Coriorretinopatia de Birdshot: relato de caso e perspectivas sobre o tratamento / Birdshot chorioretinopathy: a case report and perspectives on its treatment

RESUMO A coriorretinopatia de Birdshot é uma uveíte posterior bilateral crônica rara que acomete, preferencialmente, mulheres de meia-idade. O quadro clínico é composto de pouco ou nenhum processo inflamatório de segmento anterior, associado a vitreíte e lesões coriorretinianas ovoides branco-amareladas de característica hiperfluorescente na angiofluoresceinografia e hipofluorescente na angiografia com indocianina verde. O tratamento se dá por meio de corticoides e outras drogas imunossupressoras. Todavia, em alguns casos, a doença é refratária a tal terapêutica, sendo necessário lançar mão de outras drogas, como os agentes biológicos. O presente artigo busca relatar um caso de coriorretinopatia de Birdshot em ajuste de terapia imunossupressora que evoluiu com má resposta às drogas iniciais e bom controle após uso de imunobiológico e discutir as opções terapêuticas disponíveis atualmente.

ABSTRACT Birdshot chorioretinopathy is a rare chronic bilateral posterior uveitis that preferentially affects middle-aged women. The clinical picture is composed of little or no anterior segment inflammatory process, associated with vitritis and yellowish-white ovoid chorioretinal lesions with hyperfluorescent characteristics on fluorescein angiography and hypofluorescent characteristics on green indocyanine green angiography. Treatment is with corticosteroids and other immunosuppressive drugs. However, in some cases, the disease is refractory to such therapy, making it necessary to resort to other drugs such as biological agents. The present article seeks to report a case of Birdshot chorioretinopathy in an adjustment of immunosuppressive therapy that evolved with poor response to the initial drugs and good control after the use of immunobiologicals and discuss the currently available therapeutic options.

Distribution of tumor-infiltrating-T-lymphocytes and possible tumor-escape mechanisms avoiding immune cell attack in locally advanced adenocarcinomas of the esophagus.

INTRODUCTION: The inflammatory microenvironment has emerged as one of the focuses of cancer research. Little is known about the immune environment in esophageal adenocarcinoma (EAC) and possible tumor-escape mechanisms to avoid immune cell attack. PATIENTS AND METHODS: We measured T cell inflammation (CD3, CD8) in the microenvironment using a standardized software-based evaluation algorithm considering different predefined tumor areas as well as expression of MHC class 1 and PD-L1 on 75 analyzable primarily resected and locally advanced (≥ pT2) EACs. We correlated these findings statistically with clinical data. RESULTS: Patients with high amounts of T cell infiltration in their tumor center showed a significant survival benefit of 41.4 months compared to 16.3 months in T cell poor tumors (p = 0.025), although CD3 fails to serve as an independent prognostic marker in multivariate analysis. For the invasion zone, a correlation between number of T-cells and overall survival was not detectable. Loss of MHC1 protein expression on tumor cells was seen in 32% and PD-L1 expression using the combined positive score (CPS) in 21.2%. Most likely due to small numbers of cases, both markers are not prognostically relevant, even though PD-L1 expression correlates with advanced tumor stages. DISCUSSION: Our analyses reveal an outstanding, though not statistically independent, prognostic relevance of T-cell-rich inflammation in our group of EACs, in particular driven by the tumor center. For the first time, we describe that the inner part of the invasion zone in EACs shows significantly fewer T-cells than other tumor segments and is prognostically irrelevant. We also demonstrate that the loss of antigen presenting ability via MHC1 downregulation by the carcinoma cells is a common escape mechanism in EACs. Future work will need to show whether tumors with MHC class 1 loss respond less well to immunotherapy.

Corneal transplant follow-up study II (CTFS II): a prospective clinical trial to determine the influence of HLA class II matching on corneal transplant rejection: baseline donor and recipient characteristics.

