Quartan malarial nephrotic syndrome. Collaborative clinicopathological study in Nigerian children

Evaluation of the Performance of Rapid Diagnostic Tests for Malaria Diagnosis and Mapping of Different Plasmodium Species in Mali

BACKGROUND

The first-line diagnosis of malaria in Mali is based on the use of rapid diagnostic tests (RDT) that detect the Histidin Rich Protein 2 (HRP2) antigen specific to Plasmodium falciparum. Our study, based on a real-time polymerase chain reaction (qPCR) gold standard, aimed to describe the distribution of the Plasmodium species in each administrative region of Mali and to assess the performance of RDTs.

METHODS

We randomly selected 150 malaria-negative and up to 30 malaria-positive RDTs in 41 sites distributed in 9 regions of Mali. DNA extracted from the RDT nitrocellulose strip was assayed with a pan-Plasmodium qPCR. Positive samples were then analyzed with P. falciparum-, P. malariae-, P. vivax-, or P. ovale-specific qPCRs.

RESULTS

Of the 1496 RDTs, 258 (18.6%) were positive for Plasmodium spp., of which 96.9% were P. falciparum. The P. vivax prevalence reached 21.1% in the north. RDT displayed acceptable diagnostic indices; the lower CI95% bounds of Youden indices were all ≥0.50, except in the north (Youden index 0.66 (95% CI [0.44-0.82]) and 0.63 (95% CI [0.33-0.83].

CONCLUSIONS

Overall, RDT diagnostic indices are adequate for the biological diagnosis of malaria in Mali. We recommend the use of RDTs detecting P. vivax-specific antigens in the north.

Childhood Nephrotic Syndrome in Africa: Epidemiology, Treatment Trends, and Outcomes

Nephrotic syndrome is a common childhood glomerular disease that is associated with massive proteinuria and edema. Children with nephrotic syndrome are at risk of chronic kidney disease, disease-related complications, and treatment-related complications. Patients with frequently relapsing disease or steroid toxicity may require newer immunosuppressive medications. However, access to these medications is limited in many African countries owing to prohibitive cost, the need for frequent therapeutic drug monitoring, and a lack of appropriate facilities. This narrative review examines the epidemiology of childhood nephrotic syndrome in Africa, including trends in treatment and patient outcomes. In most of North Africa, as well as among White and Indian populations in South Africa, the epidemiology and treatment of childhood nephrotic syndrome closely resembles that of European and North American populations. Historically, secondary causes of nephrotic syndrome (eg, quartan malaria nephropathy and hepatitis B-associated nephropathy) were predominant among Blacks in Africa. Over time, the proportion of secondary cases has decreased, along with rates of steroid resistance. However, focal segmental glomerulosclerosis increasingly has been reported among patients with steroid resistance. There is a need for consensus guidelines for the management of childhood nephrotic syndrome in Africa. Furthermore, establishing an African nephrotic syndrome registry could facilitate monitoring of disease and treatment trends, and provide opportunities for advocacy and research to improve patient outcomes.

Trends in the epidemiology of childhood nephrotic syndrome in Africa: A systematic review

Background

Childhood nephrotic syndrome, if left untreated, leads to progressive kidney disease or death. We quantified the prevalence of steroid-sensitive nephrotic syndrome, steroid-resistant nephrotic syndrome, and histological types as the epidemiology of nephrotic syndrome in Africa remains unknown, yet impacts outcomes.

Methods

We searched MEDLINE, Embase, African Journals Online, and WHO Global Health Library for articles in any language reporting on childhood nephrotic syndrome in Africa from January 1, 1946 to July 1, 2020. Primary outcomes included steroid response, biopsy defined minimal change disease, and focal segmental glomerulosclerosis (FSGS) by both pooled and individual proportions across regions and overall.

Findings

There were 81 papers from 17 countries included. Majority of 8131 children were steroid-sensitive (64% [95% CI: 63-66%]) and the remaining were steroid-resistant (34% [95% CI: 33-35%]). Of children biopsied, pathological findings were 38% [95% CI: 36-40%] minimal change, 24% [95% CI: 22-25%] FSGS, and 38% [95% CI: 36-40%] secondary causes of nephrotic syndrome.

Interpretation

Few African countries reported on the prevalence of childhood nephrotic syndrome. Steroid-sensitive disease is more common than steroid-resistant disease although prevalence of steroid-resistant nephrotic syndrome is higher than reported globally. Pathology findings suggest minimal change and secondary causes are common. Scarcity of data in Africa prevents appropriate healthcare resource allocation to diagnose and treat this treatable childhood kidney disease to prevent poor health outcomes.

Funding

Funding was provided by the Canadian Institute for Health Research (CIHR) and the National Institute of Health (NIH) for the H3 Africa Kidney Disease Research Network. This research was undertaken, in part, from the Canada Research Chairs program.

Changing epidemiology of nephrotic syndrome in Nigerian children: A cross-sectional study

BACKGROUND

Recent reports from small studies in West Africa suggest that Black children may have high rate of steroid sensitivity nephrotic syndrome (SSNS) contrary to long held knowledge. Herein, we determined the proportion of children with idiopathic nephrotic syndrome (INS) who achieved complete remission with steroid therapy and identified factors associated with complete remission.

METHODS

We reviewed the medical records of 241 children with INS in two centres in Lagos from 2010 to 2019. We extracted demographic data, clinical features, laboratory values at the time of diagnosis, and receipt and response to steroids and other immunosuppressants.

RESULTS

The median (interquartile range) age at diagnosis of INS was 5.1 (3.0-8.7) years and boys were 60.2% of the study population. Children with SSNS made up 85.9% (n = 207) of the study cohort. Among those aged 0-5 years, 92.6%were SSNS compared with 69.2% in those aged 11-17 years at the time of diagnosis. In addition, the proportion of children with SSNS increased from 73.8% between year 2010 and 2012 to 88.4% afterwards. Also, children with SSNS had lower serum creatinine (0.44 vs 0.70; p<0.001) and higher estimated glomerular filtration rate (101 vs 74.3 ml/min/1.73 m2; p = 0.008) at the time of diagnosis than those with steroid resistant nephrotic syndrome (SRNS).

CONCLUSION

Among Black children in Lagos, the proportion with SSNS is comparable to proportions described in children of Asian and European descent. Furthermore, children with SSNS had lower serum creatinine and higher glomerular filtration rate than those with SRNS.

