Copper is a crucial micronutrient needed by animals and humans for proper organ function and metabolic processes such as hemoglobin synthesis, as a neurotransmitter, for iron oxidation, cellular respiration, and antioxidant defense peptide amidation, and in the formation of pigments and connective tissue. Multiple factors, either hereditary or acquired, contribute to the increase in copper deficiency seen clinically over the past decades. The uptake of dietary copper into intestinal cells is via the Ctr1 transporter, located at the apical membrane aspect of intestinal cells and in most tissues. Copper is excreted from enterocytes into the blood via the Cu-ATPase, ATP7A, by trafficking the transporter towards the basolateral membrane. Zinc is another important micronutrient in animals and humans. Although zinc absorption may occur by direct interaction with the Ctr1 transporter, its absorption is slightly different. Copper deficiency affects physiologic systems such as bone marrow hematopoiesis, optic nerve function, and the nervous system in general. Detailed pathophysiology and its related diseases are explained in this manuscript. Diagnosis is made by measuring serum copper, serum ceruloplasmin, and 24-h urine copper levels. Copper deficiency anemia is treated with oral or intravenous copper replacement in the form of copper gluconate, copper sulfate, or copper chloride. Hematological manifestations are fully reversible with copper supplementation over a 4- to 12-week period. However, neurological manifestations are only partially reversible with copper supplementation.

In Plasmodium falciparum malaria, erythrocyte invasion by circulating merozoites may occur via two distinct pathways involving either a sialic acid-dependent or -independent mechanism. Earlier, we identified two nonglycosylated exofacial regions of erythrocyte band 3 termed 5ABC and 6A as an important host receptor in the sialic acid-independent invasion pathway. 5ABC, a major segment of this receptor, interacts with the 42-kDa processing product of merozoite surface protein 1 (MSP1 42 ) through its 19-kDa C-terminal domain. Here, we show that two regions of merozoite surface protein 9 (MSP9), also known as acidic basic repeat antigen, interact directly with 5ABC during erythrocyte invasion by P. falciparum. Native MSP9 as well as recombinant polypeptides derived from two regions of MSP9 (MSP9/⌬1 and MSP9/⌬2) interacted with both 5ABC and intact erythrocytes. Soluble 5ABC added to the assay mixture drastically diminished the binding of MSP9 to erythrocytes. Recombinant MSP9/⌬1 and MSP9/⌬2 present in the culture medium blocked P. falciparum reinvasion into erythrocytes in vitro. Native MSP9 and MSP1 42 , the two ligands binding to the 5ABC receptor, existed as a stable complex. Our results establish a novel concept wherein the merozoite exploits a specific complex of co-ligands on its surface to target a single erythrocyte receptor during invasion. This new paradigm poses a new challenge in the development of a vaccine for blood stage malaria.

Immune checkpoint inhibitors (ICPis) are a novel class of immunotherapeutic agents that have revolutionized the treatment of cancer; however, these drugs can also cause a unique spectrum of autoimmune toxicity. Autoimmune hemolytic anemia (AIHA) is a rare, but often severe, complication of ICPis. We identified 14 patients from nine institutions across the United States who developed ICPi-AIHA. The median interval from ICPi initiation to development of AIHA was 55 days (interquartile range [IQR], 22-110 days). Results from the direct antiglobulin test (DAT) were available for 13 of 14 patients: 8 patients (62%) had a positive DAT and 5 (38%) had a negative DAT. The median pretreatment and nadir hemoglobin concentrations were 11.8 g/dL (IQR, 10.2-12.9 g/dL) and 6.3 g/dL (IQR, 6.1-8.0 g/dL), respectively. Four patients (29%) had a preexisting lymphoproliferative disorder, and two (14%) had a positive DAT prior to initiation of ICPi therapy. All patients were treated with glucocorticoids, with three requiring additional immunosuppressive therapy. Complete and partial recoveries of hemoglobin were achieved in 12 (86%) and 2 (14%) patients, respectively. Seven patients (50%) were rechallenged with ICPis, and one (14%) developed recurrent AIHA. Clinical and laboratory features of ICPi-AIHA were similar in DAT positive and negative patients. ICPi-AIHA shares many clinical features with primary AIHA; however, a unique aspect of ICPi-AIHA is a high incidence of DAT negativity. Glucocorticoids are an effective first-line treatment in the majority of patients with ICPi-AIHA, and most patients who are rechallenged with an ICPi do not appear to develop recurrence of AIHA. a Long-standing history of leukopenia of unclear etiology, bone marrow biopsy negative for malignancy, and leukopenia believed to be autoimmune in nature. b Received indoximod in combination with ICPi therapy as part of a clinical trial. c R-CHOP, fludarabine (received >3 years prior to development of AIHA), XRT, auto-SCT for treatment of MZL, and cisplatin and etoposide for treatment of NSCLC. d Received nivolumab on a clinical trial after conventional chemotherapy. e 5-FU, oxaliplatin, irinotecan, bevacizumab, panitumumab, regorafenib, and trifluridine/tipiracil. f Received GVAX and cyclophosphamide in combination with ICPi therapy as part of a clinical trial. g Dabrafenib, trametinib for treatment of melanoma, fludarabine (received >3 years prior to development of AIHA), cyclophosphamide, bendamustine, rituximab, obinutuzumab, and ibrutinib for treatment of CLL.

Pernicious anemia (PA) is the most common cause of vitamin B12 (cobalamin) deficiency anemia in the world. It is an autoimmune disease, comprising of salient features of autoimmune chronic atrophic gastritis (CAG) and cobalamin deficiency (CD).Although the anemia was first described as pernicious, it may well be controlled with vitamin B12 replacement. The onset and progression of PA is often insidious. Alternatively, patients may have no anemic symptoms since they become acclimatized to the subtle nature of the disease. Oftentimes, there is a possibility that the underlying disease may be missed unless a full blood count (FBC) is investigated, leading to hindrance in the treatment journey. Diagnostic challenges remain tangible for many practicing clinicians, since there is lack of reliable cobalamin assays to diagnose CD as well as clinical mimics, which simulate many other hematological conditions, such as myelodysplastic syndrome, acute leukemia, sideroblastic anemias, bone marrow failure states, thrombotic microangiopathy, and thromboembolism. Moreover, prompt recognition of the symptoms of CD is also vital, because some neurologic sequalae may become irreversible despite replenishing cobalamin. Herein, we discuss a literature review on the pathophysiology, challenging clinical presentations and diagnostic difficulties of PA.Since the cobalamin replacement therapy for PA is straightforward, it will not be discussed in this review.