UNASSIGNED: Anti-glomerular basement membrane (GBM) disease is a rare cause of glomerulonephritis usually mediated by IgG antibodies and is associated with ANCA-associated glomerulonephritis in up to 50% of cases. IgA-mediated anti-GBM disease is extremely rare and presents diagnostic difficulties as circulating IgA antibodies will not be detected by standard serological tests for anti-GBM disease.
UNASSIGNED: We present the case of a 67-year-old man with rapidly progressive glomerulonephritis requiring haemodialysis at presentation. Serological testing was positive for anti-myeloperoxidase and negative for IgG anti-GBM antibodies. Kidney biopsy revealed necrotizing crescentic glomerulonephritis with linear staining of IgA along the GBM. He was treated with a combination of immunosuppression and plasma exchange and was able to become dialysis-independent.
UNASSIGNED: To our knowledge, this is the first documented \"double-positive\" IgA anti-GBM disease and ANCA-associated glomerulonephritis.

Constitutional mismatch repair deficiency (CMMRD) is a rare childhood cancer predisposition syndrome that results from biallelic germline mutations in one of the four MMR genes, MLH1, MSH2, MSH6, or PMS2. This syndrome is characterized by a broad spectrum of early-onset malignancies, including hematologic malignancies, colorectal malignancies, brain tumors, and other malignancies. It is common to have more than one malignancy in an individual diagnosed with CMMRD. In addition to malignancies, primary immunodeficiency in the form of low or absent immunoglobulin levels can also be seen in CMMRD. Congenital abnormalities such as agenesis of the corpus callosum (ACC), cavernous hemangioma, and other non-neoplastic diseases can also be linked to it. In this case report, we discussed the case of a girl born out of consanguineous marriage initially identified as having T-cell acute lymphoblastic lymphoma and later found to have selective immunoglobulin A (IgA) deficiency. Her younger sibling with a pontine cavernous hemangioma was also diagnosed with lymphoma. The girl exhibited brain lesions on magnetic resonance imaging (MRI), which were initially diagnosed as posterior reversible encephalopathy syndrome (PRES) related changes; however, one of the lesions persisted and remained stable over a period of 2 years and more in favor of diffuse glioma. The younger sibling also showed a solitary lesion in the brain. Based on the clinical and radiological findings, a diagnosis of CMMRD was suspected. Next-generation sequence (NGS) analysis of her blood sample was done. The results showed a homozygous mutation in the MSH6 gene was diagnostic of CMMRD.

Immunoglobulin A (IgA) is the mammalian mucosal antibody, providing an important line of defense against pathogens. With 15 IgA subclasses, the European rabbit has an extremely complex IgA system, strikingly more complex than most other mammals, which have only one IgA or, in the case of hominoids, two IgA subclasses. Similar to the two hominoid primate IGHA genes, the expansion of the rabbit IGHA genes appears to have begun in an ancestral lagomorph since multiple IgA copies were found by Southern blot analysis for the genera Sylvilagus, Lepus, and Ochotona.
To gain a better insight into the extraordinary lagomorph IgA evolution, we sequenced, for the first time, expressed IgA genes for two Lepus species, L. europaeus and L. granatensis. These were aligned with the 15 rabbit IgA isotypes, and evolutionary analyses were conducted. The obtained phylogenetic tree shows that the Lepus IgA sequences cluster with and among the rabbit IgA isotypes, and the interspecies and intraspecies nucleotide genetic distances are similar. A comparison of the amino acid sequences of the Lepus and rabbit IgA confirms that there are two trans-species polymorphisms and that the rabbit and Lepus sequences share a common genetic pool. In fact, the main differences between the studied leporids IgAs reside in the characteristics of the hinge region.
The Lepus IgA sequences we have obtained strongly suggest that the great expansion of the leporid IGHA genes occurred in a common ancestral species and was then maintained in the descendants. A strong selective pressure caused the extraordinary expansion of the IGHA genes but then subsided, leading to the maintenance of the acquired polymorphisms in the descendants, with little subsequent divergence. This is a unique evolutionary pattern in which an ancient gene expansion has been maintained for approximately 18 million years.

Most patients with hepatitis E virus (HEV) infection are asymptomatic and improve naturally without any treatment, but even non-immunocompromised individuals may develop persistent HEV infections and should be monitored regularly for the onset.

Immunoglobulin A vasculitis (IgAV) is the most common vasculitis of childhood characterized by petechial or purpuric rash, abdominal pain, arthralgia, and renal involvement. Ophthalmic manifestations of IgAV are uncommon. Herein, we describe a case of bilateral upper eyelid erythema presenting in a 6-year-old male, leading to a diagnosis of IgAV.

Background: Neurofibromatosis type 1 (NF1) is a hereditary cancer syndrome characterized by multiple café-au-lait macules on the skin. Lymphoproliferative malignancies associated with NF1 are limited, although the most common are brain tumors. Case presentation: A 22-year-old woman with NF1 was admitted due to abdominal pain and bloody diarrhea. Her laboratory data exhibited macrocytic anemia and elevated IgA levels. Image studies showed diffuse increased wall thickening in the transverse and descending colon without lymphadenopathy and hepatosplenomegaly. A colonoscopy revealed a hemorrhagic ulcerated mass. Pathological analysis of the tumor tissues confirmed IgA-expressing mucosa-associated lymphoid tissue (MALT) lymphoma with histological transformation. Moreover, whole-exome sequencing in tumor tissues and peripheral blood mononuclear cells identified a somatic frameshift mutation of the A20 gene, which represents the loss of function. The patient responded well to R-CHOP chemotherapy, but the disease relapsed after 1 year, resulting in a lethal outcome. Conclusions: MALT lymphoma in children and young adults is extremely rare and is possibly caused by acquired genetic changes. This case suggests a novel association between hereditary cancer syndrome and early-onset MALT lymphoma.