Global prevalence and mortality of severe Plasmodium malariae infection: a systematic review and meta-analysis

Background

Severe complications among patients with Plasmodium malariae infection are rare. This is the first systematic review and meta-analysis demonstrating the global prevalence and mortality of severe P. malariae infection in humans.

Methods

The systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. All research articles published on the severity and mortality of P. malariae infection cases in humans were retrieved from three public databases: PubMed, Scopus, and ISI Web of Science. The pooled prevalence estimate and 95% confidence interval (CI) of complications in patients with P. malariae malaria was analysed using the random-effects model provided in Stata software. The pooled odds ratio (OR) and 95% CI of severe malaria for P. malariae infection and Plasmodium falciparum infection were analysed using Review Manager software.

Results

Six studies were used to estimate the pooled prevalence of severe P. malariae malaria. Out of 10,520 patients infected with P. malariae, the pooled prevalence estimate of severe P. malariae infection was 3% (95% CI 2–5%), with high heterogeneity (I²: 90.7%). Severe anaemia (3.32%), pulmonary complications (0.46%), and renal impairments (0.24%) were the most common severe complications found in patients with P. malariae infection. The pooled proportion of severe anaemia for P. malariae infection and P. falciparum infection was comparable among the four included studies (OR: 0.74, 95% CI 0.22–2.45, I² = 98%). The pooled proportion of pulmonary complications was comparable between patients with P. malariae infection and those with P. falciparum infection among the four included studies (OR: 1.44; 95% CI 0.17–12.31, I²: 92%). For renal complications, the funnel plot showed that the pooled proportion of renal complications for P. malariae infection and P. falciparum infection was comparable among the four included studies (OR: 0.94, 95% CI 0.18–4.93, I²: 91%). The mortality rate of patients with P. malariae infection was 0.17% (18/10,502 cases).

Conclusions

This systematic review demonstrated that approximately two percent of patients with P. malariae infection developed severe complications, with a low mortality rate. Severe anaemia, pulmonary involvement, and renal impairment were the most common complications found in patients with P. malariae infection. Although a low prevalence and low mortality of P. malariae infection have been reported, patients with P. malariae infection need to be investigated for severe anaemia and, if present, treated aggressively to prevent anaemia-related death.

Persistent transmission of Plasmodium malariae and Plasmodium ovale species in an area of declining Plasmodium falciparum transmission in eastern Tanzania

A reduction in the global burden of malaria over the past two decades has encouraged efforts for regional malaria elimination. Despite the need to target all Plasmodium species, current focus is mainly directed towards Plasmodium falciparum, and to a lesser extent P. vivax. There is a substantial lack of data on both global and local transmission patterns of the neglected malaria parasites P. malariae and P. ovale spp. We used a species-specific real-time PCR assay targeting the Plasmodium 18s rRNA gene to evaluate temporal trends in the prevalence of all human malaria parasites over a 22-year period in a rural village in Tanzania.We tested 2897 blood samples collected in five cross-sectional surveys conducted between 1994 and 2016. Infections with P. falciparum, P. malariae, and P. ovale spp. were detected throughout the study period, while P. vivax was not detected. Between 1994 and 2010, we found a more than 90% reduction in the odds of infection with all detected species. The odds of P. falciparum infection was further reduced in 2016, while the odds of P. malariae and P. ovale spp. infection increased 2- and 6-fold, respectively, compared to 2010. In 2016, non-falciparum species occurred more often as mono-infections. The results demonstrate the persistent transmission of P. ovale spp., and to a lesser extent P. malariae despite a continued decline in P. falciparum transmission. This illustrates that the transmission patterns of the non-falciparum species do not necessarily follow those of P. falciparum, stressing the need for attention towards non-falciparum malaria in Africa. Malaria elimination will require a better understanding of the epidemiology of P. malariae and P. ovale spp. and improved tools for monitoring the transmission of all Plasmodium species, with a particular focus towards identifying asymptomatic carriers of infection and designing appropriate interventions to enhance malaria control.

The reduction in the global burden of malaria has encouraged efforts for elimination. Attempts to control and monitor transmission have mainly focused on the predominant malaria parasites Plasmodium falciparum and P. vivax. However, eliminating malaria requires the elimination of all human malaria parasites and limited interest has been directed towards estimating the disease burden attributable to the neglected malaria parasites P. ovale spp. and P. malariae. The authors used molecular methods to analyse 2897 blood samples collected in five cross-sectional surveys over a period of 22 years, and described the transmission patterns of all human malaria parasites in a Tanzanian village. They demonstrate a persistent transmission of P. malariae and P. ovale spp. despite a substantial reduction in transmission of P. falciparum, highlighting the need for more attention towards non-falciparum malaria. The authors discuss the implications of these findings in the context of current efforts for regional malaria elimination.

Prospects of genetic testing for steroid-resistant nephrotic syndrome in Nigerian children: a narrative review of challenges and opportunities

The prevalence of childhood steroid-resistant nephrotic syndrome (SRNS) ranges from 35% to 92%. This steroid resistance among Nigerian children also reflects underlying renal histopathology, revealing a rare minimal-change disease and a varying burden of membranoproliferative glomerulonephritis and focal segmental glomerulosclerosis (FSGS). FSGS tends to progress to end-stage kidney disease, which requires dialysis and/or renal transplantation. While knowledge of the molecular basis of NS is evolving, recent data support the role of mutant genes that otherwise maintain the structural and functional composition of the glomerular filtration barrier to account for many monogenic forms of FSGS. With the advent of next-generation sequencing, >39 genes are currently associated with SRNS, and the number is likely to increase in the near future. Monogenic FSGS is primarily resistant to steroids, and this foreknowledge obviates the need for steroids, other immunosuppressive therapy, and renal biopsy. Therefore, a multidisciplinary collaboration among cell biologists, molecular physiologists, geneticists, and clinicians holds prospects of fine-tuning the management of SRNS caused by known mutant genes. This article describes the genetics of NS/SRNS in childhood and also gives a narrative review of the challenges and opportunities for molecular testing among children with SRNS in Nigeria. For these children to benefit from genetic diagnosis, Nigeria must aspire to have and develop the manpower and infrastructure required for medical genetics and genomic medicine, leveraging on her existing experiences in genomic medicine. Concerted efforts can be put in place to increase the number of enrollees in Nigeria’s National Health Insurance Scheme (NHIS). The scope of the NHIS can be expanded to cater for the expensive bill of genetic testing within or outside the structure of the National Renal Care Policy proposed by Nigerian nephrologists.

