RESUMO
CONCLUSIONS: Antibodies (Abs) against antigens on platelets (PLTs), including glycoprotein IV (CD36), can cause PLT refractoriness. Transfusing PLTs to patients with anti-CD36 is challenging because of the rarity of CD36-negative (CD36-) donors and the possibility of additional HLA Abs. We report a case of PLT refractoriness due to anti-CD36 and HLA Abs. A 21-year-old man (group O, D+) with assumed drug-induced aplastic anemia received multiple PLT transfusions and developed severe PLT refractoriness. He was found to have anti-CD36 as well as HLA class I Abs, with a CD36- phenotype on both PLTs and monocytes. He was diagnosed with type 1 CD36 deficiency and received intravenous immunoglobulin (IVIG) and rituximab to decrease future Ab production. The PLT corrected count increment (CCI) improved significantly with subsequent transfusions of flow crossmatchcompatible as well as uncrossmatched PLTs. He eventually received a bone marrow transplant and has been doing well since. The mean CCI before and after IVIG/rituximab treatment was 0.2 and 6.2, respectively. Soon after IVIG started, the patient's CCI after receiving CD36-, group AB, D+, and HLA untested PLTs was 0.8, but his CCI after receiving flow crossmatch-compatible PLTs was 12.6. Two months after IVIG was started, the mean CCIs for uncrossmatched apheresis PLTs and crossmatch-compatible PLTs were comparable (6.1 versus 6.0, respectively). Desensitization treatment with IVIG and rituximab lowered anti-CD36 and HLA Ab levels, and the CCI of PLT transfusion improved significantly. This case demonstrates that immune suppression is effective for successful PLT transfusion of patients with anti-CD36.
Assuntos
Trombocitopenia , Plaquetas , Antígenos HLA , Humanos , Masculino , Transfusão de Plaquetas , Trombocitopenia/terapia , Resultado do Tratamento , Adulto JovemRESUMO
BACKGROUND: Most subungual melanocytic lesions in children are benign, but some are difficult to classify due to prominent lentiginous growth and high-grade cytologic atypia. OBJECTIVE: To characterize the clinicopathologic features of these rare lesions. METHODS: Subungual atypical lentiginous melanocytic proliferations from patients <20 years of age were collected for clinical and histopathologic review. Fluorescence in situ hybridization (FISH) was performed when possible. RESULTS: Eleven patients aged 2-19 years had expanding or darkening longitudinal pigmented streak(s) with or without Hutchinson sign. Microscopically, all revealed predominantly single-cell growth, pagetoid scatter, and poor circumscription. Eight (73%) cases showed focal or poor nesting, and 3 (27%) demonstrated confluence. Nuclear enlargement, hyperchromasia, and angulation were present in 8 (73%) cases, 7 (64%) cases, and 6 (55%) cases, respectively. One of 4 cases tested by FISH was positive. Three lesions recurred locally without other adverse outcome. LIMITATIONS: Small sample size and short clinical follow-up. Two cases were examined in partial biopsies only. CONCLUSION: Some subungual melanocytic lesions in children and adolescents are histologically indistinguishable from adult subungual melanoma in situ. While the biologic potential remains elusive, FISH might aid in risk stratification. Awareness of this rare group of lesions is crucial for facilitating future investigation into its biologic behavior.
Assuntos
Lentigo/patologia , Melanócitos/patologia , Doenças da Unha/patologia , Adolescente , Criança , Pré-Escolar , Diagnóstico Diferencial , Feminino , Humanos , Sarda Melanótica de Hutchinson/diagnóstico , Sarda Melanótica de Hutchinson/genética , Sarda Melanótica de Hutchinson/patologia , Sarda Melanótica de Hutchinson/cirurgia , Hibridização in Situ Fluorescente , Lentigo/diagnóstico , Lentigo/genética , Lentigo/cirurgia , Masculino , Melanoma/diagnóstico , Melanoma/genética , Melanoma/patologia , Melanoma/cirurgia , Doenças da Unha/diagnóstico , Doenças da Unha/genética , Doenças da Unha/cirurgia , Estudos Retrospectivos , Sensibilidade e Especificidade , Neoplasias Cutâneas/diagnóstico , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/patologia , Neoplasias Cutâneas/cirurgia , Adulto JovemAssuntos
Síndrome de Li-Fraumeni/diagnóstico , Linfoma Difuso de Grandes Células B/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras B/diagnóstico , Neoplasias Vasculares/diagnóstico , Adulto , Diagnóstico Diferencial , Humanos , Síndrome de Li-Fraumeni/complicações , Síndrome de Li-Fraumeni/patologia , Masculino , Leucemia-Linfoma Linfoblástico de Células Precursoras B/etiologia , Leucemia-Linfoma Linfoblástico de Células Precursoras B/patologiaRESUMO
N-(3-fluoro-4-(4-(2,3-dichloro- or 2-methoxyphenyl)piperazine-1-yl)butyl)arylcarboxamides were prepared and evaluated for binding and function at dopamine D3 receptors (D3Rs) and dopamine D2 receptors (D2Rs). In this series, we discovered some of the most D3R selective compounds reported to date (e.g., 8d and 8j, >1000-fold D3R-selective over D2R). In addition, chimeric receptor studies further identified the second extracellular (E2) loop as an important contributor to D3R binding selectivity. Further, compounds lacking the carbonyl group in the amide linker were synthesized, and while these amine-linked analogues bound with similar affinities to the amides at D2R, this modification dramatically reduced binding affinities at D3R by >100-fold (e.g., D3R K(i) for 15b = 393 vs for 8j = 2.6 nM), resulting in compounds with significantly reduced D3R selectivity. This study supports a pivotal role for the D3R E2 loop and the carbonyl group in the 4-phenylpiperazine class of compounds and further reveals a point of separation between structure-activity relationships at D3R and D2R.