PURPOSE: To describe a study to determine the influence of HLA class II matching on allograft rejection of high-risk, full-thickness corneal transplants. METHODS: A prospective, longitudinal, clinical trial (ISRCTN25094892) with a primary outcome measure of time to first clinically determined rejection episode. Tissue typing used DNA-based techniques. Corneas were allocated to patients with ≤2 human leucocyte antigen (HLA) class I antigen mismatches by cohort minimisation to achieve 0, 1 or 2 HLA class II (HLA-DR) antigen mismatches. Transplants were to be followed up at 6 months and then annually on the anniversary of surgery for 5 years. Power calculations estimated a sample size of 856 transplants to detect a 0.1 difference in probability of rejection at 1 year between HLA class II matched and mismatched transplants at the 5% level of significance with 80% power. RESULTS: To allow for loss to follow-up, 1133 transplants in 980 patients were accrued to the study between 3 September 1998 and 2 June 2011. 17% of transplants had 0 HLA-DR mismatches. The most frequent indication was bullous keratopathy, accounting for 27% of transplants and 54% of the transplants were regrafts. Median waiting time for a matched graft was 3 months. Donor and recipient characteristics were distributed evenly across the study groups. CONCLUSION: Recruitment to the CFS II has closed with 1077/1133 transplants meeting all the study criteria. Follow-up has been completed and final analysis of the data has started. TRIAL REGISTRATION NUMBER: ISRCTN25094892 andUKCRNID9871, Pre-results.

The effect of inter-unit HLA matching in double umbilical cord blood transplantation for acute leukemia.

The effects of inter-unit HLA-match on early outcomes with regards to double cord blood transplantation have not been established. Therefore, we studied the effect of inter-unit HLA-mismatching on the outcomes of 449 patients with acute leukemia after double cord blood transplantation. Patients were divided into two groups: one group that included transplantations with inter-unit mismatch at 2 or less HLA-loci (n=381) and the other group with inter-unit mismatch at 3 or 4 HLA-loci (n=68). HLA-match considered low resolution matching at HLA-A and -B loci and allele-level at HLA-DRB1, the accepted standard for selecting units for double cord blood transplants. Patients', disease, and transplant characteristics were similar in the two groups. We observed no effect of the degree of inter-unit HLA-mismatch on neutrophil (Hazard Ratio 1.27, P=0.11) or platelet (Hazard Ratio 0.1.13, P=0.42) recovery, acute graft-versus-host disease (Hazard Ratio 1.17, P=0.36), treatment-related mortality (Hazard Ratio 0.92, P=0.75), relapse (Hazard Ratio 1.18, P=0.49), treatment failure (Hazard Ratio 0.99, P=0.98), or overall survival (Hazard Ratio 0.98, P=0.91). There were no differences in the proportion of transplants with engraftment of both units by three months (5% after transplantation of units with inter-unit mismatch at ≤2 HLA-loci and 4% after transplantation of units with inter-unit mismatch at 3 or 4 HLA-loci). Our observations support the elimination of inter-unit HLA-mismatch criterion when selecting cord blood units in favor of optimizing selection based on individual unit characteristics.

Optimized T-cell receptor-mimic chimeric antigen receptor T cells directed toward the intracellular Wilms Tumor 1 antigen.

CD19-directed chimeric antigen receptor (CAR) T cells are clinically effective in a limited set of leukemia patients. However, CAR T-cell therapy thus far has been largely restricted to targeting extracellular tumor-associated antigens (TAA). Herein, we report a T-cell receptor-mimic (TCRm) CAR, termed WT1-28z, that is reactive to a peptide portion of the intracellular onco-protein Wilms Tumor 1(WT1), as it is expressed on the surface of the tumor cell in the context of HLA-A*02:01. T cells modified to express WT1-28z specifically targeted and lysed HLA-A*02:01+ WT1+ tumors and enhanced survival of mice engrafted with HLA-A*02:01+, WT1+ leukemia or ovarian tumors. This in vivo functional validation of TCRm CAR T cells provides the proof-of-concept necessary to expand the range of TAA that can be effectively targeted for immunotherapy to include attractive intracellular targets, and may hold great potential to expand on the success of CAR T-cell therapy.

The cyclophilin-inhibitor alisporivir stimulates antigen presentation thereby promoting antigen-specific CD8(+) T cell activation.