Two cases of long-lasting, sub-microscopic Plasmodium malariae infections in adults from coastal Tanzania

Background

Malaria is endemic in Tanzania with majority of clinical cases caused by Plasmodium falciparum. Additionally, Plasmodium malariae and Plasmodium ovale spp. are also present and clinical manifestations caused by these infections are not well described. Clinical episodes caused by P. malariae infections are often characterized by a relatively mild illness with a low number of parasites, which can persist for long periods. In this report, two cases of P. malariae infections that were identified during a clinical trial evaluating the P. falciparum malaria vaccine candidate, PfSPZ Vaccine are described. The two participants were followed up and monitored for clinical and laboratory parameters to assess vaccine safety providing the opportunity to study clinical manifestations of P. malariae over 4 months.

Case presentation

Two young, healthy Tanzanian men infected with low density asexual blood stage P. malariae diagnosed by quantitative polymerase chain reaction (qPCR) are described. Retrospective analysis of collected and stored blood samples revealed that the two volunteers had constant asexual blood stage parasitaemia for more than 4 months. During the 132 days of infection, the volunteers’ vital signs, body temperature and serum biochemistry all remained within normal ranges. Haematological abnormalities, which were transiently outside normal ranges, were regarded as not clinically significant. During this time period, four consecutive evaluations of blood samples by thick blood smear microscopy conducted by an experienced microscopist were all negative, indicating the presence of low-density sub-microscopic infections.

Conclusions

The two cases of P. malariae infections presented here confirm the ability of this Plasmodium species to persist at low density in the human host for extended time periods without causing clinical symptoms. The presented data also demonstrate that clinical study sites in malaria endemic regions need to have a strong malaria diagnostic infrastructure, including the ability of capturing sub-microscopic parasitaemia and differentiation of Plasmodium species.

Trial registration ClinicalTrials.gov: NCT02613520, https://clinicaltrials.gov/ct2/show/NCT02613520, Registered: November 24th 2015, Enrolment of the first participant to the trial: December 15th 2015, Trial was registered before the first participant was enrolled

Childhood nephrotic syndrome in tropical Africa: then and now

This descriptive and comparative review examines the changing epidemiology, treatment, renal and patient outcome of childhood nephrotic syndrome (NS) in tropical Africa (TpAfr). In the 1960s to 1980s, corticosteroid-resistant non-minimal change disease (nMCD) including quartan malaria nephropathy (QMN) was the dominant renal histopathology type. The overall incidence of NS was 0.35-1.34% of hospital admissions. Median age at onset of NS ranged between 4.0 and 12.0 years while the mean (SD) age range was 5.8 (3.8) to 10.3 (4.8) years across studies. The male: female ratio was 1.6:1.0. The overall mean (SD) incidence of idiopathic minimal change disease (MCD) [21.6 (18.6%)] compared with idiopathic nMCD [59.1 (25.7%)] demonstrates significant dominance of the latter (p = 0.0001). Post-1989, the following mean (SD) incidences of histopathological types were: MCD 20.4 (17.7%), focal segmental glomerulosclerosis 39.0 (26.3%), membranoproliferative glomerulonephritis 25.4 (16.8%), proliferative glomerulonephritis 16.7 (27.0%) and membranous nephropathy 7.4 (4.5%). While the mean (SD) proportion of steroid resistance (SR) [73.5 (19.2%)] was significantly greater than the mean complete remission (CR) [26.5 (19.2%)] during 1960-1989 (p=0.005), mean (SD) SR [27.4 (25.3%)] was significantly lower than mean (SD) CR [66.1 (28.0%)] post-1989 (p < 0.001). Unlike QMN, hepatitis B virus, HIV infection, sickle cell disease and systemic lupus erythematosus are now increasingly being associated with NS in TpAfr. Mean (SD) renal survival post-1989 was 58.3 (37.0%) while all-cause mortality was 9.8%. Children with NS now survive better than before, reflecting improved access to healthcare and transition to a clinical pattern favouring idiopathic NS and increased sensitivity to corticosteroids.

Epidemiology of Histologically Proven Glomerulonephritis in Africa: A Systematic Review and Meta-Analysis

Background and aim

Glomerulonephritis (GN) is a leading cause of end-stage renal disease (ESRD) in Africa. Data on epidemiology and outcomes of glomerular diseases from Africa is still limited. We conducted a systematic review on the epidemiology of histologically proven glomerular diseases in Africa between 1980 and 2014.

Materials and methods

We searched literature using PubMed, AfricaWide, the Cumulative Index to Nursing and Allied Health Literature on EBSCO Host, Scopus, African Journals online databases, and the African Index Medicus, for relevant studies. The review was conducted using standard methods and frameworks using only biopsy-confirmed data.

Results

Twenty four (24) studies comprising 12,093 reported biopsies from 13 countries were included in this analysis. The median number of biopsies per study was 127.0 (50–4436), most of the studies (70.0%) originated from North Africa and the number of performed kidney biopsies varied from 5.2 to 617 biopsies/year. Nephrotic syndrome was the commonest indication of renal biopsy. The frequency of reported primary pathologic patterns included, minimal change disease (MCD); 16.5% (95%CI: 11.2–22.6), focal segmental glomerulosclerosis (FSGS); 15.9% (11.3–21.1), mesangiocapillary GN (MCGN); 11.8% (9.2–14.6), crescentic GN; 2.0% (0.9–3.5) and IgA nephropathy 2.8% (1.3–4.9). Glomerular diseases related to hepatitis B and systemic lupus erythematosus had the highest prevalence among assessed secondary diseases: 8.4% (2.0–18.4) and 7.7% (4.5–11.7) respectively. There was no evidence of publication bias and regional differences were seen mostly for secondary GNs.

Conclusions

Glomerular diseases remain poorly characterized in sub-Saharan Africa due to declining renal biopsy rates and consequent paucity of data on pathologic patterns of key renal diseases. Development of renal biopsy registries in Africa is likely to enable adequate characterization of the prevalence and patterns of glomerular diseases; this could have a positive impact on chronic kidney disease evaluation and treatment in the African continent since most glomerulopathies are amenable to treatment.

