from one stool specimen, and if these are negative, followed by examination of additional triplet Kato-Katz thick smears from subsequent day stool specimen can adequately assess individuals for infection status with S. mansoni.     

Prevalence of onchocercal skin disease and infection among workers of coffee plantation farms in Teppi,southwestern Ethiopia

In June 1996, a study on the economic impacts of onchocercal skin disease was initiated in southwestern Ethiopia. We made parasitological and clinicoepidemiological investigations among 1619 workers of a coffee plantation firm in Teppi, south-western Ethiopia. Sixty percent of the workers were included in the study. The prevalence of onchocercal skin disease (OSD) was 85.3%. Severe OSD (SOSD) was found in 17.3% of the study subjects. This was 1/5 of all OSD cases. The overall nodule carrier rate was 44.2%, which differed significantly by age classes from a rate of 12.3% to 73.0%. This rate varied by sex, 51.7% in males and 22.6% in females. Microfilarial carrier rate (MFCR) was 77.6%. This rate did not vary neither with severity of disease nor with presence or absence of pruritus or onchodermatitis. Mean microfilarial count was determined to be 38.1 per mg of skin snip or 44.4 per mg of infected skin snips. The geometric mean of microfilarial load per infected skin was 23.8. The community microfilarial load (CMFL) was estimated to be 14.0 per mg skin snip. The study showed that SOSD is prevalent in Teppi and affects a substantial number of the working population. An intervention program is called for.     

Epidemiological studies on intestinal schistosomiasis in Wondo Genet,southern Ethiopia

A cross-sectional epidemiological survey was made on intestinal schistosomiasis due to Schistosoma mansoni in Wondo Genet, southern Ethiopia, in 1999 to generate preintervention parasitological and malacological baseline data to be used as a reference in evaluation of community-based pilot control trial to be launched using wild-growing Endod. A total of 3000 stool specimens were collected from schoolchildren enrolled in 14 schools and microscopically examined using Kato method. The overall prevalence and intensity of schistosomiasis mansoni was 34.6% and 184 eggs per gram of stool (EPG), respectively. Children excreting Schistosoma mansoni eggs were found in all of the 14 schools surveyed with a prevalence of infection ranging from 1.9% in Abaye School to 80.6% in Shesha Kekele School. The overall prevalence of S. mansoni infection among males and females was 38.4% and 27.3%, respectively (P = 0.0001, 95% C.I = 7.5%-14.7%) where as the intensity of infection was 186 EPG and 181 EPG, respectively (P = 0.8045, 95% C.I = 1.17%-1.23%). Malacological surveys of 27 water contact sites revealed the occurrence of Biomphalaria pfeifferi in 8 sites out of which 3 harbored infected snails shedding schistosome cercariae. The necessity for initiating community-based sustainable control programme is discussed.     

Comparison of computer assisted scan diagnoses and clinical diagnoses of major mental disorders in Butajira, rural Ethiopia

One of the major difficulties in mental health research is finding suitable research instruments. In the last few decades questionnaires that are supposed to work in different languages and cultures have been developed by WHO to solve this problem. One of such instruments is SCAN, an instrument which uses computer algorithm to make a diagnosis. It is meant to be used for semi-structured interview by qualified psychiatrists or clinical psychologists. This and a few other research instruments have been translated and used in clinical and community settings for psychiatric research in Ethiopia over the last few years. In this study computer assisted SCAN Diagnoses and clinical diagnoses made by trainee psychiatrists in Butajira, a rural setting in Ethiopia, were compared Seven hundred twenty nine persons were diagnosed to have schizophrenia and bipolar disorder using both methods. The agreement between the clinical and SCAN derived diagnosis was shown to be 100% for schizophrenia (Kappa = 1.0). However, the agreement between the two methods of diagnosis was shown to be lower when it comes to subtypes of schizophrenia. The agreement for the diagnoses of bipolar disorder was 95.3%, kappa = 0.9, P < 0.0001 and for depression it was 93.0%, kappa = 0.8, p < 0.0001. Taking into account the limited number of psychiatrists and clinical psychologists in the third world countries like Ethiopia we have shown that using trainees in psychiatry for SCAN interview is a feasible and reliable method to identify major categories of mental disorders in community studies.     

Graves' thyroid ophthalmopathy in Ethiopian patients

In a prospective study, we evaluated the clinical manifestations, severity, complication and management of Graves' thyroid ophthalmopathy (GTO) in 37 Ethiopian patients. Twenty-seven were females and 10 were males (F:M = 2.7:1). The mean age was 35 years (range 19-70 yrs). The mean duration of ocular symptoms was 33.4 months (range 2-120 months) while the mean duration of hyperthyroid symptoms was 36.2 months (range 6-120 months). GTO was found in 30 (81.1%) hyperthyroid, 1 (2.7%) hypothyroid and 5 (13.5%) euthyroid patients. Upper lid retraction was the most common clinical finding, being detected in 31 (83.8%) of the patients. One (2.7%) patient had marked extraocular muscle involvement, involving the inferior rectus muscle of one eye. Though 18 (48.6) patients had signs of soft tissue inflammation, only 4 (10.8%) required the administration of systemic steroids to control the inflammatory process. None of our patients had sight loss from the complications of GTO. Larger prospective studies are suggested to evaluate both the prevalence and possible racial difference in its clinical presentation.     

Sildenafil citrate use in Addis Ababa: characteristics of users and pharmacists’ dispensing practices

International Journal of Clinical Pharmacy - Background Studies have reported misuse of sildenafil citrate for recreational purpose, not least by healthy young men. This is becoming a major...