A conceptual approach to immunodeficiency

Membranoproliferative glomerulonephritis related to a streptococcal infection in a girl with IgA deficiency: a case report

Background

IgA deficiency associated with glomerulonephritis is rare. In particular, there is no prior report regarding the association between IgA deficiency and membranoproliferative glomerulonephritis (MPGN) in children. Herein, we describe the case of a 5-year-old girl with selective IgA deficiency and MPGN.

Case presentation

The patient presented with persisting urinary abnormality and hypocomplementemia following a group A treptococcal infection. Renal biopsy revealed the presence of diffuse mesangial hypercellularity, endocapillary proliferation, and focal thickening of the walls of the glomerular capillaries using light microscopy, with IgG and moderate C3 deposits observed using immunofluorescence. Electron microscopy images revealed nodular deposits in the subendothelial areas, with hump-shaped subepithelial deposits. The pathological diagnosis was confirmed as MPGN. Treatment using oral prednisolone (PSL), mizoribine (MZR), and angiotensin-converting enzyme inhibitors reduced the proteinuria. The PSL dose was gradually tapered, with the low dose of PSL and MZR continued for 4 years. Histological findings were improved on repeated renal biopsy, and PSL and MZR administration was discontinued.

Conclusions

We report a rare case of MPGN related to a streptococcal infection in a child. The clinical presentation included selective IgAD, with several pathological findings and a clinical course typical of glomerulopathy. The patient was successfully treated using multidrug therapy.

IgA deficiency and autoimmunity

IgA is the most abundant immunoglobulin in the human body, and performs a very specialized role which involves mucosal immunity, development of tolerance and protection against infection. IgA is the key immunoglobulin in the respiratory and gastrointestinal tracts, which provide the most intimate interface between the environment and self. Normal levels of IgA are based on early studies consisting of only small numbers of patients. The international consensus definition of IgA deficiency is a level of 0.07g/l after the age of four years in the absence of IgG and IgM deficiencies. The epidemiology of IgA deficiency reveals interesting variances between geographical regions - the incidence in Caucasians being much higher than that in Asians. IgA deficiency has also been found to co-exist with autoimmune diseases, allergies and malignancies. The association with autoimmunity is particularly interesting because it suggests a common genetic linkage that could potentially also explain the diversity in geoepidemiology. Both MHC and non-MHC associations have been described and the 8.1 haplotype has been significantly associated with autoimmunity in IgA deficiency patients over controls. Non-MHC genetic associations include IFIH1 and CLEC16A. The mutations leading to IgA deficiency have not been defined, but in some cases of IgA deficiency it has been suggested that the pathogenesis involves a failure in switched memory B cells that can lead to this cohort experiencing an increased incidence of recurrent bacterial infections or autoimmune diseases. Attempts to investigate the role of cytokines that can induce IgA synthesis in cells of patients with IgA deficiency, such as IL21 or the combination of CD40L/anti-CD40, IL-4 and IL10, are underway.

Immune-mediated disease in the old English sheepdog

Immunological data are reported from 19 cases of immune-mediated disease recorded in the old English sheepdog breed in Western Australia between 1978 and 1989. The conditions included autoimmune haemolytic anaemia (seven), idiopathic thrombocytopenia (one), Evans' syndrome (five), multiple myeloma (two), systemic lupus erythematosus (one), discoid lupus erythematosus (one) and hypothyroidism (two). The most consistent serological findings were raised serum IgG (60 per cent), depressed serum IgM (60 per cent) and the presence of multiple autoantibodies (anti-red blood cell 78 per cent, antinuclear antibody 44 per cent, rheumatoid factor 19 per cent). An underlying, breed-related disorder of immune regulation may account for these observations.

Persistent or recurrent pneumonia in Saudi children seen at King Khalid University Hospital, Riyadh: clinical profile and some predisposing factors

Children with persistent or recurrent pneumonia without an apparent cause constitute an important clinical category with much morbidity and mortality and can be perplexing and frustrating to the treating physician and the parents. To identify the clinical profile and predisposing factors in this group of patients, 18 Saudi children were studied. Their ages ranged from 3 months to 12 years (mean age 5.7 years) with male preponderance--12 boys and 6 girls (M:F ratio 2:1). About 44.4% had immune and inherited metabolic disorders. Anatomical abnormalities were found in four (22.2%). Two had measles as a predisposing factor. None had tuberculosis or pertussis. One child each had pulmonary candidiasis and laryngeal papilloma, probably contracted from their mothers as congenital infections. Though the pattern seems to follow that found in developed countries, it is noteworthy that cystic fibrosis was not identified in any of our patients.

Central nervous system involvement in patients with acquired immune deficiency syndrome (AIDS)

Central nervous system involvement occurred in 28 of 121 patients with acquired immune deficiency syndrome (AIDS). The major risk factor in this AIDS population was intravenous drug abuse (64%). A neurologic symptom or disability was the principal reason for hospitalization in 16 cases (57%). Three patients had primary lymphoma of the brain and the remainder had opportunistic infections. Patients with focal neurological features usually had toxoplasmosis. Progressive headache and meningeal signs occurred with cryptococcosis. A progressive subacute dementia was probably due to cytomegalovirus. Other infections included atypical mycobacteria, candida, herpes zoster and possible progressive multifocal leukoencephalopathy.

Effects of phenytoin on man's immunity. Evaluation of changes in serum immunoglobulins, complement, and antinuclear antibody

To determine the effects of phenytoin on serum immunoglobulins, complement, and antinuclear antibody conversion, a prospective, five-year longitudinal study was undertaken in 118 patients. Three major diagnostic groups were evaluated: 27 patients with idiopathic epilepsy, 50 with secondary epilepsy, and 41 with neuropathic syndromes without epilepsy. In addition, 83 normal volunteers were studied in a similar manner. Evaluations were performed prior to administration of phenytoin and at six-month intervals thereafter. Prior to treatment, patients with idiopathic epilepsy had a higher than expected incidence (13.5 percent, p less than 0.01) of low serum IgA (less than 61 mg/dl). Patients with secondary epilepsy and neuropathic disorders without epilepsy had a greater than expected incidence (9.2 percent, p less than 0.01; and 12 percent, p less than 0.01, respectively) of high serum IgA (greater than 417 mg/dl). Phenytoin treatment was associated with further decreases in serum IgA in patients with idiopathic epilepsy (p = 0.063) and secondary epilepsy (p = 0.008). Total serum IgE concentrations also decreased significantly in all patient categories during treatment with phenytoin. Minor decreases in serum IgG and IgM were noted, but serum IgD and complement remained unaffected. Antinuclear antibodies were observed with essentially the same frequency (10 percent) before and after phenytoin therapy.