Trends in the histopathology of childhood nephrotic syndrome in Ibadan Nigeria: preponderance of idiopathic focal segmental glomerulosclerosis

Background

Reports on the histopathology of childhood nephrotic syndrome (NS) had emanated from our Centre since the 1960s and by the late 1980s and early 1990s, a change was observed and reported. Taking into consideration the worldwide changing trend in the histopathology of the NS and our Unit policy change in the indications for renal biopsy, a change was envisaged. We therefore evaluated the current histologic pattern of childhood NS in Ibadan with the view to highlighting any variations from the past and comparing the findings with regional and global trends.

Methodology

We reviewed our database and analyzed the renal biopsy findings in patients who were biopsied before treatment was administered between 1997 and 2001 and those with mostly idiopathic steroid resistant NS (SRNS) and secondary NS, managed between 2006 and 2013. A comparative analysis of the findings from the present study was carried out with two previous reports from our Unit in the 1970s and early 1990s and also with reports from other Centres.

Results

A total of 78 patients had successful biopsies done during the study period in children aged between 2 ½ and 16 years. In both pre-treatment biopsy era (1997–2001) and post-treatment biopsy era (2006–2013), focal segmental glomerulosclerosis (FSGS) predominated. 75 % of the patients had idiopathic NS and among the patients that had idiopathic steroid resistant NS, FSGS was the most common followed by MPGN. For secondary NS, MCD was the most common but could be the early stages of either membranous nephropathy (MN) or FSGS. Chronic pyelonephritis and chronic interstitial nephritis occurred in 25 % of the study population but they were more prevalent in secondary nephrotic syndrome.

Conclusion

FSGS is the most common histopathology in children requiring renal biopsy in Ibadan presently. FSGS is also the most common histopathology in idiopathic SRNS, which is in keeping with reports from most parts of the world.

There has been a transition from the preponderance of Quartan Malarial Nephropathy (QMN) in the 1960s to MPGN in the 1980s to FSGS presently. This has great implications with regards to searching for new aetiologic factors, providing more efficacious treatment modalities and ensuring facilities for immunofluorescence, electron microscopic and genetic studies.

Glomerulonephropathies in Plasmodium inui-infected rhesus monkey: a primate model and possible applications for human quartan malaria

SUMMARY None of the few animal models proposed for the study of human quartan malaria nephritic syndrome have shown complete pathological findings that are similar to those seen in humans. This study investigated the histopathological changes in kidneys in 10 Plasmodium inui infected Macaca mulatta monkeys by light and electron microscopy in order to develop a suitable animal model for human quartan malaria. Ten healthy adult rhesus monkeys were infected with P. inui and clinical chemistry and haematologic tests were done before and after infection. A renal biopsy sample was collected before infection as a baseline control and another biopsy was collected after infection. Histopathological changes examined by light and transmission electron microscopy (TEM) revealed abnormalities in all infected monkeys to variable degrees. Several electron-dense discrete or diffused mesangial deposits, and increase in mesangial cells and matrix were associated with the morphological changes observed by light microscope. This pattern is consistent with membranoproliferative glomerulonephritis type reported in humans infected with Plasmodium malariae. Results strongly support that the P. inui-infected rhesus monkey develop an immune-complex-mediated glomerulonephritis in the course of the infection. Therefore, this experimental model represents a useful tool to better understand the different parameters and the consequences of quartan malaria infections comparable to situations in humans.

Acute kidney injury associated with Plasmodium malariae infection

According to current estimates, Plasmodium malariae is not very common in Senegal, as more than 98% of malaria cases are suspected to be due to Plasmodium falciparum. However, it is possible that other malarial species are being under-reported or misdiagnosed. This is a report of a case of P. malariae in a 30-year-old man previously hospitalized with acute kidney injury after treatment with quinine and re-hospitalized three months later. He was diagnosed with renal cortical necrosis post malaria treatment. Plasmodium malariae was identified with light microscope and confirmed using species-specific small-subunit rRNA (ssrRNA) amplification.The patient was treated for malaria with intravenous quinine for seven days, followed by three days of oral treatment; the bacterial infection was treated using ceftriaxone during the first hospitalization and ciprofloxacin associated with ceftriaxone the second time. He also had four rounds of dialysis after which he partially recovered the renal function. Given the complications that can be caused by P. malariae infection, it should be systematically looked for, even if the predominant species is P. falciparum in Senegal.

Acute respiratory distress syndrome and acute renal failure from Plasmodium ovale infection with fatal outcome

BACKGROUND

Plasmodium ovale is one of the causative agents of human malaria. Plasmodium ovale infection has long been thought to be non-fatal. Due to its lower morbidity, P. ovale receives little attention in malaria research.

METHODS

Two Malaysians went to Nigeria for two weeks. After returning to Malaysia, they fell sick and were admitted to different hospitals. Plasmodium ovale parasites were identified from blood smears of these patients. The species identification was further confirmed with nested PCR. One of them was successfully treated with no incident of relapse within 12-month medical follow-up. The other patient came down with malaria-induced respiratory complication during the course of treatment. Although parasites were cleared off the circulation, the patient's condition worsened. He succumbed to multiple complications including acute respiratory distress syndrome and acute renal failure.

RESULTS

Sequencing of the malaria parasite DNA from both cases, followed by multiple sequence alignment and phylogenetic tree construction suggested that the causative agent for both malaria cases was P. ovale curtisi.

DISCUSSION

In this report, the differences between both cases were discussed, and the potential capability of P. ovale in causing severe complications and death as seen in this case report was highlighted.

CONCLUSION

Plasmodium ovale is potentially capable of causing severe complications, if not death. Complete travel and clinical history of malaria patient are vital for successful diagnoses and treatment. Monitoring of respiratory and renal function of malaria patients, regardless of the species of malaria parasites involved is crucial during the course of hospital admission.

Increased steroid responsiveness of young children with nephrotic syndrome in Nigeria

A previous study on the nephrotic syndrome (NS) in our unit showed that the histological patterns associated with steroid resistance were more common in children over 5 years of age.

AIM

The aim of the study was to determine the incidence of steroid-responsiveness amongst nephrotic children <or=5 years.

SUBJECTS AND METHODS

All children with NS aged <or=5 years at the onset of disease presenting to University College Hospital, Ibadan were enrolled. Prednisolone was given daily, 60 mg/m2, for 4 weeks and then 40 mg/m2 on alternate days for at least 12 weeks.