BACKGROUND & AIMS: Cyclophilin-inhibitors have potent antiviral activity against Hepatitis C virus (HCV) and are promising candidates for broad-spectrum antiviral therapy. Cyclosporine A (CsA) acts immunosuppressive by blocking T cell activation and antigen presentation. Alisporivir, a non-immunosuppressive CsA analog in clinical development, does not inhibit T cell activation. In this study we explored the impact of alisporivir on antigen presentation. METHODS: Hepatoma cells endogenously expressing the epitope-restricting major histocompatibility complex-class I (MHC-I) allele HLA-A2 and constitutively expressing a viral antigen were established to study the impact of cyclophilin-inhibitors on antigen presentation. Antigen-specific CD8(+) T cell activation and MHC-I surface expression were measured to quantify antigen presentation. RESULTS: Our work establishes a novel cell culture model to study antigen presentation in liver-derived cells. Authentic regulation of antigen presentation was ensured by the action of pro- and anti-inflammatory cytokines. Alisporivir pretreatment stimulated antigen presentation by hepatoma target cells, leading to enhancement of antigen-specific CD8(+) T cell activation by 40%. Alisporivir, as well as a panel of other cyclophilin-inhibitors, induced an increase of MHC-I and beta-2 microglobulin on the surface of several cell lines. The drug neither enhanced MHC-I transcript or protein levels nor affected surface expression of other proteins or protein trafficking in general. Proteasome-inhibitors completely blocked the alisporivir-directed enhancement of surface MHC-I, suggesting an influence of the drug on peptide-availability. CONCLUSIONS: Alisporivir stimulates antigen presentation by inducing enhanced MHC-I surface expression, thereby promoting antigen-specific CD8(+) T cell activation. This immunostimulatory function might further contribute to the antiviral activity of non-immunosuppressive cyclophilin-inhibitors.

HLA-A29-POSITIVE BIRDSHOT CHORIORETINOPATHY IN AN AFRICAN AMERICAN PATIENT.

PURPOSE: To report the first documented case of HLA-A29-positive birdshot chorioretinopathy in an African American patient. METHODS: A 51-year-old African American woman presented with a 10-year history of photopsia, progressive decrease in visual acuity, metamorphopsia, and new nyctalopia. Both fundi showed evidence of periphlebitis, arterial attenuation, macular edema, and diffuse chorioretinal atrophy. RESULTS: Fluorescein angiography revealed diffuse vascular leakage, and indocyanine green showed evenly distributed and symmetrical hypofluorescent spots, which were difficult to appreciate on fundoscopy. Workup revealed a positive HLA-A29 and was negative for sarcoid, tuberculosis, and syphilis. CONCLUSION: Birdshot chorioretinopathy overwhelmingly affects non-Hispanic Caucasians, but there have been rare reported cases in other ethnicities including Hispanics and African Americans. This patient's ethnicity may have contributed to the 10-year delay in diagnosis. To our knowledge, this is the first documented HLA-A29 positive case of birdshot chorioretinopathy in an African American. HLA-A29 may be a useful supportive test in cases with classic clinical presentation in non-Caucasian patients to enable the correct diagnose in a timely manner.

CXCL10, CXCL11, HLA-A and IL-1ß are induced in peripheral blood mononuclear cells from women with Chlamydia trachomatis related infertility.

Chlamydia trachomatis infections can result in the development of serious sequelae such as pelvic inflammatory disease and tubal infertility. In this study, peripheral blood mononuclear cells from women who were undergoing or had recently undergone IVF treatment were cultured ex vivo with C. trachomatis to identify the immune responses associated with women who had serological evidence of a history of Chlamydia infection. Cytokines secreted into the supernatant from the cultures were measured using ELISA, and the level of IL-1ß was found to be significantly higher in Chlamydia positive women than Chlamydia negative women. qRT-PCR analysis of the expression of 88 immune-related genes showed trends towards an upregulation of CXCL10, CXCL11 and HLA-A in Chlamydia positive women compared with Chlamydia negative women. These findings support that some women launch a more marked proinflammatory response upon infection with C. trachomatis and this may be associated with why C. trachomatis induces infertility in some infected women.

Survival and HLA-B*57 in HIV/HCV Co-Infected Patients on Highly Active Antiretroviral Therapy (HAART).