BACKGROUND: IgA vasculitis is the most common form of systemic vasculitis in children but can occur in adults. Inciting antigens include infections, drugs, foods, insect bites, and immunizations. Antibiotics and tumor necrosis factor (TNF) alpha inhibitors are the most common class of drugs that cause IgA vasculitis. Although sotalol and rivaroxaban have been documented to cause leukocytoclastic vasculitis, we have never come across any literature attributing IgA vasculitis to either drug. Additionally, Rocky Mountain spotted fever has not been associated with IgA vasculitis despite being described in cutaneous and systemic vasculitis cases. Here, we present a case of IgA vasculitis triggered by sotalol with challenging differentials, including a recent infection with Rocky Mountain spotted fever, malignancy, and rivaroxaban as possible triggers.
METHODS: 68 yr old male with a history of lung cancer treated with resection and chemotherapy 5 years ago is currently in remission, and recently was started on sotalol and rivaroxaban for new-onset paroxysmal atrial fibrillation. He presented with diffuse petechial/purpural rash on the lower limbs, multiple joint pain, severe abdominal pain and rectal bleeds, hemoptysis, and renal dysfunction. IgG titers for RMSF were high. Punch biopsy of skin and renal biopsy were consistent with IgA vasculitis. Sotalol and rivaroxaban were stopped. The patient was treated with oral prednisone, and his condition relatively improved.
CONCLUSIONS: Ig A vasculitis is mostly a self-limiting disease, but adults tend to have a severe course. It is important to diagnose early and identify a trigger. Removing the offending agent or treating the underlying infection is an important aspect of management.

An elevated IgA level obtained in a 10-year-old male a year after an episode of pneumococcal sepsis led to the discovery of a broad-based IgG-specific antibody deficiency syndrome. The specifics of the case and pertinent literature are presented, including a discussion of the hyper-IgD syndrome. An elevated IgA, greater than two standard deviations above the expected age range should prompt a complete workup for selective antibody deficiency syndrome and adds an additional associated marker of an indolent hyper-IgD syndrome in a different clinical circumstance, although the lack of antibody response to vaccines is atypical of the hyper-IgD syndrome.

Currently, there are no evidence-based treatment options for long COVID-19, and it is known that SARS-CoV-2 can persist in part of the infected patients, especially those with immunosuppression. Since there is a robust secretion of SARS-CoV-2-specific highly-neutralizing IgA antibodies in breast milk, and because this immunoglobulin plays an essential role against respiratory virus infection in mucosa cells, being, in addition, more potent in neutralizing SARS-CoV-2 than IgG, here we report the clinical course of an NFκB-deficient patient chronically infected with the SARS-CoV-2 Gamma variant, who, after a non-full effective treatment with plasma infusion, received breast milk from a vaccinated mother by oral route as treatment for COVID-19. After such treatment, the symptoms improved, and the patient was systematically tested negative for SARS-CoV-2. Thus, we hypothesize that IgA and IgG secreted antibodies present in breast milk could be useful to treat persistent SARS-CoV-2 infection in immunodeficient patients.

Lithium is one of the first-line agents for treating bipolar disorder. Although this agent is highly effective in treating mood disorders, renal toxicity is a frequent side effect. Lithium metabolism is affected by sodium-lithium counter-transporter (SLC-T) in erythrocytes. The high activity of SLC-T can result in decreased urinary lithium clearance and may lead to accumulation of lithium in the distal renal tubular cells, causing lithium toxicity. SLC-T is a genetic marker in primary hypertension (HTN), HTN in pregnancy, diabetic nephropathy, and IgA nephropathy (IgA-N) with HTN. Patients with IgA-N have been reported to have enhanced SLC-T activity and are likely to have considerably lower renal fractional clearance of lithium. Therefore, patients taking lithium for bipolar disorder with coexisting IgA-N can have severe lithium-induced nephropathy and nephrotoxicity even at therapeutic serum levels. Serum lithium levels reflect only extracellular lithium concentration. However, lithium exerts its effects once it has moved to the intracellular compartment. This phenomenon illustrates the reason why patients with significantly elevated serum levels might be asymptomatic. Creatinine clearance is inversely related to the duration of lithium therapy. The degree of interstitial fibrosis on renal biopsy has been known to be associated with the duration of lithium therapy and cumulative dose. We present a case with a past medical history of bipolar disorder treated with lithium for almost 20 years. His family history was significant for HTN. The patient was diagnosed with renal insufficiency of unknown causes, for which he underwent renal biopsy. The renal biopsy showed a typical lithium-induced tubulointerstitial nephritis and a coincidental finding of IgA-N. We suspect a high activity of SLC-T seen in IgA-N, and the adverse effects of lithium on SLC-T activity might cause reduction of urinary lithium clearance and accumulation of lithium in distal renal tubular cells, contributing to nephrotoxicity. There is a lack of the literature on the coexistence of IgA-N and lithium nephrotoxicity. We recommend in patients with concomitant IgA-N, taking lithium, more frequent monitoring of renal functions, and dose adjustments may reduce the risk of lithium-induced nephrotoxicity.