RESULTS

Twenty children (9 boys and 11 girls) were enrolled between 1999 and 2002. The median age (range) at onset of disease was 4 (2-5) years. Remission was achieved in 12 (60%) children.

CONCLUSION

There is a satisfactory response to prednisolone in two-thirds of Nigerian children aged <or=5 years with NS.

Parasitic kidney disease: milestones in the evolution of our knowledge

Of the 342 parasites that infect humans, 20 are associated with kidney disease, yet of these, only schistosomes, plasmodia, filariae, and leishmanias are held responsible for significant clinical or epidemiologic impact. Reviewing the evolution of human knowledge for these parasites discloses a lot of similarities regarding their discovery, patterns of kidney injury, and pathogenic mechanisms. From a historical perspective, our relevant information may be classified into 4 phases: (1) disease documentation in ancient and medieval scripts as far back as 2000-3000 bce; (2) discovery of the parasites, their life cycles, and clinical correlates by European clinicians working in African and Asian colonies during the second half of the 19th century; (3) discovery and characterization of the renal manifestations of monoparasitic infections during the second half of the 20th century; and (4) recognition of the confounding effects of coinfection with bacteria, viruses, or other parasites. The spectrum of respective kidney diseases extends all the way from acute kidney injury to glomerulonephritis, amyloidosis, urologic disorders, and malignancy. Discovery of the common immunopathogenetic host response to parasitic infections has provided a knowledge core that explains the similarities, diversities, and interactions with regard to kidney injury.

Quartan malaria-associated childhood nephrotic syndrome: now a rare clinical entity in malaria endemic Nigeria

BACKGROUND

The study determined (i) whether or not quartan malaria nephropathy (QMN) is still a major cause of childhood nephrotic syndrome (CNS) in Nigeria, (ii) secondary causes other than QMN and their associated glomerular pathology and (iii) renal and patient outcome.

METHODS

The study was a prospective non-randomized study of consecutive cases of secondary CNS. Patients with idiopathic CNS were excluded.

RESULTS

Twenty-four of 78 (30.8%) CNS cases were of secondary aetiology. Overall mean ages at onset of secondary CNS aetiology and CNS onset were 8.97 +/- 3.59 (1-15.3) and 9.95 +/- 3.15 (5-15.3) years, respectively. Male (14)/female (10) ratio was 1.4. Secondary causes comprised systemic lupus erythematosus (SLE, 37.5%), sickle cell anaemia (SCA, 16.7%), hepatitis B virus (HBV, 16.7%) infection, Churg-Strauss syndrome (12.6%), SLE/human immunodeficiency virus infection (4.2%), rhabdomyosarcoma (4.2%), bee stings (4.2%) and Addison's disease (4.2%). The overall cumulative complete remission (CR) rate was 88.0%. Remission was sustained in 11 of 16 (68.8%) CR patients, while one patient (6.25%) relapsed; the remaining four patients (24.95%) were yet to attain sustained remission. Median relapse-free period was 10.5 (0.75-25) months. Cumulative renal survival was 75.2% at 3 years. Three patients were lost to follow-up, while two died. Overall cumulative patient survival probability at 36 months was 90.8%. All patients were followed for a median period of 12.5 (0.11-36.0) months.

CONCLUSION

Overall outcome of CNS has improved significantly compared to the 1960s and 1970s when the poor outcome of QMN was the predominant glomerular lesion in Nigeria. While quartan malaria-associated nephrotic syndrome has become a rare clinical entity, SLE, SCA and HBV infection have become the major secondary aetiologies of CNS in Nigeria.

Plasmodium malariae: parasite and disease

A review of the life history of Plasmodium malariae, the quartan malaria parasite of humans, is presented. Much of the information is based on data obtained from induced infections in humans who were given malaria therapy for the treatment of neurosyphilis between 1940 and 1963. Prepatent periods (i.e., the time until the first day of parasite detection) fever episodes, and maximum parasitemias as a result of infection with P. malariae were obtained and are presented. Experimental and known vectors of the parasite are also discussed. Splenectomized chimpanzees and New World monkeys are readily infected and serve as sources of parasites and antigens for diagnostic and molecular studies. South American monkeys are naturally infected with a parasite known as Plasmodium brasilianum. This parasite appears to be P. malariae that has adapted from humans to grow in monkeys, probably within the last 500 years. Infection with P. malariae is associated with the production of immune complexes in the kidneys and the associated nephrotic syndrome. The essential lesions are a thickening of the glomerular basement membrane and endocapillary cell proliferation. Studies of monkeys infected with P. malariae indicate the same pathology as that demonstrated in humans.

Epidemiology, pathophysiology, management and outcome of renal dysfunction associated with plasmodia infection

Malaria remains a serious health problem in many parts of the world. It causes high morbidity and claims many lives in developing countries each year. Humans are generally infected by four species of malaria parasites. However, malaria infection caused by Plasmodium malariae or P. falciparum is recognized as an important cause of acute renal failure (ARF) and other renal-related disorders (nephropathy) in infected patients. The increasing incidence of malarial ARF (MARF) and the emergence of clinical malarial infection after renal transplantation represent a serious challenge. Additionally, the impact of immunosuppressive therapies on malarial infection is intricate, complex, and not yet well defined. Pathogenesis of MARF is most likely to be due to immune complex-mediated glomerulonephritis caused by immune-complex deposition and endothelial damage, which may lead to fatal forms of quartan malarial nephropathies. Effects of mechanical, immunologic, cytokine, humoral, acute phase response, and hemodynamics factors in inducing malarial nephropathy have also been postulated. Development of preventive strategies aimed at combating MARF and other renal disorders associated with malaria infection requires (1) prevention of malarial infection, (2) early diagnosis, and (3) early referral to well-equipped centers to provide renal replacement therapy, if necessary, along with antimalarial therapy and support. These measures could significantly reduce mortality and enhance recovery of renal function.