BACKGROUND AND AIMS: HLA class I alleles, in particular HLA-B*57, constitute the most consistent host factor determining outcomes in untreated HCV- and HIV-infection. In this prospective cohort study, we analysed the impact of HLA class I alleles on all-cause mortality in patients with HIV-, HCV- and HIV/HCV- co-infection receiving HAART. METHODS: In 2003 HLA-A and B alleles were determined and patients were prospectively followed in 3-month intervals until 2013 or death. HLA-A and B alleles were determined by strand-specific oligonucleotide hybridisation and PCR in 468 Caucasian patients with HCV- (n=120), HIV- (n=186) and HIV/HCV-infection (n=162). All patients with HIV-infection were on HAART. In each patient group, HLA class I-associated survival was analysed by Kaplan-Meier method and Cox regression analysis. RESULTS: At recruitment the proportion of patients carrying a HLA-B*57 allele differed between HIV- (12.9%) and HCV-infection (4.2%). Kaplan Meier analysis revealed significantly increased mortality in HLA-B*57-positive patients with HIV-infection (p=0.032) and HIV/HCV-co-infection (p=0.004), which was apparently linked to non-viral infections. Cox logistic regression analysis confirmed HLA-B*57 (p=0.001), serum gamma-glutamyltranspeptidase (p=0.003), serum bilirubin (p=0.022) and CD4 counts (p=0.041) as independent predictors of death in HIV-infected patients. CONCLUSION: Differences in the prevalence of HLA-B*57 at study entry between HIV- and HCV- infected patients may reflect immune selection in the absence of antiviral therapy. When patients were treated with HAART, however, HLA-B*57 was associated with increased mortality and risk to die from bacterial infections and sepsis, suggesting an ambiguous role of HLA-B*57 for survival in HIV/HCV infection depending on the circumstances.

Diagnostic Sensitivity of Indocyanine Green Angiography for Birdshot Chorioretinopathy.

IMPORTANCE: To describe a cohort of patients with birdshot chorioretinopathy who did not manifest birdshot lesions on clinical examination but had retinal vasculitis, low-grade to moderate vitritis, and hypocyanescent lesions on indocyanine green angiography (ICGA). OBSERVATIONS: Case series of 3 patients with mild to moderate vitritis and retinal vasculitis without definite birdshot lesions on clinical examination evaluated from January 2007 to December 2014 at 4 academic ophthalmology centers. All patients' results were positive for human leukocyte antigen-A29. All cases had hypocyanescent lesions visible on ICGA but not detectable on fluorescein angiography. CONCLUSIONS AND RELEVANCE: Patients with retinal vasculitis and low-grade vitritis with or without macular edema may have birdshot chorioretinopathy evident on ICGA before lesions are visible on clinical examination or fluorescein angiography. Expanding birdshot chorioretinopathy diagnostic criteria to include the presence of hypocyanescent lesions on ICGA could improve the sensitivity of diagnosis.

Rapid detection of HLA-A*31:01 allele in DNA and blood samples using loop-mediated isothermal amplification.

BACKGROUND: The human leucocyte antigen (HLA) allele, HLA-A*31:01, is a biomarker for adverse cutaneous reactions to carbamazepine, a first-line antiepileptic drug. OBJECTIVES: To develop a platform that can rapidly detect the HLA-A*31:01 allele in blood samples to facilitate pretreatment screening. METHODS: A novel protocol based on loop-mediated isothermal amplification (LAMP) was designed and optimized. It was applied to purified genomic DNA samples derived from B-cell lines with known HLA genotypes, and to DNA and whole blood samples collected from patients with epilepsy, in whom HLA-A genotypes were determined by sequence-based typing. RESULTS: The turnaround time for the LAMP-based protocol was < 45 min. In the DNA samples derived from B-cell lines (n = 66), the sensitivity, specificity, positive predictive value and negative predictive value of the LAMP-based protocol for detecting HLA-A*31:01 were 1·00 [95% confidence interval (CI) 0·88-1·00], 0·95 (95% CI 0·82-0·99), 0·94 and 1·00, respectively. The LAMP-based protocol produced the same results in the DNA and whole blood samples collected from patients (n = 34). Its sensitivity, specificity, positive predictive value and negative predictive value in detecting HLA-A*31:01 in the patient samples were 1·00 (95% CI 0·57-1·00), 0·97 (95% CI 0·83-0·99), 0·83 and 1·00, respectively. CONCLUSIONS: The findings demonstrated the feasibility of accurately detecting HLA-A*31:01 in DNA and whole blood samples using a LAMP-based protocol. Given its rapid turnaround time, this novel platform has the potential to be adapted into a point-of-care screening test.

Simple and rapid detection of HLA-A*31:01 for prediction of carbamazepine-induced hypersensitivity using loop-mediated isothermal amplification method.