Malaria-induced renal damage: facts and myths

Malaria infections repeatedly have been reported to induce nephrotic syndrome and acute renal failure. Questions have been raised whether the association of a nephrotic syndrome with quartan malaria was only coincidental, and whether the acute renal failure was a specific or unspecific consequence of Plasmodium falciparum infection. This review attempts to answer questions about "chronic quartan malaria nephropathy" and "acute falciparum malaria nephropathy". The literature review was performed on all publications on kidney involvement in human and experimental malarial infections accessible in PubMed or available at the library of the London School of Hygiene and Tropical Medicine. The association of a nephrotic syndrome with quartan malaria was mostly described before 1975 in children and rarely in adult patients living in areas endemic for Plasmodium malariae. The pooled data on malaria-induced acute renal failure included children and adults acquiring falciparum malaria in endemic areas either as natives or as travellers from non-tropical countries. Non-immunes (not living in endemic areas) had a higher risk of developing acute renal failure than semi-immunes (living in endemic areas). Children with cerebral malaria had a higher rate and more severe course of acute renal failure than children with mild malaria. Today, there is no evidence of a dominant role of steroid-resistant and chronic "malarial glomerulopathies" in children with a nephrotic syndrome in Africa. Acute renal failure was a frequent and serious complication of falciparum malaria in non-immune adults. However, recently it has been reported more often in semi-immune African children with associated morbidity and mortality.

Identification and typing of Cameroonian isolates of P. malariae using monoclonal antibodies against P. brasilianum

In the present study, monoclonal antibodies raised against Plasmodium brasilianum were used to demonstrate, for the first time, antigenic diversity in natural populations of Plasmodium malariae isolates and as diagnostic tool to detect low parasitaemia P. malariae infection. Seventeen McAbs reacting by indirect immunoflorescence antibody (IFA) assay with no other Plasmodium species than P. brasilianum, were shown to react with P. malariae and were used for typing 29 P. malariae isolates from hyperendemic areas in Yaounde and in three villages of South Cameroon with parasitaemia ranging from 0.01% to 1.8%. All 29 isolates were distinguished by their ability to react with certain antibodies and considered as representing different isolates of P. malariae. One of these McAbs (No. 14) recognized P. malariae isolates to both in Yaounde and from Mengang but not in Edou or in Nkol Mvae, which may recognize a specific epitope that is less common in strains found in these villages and provide evidence of regional variation within the P. malariae parasites. The McAbs Nos. 16 and 17 were used to determine their usefulness as diagnostic tools for 30 suspected blood samples that were collected from patients with fever and it became clear that they could detect sub-microscopical infections of P. malariae. This study supports the concept of using of P. brasilianum as a substitute for P. malariae during immuno-diagnosis of malaria in endemic areas where PCR assay cannot be used for identification of the P. malariae parasites. In addition our results for the first time provide evidence of considerable antigenic diversity of clinical P. malariae isolates in Cameroon.

Nephrotic syndrome in African children: lack of evidence for ‘tropical nephrotic syndrome’?

BACKGROUND

Infections such as malaria, schistosomiasis, hepatitis B and HIV have been suggested as major causes of the nephrotic syndrome (NS) in African children. We retrospectively analysed the course of the NS in 32 children from Ghana and reviewed the literature on NS from 18 different African countries for the presence of 'the tropical nephrotic syndrome'.

METHODS

Thirty-two children (22 boys, 10 girls, median age 12 years, range 1-18 years) with NS were treated from 2000-2003 at Battor Hospital, Ghana. Thirteen out of 32 children underwent a renal biopsy which was investigated by light, immune and electron microscopy. All 32 patients were initially treated with oral prednisone (PRED) therapy (29 with standard therapy for 8 weeks and three individually tailored), and steroid-resistant children received also intravenous methylprednisolone pulses (three children) or oral cyclophosphamide (two children).

RESULTS

All patients fulfilled the clinical and laboratory criteria of a NS. The initial median serum creatinine was 65 micromol/l (range 44-133 micromol/l). Renal biopsy was performed in 13/32 children and revealed focal and segmental glomerulosclerosis (FSGS) in 10 patients, minimal change disease (MCNs) in two and no conclusive result in one patient. Glomerular immune complex deposition was absent in all biopsies. After treatment with PRED, oedema disappeared in 24/32 patients; however, proteinuria normalized in 16/32 patients only. The NS relapsed in 9/16 steroid-sensitive patients after cessation of PRED therapy, and two children were frequent relapsers. The steroid-resistant NS did not respond to an intensified immunosuppression in 5/16 children receiving methylprednisolone or cyclophosphamide. Five out of 32 children died, all were steroid resistant.

CONCLUSIONS

There was no evidence for a dominating role of steroid-resistant 'tropical glomerulopathies' in children with a NS in Ghana. Similar to South Africa, focal and segmental glomerulosclerosis (FSGS) and minimal change disease were the most frequent findings on histology. Contrary to Nigeria, membrano-proliferative glomerulonephritis was not found in these patients. We conclude from this data and from the literature that the histological pattern of NS may vary between different African countries. Concerning therapy of NS under tropical conditions, we emphasize that despite the limited therapeutic facilities half of these patients may benefit from corticosteroids; however, steroid resistance and FSGS resulted in a high mortality.

Pathology of renal diseases in the tropics

Renal diseases unique to the tropics are those that occur in association with infectious diseases including dengue hemorrhagic fever, typhoid fever, shigellosis, leptospirosis, lepromatous leprosy, malaria, opisthorchiasis, and schistosomiasis. These renal complications can be classified on the basis of their clinical and pathologic characteristics into acute transient reversible glomerulonephritis, chronic progressive irreversible glomerulonephritis, amyloidosis, and acute renal failure (ARF) resulting from acute tubular necrosis, acute tubulointerstitial nephritis, and thrombotic microangiopathy. Certain primary glomerular diseases including immunoglobulin (Ig) M nephropathy and focal segmental and global glomerulosclerosis are prevalent in some tropical countries. Renal complications of venomous snakebites also are common in the tropics. This article discusses and summarizes important works in the literature in respect to the clinical syndromes, pathologic features, and pathogenesis of tropical renal diseases both in humans and experimental animal models.

[Primary nephrotic syndrome in the black African child]

Idiopathic nephrotic syndrome (INS) in black African children differs from that of children in temperate areas. The main differences are the high rate of corticosteroid non-responders and the low rate of minimal change glomerulopathy in black African children, possibly related to a racial factor. The identification of a high corticosensibility in certain African regions (Togo and Ghana) can lead to the identification of an ethnic factor. Further genetic studies should be carried out in order to provide a better approach to INS in Africa.

Traditional medicine to DNA vaccines: the advance of medical research in West Africa

West Africa has a rich medical history. Herbal medicine has been practiced for hundreds of years and the establishment of an effective herbal pharmacopoeia was probably the first medical research carried out in West Africa. Arabic medicine was practiced in the countries of the Sahel in the 15th and 16th centuries. The coming of the Europeans focused research on infectious diseases such as malaria, yellow fever and sleeping sickness, to which Europeans were very susceptible and which caused devastating epidemics among the populations of their new colonies. The end of the colonial era saw the establishment of a few large, well-equipped teaching hospitals but these proved too expensive for the newly independent states of West Africa to run effectively, and the second generation of West African medical schools was based on more modest government hospitals. This led to a change in the focus of research away from the more unusual conditions seen in a specialist referral hospital to an interest in conditions, such as the common infectious diseases, seen more frequently in district hospitals. The advent of the primary health care movement in the 1970s was followed by an increased emphasis on community studies. Molecular biology is likely to have an enormous impact on medicine in general in the coming years. One of the main challenges facing medical researchers in West Africa is how these new technologies can be used most effectively to improve health in countries with limited resources.

Ethnicity, hypertension, coronary heart disease and renal diseases in South Africa

This paper reviews the impact of race and environment upon hypertension, coronary heart disease and renal diseases in South Africa. Inequalities of socioeconomic status, lifestyle, and access to South African health care have produced striking differences in the prevalence and complications of hypertension. Coronary heart disease is 'epidemic' in the white and Indian population and is still relatively uncommon in blacks. There are different histological patterns of glomerulonephritis among the racial groups, which may lead to end-stage renal disease. Hypertension is an important cause of end-stage renal disease in the black population whilst analgesic nephropathy is important in the white population. Efforts are now being made to comprehend these daunting realities and to minimize the inequalities.

Immune complex-mediated glomerulopathy in experimental Chagas' disease

To investigate the development of glomerulopathy during the chronic phase of experimental Chagas' disease, C3H-Hej mice were infected with Trypanosoma cruzi trypomastigotes. Deposits of IgG, IgM, and C3 in renal mesangium were observed by immunofluorescence (IF) to increase in size as a function of time after infection (4-6 months). T. cruzi antigens were codeposited in glomeruli with Ig and C3. Electron-dense deposits were visualized in mesangial and paramesangial areas by electron microscopy. Anti-T. cruzi and rheumatoid factor (RF) antibodies (of IgG isotypes) were detected both in serum and in renal eluates. In serum, the titers of both antibodies progressively decreased as a function of time after infection. In renal eluates, titers of anti-T. cruzi antibodies appeared to be stable during the three time periods after infection. By contrast, titers of RF antibodies in renal eluates were shown to increase progressively during these same time periods, paralleling the increase in size of mesangial Ig deposits observed by IF. Several T. cruzi proteins were immunoprecipitated from radiolabeled renal eluates by a control anti-T. cruzi antibody. In addition, antibodies from renal eluates specifically precipitated a 85-kDa protein from radiolabeled T. cruzi lysates, whereas serum antibodies precipitated a broad pattern of T. cruzi proteins. These results demonstrate that mice experimentally infected with T. cruzi can develop a mesangial glomerulopathy during the chronic phase of the disease, which appears to be mediated through immune complexes containing parasite antigens associated with secondary deposition of RF.

Clinicopathological features of childhood nephrotic syndrome in Saudi Arabia

The clinicopathological features are described in 119 Arab children in Saudi Arabia with the nephrotic syndrome. The clinical and laboratory data are similar to those described in other parts of the world. However, mesangial proliferative glomerulonephritis (MesPGN) was found in 21 of 66 biopsies (31.8%), giving a frequency of 17.6% of all children with the nephrotic syndrome. Minimal-change nephrotic syndrome (MCNS) was diagnosed in 17 biopsies (25.8%) and in 58 patients (48.7%). Onset of the nephrotic syndrome was at less than 1 year of age in 17 patients (14.3%). Seven children had 11 episodes of peritonitis. Seven children had positive hepatitis B surface antigen (HBsAg) in their serum: renal biopsy carried out on four of them showed membranous glomerulonephritis (MGN) in three, and four of the seven patients developed end-stage renal disease (ESRD). There were nine deaths, all in patients with end-stage renal disease: six of the deaths occurred in infants. The pattern of childhood nephrotic syndrome in Saudi Arabia is different from the pattern in tropical countries.

Tumor-necrosis factor and other cytokines in cerebral malaria: experimental and clinical data

Evidence is presented here that tumor necrosis factor/cachectin (TNF), is of crucial importance in the pathogenesis of cerebral malaria. First, the central lesion of CM, hemorrhagic necrosis of cerebral vessels, corresponds to lesions observed during other pathological conditions associated with high serum TNF levels, such as endotoxemic shock or administration of TNF. Second, in both mouse and human, there is a close correlation between high serum TNF levels and CM. At least in mouse, high TNF levels and CM depend upon T lymphocytes of the CD4+ phenotype. Third, passive immunization against mouse TNF significantly prolongs the survival of P. berghei-infected CBA/Ca mice, and prevents the development of neurologic signs. Treatment with the anti-TNF antibody also prevents hemorrhagic necrosis of brain vessels. Fourth, in the mouse model, a cytokine cascade including at least GM-CSF, IL-3 and IFN-gamma is required for the elevation of TNF level. This cascade appears to involve two components: (a) a quantitative component: increased accumulation of macrophages results from the concomitant release of IL-3 and GM-CSF, and (b) a qualitative component: macrophage number has not only to be raised, but macrophages need to be activated by IFN-gamma. Fifth, metabolic parameters of CM and its main lesion in both mouse and human, i.e. the hemorrhagic necrosis of small brain vessels, correspond to the known properties of TNF.

The effect of substance(s) associated with malarial parasites on C3b inactivator

The effects of a substance or substances associated with malarial parasites on the inhibitory role of C3b inactivator in immune adherence were investigated. The test system involved adherence of immune complexes of complement-bearing sheep erythrocytes and rabbit antibody, using human group O erythrocytes and human renal glomerular tissues as indicators. Malarial antigen and other soluble by-products of the malarial parasites, presumably present in spent culture medium, did not interfere with the inhibitory role of C3b inactivator. However, malarial pigment, both crude and purified, enhanced immune adherence in the presence of C3b inactivator. It is suggested that malarial pigment, by inhibiting the action of C3b inactivator, may play a significant role in the immunopathogenesis of renal lesions associated with malarial infections.