BACKGROUND: Carbamazepine (CBZ), which is widely used in management of epilepsy or neuropathic pain, causes fatal severe cutaneous adverse reactions (SCARs). CBZ-induced SCARs are known to occur in strong association with human leukocyte antigen (HLA)-A*31:01 in Japanese and European populations. HLA genotyping is currently used to detect human HLA-A*31:01. OBJECTIVE: To establish a simple and rapid screening assay specific for HLA-A*31:01, the loop-mediated isothermal amplification (LAMP) method was employed on a sample Japanese population. METHODS: A set of LAMP primers targeting exon 2 of HLA-A*31:01 were designed. Thirty-two clinical samples including the representative HLA-A allele in Japan were used to assess the specificity of LAMP primers in the detection of HLA-A*31:01. RESULTS: The HLA-A*31:01-specific LAMP assay showed consistency with polymerase chain reaction reverse sequence-specific oligonucleotide probe (PCR-rSSO) and polymerase chain reaction-sequence based typing (PCR-SBT) results. CONCLUSION: High sensitivity and specificity of the HLA-A*31:01 LAMP assay was confirmed. Considering its convenience, the assay can be widely used to screen patients at high genetic risk of CBZ-induced SCARs.

Birdshot retinochoroidopathy masquerading as intraocular lymphoma.

We present a case of a patient with bilateral posterior uveitis HLA-A29 positive, masquerading intraocular lymphoma. A 43 year-old woman presented with bilateral vitritis and chorioretinal lesions compatible with "birdshot lesions". The patient was initially diagnosed with birdshot retinochoroidopathy and later on, during follow up, the occurrence of neurologic involvement and the lack of response to systemic immunosuppression led us to re-evaluate the diagnosis. A definite diagnosis of intraocular lymphoma with central nervous system involvement was made. This case is presented to highlight the importance of careful follow-up of patients with chronic uveitis and re-evaluation of systemic symptoms and signs, in particular when ocular findings are highly suggestive for masquerade syndrome.

Exploiting the glioblastoma peptidome to discover novel tumour-associated antigens for immunotherapy.

Peptides presented at the cell surface reflect the protein content of the cell; those on HLA class I molecules comprise the critical peptidome elements interacting with CD8 T lymphocytes. We hypothesize that peptidomes from ex vivo tumour samples encompass immunogenic tumour antigens. Here, we uncover >6000 HLA-bound peptides from HLA-A*02(+) glioblastoma, of which over 3000 were restricted by HLA-A*02. We prioritized in-depth investigation of 10 glioblastoma-associated antigens based on high expression in tumours, very low or absent expression in healthy tissues, implication in gliomagenesis and immunogenicity. Patients with glioblastoma showed no T cell tolerance to these peptides. Moreover, we demonstrated specific lysis of tumour cells by patients' CD8(+) T cells in vitro. In vivo, glioblastoma-specific CD8(+) T cells were present at the tumour site. Overall, our data show the physiological relevance of the peptidome approach and provide a critical advance for designing a rational glioblastoma immunotherapy. The peptides identified in our study are currently being tested as a multipeptide vaccine (IMA950) in patients with glioblastoma.

The prevalence of dysplasia and malignant lip lesions in transplant patients.

BACKGROUND: Solid organ transplant patients are at an increased risk of developing lip malignancies. The role of HLA mismatch as a risk factor for such changes has only been described in skin. METHODS: Lip lesions were evaluated in 403 solid organ transplant patients (immunosuppressed for at least 3 months) and findings compared to age and sex matched, otherwise healthy patients who acted as controls. HLA typing was provided for the transplant patients. All patients provided details of smoking history, alcohol consumption, skin type, as assessed by ease of burning to sunlight, and exposure to sunlight or other forms of ultraviolet radiation. RESULTS: Lip lesions were identified in 36 transplant patients and 29 were biopsied. Fourteen of the biopsies confirmed dysplastic or malignant changes. For the control patients, one lesion was identified as dysplastic. The prevalence of dysplastic and malignant lip lesions was significantly higher (P = 0.006) in the transplant patients when compared to controls. Risk factors for dysplastic/malignant changes in the transplant group included age (P = 0.01), smoking (P = 0.033) and HLA-B mismatch (P = 0.001). Lip covering provided a significant reduction (P = 0.045) in the development of lip changes. CONCLUSION: All transplant patients should be regularly screened for lip malignancies and consulted on smoking and sunlight exposure. HLA-B mismatch does appear to make these patients more susceptible to dysplastic/malignant changes.