Normal and abnormal aspects of proteinuria. Part I: Mechanisms, characteristics and analyses of urinary protein. Part II: Clinical considerations

Part I highlights the mechanisms of glomerular filtration and tubular reabsorption of plasma proteins, selected characteristics of urinary proteins based upon electrophoretic properties and recent advances in clinical laboratory analysis of proteinuria. Both structural characteristic of the glomerular capillary wall and molecular properties of plasma proteins are important determinants of glomerular filtration. Proteins filtered by the glomerulus subsequently appear in urine only after escaping the efficient mechanisms of tubular reabsorption. Albumin is one such protein and constitutes the major protein in normal urine although trace amounts of alpha, beta, and gamma globulins are also detectable. Several techniques of protein analysis have thus been developed to specifically measure albumin as well as other plasma proteins. Other methods have been adapted to measure total urinary protein content enabling the clinician to readily monitor renal function in health and disease. The second part of this review will consider conditions associated with proteinuria in both asymptomatic individuals and patients with renal disease. Asymptomatic proteinuria encompasses states of excess protein excretion during conditions of orthostasis, exercise, travel to high altitude of fever. Proteinuria during renal disease has received considerable interest as a means to monitor kidney function. It is therefore classified according to the type of damage incurred: (1) glomerular-type where large molecular weight proteins are excreted (2) tubular-type where small molecular weight proteins are excreted and (3) mixed-type characterized by both large and small molecular weight proteinuria.

Prevalence and pattern of renal disease in eastern Libya

A prospective study was conducted to identify the pattern and aetiology of kidney disease in children living in eastern Libya. A total of 343 patients was studied, representing 3% of annual admissions to the children's hospital. The major renal diseases were post-streptococcal glomerulonephritis (in 116), acute renal failure (in 93), and idiopathic nephrotic syndrome (in 65). Less common diseases were tubular transport defect (in 3) and end-stage renal disease (in 3). The mortality rate (excluding neonates) was below 1%. The pattern of kidney disease referred to this hospital in Libya was different from that reported in other parts of Africa.

Ocular findings in human babesiosis (Nantucket fever)

Human babesiosis (Nantucket fever) is a rare, tick-borne intraerythrocytic parasitic disease characterized by fever, lymphadenopathy, arthralgias, and hemolytic anemia. A 34-year-old woman, who had previously undergone surgical removal of her spleen, was hospitalized because of presumed hepatitis. The many retinal nerve fiber layer infarcts and serologic abnormalities suggested collagen disease. The diagnosis of babesiosis was established by the demonstration of intraerythrocytic parasites and a greatly elevated titer to Babesia microti. The infection was treated with chloroquine, orally administered quinine, and pyramethamine, and her symptoms resolved within one month. The retinopathy was probably the result of focal vasculitis secondary to immune complex disease caused by chronic infection.

Influence of antigen on immune complex behavior in mice

To explore the possibility that the behavior of immune complexes can, under some circumstances, be directed by the antigen, we have studied the behavior of complexes of identical size made with the glycoproteins, orosomucoid (OR), and ceruloplasmin: or with their desialylated derivatives, asialo-orosomucoid (ASOR) and asialo-ceruloplasmin. Such desialylated proteins are rapidly removed from the circulation by a hepatic cell receptor for galactose, the sugar exposed upon removal of sialic acid. Mixtures of 125I-goat anti-ASOR with either ASOR or OR and mixtures of 125I-rabbit anti-OR with either ASOR or OR form complexes identically. The complexes were separated by density gradient centrifugation and injected intravenously into C3H mice. Blood clearance and hepatic uptake of the OR complexes and ASOR complexes were markedly different. T 1/2 for the goat OR complexes exceeded 300 min, whereas that for the ASOR complexes was 15 min. More detailed studies using rabbit complexes of various sizes revealed that light rabbit complexes behaved similarly to the goat complexes. The light rabbit OR complexes were cleared slowly, with only 18% found in the liver at 60 min, whereas the light rabbit ASOR complexes were cleared much more rapidly, with 62% found within the liver by 30 min. This rapid clearance was completely suppressed by a prior injection of a blocking dose of ASOR, which implies uptake by a galactose-mediated mechanism on hepatocytes. As the size of the rabbit complexes increased, so did the rate of Fc receptor-mediated clearance. Heavy rabbit OR complexes were cleared more rapidly than light OR complexes but not so rapidly as heavy ASOR complexes. The clearance and hepatic uptake of the heavy OR complexes were markedly suppressed by a prior injection of heat-aggregated gamma globulin, a known Fc receptor-blocking agent (45% hepatic uptake without and 6% with aggregated gamma globulin). The heavy rabbit ASOR complexes exhibited inhibition of blood clearance and hepatic uptake by both galactose receptor-blocking and Fc receptor-blocking agents. A blocking dose of ASOR reduced the hepatic uptake at 30 min from 75 to 49%, and heat-aggregated gamma globulin reduced it from 75 to 39%, which suggests that these heavy complexes were removed from the circulation by receptors both for the immunoglobulin and for the antigen. Cell separation studies and autoradiographs confirmed that those complexes cleared primarily by galactose-mediated mechanism were within hepatocytes, and those cleared by Fc receptors were within the nonparenchymal cells of the liver. It seems probable, therefore, the some antigen-antibody complexes may be removed from the circulation via receptors not only for immunoglobulin but also for antigen.

Immunological aspects of nephrotic syndrome in northern Nigeria

Immunological aspects of 40 northern Nigerian children with nephrotic syndrome of recent onset are reported. Eight our of 30 had hepatitis-associated antigen in their sera. Hypocomplementaemia was rare. Measurement of serum C3, C4, and ASOT was not of diagnostic value. Proteinuria selectivity index was poor in half of the patients, and appeared t o depend on the severity of the kidney lesion. Abnormal immunofluorescence of kidney glomeruli to immunoglobulins, complement, Plasmodium malariae, and Plasmodium falciparum was found in 26 of the 29 children. The pattern of immunofluorescence was chiefly granular and was confined to the glomeruli. IgM was predominant. It was concluded that immunological reaction is involved in the pathogenesis of nephrotic syndrome in northern Nigerian children.