Human leukocyte antigen class I polymorphisms influence the mild clinical manifestation of Plasmodium falciparum infection in Ghanaian children.

A prospective study that included 429 children for active detection of mild malaria was conducted in a coastal region of Ghana to reveal whether the incidence of malaria is affected by human leukocyte antigen (HLA) polymorphism. During 12 months of follow-up, 85 episodes of mild clinical malaria in 74 individuals were observed, and 34 episodes among them were accompanied with significant parasitemia at >5000 infected red blood cells per cubic millimeter. Attributable and relative risks conferred by genetic factors in the HLA region were evaluated by comparison of the incidence in children, stratified by carrier status, of a given allele of HLA-A, -B, -DRB1 and TNFA promoter polymorphism. HLA-B*35:01 reduced the incidence by 0.178 events per person per year (0.060 versus 0.239 for B*35:01-positive and -negative subpopulations, respectively), and a relative risk of 0.25, which remained statistically significant after Bonferroni's correction for multiple testing (p(c) = 8.2 × 10(-5)). Further, HLA-B*35:01 and -B*53:01 exhibited opposite effects on the incidence of malaria with significant parasitemia. When parasite densities in different HLA carriers status were compared, HLA-A*01 conferred an increase in parasite load (p = 6.0 × 10(-7)). In addition, we found a novel DRB1 allele that appears to have emerged from DRB1*03:02 by single nucleotide substitution.

The distribution of human leukocyte antigen-A, -B, and -DRB1 alleles and haplotypes based on high-resolution genotyping of 167 families from Jiangsu Province, China.

We investigated the human leukocyte antigen (HLA)-A, -B, and -DRB1 allele frequencies, the A-B-DRB1, A-B, B-DRB1, and A-DRB1 haplotype frequencies, and the characteristics of linkage disequilibrium between 2 loci in high resolution based on 167 unrelated families from Jiangsu Province, China. A total of 26 alleles at the A locus, 55 alleles at the B locus, and 34 alleles at the DRB1 locus were reported in this study. The top 5 most frequent HLA alleles at the HLA-A, -B, and -DRB1 loci, respectively, were A*11:01, A*24:02, A*02:01, A*33:03, A*30:01; B*13:02, B*40:01 B*46:01, B*58:01, B*54:01; DRB1*09:01, DRB1*07:01, DRB1*12:02, DRB1*15:01, and DRB1*08:03. Several haplotypes with high frequencies were deduced in this study. The top 3 most common A-B-DRB1 haplotypes observed were A*30:01-B*13:02-DRB1*07:01, A*33:03-B*58:01-DRB1*03:01, and A*02:07-B*46:01-DRB1*09:01. The top 3 most common A-B haplotypes were A*30:01-B*13:02, A*33:03-B*58:01, and A*02:07-B*46:01. The top 4 most common A-DRB1 haplotypes were A*30:01-DRB1*07:01, A*33:03-DRB1*13:02, A*24:02-DRB1*09:01, and A*33:03-DRB1*03:01. Finally, the top 3 most common B-DRB1 haplotypes were B*13:02-DRB1*07:01, B*46:01-DRB1*09:01, and B*58:01-DRB1*03:01. From the linkage disequilibrium calculation, the most prominent associations were A*30:01-B*13:02, B*13:02-DRB1*07:01, and A*01:03-DRB1*01:02. These allele and haplotype frequencies could be useful for finding the best matched donors for patients in the China Marrow Donor Program Jiangsu Branch.

Human leukocyte antigen class I haplotypes of human immunodeficiency virus-1-infected persons on Likoma Island, Malawi.

Human leukocyte antigen (HLA) allele frequencies vary between different human populations, with implications both for the evolutionary pressures shaping those populations as well as for the outcome of new infectious epidemics. We defined HLA class I types in a well-described cohort of persons on Likoma Island in Malawi, a population for which there are lacking data on allelic frequencies. The profile of HLA frequencies was similar but phylogenetically distinct from those of other sub-Saharan African populations in neighboring regions. The most common A alleles included A30, A23, A28 (A*68), and A2, and the most common B alleles included B15 (group), B53, B58, and B44. Notably, the frequency of B53, which is protective against malaria, was similar to that of other malaria-endemic African countries, and higher than that in countries with less malaria. This is the first reported significant dataset of HLA class I allelic frequencies in Malawians.